Abstract:
The pipe repair coupling includes a sleeve and two seal retainers that secure to the sleeve ends to retain corresponding seals therein. The repair coupling is installed about a damaged section of pipe without need for substantial displacement of either portion of the broken pipe or need to dress or otherwise modify the broken ends of the pipe. A seal retainer and 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 locked into place on the sleeve ends by splines inserted into cooperating circumferential grooves in the sleeve ends and retainers, 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. Moreover, many such pipe repair systems result in permanent installations that cannot be removed, repositioned or resealed should circumstances require. 
     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 secured 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. Each end of the sleeve also has a circumferential internal groove to accept a locking spline, as explained below. 
     Each seal retainer has a circumferential external groove. The groove at each end of the sleeve aligns with the corresponding groove of the seal retainer to define a circumferential spline channel when the components are properly assembled. A locking spline is inserted into each spline channel through a passage in the outer wall of the sleeve at each end thereof. This locks each seal retainer in place in the respective ends of the sleeve. The locking splines may be removed to allow the seal retainers to be removed in order to remove or reposition the assembly as desired, e.g., for replacement of the seals therein. 
     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, except that a hammer or other suitable impact tool may be needed to drive the gasket or seal into place during assembly. 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. Each seal retainer is then pushed into an end of the sleeve or coupling to the extent that its external groove aligns with the corresponding internal groove of the sleeve. A locking spline is then inserted through the external hole or passage in each end of the coupling or sleeve, and pushed through the hole or passage to wrap around the retainer in the circumferential channel formed by the internal and external grooves of the sleeve and retainer. This locks the retainer in place in the end of the sleeve or coupling, and forces the seal into position between the end of the tubular extension of the seal retainer 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. The pipe repair coupling is configured to allow its components to be separated and reassembled without damage, thereby allowing the coupling to be reused and/or for deteriorated seals to be replaced.  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 P1 and P2 to one another, and  FIG. 5  provides an external view of the installed coupling  10  on the pipe sections P1 and P2. The coupling  10  includes seven basic components: a cylindrical sleeve  12 ; first and second seal retainers  14   a  and  14   b ; 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 ; and first and second flexible splines  18   a  and  18   b  that serve to lock the seal retainers to the ends of the sleeve. The sleeve  12  and the two seal retainers  14   a ,  14   b  are preferably formed of a durable plastic, such as high-density polyethylene (HDPE), although other suitable materials may be used. The two seals  16   a ,  16   b  are preferably formed of a resilient material, such as silicone rubber, although other materials may be used. The two splines  18   a ,  18   b  may be formed of any suitable flexible material, such as Nylon® or other plastic material, flexible wire, etc. The splines  18   a ,  18   b  may have circular cross sections, as shown, or alternatively, may have any other suitable non-circular cross section. 
       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  20   a  and  20   b . Annular seal seats, respectively  22   a  and  22   b , are disposed within the respective sleeve ends  20   a  and  20   b . Each of the seal seats  22   a ,  22   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 . The minor diameters of the seal seats  22   a ,  22   b  are equal to the internal diameter  24  of the through bore or passage  26  that extends axially through the length of the sleeve  12 , and the major diameters of the seal seats are equal to the internal diameters  28   a ,  28   b  of the seal retainer receptacles  30   a  and  30   b  (shown in  FIG. 4 ) formed at each end of the through bore  26 . 
     Larger diameter portions  32   a  and  32   b  are formed immediately within the extreme ends of the sleeve  12 . These larger diameter end portions  32   a ,  32   b  provide greater clearance for the initial insertion of the seals  16   a  and  16   b  before the seals reach the narrower diameter seal retainer receptacle areas  30   a  and  30   b . These larger diameter portions  32   a ,  32   b  are configured to fit closely around the intermediate portions of the seal retainers  14   a ,  14   b  between their outermost and innermost ends. A shallow frustoconical portion  34   a ,  34   b  extends between the larger diameter end portions  32   a ,  32   b  and the seal retainer receptacles  30   a ,  30   b , to provide a smooth transition between the two diameters. Internal spline retaining grooves, respectively  36   a  and  36   b , are formed circumferentially in the larger diameter portions  32   a ,  32   b  immediately within each of the two sleeve ends  20   a  and  20   b . The spline retaining grooves  36   a ,  36   b  may have rectangular cross sections as shown, or may have some other cross-sectional shape. 
     The seal retainers  14   a ,  14   b  are shown installed in the sleeve ends  20   a ,  20   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 an external shape that mates closely with the internal shape of each end of the sleeve  12 , i.e., each seal retainer  14   a ,  14   b  has a tubular extension  38   a ,  38   b ; an intermediate portion  40   a ,  40   b  having a larger diameter than the extension  38   a ,  38   b ; and a shallow frustoconical portion  42   a ,  42   b  between the extension and intermediate portion. The tubular extensions  38   a ,  38   b  seat within the seal retainer receptacles  30   a ,  30   b  of the sleeve  12  when the seal retainers  14   a ,  14   b  are installed therein. The frustoconical portions  42   a ,  42   b  of the seal retainers seat closely within the corresponding frustoconical portions  34   a ,  34   b  in the sleeves, and the larger diameter intermediate portions  40   a ,  40   b  of the seal retainers  14   a ,  14   b  seat closely within the corresponding larger diameter portions  32   a ,  32   b  immediately within each of the ends  20   a  and  20   b  of the sleeve  12 . 
     The intermediate portions  40   a ,  40   b  of the two seal retainers  14   a ,  14   b  may be more specifically described as having flanges  44   a ,  44   b  at the ends of the larger diameters of their frustoconical portions  42   a ,  42   b . These flanges define smaller diameter circumferential spline retaining grooves  46   a ,  46   b  disposed between each flange and the respective larger diameter outer ends  44   a ,  44   b  of the seal retainers. These spline retaining grooves  46   a ,  46   b  are formed externally about each of the seal retainers  14   a ,  14   b  and align with the corresponding internal grooves  36   a ,  36   b  of the sleeve  12  to form spline channels (or annular keyways) when the seal retainers  14   a ,  14   b  are properly installed with the sleeve  12 . The spline retaining grooves  46   a ,  46   b , and the channels formed by the aligned internal spline retaining grooves  36   a ,  36   b  of the sleeve  12  may have rectangular cross sections, as shown particularly in  FIGS. 2 and 3 , or may have any other suitable cross section. 
     The sleeve  12  has a smooth, continuous concentric bore or pipe passage  26  formed axially therethrough as noted further above, shown most clearly in  FIG. 4 . The pipe repair coupling  10 , and particularly the internal diameter  24  of the bore  26 , is capable of being adapted to different pipe diameters. The bore  26  is devoid of any pipe stops or other discontinuities therein, permitting a length of pipe P1 or P2 to be passed completely through the sleeve  12 . The tubular extensions  38   a  and  38   b  of the seal retainers  14   a  and  14   b  have internal diameters  48   a  and  48   b  substantially identical to the internal diameter  24  of the bore or passage  26  of the sleeve  12 . The larger internal diameters  28   a ,  28   b  of the seal retainer receptacles  30   a ,  30   b  of the sleeve  12  form the annular frustoconical seal seats  20   a  and  20   b  with the smaller internal diameter  24  of the bore  26  of the sleeve  12 , as noted further above. 
     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  30   a  and  30   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 . However, the two seals  16   a ,  16   b  may be provided with other cross-sectional shapes. The larger internal diameter portions  32   a ,  32   b  of the seal retainers  14   a  and  14   b  between their outer ends  50   a  and  50   b  and their tapering frustoconical intermediate portions  42   a ,  42   b  provide clearance for the seals  16   a  and  16   b  to facilitate their insertion into the seal retainers. The seals  16   a  and  16   b  preferably fit closely within the smaller internal diameter seal retainer receptacles  30   a ,  30   b.    
     As the tubular extensions  38   a  and  38   b  of the two seal retainers  14   a  and  14   b  are inserted into their respective retainer receptacles  30   a  and  30   b  of the sleeve  12 , the seals or gaskets  16   a  and  16   b  are compressed between the frustoconical seal seats  22   a  and  22   b  of the sleeve  12  and the seal retaining ends  52   a  and  52   b  of the tubular extensions  38   a  and  38   b  of the seal retainers  14   a  and  14   b , so that the outer diameters  54   a ,  54   b  of the extensions  38   a ,  38   b  are substantially equal to and fitting closely within the internal diameters  28   a ,  28   b  of the respective seal retainer receptacles  30   a  and  30   b  of the sleeve  12 . 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 P1 and P2, thereby forming a leakproof seal against the pipe sections. 
     The leakproof seal is retained by pressing the two seal retainers  14   a ,  14   b  into the respective ends  20   a  and  20   b  of the sleeve  12  until each of the spline retaining grooves  46   a  and  46   b  of the retainers align with the respective spline retaining grooves  36   a  and  36   b  of the sleeve  12  to form or define first and second spline retaining channels. The two flexible splines  18   a ,  18   b  (or keys) are then inserted into their respective spline retaining channels (or annular keyways) through the first and second spline access holes or passages  56   a  and  56   b  formed through the outer surface or wall  58  of the sleeve  12 , each of the spline access passages  56   a ,  56   b  being aligned with the respective grooves  36   a ,  36   b  and thus with the channels formed when those grooves  36   a ,  36   b  are aligned with the seal retainer grooves  46   a  and  46   b . This completes the assembly process, holding the two seals  16   a ,  16   b  firmly in their respective seats  22   a ,  22   b  within the sleeve  12  with the seal retaining ends  52   a ,  52   b  of the two seal retainers  14   a ,  14   b  exerting sufficient pressure on the seals to distend the seals against the sides of the pipe P1, P2 and inner diameters  28   a ,  28   b  of the seal retainer receptacles  30   a ,  30   b  to seal fluids flowing within the pipe P1, P2 and pipe repair coupling  10 . 
     It will be noted that the external diameters  60   a  and  60   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  62  of the sleeve  12 . The sleeve  12  is constructed to have a minimum external diameter  62  based upon the required thickness of the material between the two spline retaining grooves  36   a ,  36   b  and the outer diameter  62 . This sleeve diameter  62  is preferably uniform throughout the entire length of the sleeve  12 . The uniform diameter  62  of the sleeve  12  and the substantially equal diameters  60   a  and  60   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 specialized tools or equipment for installation, as the two seal retainers  14   a  and  14   b  merely slide into place in the respective ends  20   a  and  20   b  of the sleeve  12 . Under some circumstances, a hammer or other suitable impact tool may be required to seat the gaskets or seals in place during assembly of the repair coupling  10  on the pipe. Further, the pipe components or sections P1 and P2 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  16   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 P1 and P2, 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. 
     Moreover, the ability to remove either or both of the two splines  18   a ,  18   b  to remove either or both of the seal retainers  14   a ,  14   b  allows the respective seal(s)  16   a  and/or  16   b  to be accessed for replacement, should such become necessary after the initial installation of the pipe repair coupling  10 . The outer ends of the two splines  18   a ,  18   b  may be left to protrude slightly from their respective spline access passages  56   a ,  56   b  in the sleeve  12 , as shown in  FIG. 5 , to facilitate their future access should disassembly of the pipe repair coupling  10  be desired. In fact, the entire pipe repair coupling  10  may be removed from the damaged section of pipe P1, P2 should that damaged section be replaced with new pipe, and the pipe repair coupling retained for future reuse as needed. 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.