Patent Publication Number: US-2018045344-A1

Title: Plumbing Apparatus for Connecting a Tail Piece to a Waste Pipe

Description:
RELATION TO PRIOR APPLICATIONS 
     This application claims priority from U.S. Provisional Application No. 62/373,530, filed on Aug. 11, 2016 and the contents of which are herein incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present specification relates generally to a plumbing apparatus, and more specifically to a plumbing apparatus for connecting a tail piece to a waste pipe. 
     BACKGROUND OF THE INVENTION 
     Buildings such as residential structures and homes generally include a waste system having a network of waste pipes for removing waste water from the structure. For example, in a typical bathroom, waste pipes are used to remove water from various plumbing fixtures such as sinks, toilets, bath tubs, etc. The waste pipe often extends through the walls of the building and ends in an opening in the floor where a fixture is intended to be installed. Plumbing fixtures generally have a tail piece through which waste water is collected and exits the fixture. The tail piece of the fixture is then connected to the waste pipe such that the waste water is transferred from the tail piece into the waste pipe. 
     A plumbing apparatus which connects a tail piece to a waste pipe typically contains a nut or fastener that needs to be tightened once the tail piece is inserted into the waste pipe, in order to have a sealing connection therebetween. A problem arises when replacing or installing a plumbing fixture where access to tighten the nut or fastener is not possible. This is the case, for example, where a bathtub, such as an island bathtub, needs to be installed in a house that has been already built. In this case there is no access to the apparatus from below. It is therefore necessary to destroy the ceiling of the floor below the waste pipe in order to provide access to the apparatus from the waste pipe side so that the nut or fastener may be tightened to effect a seal between the tail piece and waste pipe. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention, there is provided a plumbing apparatus for connecting a tail piece to a waste pipe. The plumbing apparatus comprises a body having a top flanged end having an inlet configured for receiving the tail piece; and a bottom end having an outlet opposite the inlet, the outlet configured for receiving the waste pipe. The body has a channel formed by an inner wall thereof, the channel extending between the inlet and the outlet. The apparatus further comprises a seal extending about the channel for forming a watertight seal between the tail piece and the waste pipe when the tail piece is inserted through the inlet and into the waste pipe; and stop means disposed at the inner wall for stopping the waste pipe when the waste pipe is inserted into the channel via the outlet. 
     In one embodiment, the stop means comprises a stop ring. 
     In one embodiment the plumbing apparatus further comprises a plate secured to the top flanged end for mounting the plumbing apparatus to a floor over the waste pipe. The plate has an opening surrounding at least a portion of the top flanged end and providing access to the inlet so that the tail piece may be inserted into the inlet. 
     In one embodiment, the plate is removably secured to the top flanged end. 
     In one embodiment, the plate opening is located off-center with respect to the plate. 
     In one embodiment, the plate is oval in shape. 
     In one embodiment, the plate contains at least one slot for permitting wet concrete therethrough for securing the plate onto a floor. 
     In one embodiment, the plate contains at least one body hole for receiving a fastener to secure the plate to the top flanged end. 
     In one embodiment, the plate contains at least one mounting hole for receiving a fastener to secure the plate to the floor over the waste pipe. 
     In one embodiment, the top flanged end comprises a taper section providing a slope from an outer edge of the top flanged end to the inlet for guiding an end of a tail piece into the inlet. The taper section may comprise at least one oval recess for further guiding an end of a tail piece into the inlet. 
     In one embodiment, the body includes gripping means on an exterior surface thereof for providing improved grip during installation. The gripping means may comprise a plurality of ridges. 
     In one embodiment, the seal is cylindrical. The seal may be disposed above the stop means. The seal may be provided with a plurality of internal cylindrical ribs for gripping the tail piece when the tail piece is inserted therein. 
     In one embodiment, the plumbing apparatus further comprises: a tail piece having a threaded end; and a nut operably connected to the threaded end for connecting the tail piece to a plumbing fixture. 
     In another aspect of the present invention, there is provided a method of using the plumbing apparatus to connect a fixture having a tail piece to a waste pipe. The method comprises: slipping the body on the waste pipe such that the waste pipe enters the channel via the outlet and is stopped by the stop means; mounting the plate to the top flanged end; mounting the plate to the floor above the waste pipe; positioning the fixture above the body and lowering the fixture such that the tail piece is guided into the inlet, through the seal, and at least partially into the waste pipe. 
     In one embodiment, the method of using the plumbing apparatus further comprises: applying an adhesive to the top end portion of the waste pipe and to the outlet prior to slipping the body on the waste pipe; and turning the body with respect to the waste pipe to evenly distribute the adhesive at a junction between the outlet and the top end portion of the waste pipe. 
     In yet another aspect of the present invention there is provided a method of manufacturing a plumbing apparatus for connecting a tail piece to a waste pipe. The method comprises: molding a main body with an internal cavity to receive both a seal and a retaining body; molding a retaining body having an internal cavity sized to fit and seat onto the top of a standard waste pipe, and having a stop ring at a top end thereof; applying a solvent based glue to an outside of the retaining body; sliding the retaining body into the cavity of the main body behind the seal; and holding the retaining body in position until the retaining body is solvent-welded to the main body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top-front perspective view of a plumbing apparatus for connecting a tail piece to a waste pipe, in accordance with an embodiment of the present invention; 
         FIG. 2  is a bottom-front perspective view of the plumbing apparatus of  FIG. 1 ; 
         FIG. 3  is a top perspective view of the plumbing apparatus of  FIG. 1 ; 
         FIG. 4  is a bottom perspective view of the plumbing apparatus of  FIG. 1 ; 
         FIG. 5  is a front view of the plumbing apparatus of  FIG. 1 ; 
         FIG. 6  is a side view of the plumbing apparatus of  FIG. 1 ; 
         FIG. 7  is a top-front perspective view of the plumbing apparatus of  FIG. 1  shown connected to a waste pipe; 
         FIG. 8  is a top-front perspective view of the plumbing apparatus of  FIG. 1  shown connected to a waste pipe and a tail piece; 
         FIG. 9  is a cross-sectional view of the plumbing apparatus of  FIG. 8 ; 
         FIG. 10  is a top perspective view of the a body of the plumbing apparatus of  FIG. 1 ; 
         FIG. 11  is a bottom perspective view of the body of the plumbing apparatus of  FIG. 1 ; 
         FIG. 12  is a side view of the body of the plumbing apparatus of  FIG. 1 ; 
         FIG. 13  is a top view of the body of the plumbing apparatus of  FIG. 1 ; 
         FIG. 14  is a sectional view of the body of the plumbing apparatus of  FIG. 12 ; 
         FIG. 15  is a sectional view showing the body of the plumbing apparatus and the seal during manufacturing; 
         FIG. 16  is a perspective view of a seal which is part of the plumbing apparatus of  FIG. 1 ; 
         FIG. 17  is a sectional view of the seal of  FIG. 16  taken at lines  17 - 17 ; and 
         FIG. 18  is a top perspective view of the plate of the plumbing apparatus. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT 
     As used herein, any usage of terms that suggest an absolute orientation (e.g. “top”, “bottom”, “front”, “back”, etc.) are for illustrative convenience and refer to a specific orientation. However, such terms are not to be construed in a limiting sense as it is contemplated that various components will, in practice, be utilized in orientations that are the same as, or different than those described or shown. 
     Referring to the attached figures, an apparatus  50  for connecting a fixture having a tail piece to a waste pipe is shown. It is to be understood that the apparatus  50  is purely exemplary and that it will become apparent to those skilled in the art that modifications to the apparatus  50  are contemplated. In the present embodiment, the apparatus  50  includes a body  55 , a seal  60 , and a plate  65 . In another embodiment, the body  55  may be made of resilient material that a seal  60  may not be needed, as explained below. 
     The body  55  is generally cylindrical but other shapes may be contemplated. In one embodiment, body  55  has tapered external sidewalls from the top to the bottom. Body  55  has a longitudinal opening, passage, or channel formed therein and extending therethrough. The channel extends from an inlet  51  formed in a top flanged end  71  of body  55 , to an opposite outlet  52  formed in a bottom end  77  of body  55 . The body  55  is configured to receive a tail piece  100  at the inlet  51 , and to connect to a waste pipe  110  at the outlet  52 . In one embodiment, it is preferred that inlet  51  is sized to frictionally receive a tail pipe  100 . Similarly, the outlet  52  preferably is sized to fit on a waste pipe, and hence the inner diameter of outlet  52  is preferably 1.5″ to fit on a standard waste pipe. Alternatively, the diameter of outlet  52  may be larger than 1.5″ but in this case a reduction ring would need to be used to fit onto a standard 1.5″ waste pipe. The body  55  is configured to secure a tail piece  100  and a waste pipe  110  to provide fluid communication between the tail piece  100  and the waste pipe  110 . The manner by which the body  55  secures the tail piece  100  and the waste pipe  110  is not particularly limited. For example, the body  55  can secure the tail piece  100  and the waste pipe  110  using a friction fit. In particular, the body  55  can be made from a resilient material and the opening can be configured to be slightly smaller than external diameters of the tail piece  100  and the waste pipe  110  at the respective inlet  51  and outlet  52 . It is to be understood by a person of skill in the art that the body  55  is not particularly limited to any material and that several types of materials are contemplated. The body  55  is typically made from materials suitable for waste water applications and that would be suitable resistant to degradation over time in such applications where the body  55  can be exposed to air, moisture, and a range of temperatures. 
     With specific reference to  FIGS. 10-14 , the body  55  of the present embodiment has a top flanged end  71  that, when installed, is substantially aligned with the floor surrounding the hole containing the waste pipe  110 . The flanged end may extend radially outwardly to cover the floor hole containing the waste pipe. Alternatively, the top flanged end may be adapted to receive a plate which covers the floor hole. For example, top flanged end  71  may contain one or more holes  79  for receiving a fastener that secures a plate onto the top surface of top flanged end  71  thus covering the floor hole containing the waste pipe. In one embodiment, body  55  further includes a tapered section  74  at the top flanged end  71  of the body  55 . As shown, the taper section  74  provides a slope from the outer edge of the top flanged end  71  of body  55  to the inlet  51 . In the present embodiment, the slope angle of taper section  74  is about 10 degrees below the horizontal when the body  55  is oriented as shown in  FIGS. 9 and 14 . It is to be appreciated by a person of skill in the art that the taper section  74  is not particularly limited and can be greater or less than 10 degrees. For example, the angle can be anywhere in the range of 5 to 80 degrees. By increasing the angle of the taper section  74 , the taper section  74  provides improved guidance of the end of the tail piece  110  through the inlet  51  at the cost of increasing the longitudinal length of the body  55 . Taper section  74  may optionally contain oval recesses  76  which further guide the end of the tail piece  110  through the inlet  51 . In one embodiment, as better seen in  FIGS. 10, 12 , and  14  taper section  74  is made higher than the top surface of flanged top end  71  by the thickness of the plate used to cover the floor hole such that the top surface of the plate aligns with the highest point of taper section  74 . 
     In the present embodiment, the body  55  optionally includes gripping means in the form of a plurality of parallel ridges  70  on the exterior surface thereof. The ridges  70  extend longitudinally along the exterior surface of the body  55  and are generally configured to provide improved grip during installation over an existing waste pipe  110 . The improved grip advantageous, since typically a quarter turn is required during that installation to evenly distribute the adhesive used at the junction between body  55  and waste pipe  110 . It is to be appreciated by a person of skill in the art with the benefit of this description that the ridges  70  are not particularly limited and can be varied. For example, the ridges  70  can form a different pattern for providing improved grip, such as a diagonal or a cross pattern. In other embodiments, the ridges  70  can be omitted and the external surface of the body  55  can be treated with a substance having a high coefficient of friction. In other embodiments, the external surface of the body  55  can be smooth or rough with no additional features to improve grip. 
     With reference to  FIG. 9  and  FIG. 14 , the body  55  can include a stop means for stopping waste pipe  110  at a particular point as it is inserted into the channel of body  55 . This is preferred in embodiments where a seal is used within the channel. The stop means prevent damage to the seal from forces imparted thereon by the waste pipe  110  and the weight of the fixture transferred via body  55 . As an example, the stop means may be a stop ring  72  formed at the interior walls of body  55  within the channel. The stop ring  72  is generally configured to position the body  55  relative to the waste pipe  110  by providing a stop when the body  55  is installed over the waste pipe  110 . In the present embodiment, the stop ring  72  has the same height as the thickness of the waste pipe  110 . It is to be appreciated by a person of skill in the art that by configuring the height of the stop ring  72  to be the same as the width of the waste pipe  110 , the tail piece  100  can slide past the stop ring  72  and into the drain pipe  110  by about one inch when inserted from the inlet  51  of the channel of the body  55 . However, it is to be appreciated that the amount the tail piece  100  is inserted into the waste pipe can be more or less. In other embodiments, the height of the stop ring  72  can be slightly greater than the width of the waste pipe  110  to provide a passage slightly smaller than the exterior diameter of the tail piece  100 . By having the passage slightly smaller, a friction fit is provided when the tail piece  100  passes through the stop ring  72 . It would be appreciated by a person of skill in the art that stop ring  72  is only a possible implementation of the stop means, and that other stop means are contemplated. For example, a plurality of radial tabs or pegs (not shown) extending radially inwardly from the inner wall of body  55  into the channel may also be used as a stop for waste pipe  100  within the channel. 
     Seal  60  is disposed within the body  55  and generally configured to seal the connection between the tail piece  100  and the waste pipe  110 . The manner by which the seal  60  provides a seal is not particularly limited. In the present embodiment, the seal  60  is disposed above the stop ring  72  and has about the thickness as the height of the stop ring  72 , and such that the inner diameter is about the same as or slightly smaller than the outer diameter of the tail piece  100 . Therefore, the seal  60  can allow for the tail piece  100  to slide therethrough while maintaining contact to create a seal against the tail piece  100  to prevent waste water from leaking up the channel towards the inlet  51 . 
     It is to be understood by a person of skill in the art that the seal  60  is not particularly limited to any material and that several types of materials are contemplated for creating a seal against the tail piece  100 . In the present embodiment, the seal  60  is rubber. Some examples of other suitable materials include plastic, silicone and a number of other soft polymers. In the present embodiment, and referring to  FIGS. 16 and 17 , the seal  60  is cylindrical in shape and is provided with internal cylindrical ribs  61  for gripping the tail piece  100 , when the tail piece is inserted therein. In other embodiments, the seal  60  can be modified or replaced with other sealing mechanisms. For example, the insert  60  can be replaced with a standard O-ring or other type of gasket. Alternatively, the tail piece  100  can be sealed using an adhesive or weld (subject to the materials that the body  55  and the tail piece  100  are made from). 
     With reference to  FIGS. 1-9 and 18 , a plate  65  is connected to the body  55  and is generally configured to mount the apparatus  50  securely onto the floor over the waste pipe  110 . It is to be understood by a person of skill in the art with the benefit of this description that the plate  65  is not particularly limited to any material and that several types of materials are contemplated for providing a rigid mount to the floor. In the present embodiment, the plate  65  is steel. In the present embodiment, the plate  65  can be optionally powder coated or otherwise treated to protect the plate  65  from rust or other damage. Some examples of other suitable materials include aluminum, brass, and plastic. 
     In the present embodiment, the plate  65  is oval or elliptical and includes an off-center opening  80  through which the body  55  may fit. The shape of the plate is not particularly limiting and it may be circular or have other shapes. The exact location of the off-center opening  80  with respect to the plate is not particularly limited and the amount that the off-center opening  80  is offset from the center of the plate  65  by can be varied. In the present embodiment, the center of the off-center opening  80  is about three inches away from the center of the plate  65 . However, in other embodiments, the offset can be greater or less than three inches. By offsetting the opening  80  from the center of the plate  65 , the plate  65  can be rotated to accommodate a waste pipe  110  that may not be centered in a hole on the floor. For example, if the waste pipe  110  is offset to the left of the hole in the floor, the plate  65  can be positioned such that the wider side of the plate covers the wider side of the hole in the floor created by the offset waste pipe  110 . Similarly, if the hole in the floor is very close to a wall, the plate  65  may be oriented such that the narrower side from opening  80  to the edge of plate  65  may fit in the space between the hole in the floor and the wall. Advantageously, the off-center positioning of the opening  80  permits the accommodation of various floor hole configurations. In one embodiment, opening  80  is sized and shaped to fit around taper section  74 . In other embodiments, opening  80  may be larger than section  74  or smaller overlapping an outer portion of section  74 . In all embodiments opening  80  provides access to inlet  51  so that a tail piece may be inserted therein. 
     The plate  65  further includes a plurality of mounting holes  82  and body holes  84 . The mounting holes  82  and body holes  84  are not particularly limited and are each generally configured to engage with a fastener. In the present embodiment, the mounting holes  82  and body holes  84  are all countersunk to provide a flat surface when mounted to the floor and/or the body  55 . In other embodiments, the mounting holes  82  and body holes  84  can be simple holes drilled through the plate  65 . The mounting holes  82  are generally configured to allow a fastener such as a screw or bolt to pass through and mount the apparatus  50  to the floor. The body holes  84  are generally configured to allow a fastener  120  such as a screw to pass therethrough and mount the plate  65  to the body  55  at top flanged end  71  when installing the apparatus  50 . It is to be appreciated by a person of skill in the art with the benefit of this description that the mounting holes  82  and body holes  84  can include more or fewer holes than shown in the figures, and in some embodiments omitted completely. For example, in some embodiments, the body  55  can be connected to the plate  65  using other means such as adhesives or welds which would not require the body holes  84 . However, the use of fasteners  120  is preferred so that the plate  65  is easily removable thus permitting post-installation maintenance or future replacement if required. For example, where a new fixture having a tail piece is to be installed in the future in place of the current fixture, the plumbing apparatus  50  may be removed and replaced with a new one suitable for receiving the new fixture. This is made possible since the large floor hole around the waste pipe  110  and the removable plate  65  both permit access to the waste pipe  110  beneath plumbing apparatus  50 , thus allowing the waste pipe  110  to be cut and facilitating the easy removal of the plumbing apparatus  50 . 
     The plate  65  also includes a plurality of slots  86 , which can be used as an alternative method for mounting the plate  65  to the floor. For installations that involve pouring fresh concrete around the waste pipe  110 , the plate  65  can be pressed into the wet concrete to be permanently mounted to the floor. As the plate  65  is pressed into the concrete, the slots  86  allow the concrete to pass therethrough to encase the plate  65  into the floor. It is to be appreciated by a person of skill in the art that the exact shape of the slots is not particularly limited. For example, the slots  86  can be modified to be a straight or zigzag pattern instead of being curved. In other embodiments, the slots  86  can be modified to be some other shape completely, such as a plurality of holes. 
     As an example of a variation, the plate  65  can be modified to omit the slots  86  or the mounting holes  82  to provide only a single option of mounting the plate  65  to the floor. As another variation, the pattern of the mounting holes  82  can be modified and spaced sufficiently far apart to also serve a function similar to the slots  86  such that separate slots  86  are not needed. 
     A tail piece  100  is typically connected to a plumbing fixture. For example, the tail piece  100  can be connected to the drain of a bath tub or other basin (not shown). It is to be appreciated by a person of skill in the art that the tail piece  100  is not particularly limited and can be part of the fixture or an additional part for connecting the fixture to the apparatus  50 . In other embodiments, the tail piece  100  can be sold as part of a kit with the apparatus  50  and configured to connect with specific fixtures using various fastening means such as a threaded fastener or a weld. With reference to  FIGS. 8 and 9 , for example, tail piece  100  has a threaded portion and a nut  105  is coupled to the threaded portion so that the tailpiece  100  may be connected to any suitable plumbing fixture. It is to be understood by a person of skill in the art that the tail piece  100  is not particularly limited to any material and that several types of materials are contemplated. In the present embodiment, the tail piece  100  is brass. Some examples of other suitable materials include plastic, copper and other metals. 
     The waste pipe  110  is generally part of the network of pipes for removing waste water from a building. Accordingly, the waste pipe  110  is typically a polyvinyl chloride (PVC) pipe or acrylonitrile butadiene styrene (ABS) oriented vertically with an opening for receiving waste water. In general the waste pipe  110  ends in an opening on a floor that is larger in diameter than the diameter of the waste pipe  110 . 
     In use, the present embodiment of the apparatus  50  allows for fast and easy installation of various plumbing fixtures over a waste pipe  110  in a hole on the floor. First, the body  55  is installed over the waste pipe  110 . The manner by which the body  55  is installed is not particularly limited. In the present embodiment the body  55  is slipped over the waste pipe  110  such that the waste pipe  110  enters the channel of body  55  via outlet  52 . In one embodiment, where a seal  60  is disposed above stop ring  72 , the waste pipe  110  abuts against the stop ring  72 . In another embodiment, where no seal  60  is present, waste pipe  110  extends through the channel until it abuts a bottom of the top flanged end  71 . As is known in the art, an appropriate adhesive is applied at the junction between the outlet  52  of body  55  and the waste pipe  110 . Also, as is known in the art, the body  55  is given a quarter-turn relative to the waste pipe  110  to evenly distribute the adhesive at the junction. Next, the plate  65  is connected to the body  55  using fasteners  120  through the body holes  84 . The plate  65  is then mounted to the floor, using fasteners through mounting holes  82 , in a suitable position and with a suitable orientation depending on the position of the hole in the floor as explained above. 
     The tail piece  100  may then be connected to the drain of the plumbing fixture. For example, if the tail piece has a threaded portion and nut  105  as described above then the tail piece may be connected to the drain of the fixture using nut  105 . The plumbing fixture is then positioned over the floor hole containing the waste pipe  110 . The plumbing fixture is then lowered towards the body  55  such that the tail piece  100  is guided into the inlet  51  by the taper section  74  to complete the installation of the plumbing fixture using the apparatus  50 . Advantageously, the apparatus  50  allows for connecting a fixture having a tail piece  100  to a waste pipe  110  where no tightening of any members below the floor is necessary. This alleviates the need to damage the ceiling below the waste pipe from underneath to be able to access a nut or a fastener to tighten the seal between the tail piece  100  and the waste pipe  101 . 
     It is to be appreciated by a person of skill in the art that the apparatus  50  can also be sold as a kit of parts for assembly described above or in a semi-assembled state. For example, apparatus  50 , the tail piece  100  and nut  105  which fits on a threaded top end of tail piece  100 , may be sold together as a kit which may fit a number of plumbing fixtures such as bathtubs, basins and showers. 
     It is to be re-emphasized that the structures described herein are non-limiting representations only. In particular, it is to be understood that various features of the embodiments described herein can be combined, modified, or omitted. For example, it is to be appreciated by a person of skill in the art with the benefit of this description that the seal  60  can be omitted in embodiments where the channel of body  55  is sized to form a sufficient seal with the tail piece  100  at the inlet  51 , and the body  55  is made with a sufficiently resilient material. 
     Various advantages will now be apparent to a person of skill in the art. Of note is the ability to install plumbing fixtures quickly and efficiently with few parts. For example, by using a single unitary body  55  to connect the fixture to the waste pipe  110 , the installation of the fixture becomes easier and the cost of manufacturing the apparatus is reduced. Additionally, the single unitary body  55  does not require access from below to secure and seal the connection between the tail piece  100  and the waste pipe  110  thus making it suitable for installing a variety of fixtures in already built homes. The oval shape and off-center positioning of the body with respect to the plate is suitable for use with island tubs, retrofit tubs, and claw foot tubs. Another example of an advantage is that the plate  65  can accommodate off-center waste pipes  110  which reduces the cost of labor involved in such installations. For example, if a conventional plate with a central opening were used, an off-center waste pipe  110  would need to be re-centered in the floor opening which may require additional construction work. 
     To manufacture the body  55  of apparatus  50 , the following steps are carried out with reference to  FIG. 15 . A main body  54  is molded with an internal cavity to receive both a seal  60  and then a retaining body  53  featuring stop ring  72 . The interior of the retaining body  53 , below stop ring  72 , is sized to fit and seat onto the top of a standard waste pipe  110 , which is typically 1.5″ in diameter. First the seal  60  is inserted into the cavity of the main body  54 . A solvent based glue is applied to the outside of the retaining body  53  which is then slid into the cavity of the main body  54  behind the seal  60  and held in position until the retaining body  53  is solvent-welded to the main body  54 . At this point the apparatus body  55  assembly becomes a single part that cannot be disassembled without causing damage to the components. 
     In one embodiment, the retaining body  53 , is inserted without solvent based glue, and is frictionally engaged within the cavity of the main body  54  due to the interaction between the outer surface of the retaining body  53  and the inner surface of the cavity in the main body  54 . The friction between these surfaces is sufficient to retain the retaining body  53  in position when the unit is oriented as shown in  FIG. 15 . However, when the part leaves the factory, the retaining ring  53  will have been solvent-welded into the cavity in the main body  54 . Advantageously, as body  55  is assembled into a single part, this prevents leakage therefrom, alleviates the need to tighten the part after installation which is not possible where bottom access to the apparatus  50  is not available without damaging the ceiling below the waste pipe. Additionally, there is no possible relative rotational movement between retaining body  53  and main body  54 , thus installation which includes a quarter turn of the apparatus relative to a waste pipe is facilitated. 
     While specific embodiments have been described and illustrated, such embodiments should be considered illustrative only and should not serve to limit the accompanying claims.