Patent Abstract:
A glueless union suitable for joining piping and other plumbing components. Several components are used to create the union. The portion of each plumbing component that is to be joined is a circular, thick-walled section which is centered on a central axis. This portion has a mating face that is perpendicular to the central axis. The union includes an annular face seal which is compressed between the opposing mating faces of the plumbing components to be joined.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the field of plumbing. More specifically the invention comprises an assembly for joining two plumbing components without the use of adhesives. 
     2. Description of the Related Art 
     Poly vinyl chloride (“PVC”) piping and plumbing components have become increasingly common in recent years. Such components are typically joined using an adhesive (“PVC cement”).  FIG. 1  shows a typical assembly in the prior art. The installation requires that two plumbing components (in this example two pipes  10 ) be joined together. Coupler  12  is used for this purpose. Coupler  12  includes inner diameter  14 , which is sized to be a close sliding fit over the outer diameter of each of the two pipes  10 . The mating surfaces are typically cleaned and primed, then coated with PVC cement. The two pipes are then slipped into coupler  12 . The coupler often has an internal stop—a ring having a reduced diameter—which prevents either pipe being shoved in too far. 
     The PVC cement will cross-link in a matter of minutes and gain sufficient strength to hold the components together. It will continue to harden and the completed assembly is typically ready for pressurization in about one hour. Thus, the prior art components can be joined effectively using PVC cement. 
     This approach is not without disadvantages however. A first disadvantage is the delay involved. The installer must assemble the components and then wait to test them. This is a particular concern for a technician who is installing pool pump and filtration lines. These must be carefully spaced in order to properly locate the components they connect. As some of these lines run at 25-50 psi, the installer often must wait for the PVC cement to fully cure before testing. 
     In addition, prolonged exposure to PVC primers and cements can be hazardous to human health. Persons using these chemicals are cautioned to use protective gloves and masks, but many choose to ignore this safety measure. The cement can also contaminate surrounding components. 
     Glueless plumbing connections therefore offer advantages over the use of PVC cement. Such connections are certainly known in the art. However, these tend to operate by compressing a gasket against a flange or flare. They must generally be assembled in a predetermined order. For example, a compression nut must be slipped on a piece of piping from the end of the pipe that is distal to the joint being made, since the nut cannot pass over the flare or flange which lies next to the joint. This fact obviously limits the application of the prior art compression unions. Accordingly, a glueless plumbing union which can be assembled entirely from the end of the pipe adjacent to the joint would be desirable. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention comprises a glueless union suitable for joining piping and other plumbing components. Several pieces are combined to create the union. The portion of each plumbing component that is to be joined has a circular, thick-walled section which is centered on a central axis. Each such section has a mating face which is perpendicular to the central axis. The union includes an annular face seal which is compressed between the opposing mating faces of the plumbing components to be joined. 
     A first engagement feature such as an external thread is provided on the first plumbing component to be joined. A circumferential clip receiver is provided on the second plumbing component to be joined. A union nut is passed along the component having the clip receiver. A C-clip is then temporarily expanded and snapped into the clip receiver. The union nut is then advanced toward the first component. The union nut engages the C-clip, which forces the second component toward the first component—thereby compressing the annular face seal and forming the joint. The union nut includes a second engagement feature—such as a female thread—which is configured to attach to the first engagement feature on the first plumbing component. The two engagement features are used to pull the first and second plumbing components tightly together. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a perspective view, showing a prior art plumbing connection. 
         FIG. 2  is an exploded perspective view, showing the components of the present invention. 
         FIG. 3  is a detailed section view, showing the relative position of the face seal with respect to the components being joined. 
         FIG. 4  is a detailed section view, showing all the components in position for assembly. 
         FIG. 5  is a detailed section view, showing all the components after an assembly is completed. 
         FIG. 6  is a detailed section view, showing additional details from the configuration of  FIG. 5 . 
         FIG. 7  is a detailed perspective view, showing some features of the C-clip. 
         FIG. 8  is a detailed section view, showing the C-clip in a reversed orientation. 
         FIG. 9  is a detailed section view, showing an alternate embodiment for the face seal. 
     
    
    
     REFERENCE NUMERALS IN THE DRAWINGS 
     
         
         
           
               10  pipe 
               12  coupler 
               14  inner diameter 
               16  external thread 
               18  face seal 
               20  C-clip 
               22  union nut 
               24  central axis 
               26  clip receiver 
               28  annular clevis 
               30  annular tang 
               32  gasket overlay 
               34  protrusion 
               36  first mating surface 
               38  second mating face 
               40  gap 
               42  internal thread 
               44  nut bearing surface 
               46  C-clip bearing surface 
               48  C-clip angled surface 
               50  clip receiver angled surface 
               52  protrusion 
               54  void 
               56  minor diameter 
               58  outer surface 
               60  diamond face seal 
               62  diamond seal groove 
           
         
       
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 2  shows the components of the present invention in an exploded state. The glueless union is an assembly which is capable of joining a first and second plumbing component together. In  FIG. 2 , the first and second plumbing components are pipes  10  aligned along central axis  24 . Examples of other plumbing components include filters, pumps, valves, etc. Each of these types of components can be provided with mating features made according to the present invention. The illustrations provided show pipes, but any other plumbing component could be substituted. 
     The first plumbing component (pipe  10 ) is shown in the left hand side of the view. It is provided with an engagement feature configured to engage another engagement feature on the second plumbing component (the right hand pipe  10  in the view). This engagement feature can assume a variety of forms. In the embodiment shown external thread  16  is used as the engagement feature on the first plumbing component. 
     Face seal  18  is designed to be compressed between the two plumbing components and thereby form a pressure-tight seal. It has an unbroken circumference. (There are no gaps in its circumference). Clip receiver  26  is an annular groove cut into the exterior surface of the second plumbing component. C-clip  20  is designed to snap into clip receiver  26 . The reader will note that C-clip  20  includes gap  40 . This feature allows the C-clip to expand and pass over the outer diameter of the second plumbing component. The diameter of the C-clip is preferably sized so that—in a relaxed state—it is smaller than the outer diameter of the second plumbing component. Thus, the user must expand C-clip  20  to pass over the right hand pipe  10 . Once it reaches the position of clip receiver  26 . C-clip  20  is able to contract (gap  40  will narrow) and snap into clip receiver  26 . 
     Union nut  22  is sized to slide over pipe  10 . It contains an engagement feature or features configured to engage the engagement feature or features on the first plumbing component. In the embodiment shown, union nut  22  has an internal thread sized to engage external thread  16 . The reader should note that the use of the term union “nut” does not imply a hexagonal external perimeter for this component, or any other particular shape. In fact, many embodiments may be configured to be hand-tightened. Thus, the exterior of union nut  22  is preferably covered with grip-enhancing features such as raised ribs. 
       FIG. 3  is a detailed section view showing how the components of the glueless union assembly fit together. The union is designed to work by clamping face seal  18  between first mating face  36  (on the first plumbing component) and second mating face  38  (on the second plumbing component). It is preferable to provide a mechanical interlocking feature between face seal  18  and one or both of the plumbing components so that the face seal is properly positioned. In the embodiment shown, annular clevis  28  is provided in first mating face  36 . A corresponding annular tang  30  is provided on one side of the face seal. The user may properly place the face seal by pressing annular tang  30  into annular clevis  28 . One or more protrusions  34  are provided on the side of the face seal opposite annular tang  30 . These form annular ring seals when they are pressed against second mating face  38 . The tang and clevis joint allows the face seal to remain in position while the union is assembled and may in some instances allow the union to remain sealed under higher pressures. 
     Those skilled in the art will realize that the mechanical interlock feature between the plumbing component and the face seal could assume a virtually endless variety of forms. Likewise, the annular clevis could just as easily be provided in second mating face  38  of the second plumbing component. It is also possible to provide a tang in one of the mating faces and a clevis in the face seal. 
     In the embodiment illustrated, external thread  16  is provided in the exterior of the first plumbing component proximate first mating face  36 . Clip receiver  26  is provided in the exterior of the second plumbing component proximate second mating face  38 .  FIG. 4  shows all the components in position for assembly. The reader may benefit from some understanding of the preferred order of operations for creating a completed assembly. Union nut  22  is placed over the right hand pipe  10  and moved down its length (a short distance away from second mating surface  38 ). C-clip  20  is then slipped over the right hand pipe  10  and snapped into clip receiver  26 . The reader will observe that once C-clip  20  is snapped into the clip receiver, internal thread  42  on union nut  22  is able to pass over the exterior of the C-clip and advance toward external thread  16  on the left hand pipe  10 . 
     Face seal  18  is appropriately positioned between the two mating surfaces. Forcing the two mating surfaces toward each other will then form a pressure-tight seal.  FIG. 5  shows the same assembly after union nut  22  has been threaded onto external thread  16  and tightened. The reader will observe how face seal  18  is appropriately positioned and compressed between first mating surface  36  and second mating surface  38 . 
       FIG. 6  shows the same assembly in more detail. Union nut  22  has nut bearing surface  44  which is positioned to bear against C-clip bearing surface  46 . Thus, as the union nut is tightened, it will urge the C-clip toward the first plumbing component. Of course, the C-clip is engaged into the clip receiver on the second plumbing component, so the tightening of the union nut thereby urges the first and second plumbing components together. 
     The clip receiver is preferably provided with clip receiver angled surface  50 . This bears against C-clip angled surface  48 , thereby creating a wedging effect between these two frusto-conical surfaces. The result is that the C-clip is urged outward into tight contact with the union nut, thereby ensuring appropriate engagement during the tightening process. 
       FIG. 6  also shows how the components can be sized to create an annular void  54  between the first plumbing component and C-clip  20 .  FIG. 7  shows a detailed perspective view of C-clip  20  in the vicinity of gap  40 . It is preferable for the C-clip to be snapped into the clip receiver in the proper orientation (as shown in  FIG. 6 ). However, it is possible for a user to attempt to snap the C-clip in place in a reversed orientation.  FIG. 7  shows how features can be provided on the side of the C-clip which is intended to face the first plumbing component. One or more protrusions  52  can be provided on this side. These fit easily into void  54  if the C-clip is installed correctly. If the C-clip is installed incorrectly, however, protrusions  52  will bear against the internal threads on the union nut and the user will note this problem. The protrusions are preferably sized so that the leading portion of the union nut cannot pass over the C-clip (and thereby hide it from the user&#39;s sight) before the protrusions bear against the internal threads and thereby arrest any further motion of the union nut. 
       FIG. 8  illustrates another feature intended to prevent incorrect installation of the C-clip. In  FIG. 8 , C-clip  20  has been installed with C-clip angled surface  48  facing away from the first plumbing component rather than toward it. The angled surface on the C-clip is therefore not positioned to mate against the angled surface in clip receiver  26 . The result is that C-clip  20  will only snap part of the way into the clip receiver, and outer surface  58  of C-clip  20  will protrude further outward than would be the case if the C-clip were properly installed. 
     The engagement features on union nut  22  can be sized to cause an interference in this scenario. Internal thread  42  is sized so that its minor diameter  56  passes just over outer surface  58  of the C-clip when the C-clip is properly installed. If, however, the C-clip is installed in the wrong orientation (as shown in  FIG. 8 ), internal thread  42  strikes the C-clip and will not allow union nut  22  to advance toward external thread  16 . Thus, the fact that the C-clip has been improperly installed will be made apparent to the user. 
     Many variations on the embodiment shown will be apparent to those skilled in the art. As one example, a female thread in a receiving collar could be provided on the first plumbing component and the union nut could be provided with an external male thread sized to engage this female thread. Of course, threads are certainly not the only type of engagement features that could be provided. A bayonet lug type of engagement could be provided. Camming levers could also be used to draw the first and second plumbing components together. Thus, the use of threads in the illustrated embodiments should properly be viewed as exemplary. 
     The specific type of face seal used is likewise open to many variations.  FIG. 9  shows a different type of face seal. Diamond face seal  60  is still designed to be compressed between first mating surface  36  and second mating surface  38 . However, it is retained by the use of an annular groove en both mating surfaces. The reader will note the presence of an annular groove  62  in first mating surface  36  and an annular groove  62  in second mating surface  38 . As the two plumbing components are pulled together diamond face seal  60  compresses into the two annular grooves and forms an effective seal. An example of such a sealing device is the DIAMOND SEAL product (a diamond-shaped face seal) offered by Parker Hannifin Corporation of Syracuse, Ind. 
     The preceding description contains significant detail regarding the novel aspects of the present invention. It should not be construed, however, as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. Thus, the scope of the invention should be fixed by the following claims, rather than by the examples given.

Technology Classification (CPC): 5