Abstract:
A coupling for creating a fluid-conducting connection between a pipe and a stub, where the stub has no pipe-supporting extension over which the pipe is to be connected. The coupling includes a coupling body having a forward end for being secured to the stub, a rearward end for receiving the pipe, and an internal bore therethrough; stub securing means for securing the forward end of the coupling body to the stub; a gripper located within the internal bore of said coupling body for gripping said pipe; gripper retaining means for retaining said gripper within said coupling body during handling of the coupling body; pipe-supporting means for providing internal support for an end section of the pipe being engaged by the coupling; gripper engaging means for causing the gripper to grip the pipe; and sealing means for creating a seal between the stub and the pipe.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to pipe couplings, and in particular to couplings used to connect pipes to fittings such as valves and adapters.  
       BACKGROUND OF THE INVENTION  
       [0002]     Particularly in the plumbing and waterworks industries, situations frequently arise during installation or repair of piping where it is necessary to connect pipes to various fittings such as corporation valves, curb valves and various adapters. These situations can arise for example during water service line installation or repair. Such piping can include service tubes and may be made of polyethylene pipe/tubing for example.  
         [0003]     Typically, such fittings are provided with a stub, usually externally threaded, for receiving a sealed fluid-communicating connection with the pipe. The threading on such stubs is typically of an industry standard such as corporation fitting thread, to allow standard threaded couplings to be mounted thereon.  
         [0004]     Such pipe-fitting couplings typically come in two main forms. In a first form the coupling is integral with the pipe. The present invention is directed to the second form where the coupling is a separate device that clamps on to, or is otherwise sealingly affixed to the end of the pipe. In either case the end of the coupling intended to engage the fitting stub is provided with internal threading and the coupling is connected to the fitting stub by turning one relative to the other thereby engaging the internal threading of the coupling with the external threading of the stub.  
         [0005]     A typical manner in which such a separate coupling is used to connect a pipe to a fitting stub is as follows. First a coupling body, having internal threads at a forward end for engaging the external threads of the stub, and a constricted rearward end, is slid on to the pipe, rearward end first. A combination of various internal elements including seals and camming or gripping means are then slid on to and/or in to the pipe. Finally, the coupling body is screwed onto the stub trapping and compressing the seals and the camming or gripping means. In particular, the constricted rearward end of the coupling body presses the seals and camming or gripping means against the end of the stub or against the exterior or interior surface of the pipe. The compressed seals create a hydrostatic seal between the stub and the pipe, while the camming or gripping means are urged to a locking and restraining position preventing the pipe from being pulled out of the coupling inadvertently. Using such a coupling, a secure pressure-sealed connection is made.  
         [0006]     Where the pipe has a high level of structural integrity, the camming or gripping means may be applied against the outside surface of the pipe without the need for any additional support on the interior of the pipe. However, where excessive exterior pressure on the pipe would result in the pipe collapsing such that the pipe is damaged and/or the seals or camming or gripping means fails, internal support is typically provided in the form of a tubular insert either in plastic or stainless steel. Where the fitting stub already has a pipe-supporting extension for insertion within the pipe, the coupling need not provide a tubular insert.  
         [0007]     One difficulty with such couplings is the need for the user to handle a number of small elements (typically the seals, and camming and gripping elements) during installation. This can result in frustration on the part of the user while he fumbles with the various parts to ensure that they are installed in the correct order and orientation. If the user fails to install these parts in the correct order and orientation, the connection can fail resulting in leakage. This disadvantage is particularly acute where installation takes place in difficult conditions, for example where the fitting is located in an awkward location, or where the installation is taking place on waterworks, often with the user standing in a wet and muddy hole where fingers are slippery and where a dropped part is irretrievably lost.  
         [0008]     Further, the camming or gripping means typically used on the exterior of the pipe can often result in an excessive localization of forces that may result in damage and/or collapse of the pipe that can result in failure.  
         [0009]     Additionally, most present couplings are not reusable since the camming or gripping means used are permanently deformed during use.  
         [0010]     Finally, with most present couplings the coupling can easily be under-tightened or over-tightened onto the pipe and/or the fitting, which may result in damage to the pipe, to the fitting or to the coupling and may also result in failure of the coupling.  
       SUMMARY OF THE INVENTION  
       [0011]     This invention provides an improved coupling for connecting pipes to fittings, which improved coupling addresses one or more of the problems noted above.  
         [0012]     In a broad aspect, the present invention provides a coupling for creating a fluid-conducting connection between a pipe and a stub, said stub being free of a pipe-supporting extension over which the pipe is to be slid, said coupling comprising: a coupling body having a forward end for being secured to the stub, a rearward end for receiving the pipe, and an internal bore therethrough; stub securing means for securing the forward end of the coupling body to the stub; a gripper located within the internal bore of said coupling body for gripping said pipe; gripper retaining means for retaining said gripper within said coupling body during handling of the coupling body; pipe-supporting means for providing internal support for an end section of the pipe being engaged by the coupling; gripper engaging means for causing the gripper to grip the pipe; and sealing means for creating a seal between the stub and the pipe.  
         [0013]     Other aspects of the invention include the above coupling wherein: 
        the gripper is a gripper ring having three or fewer spaced annular interior gripping surfaces for gripping said pipe;     the gripper ring has two spaced annular interior gripping surfaces for gripping said pipe;     the gripper ring is a split ring such that the gripper ring can constrict radially;     the annular gripping surfaces have annular teeth thereon;     the gripper is sized to fit between an interior surface of the coupling body and an outer surface of the pipe once the pipe is received within the rearward end of the coupling body;     the pipe-supporting means is an insert having a rigid support tube at its rearward end, said support tube being adapted to be slid within the end section of the pipe;     a rear end of said support tube is located rearwardly of said gripper;     the sealing means for creating a seal between the stub and the pipe includes a rearward seal mounted on an exterior surface of said support tube to create a seal between the support tube and the pipe when the support tube is slid within the pipe;     the rearward seal is an O-ring;     the support tube has forward-facing barbs on its exterior surface to resist inadvertent pullout of the pipe from the coupling;     the barbs on the support tube are annular;     an interior surface of a rearward end of said support tube is beveled;     the support tube is sized such that its exterior surface closely fits within the pipe;     the insert has at its forward end, an inner web adapted to be inserted within the stub;     the inner web is sized to fit closely within the stub;     the sealing means for creating a seal between the stub and the pipe includes a forward seal mounted on an exterior surface of said inner web to create a seal between the inner web and the stub when the inner web is slid within the stub;     the forward seal is an O-ring;     the insert has a radially outwardly projecting annular rib extending from a forward end of the support tube;     the annular rib has a forward face adapted to abut against a rearward end of said stub, and a rearward surface adapted to abut against a forward end of said pipe;     the insert has an outer web extending rearwardly from an outer end of said annular rib;     the outer web is sized to fit closely between the pipe and the coupling body;     the gripper engaging means comprises gripper constricting means for radially constricting the gripper such that the gripper engages an exterior surface of said pipe;     when constricted, at least a portion of said gripper intersects a plane which includes the rearward seal and which is perpendicular to a longitudinal axis of said coupling body;     the gripper has a sloped rearward surface, the gripper retaining means is a gripper retaining recess formed on an inner surface of the coupling body for receiving said gripper, said gripper retaining recess having a sloped rearward surface, said sloped rearward surface of said gripper retaining recess adapted to abut the sloped rearward surface of the gripper, and said gripper constricting means comprising moving the coupling body forward relative to the gripper such that cooperation between the sloped rearward surface of the gripper and the sloped rearward surface of the gripper retaining recess causes the gripper to radially constrict;     the coupling body is moved forward relative to the gripper by moving the coupling body forward and resisting substantial forward movement of the gripper by abutting of the forward end of the gripper against a rearward end of said outer web of said insert, forward movement of said insert being restrained by abutting of said forward face of said annular rib against the rearward end of said stub;     the gripper has a sloped forward surface, the rearward end of the outer web has a beveled inner surface, said beveled inner surface of said rearward end of said outer web adapted to abut the sloped forward surface of the gripper, said gripper constricting means further comprising moving the gripper forward relative to the outer web such that cooperation between the sloped forward surface of the gripper and the beveled inner surface of said outer web further causes the gripper to radially constrict;     the gripper is moved forward relative to the outer web by the forward movement of the coupling body causing the gripper to move forward slightly;     the stub is externally threaded and the stub securing means is an internal threading of a forward portion of said coupling body, an interior of said forward portion of the coupling body being sized to fit closely over the stub, and said internal threading of said coupling body matching the external threading of said stub;     the coupling body is moved forward by screw-tightening the forward portion of the coupling body onto the stub;     the gripper retaining recess is a circumferential groove;     an exterior surface of the forward portion of said coupling body is hexagonal to facilitate tightening of the coupling body onto the stub;     the stub further comprises a shoulder positioned forwardly of said external threading, said shoulder having a rearward face, and said coupling being fully tightened when a forward face of said coupling body abuts against the rearward face of the shoulder of the stub;     the pipe is polyethylene;     coupling is coupled to the stub; and/or     the coupling is coupled to the pipe.        
 
         [0049]     Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0050]     The present invention will be more fully understood by reference to the following detailed description of a preferred embodiment of the present invention when read in conjunction with the accompanying drawing, in which like reference characters refer to like parts throughout the views and in which:  
         [0051]      FIG. 1  is a side cross-sectional view of a coupling in accordance with a preferred embodiment of the present invention, installed on a fitting stub and pipe;  
         [0052]      FIG. 2  is an exploded side view of the coupling;  
         [0053]      FIG. 3  is a side partial cross-sectional view of the coupling;  
         [0054]      FIG. 4  is a side cross-sectional view of a coupling body of the coupling;  
         [0055]      FIG. 5A  is a side non-cross-sectional view of a gripper ring of the coupling;  
         [0056]      FIG. 5B  is a side cross-sectional view of the gripper ring of  FIG. 5A ; and  
         [0057]      FIG. 6  is a side cross-sectional view of an insert of the coupling. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0058]     A preferred embodiment of the coupling of the present invention is shown in the attached drawings. In the exemplary application illustrated, the coupling is used to connect a polyethylene pipe to a cast brass alloy fitting stub in a waterworks application. The coupling is located between the pipe and the stub.  
         [0059]     In this description and in the claims, the terms “axial” and “axially” are used to describe a direction parallel to a centerline of the pipe once the coupling is installed, while “radial” and “radially” are used to describe a direction perpendicular to and extending from the centerline of the pipe once the coupling is installed. Further, “forward” is used to describe features which are located nearer the fitting stub and away from the pipe once the coupling is installed, while “rearward” is used to describe features which are located nearer the extended pipe and away from the fitting stub once the coupling is installed.  
         [0060]      FIG. 1  is a cross-sectional view of the coupling  10  installed on a fitting stub  22  and pipe  24 . The coupling  10  consists mainly of a coupling body  12 , a gripper ring  14 , and an insert  18  having a forward seal  20  and a rearward seal  16 . The coupling  10  is shown affixed to the stub  22  of a fitting (not shown), and with the pipe  24  installed therein. In this exemplary application, the fitting can be any plumbing or waterworks fitting having an externally-threaded stub  22  having the features described herein, onto which it is desirable to connect the pipe  24 . The bottom half of  FIG. 1  depicts the coupling  10  loosely engaging the stub  22  while the top half shows the coupling  10  tightened on to the stub  22 .  FIG. 2  shows an exploded side view of the coupling  10  while  FIG. 3  shows a side partial cross-sectional view of the coupling.  
       Coupling Body  
       [0061]     The coupling body  12  in the preferred embodiment (illustrated in detail in  FIG. 4 ) is made of cast brass alloy and is generally a hollow cylinder. The coupling body  12  has a nut section  26  at a forward end, a constricted section  28  at a rearward end, and an intermediate section  30  in between.  
         [0062]     The nut section  26  of the coupling body  12  is provided with a hexagonal exterior to accommodate hand-tightening or tool-tightening of the coupling body  12  on to the fitting stub  22 . The interior of the nut section  26  is sized so as to engage an outer surface of the stub  22  and is provided with internal threading  31  which matches external threading  33  of the stub  22 . In the preferred embodiment, the threading  33 ,  31  on the stub  22  and the interior of the nut section  26  is corporation fitting thread, though it is to be understood that other threads can be used. A forward end of the nut section  26  is provided with a flat face  35  which abuts a rearward face  37  of a shoulder  39  on the stub  22  when the coupling body  12  is fully tightened onto the stub  22  as shown in the top half of  FIG. 1 .  
         [0063]     The coupling body  12  is provided at its rearward end with a constricted section  28  having an interior constriction  32 . The interior constriction  32  is sized so as to fit closely over the pipe  24  and serves to retain the gripper ring  14 , and insert  18  within the coupling body  12  when the coupling body  12  is screwed onto the stub  22 .  
         [0064]     Located at an interface between the constricted section  28  and the intermediate section  30  is a gripper-constricting slope  34  which is an angled surface in the interior of the coupling body  12  formed as the interior diameter of the coupling body  12  expands from the interior constriction  32  to a gripper retainer groove  36  (discussed further below). This gripper-constricting slope  34  causes the gripper ring  14  to constrict around the pipe  24  once the coupling body  12  is tightened onto the stub  22 , as further discussed below. In the preferred embodiment, the angle of the gripper-constricting slope  34  is approximately 45 degrees though it is to be understood that other suitable angles may be utilized.  
         [0065]     Adjacent the gripper-constricting slope  34  is the gripper retainer groove  36  which is an interior circumferential groove formed in the coupling body  12  and which has a sloped forward face  37 . The gripper retaining groove  36  retains the gripper ring  14  in place within the coupling body  12 .  
       Gripper Ring  
       [0066]     The gripper ring  14  is made of brass alloy and is an annular split ring.  
         [0067]     In side cross-section, the radially exterior surface of the gripper ring  14  has a substantially horizontal central surface  40  with radially inwardly sloped surfaces  42 ,  43  extending forwardly and rearwardly therefrom. In the preferred embodiment, the angle of the exterior sloped surfaces  42 ,  43  is 25 degrees to the horizontal central surface  40 .  
         [0068]     The exterior surface of the gripper ring  14  is shaped such that the gripper ring  14  will be retained within the gripper-retaining groove  36  of the coupling body  12  once it is inserted within, and such that movement of the gripper ring  14  rearwardly relative to the gripper-retaining groove  36  will cause the gripper ring  14  to constrict radially. Once inserted within the gripper-retaining groove  36  of the coupling body  12 , rearward movement of the gripper ring  14  is resisted by the rearward exterior sloped surface  43  of the gripper ring  14  abutting against the gripper-constricting slope  34  of the coupling body  12 . If the gripper ring  14  is urged in a rearward direction within the gripper-retaining groove  36 , the rearward exterior sloped surface  43  of the gripper ring  14  slides along the gripper-constricting slope  34  causing the gripper ring  14  to constrict. Forward movement of the gripper ring  14  is resisted by the forward exterior sloped surface  42  of the gripper ring  14  abutting against the sloped forward surface  37  of the gripper-retaining groove  36  of the coupling body  12 .  
         [0069]     Still in side cross-section, the radially interior surface of the gripper ring  14  is shaped such that the interior of the gripper ring  14  has two annular gripping surfaces  44  separated by a central annular groove  46 . In other embodiments the gripper ring  14  may have three or more spaced gripping surfaces  44 . Additionally, to improve gripping strength, these annular gripping surfaces  44  may be provided with annular ridges or teeth.  
         [0070]     The gripper ring  14  is also provided with a split  48  to allow radial constriction of the gripper ring  14  during insertion into the coupling body  12  and when gripping the pipe  24 .  
       Insert  
       [0071]     The insert  18  is made of copper alloy and consists, moving from its forward end to its rearward end, of an inner web  62 , an annular rib  64 , an outer web  66  and a support tube  67 .  
         [0072]     The inner web  62  is of a diameter smaller than the outer web  66  and its exterior surface is sized to fit closely within an inner surface of the stub  22 . The inner web also has on its outer surface a circumferential forward seal groove  68  shaped and sized to accommodate the forward seal  20 .  
         [0073]     The annular rib  64  connects the inner web  62 , the outer web  66  and the support tube  67 , has a forward face  70  shaped to engage a rearward end face of the stub  22 , and a rearward face  72  shaped to engage a forward end face of the pipe  24 .  
         [0074]     The outer web  66  is sized such that its outer surface closely fits within the coupling body  12  and its inner surface fits over the pipe  24 . A rearward face  73  of the outer web  66  is angled 45 degrees so as to engage the forward exterior sloped surface  42  of the gripper ring  14 .  
         [0075]     The support tube  67  extends rearwardly from the inner web  62  and its exterior surface is sized to fit closely within an inner surface of the pipe  24 . The support tube  67  has on its exterior surface forwardly-oriented barbs  74  which serve to resist pull-out of the pipe  24  once the pipe  24  is inserted into the coupling  10  and the coupling  10  is tightened onto the stub  22 . The exterior surface of the support tube  67  also has a circumferential rearward seal groove  76  shaped and sized to accommodate the rearward seal  16 . An interior surface  77  of a rearward end of the support tube  67  is sloped outwardly so as to direct fluid flowing forwardly through the pipe  24  into the interior of the insert  18 .  
       Use  
       [0076]     A description of an exemplary manner in which the preferred embodiment of the coupling of the present invention may be used is set out below.  
         [0077]     First, the coupling body  12 , and the gripper ring  14  are assembled into a coupling body assembly. To do so, the gripper ring  14  is slid into the forward end of the coupling body  12 . This step can be performed either manually, or using an insertion device and is facilitated by the split  48  in the gripper ring  14 . The gripper ring  14  is pushed into the coupling body  12  until it is positioned within the gripper retaining groove  36  on the interior surface of the coupling body  12  at which point the resiliency of the gripper ring  14  causes it to expand to seat within the gripper retaining groove  36 . Once in this position, extraction of the gripper ring  14  from the coupling body  12  is resisted by abutment of the forward exterior sloped surface  42  of the gripper ring  14  against the sloped forward surface  37  of the gripper-retaining groove  36  of the coupling body  12 . Thus, once the gripper ring  14  is positioned within the coupling body  12  as described, the gripper ring  14  is held in place and will not fall out under normal handling.  
         [0078]     The assembly of the coupling body  12  and gripper ring  14  may be performed at the factory such that the user receives a preassembled unit, or the user may assemble these elements just prior to use. Once the coupling body  12  and the gripper ring  14  are assembled into an assembled coupling body, the only remaining loose part of the coupling  10  is the insert  18  which comes preassembled with the forward seal  20  and the rearward seal  16  mounted thereon.  
         [0079]     At a work site, the forward end of the pipe  24  is cut so that the end is square. The inside of the pipe  24  is then optionally bevelled with a reaming tool so that the pipe  24  can slide over the support tube  67  of the insert  18  easily.  
         [0080]     Next, the insert  18  is inserted into the fitting stub  22  such that the inner web  62  of the insert  18  resides within the end of the stub  22 . The insert  18  is slid into the stub  22  until the rearward end face of the stub  22  engages the forward face  70  of the annular rib  64  of the insert  18 . In this position, the forward seal  20  creates a seal against the stub  22  thereby preventing leakage of fluid out the forward end of the coupling  10 .  
         [0081]     The coupling body assembly is then placed over the insert  18  such that the forward end of the coupling body  12  slides over the outer web  66  of the insert  18  until the internal threading  31  of the nut section  26  of the coupling body  12  first engages the exterior threading  33  of the stub  22 . The coupling body  12  is then hand-tightened onto the stub  22 , thereby further engaging the interior threading  31  of the coupling body  12  and the exterior threading  33  of the stub  22 , and moving the coupling body  12  further over the insert  18  and the stub  22 . Typically, the coupling body  12  is hand-tightened onto the stub  22  until the rearward face  73  of the outer web  66  of the insert  18  abuts against the forward exterior sloped surface  42  of the gripper ring  14  thereby creating some resistance to further tightening.  
         [0082]     The pipe  24  is then “stab-fitted” over the support tube  67  of the insert  18  and into the rearward opening of the coupling body  12 . The pipe  24  is pushed forward until the forward end face of the pipe  24  abuts against the rearward face  72  of the annular rib  64  of the insert  18 .  
         [0083]     The coupling body  12  is then further tightened onto the stub  22  either by hand or by using a tool. Because the stub  22 , the insert  18 , the gripper ring  14  and the interior constriction  32  of the coupling body  12  all abut against one another, this further tightening causes the gripper ring  14  to move rearwardly to accommodate the decreasing distance between the rearward face  73  of the outer web  66  of the insert  18  and the gripper-constricting slope  34 . As it does so, cooperation between the rearward exterior sloped surface  43  of the gripper ring  14  and the gripper constricting slope  34  of the coupling body  12  causes the gripper ring  14  to be urged inwardly and to constrict, thereby resulting in an engagement of the outer surface of the pipe  24  by the gripping surfaces  44  of the gripper ring  14 . Further tightening of the coupling body  12  onto the stub  22  causes the gripping surfaces  44  of the gripper ring  14  to engage the outer surface of the pipe  24  more securely.  
         [0084]     The configuration of the gripper ring  14  enhances gripping strength of the coupling  10  while reducing the potential for damage to, and/or collapse of the pipe  24 . First, the axial separation of the two gripping surfaces  44  provides stability to the gripper ring  14  as it is pressed against the pipe  24 . Second, by having two spaced gripping surfaces  44 , the pressure exerted by the coupling  10  on the gripper ring  14  is spread over a wider area on the pipe thereby reducing the likelihood of the gripper ring  14  causing damage to and/or collapse of the pipe  24 . Third, by having the central annular groove  46  between the two gripping surfaces  44 , a space is created for the pipe material to extrude slightly into this central annular groove  46  as the gripping surfaces  44  press into the pipe  24  thereby improving the gripping capacity of the coupling  10 . Although the number of gripping surfaces  44  can be three or greater, the preferred number is two so as to concentrate the inward force on the pipe  24  onto two annular regions, and preferably directly over the rearward seal  16 .  
         [0085]     Additionally, as the coupling body  12  is tightened onto the stub  22 , an inward force is imparted to the pipe  24  thereby causing the pipe  24  to press against both the barbs  74  and the rearward seal  16 . Movement of the barbs  74  and rearward seal  16  inwardly is resisted by the rigidity of the support tube  67  of the insert  18 . In this manner the rearward seal  16  creates a seal between the support tube  67  and the pipe  24  preventing leakage out the rearward end of the coupling  10 . Additionally, the barbs  74  bite into the pipe  24  assisting in preventing inadvertent pull-out of the pipe  24 .  
         [0086]     Once the forward flat face  35  of the nut section  26  of the coupling body  12  abuts the rearward face  37  of the shoulder  39  of the stub  22 , the coupling  10  is fully engaged and a sealed, secured connection between the pipe  24  and the stub  22  has been established. As designed, an ideal seal and securement is established by the coupling  10  when the coupling body  12  is fully tightened onto the nut with the forward flat face  35  of the nut section  26  of the coupling body abutting the rearward face  37  of the shoulder  39  of the stub  22 . Thus, it is easy for a user to tell if the coupling  10  is under-tightened, and it is not possible for the coupling  10  to be over-tightened.  
         [0087]     To release the connection, the coupling body  12  is unscrewed from the stub  22  thereby disengaging the gripper ring  14  from the pipe  24 . The coupling body assembly can then be removed from the stub  22  and the pipe  24  can be slid out of the coupling body assembly.  
         [0088]     Because none of the elements of the preferred embodiment coupling has been permanently deformed during use, the coupling  10  can then be reused.  
         [0089]     Although an exemplary manner of using the preferred embodiment coupling of the present invention has been described above in detail, it is to be understood that the preferred embodiment coupling can be used in ways other than as explicitly set out above, as readily understood by those skilled in the art. For example, instead of mounting the insert  18  within the stub  22  first and placing the assembled coupling body over the insert  18 , the insert  18  can be placed within the coupling body assembly first and then the coupling body assembly with insert  18  within may be placed onto the stub  22 . As a further example, the pipe  24  may be inserted into the coupling body assembly first before the insert  18  is installed in the coupling body  12 , or before the coupling body assembly is placed over the insert  18  and stub  22 .  
         [0090]     Although the preferred embodiment coupling has been described above as being used to attach a polyethylene pipe  24  to a fitting, it is to be understood that pipes made of other materials may be used. Indeed any pipe having sufficient rigidity to avoid excessive deformation during tightening and which has a surface soft enough to permit the gripper ring  14  to bite into it, may be used.  
         [0091]     Specific materials used for the various elements of the coupling  10  and for the fitting stub  22  have been provided. However, it is to be understood that other suitable materials may be used for these elements as will be understood by those skilled in the art.  
         [0092]     Very specific geometries of the various elements have also been provided. However, it is to be understood that persons skilled in the art may use other suitable geometries without necessarily departing from the scope of the invention.  
         [0093]     The preferred embodiment coupling has also been described in the context of a waterworks application. However, it is to be understood that the coupling can be used in other applications, plumbing applications for example.  
         [0094]     Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practised otherwise than as specifically described herein.