Abstract:
The pipe repair coupling includes a sleeve and two seal retainers that clip to the ends of the sleeve to retain corresponding seals therein. The repair coupling is installed about a damaged section of PVC or other hard plastic pipe without the need for substantial displacement of either portion of the broken pipe or the need to dress or otherwise modify the broken ends of the pipe. A seal retainer and a seal are placed over each portion of the broken pipe, and the sleeve is slipped over one of the broken pipe portions. The two pipe portions are aligned with one another, and the sleeve is generally centered over the break. The two seal retainers are then snapped into place on the ends of the sleeve, capturing the seals between the seal retainers and corresponding seats and distending the seals to bear against the broken pipe therein.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to plumbing pipes, tubes, and fluid conveyance systems, and particularly to a pipe repair coupling for the effective repair of polyvinyl chloride (PVC) and similar plastic pipes. 
     2. Description of the Related Art 
     Plastic pipe, and particularly polyvinyl chloride (PVC) plastic, has become increasingly popular for installation in household, commercial, and other water supply lines. While such plastic material has its limitations insofar as high temperatures are concerned, it has many advantages over metal pipe and tubing for use as water supply and drain pipe, such as economy, ease of installation, resistance to corrosion, and lack of toxicity. 
     Nevertheless, such PVC pipe is still subject to damage under certain conditions. Freezing temperatures that allow water within the pipe to freeze and expand may cause the pipe to split. Buried pipe may be damaged by excavation for construction, tree roots, and/or other causes. Obviously, when such damage occurs, it must be repaired. 
     Accordingly, a number of plastic pipe repair devices and systems have been developed in the past. Many, if not most, such repair devices and systems require that at least one end of the broken pipe be displaced laterally from its alignment with the pipeline. Plastic pipe is reasonably flexible and may accommodate a certain amount of bending to allow for the installation of the repair components. However, the use of many such repair components requires that a considerable amount of material be removed along the length of a buried pipe in order to allow sufficient movement of the pipe for the installation of the repair components without damaging the pipe further. This clearly adds to the difficulty of the repair, particularly if the pipe is encased in concrete or other extremely hard material. Other repair systems require that the ends of the pipe be dressed, grooved, or treated in some manner, which is extremely difficult to perform in a buried pipeline installation. 
     Thus, a pipe repair coupling solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The pipe repair coupling is an assembly comprising a central coupling body or sleeve and first and second seal retainers that are clipped to the ends of the central sleeve to retain corresponding seals therein. The repair coupling may be installed about a damaged section of PVC or other hard plastic pipe without the need for substantial displacement of either portion of the broken pipe or the need to dress or otherwise modify the broken ends of the pipe. 
     The coupling body or sleeve has a smooth, continuous central bore that is unbroken by any stops or other discontinuities therein. The broken pipe is installed through the bore of the sleeve. Each end of the sleeve has a larger internal diameter than the central bore to accommodate a seal and the tubular extension of a seal retainer installed thereon. An additional expansion of the internal diameter is provided in each end of the sleeve to accept a circumferential barbed flange formed about the tubular extension of the seal retainer. Each end of the sleeve is provided with a plurality of axial slits defining a corresponding series of axial fingers, which flex radially outward to allow insertion of the barbed flange of the seal retainer therein. Each of the fingers terminates in an internally oriented prong. The prongs engage a circumferential groove about the seal retainer and grip the back of the barbed flange to lock the seal retainer to the sleeve. 
     An O-ring or other suitable resilient elastomer seal is captured between the end of the extension of each seal retainer and the face of the smaller diameter central bore of the sleeve. When the pipe is pressurized with water or other fluid, the fluid pressure is transmitted through the broken section of pipe between the pipe and the surrounding sleeve to bear against the inner face of the seal. This forces the seal outward against the end of the extension of the seal retainer, and distends the seal to force it both inward against the pipe and outward against the inner surface of the sleeve to provide a positive seal. 
     The present pipe repair coupling is quickly and easily installed. No tools or equipment are required once the damaged section of pipe is accessed. It may be necessary to completely separate the pipe at the break if the pipe still forms a continuous length. This may be done with any suitable tool, e.g., breaking the pipe with a shovel blade, etc., as the condition of the broken ends of the pipe is acceptable so long as the ends fit within the sleeve. One of the seal retainers and a seal are then placed over each portion of the pipe, i.e., to each side of the break, and the sleeve is placed over one of the portions of the pipe. The two sections of pipe are aligned with one another and the sleeve is slid back over the break in the pipe, positioning the break at approximately the midpoint of the sleeve. The two seal retainers are then snapped into place on the ends of the sleeve, with the prongs of the sleeve engaging the grooves of the seal retainers and gripping the backs of the barbed flanges of the retainers. This forces the seals into position between the ends of the tubular extensions of the seal retainers and the face of the smaller diameter central bore of the sleeve to complete the pipe repair. 
     These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a pipe repair coupling according to the present invention, illustrating its components. 
         FIG. 2  is an environmental elevation view in section of the pipe repair coupling according to the present invention, showing the pipe repair coupling assembled along a broken pipe. 
         FIG. 3  is an elevation view in section of one of the seal retainer components of the pipe repair coupling according to the present invention, illustrating various details thereof. 
         FIG. 4  is an elevation view in section of the coupling body of the pipe repair coupling according to the present invention, illustrating various details thereof. 
         FIG. 5  is an environmental elevation view of the pipe repair coupling according to the present invention, showing the completed pipe repair coupling assembly installed upon a broken pipe. 
     
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The pipe repair coupling provides for the repair of broken or damaged PVC or other hard plastic pipe without the need for assembly tools, pipe cement, or other ancillary tools and/or equipment.  FIG. 1  of the drawings provides an exploded perspective view of the components of the pipe repair coupling  10 ,  FIG. 2  provides a view in section of the coupling  10  connecting two broken pipe sections P 1  and P 2  to one another, and  FIG. 5  providing an external view of the installed coupling  10  on the pipe sections P 1  and P 2 . The coupling  10  includes five basic components: (1) a cylindrical sleeve  12 ; (2) and (3) first and second seal retainers  14   a  and  14   b ; and (4) and (5) first and second seals  16   a  and  16   b  that are secured in the opposite ends of the sleeve  12  by the seal retainers  14   a  and  14   b.    
       FIGS. 2 and 4  provide views in section showing the internal configuration of the sleeve  12 . The sleeve  12  is laterally and axially symmetrical, having mutually opposed first and second ends  18   a  and  18   b . An annular seal seat, respectively  20   a  and  20   b , is disposed within each of the sleeve ends  18   a  and  18   b . Each of the seal seats  20   a ,  20   b  has a frustoconical section, as can be seen by the tapering shape of the seats in the two sectional views of  FIGS. 2 and 4 . 
     Each of the sleeve ends  18   a ,  18   b  includes a plurality of axially oriented slots defined therein, dividing the ends into a corresponding plurality of axially disposed fingers  22 , best seen in  FIG. 1 . As the sleeve  12  (and the two seal retainers  14   a ,  14   b , as well) are preferably formed of a reasonably hard but ductile material, such as PVC plastic or the like, the fingers  22  may be flexed radially outward to allow the insertion of the seal retainers  14   a  and  14   b  therein, as described further below. Each of the fingers  22  has a distal end  24  and a prong  26  extending radially inward from the distal end  24  of each finger  22 . The portions of the fingers  22  immediately inward from the prongs  26  are relatively thin, defining a relatively large internal diameter for accepting the medial portion of each of the seal retainers  14   a  and  14   b . The plurality of prongs  26  of the circumferentially disposed fingers  22  at each of the sleeve ends  18   a  and  18   b  collectively form an acute angle between the faces of the prongs and the internal surface of the internal diameter of the fingers  22 . This acute angle of the prong faces results in the prongs  26  locking the seal retainers  14   a  and  14   b  into the ends  18   a ,  18   b  of the sleeve  12  when assembled therewith, as described further below. 
     The seal retainers  14   a ,  14   b  are shown installed in the sleeve ends  18   a ,  18   b  in  FIG. 2 , and as a separate component in  FIG. 3 . It will be understood that the two seal retainers  14   a ,  14   b  are identical to one another. The seal retainer depicted in  FIG. 3  may represent the second seal retainer  14   b  by inverting the image or reversing the image to form a mirror image. Each of the seal retainers  14   a ,  14   b  has a tubular extension, respectively  28   a  and  28   b , and a seal retaining end  30   a ,  30   b  facing the corresponding seal seat  20   a ,  20   b  of the sleeve  12  when the seal retainers  14   a ,  14   b  are installed therein. Each of the tubular extensions  28   a ,  28   b  has an external diameter  32   a ,  32   b . The internal diameter  34   a ,  34   b  of each of the seal retainer receptacles  36   a ,  36   b  is substantially the same and fits closely about the respective tubular extensions  28   a ,  28   b  of the seal retainers  14   a ,  14   b.    
     Each of the seal retainers  14   a ,  14   b  has an outer end  38   a ,  38   b  and a circumferential flange  40   a ,  40   b  extending outwardly therefrom. Each of the flanges  40   a ,  40   b  is disposed generally medially about its respective seal retainer. The flanges  40   a ,  40   b  and outer ends  38   a ,  38   b  define respective circumferential grooves  42   a ,  42   b  therebetween. The circumferential flanges  40   a  and  40   b  form acute angles between their faces and the bottoms of the grooves  42   a  and  42   b , i.e., the outer surfaces of the tubular extensions  28   a ,  28   b  of the seal retainers  14   a ,  14   b . The faces of these acute angles mate against the corresponding faces of the prongs  26  of the sleeve fingers  22 , thereby locking the prongs  26  of the sleeve fingers  22  into the respective grooves  42   a ,  42   b  of the seal retainers  14   a ,  14   b  to retain the seal retainers in the ends  18   a  and  18   b  of the sleeve  12  when assembled with one another. 
     The sleeve  12  has a smooth, continuous concentric bore or pipe passage  44  formed axially therethrough as shown most clearly in  FIG. 4 . The pipe repair coupling  10 , and particularly the internal diameter  46  of the bore  44 , is capable of being adapted to different pipe diameters. The bore  44  is devoid of any pipe stops or other discontinuities therein, permitting a length of pipe P 1  or P 2  to be passed completely through the sleeve  12 . The tubular extensions  28   a  and  28   b  of the seal retainers  14   a  and  14   b  have internal diameters  48   a  and  48   b  substantially identical to the internal diameter  46  of the sleeve  12 . The larger internal diameters  34   a ,  34   b  of the seal retainer receptacles  36   a ,  36   b  of the sleeve form the annular seal seats  20   a  and  20   b  with the smaller internal diameter  46  of the bore  44  of the sleeve  12 . 
     The toroidal seals or gaskets  16   a  and  16   b , e.g., resilient elastomer O-rings or the like, are installed within the respective seal retainer receptacles  36   a  and  36   b  of the sleeve  12 . The material of which the two seals  16   a ,  16   b  are formed is preferably an NSF-approved elastomer suitable for use with pipes carrying potable water, although other materials may be used, where suitable. The seals  16   a  and  16   b  preferably have rectangular cross-sections, as shown in  FIG. 1 , and particularly in the cross-sectional view of  FIG. 2 . As the tubular extensions  28   a  and  28   b  of the two seal retainers  14   a  and  14   b  are inserted into their respective retainer receptacles  36   a  and  36   b  of the sleeve  12 , the seals or gaskets  16   a  and  16   b  are compressed between the frustoconical seal seats  20   a  and  20   b  of the sleeve  12  and the seal retaining ends  30   a  and  30   b  of the tubular extensions  28   a  and  28   b  of the seal retainers  14   a  and  14   b . As the seals  16   a ,  16   b  are compressed further, the frustoconical slopes of the two seal seats  20   a ,  20   b  force the seals to flow inward to press against the outer walls of the two pipe sections P 1  and P 2 , thereby forming a leakproof seal against the pipe sections. The leakproof seal is retained by the locking of the flanges  40   a  and  40   b  of the seal retainers  14   a  and  14   b  by the prongs  26  of the fingers  22  extending from the ends of the sleeve  12 . The resilient fingers  22  flex back into position as the prongs  26  pass over the flanges  40   a  and  40   b  of the seal retainers  14   a  and  14   b  so that the prongs  26  drop into the grooves  42   a  and  42   b  of the respective seal retainers  14   a  and  14   b , thereby locking the seal retainers in place in the two ends  18   a  and  18   b  of the sleeve  12 . 
     It will be noted that the external diameters  50   a  and  50   b  of the outer ends  38   a  and  38   b  of the two seal retainers  14   a  and  14   b  are substantially equal to the external diameter  52  of the sleeve  12 . The sleeve  12  is constructed to have a minimum external diameter  52  based upon the required thicknesses of the fingers  22  inboard of their prongs  26 . This sleeve diameter  52  is preferably uniform throughout the entire length of the sleeve  12 . The uniform diameter  52  of the sleeve  12  and the substantially equal diameters  50   a  and  50   b  of the two seal retainers  14   a  and  14   b  provide a smooth external surface for the pipe repair coupling assembly  10  to preclude or at least greatly reduce the chances of the device catching upon some external object during installation. 
     Accordingly, the pipe repair coupling  10  provides a much easier means of repairing a broken PVC or other similar plastic pipe. The pipe repair coupling  10  does not require any tools or equipment for installation, as the two seal retainers  14   a  and  14   b  merely clip or snap into place in the respective ends  18   a  and  18   b  of the sleeve  12 . Further, the pipe components or sections P 1  and P 2  do not require further work in preparation for installing the coupling  10 , other than completely separating the two sections at the break point as necessary so that the sleeve  12 , the two seal retainers  14   a  and  14   b , and their seals  1   a  and  16   b  may be slipped over the pipe sections. The relatively small diameter of the repair coupling  10 , i.e., on the order of twice the diameter of the pipe sections P 1  and P 2 , requires minimal lateral displacement of either of the pipe sections for installation of the coupling, thereby further reducing the time and effort required for installation. The result will be much appreciated by anyone who has occasion to repair a broken plastic pipe. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.