Abstract:
A device for removing an outer pipe member of a plastic pipe joint. The device may include a mechanism that releaseably attaches to the outside of a pipe joint and a blade structure provided about the releaseable attachment mechanism that is configured to remove the outer member of a pipe joint. The device is configured to securely and releasably attachment, to remove the desired pipe section without damaging other components, and to leave a finished structure that resembles the original, among other disclosed features.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/814,503, filed Jun. 16, 2006, and having the same title and inventor as above. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to a cutting device for removing the outer member of a plastic pipe joint.  
       BACKGROUND OF THE INVENTION  
       [0003]     Various types of plastic piping are known in the art and these include but are not limited polyvinyl chloride (PVC) and Acrylonitrile-Butadiene-Styrene (ABS). During coupling, one pipe is typically mounted inside another with the respective diameters configured to achieve a snug fit that is secured with adhesive. A piece of pipe may be configured to have an end that directly fits into the end of another piece of pipe or a coupler may be used to join pipe sections. The coupler or mating pipe section may be straight, angled, provide a Y or a T intersection, or be otherwise configured.  
         [0004]     There are times when it is necessary or desirable to cut a coupled pipe section and remount a pipe piece, for example, when a pipe is installed wrong or breaks or a redesign is implemented, etc. In certain situations, it is desirable to retain the smaller diameter inner pipe member and remove the outer pipe or coupler.  
         [0005]     One example is when a pipe member is stubbed out of a wall and only a limited amount of pipe is present. In this instance, the length of pipe extending from the wall may be so small that it is undesirable to cut it, or cutting it will leave an insufficient length of pipe for adequate mounting. If the inner pipe stubbed out from the wall is cut too short, the wall must be opened to stub out a larger piece at significant expense and inconvenience. In these, like and other situations, it may be desirable to remove the outer pipe member of a pipe joint.  
       SUMMARY OF THE INVENTION  
       [0006]     Accordingly, a need exists for an apparatus and method that readily removes the outer pipe member from a plastic pipe joint in a manner that does not significantly impact the shape or size of the remaining inner pipe member and leaves the inner pipe member ready for the remounting of another outer pipe member.  
         [0007]     These and related objects of the present invention are achieved by use of a apparatus and method for removing the outer member of a plastic pipe joint as described herein.  
         [0008]     The attainment of the foregoing and related advantages and features of the invention should be more readily apparent to those skilled in the art, after review of the following more detailed description of the invention taken together with the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is an exploded perspective view of a device for removing the outer member of a plastic pipe joint.  
         [0010]      FIG. 2  is a perspective view of the components of  FIG. 1  assembled into their respective collet and cutter sections and mounted to a pipe (shown in phantom lines).  
         [0011]      FIGS. 3A-3B  are a cross-sectional and a top plan view of a wedge in accordance with the present invention.  
         [0012]      FIGS. 4A-4B  are a side view and a top plan view of a bushing in accordance with the present invention.  
         [0013]      FIGS. 5A-5B  are a cross-sectional side view and a top plan view of a bushing nut in accordance with the present invention.  
         [0014]      FIGS. 6A-6C  are a cross-sectional, side elevation and a plan view, respectively, of one embodiment of the cutter head.  
         [0015]      FIG. 7  is a perspective view of an alternative cutter head and blade section arrangement in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0016]     Referring to  FIG. 1 , an exploded perspective view of a device  20  for removing the outer member of a plastic pipe joint in accordance with the present invention is shown.  
         [0017]     Device  20  includes an expansion collet (“collet”)  30  and a cutting tool (“cutter”)  40 . The collet may include a bushing  1 , a wedge  2 , a washer  4 , a snaplock ring  5  and a bushing nut  6 . Bushing  1  is preferably positioned over wedge  2  with washer  4  and bushing nut  6  adjacent and held in place by snap ring  5  positioned in circumferential recess  11 . Wedge  2  includes a substantially conical section  32  and a substantially cylindrical section  33 . The base  35  of bushing  1  and collet nut  6  are provided about the cylindrical section  33 , with threads  37  ( FIG. 5 ) mounted on to threads  38  ( FIG. 3 ) in the cylindrical section  33 . Turning bushing nut  6  expands or contracts the individual collet fingers  12  by forcing them onto or off conical section  32 .  
         [0018]     Cutter  40  may include a pilot shaft  7 , cutter head  8 , insert blades  3 , fasteners  9  and set screw  10 . Pilot shaft may be inserted into a drill or other rotary device on one end and inserted into the central hole  21  in wedge  2  on the other end.  
         [0019]     In use, collet  30  is inserted into inner pipe member  51  and nut  6  is turned until the collet is securely mounted in the inner pipe member. Shaft  7  is then inserted through nut  6  into cylindrical opening  21 . The shaft is rotated which in turn rotates head  8  and blades  3 . Blades  3  are positioned to cut away at the plastic outer pipe member  52 . An operator can visually inspect progress and continue cutting until the outer pipe member is removed entirely or to a desired depth. The inner pipe member is then available for the secure mounting of another outer pipe member.  
         [0020]     Referring to  FIG. 2 , a perspective view of the components of  FIG. 1  assembled into their respective collet  30  and cutter  40  sections and mounted to a pipe  50  (shown in phantom lines) is shown in accordance with the present invention.  
         [0021]     Pipe section  50  includes inner pipe member  51 , of the type that might extend from the wall or be elsewhere located, and outer pipe member  52  that may be part of a coupler or a piece of pipe or otherwise configured.  FIG. 2  illustrates collet  30  inserted into inner pipe member  51  and screwed in with collet fingers  12  contacting the interior or inner pipe member  51 . Cutter  40  is mounted onto the collet with shaft  7  transversing opening  21 . Head  8  is configured to industry standardized dimensions to approximate the diameter of the outer pipe member  52 . Blades  3  can be adjusted inward or outward to accommodate for minor variations in size. For larger size variations different sized cutter heads can be provided. The drill device by which shaft  7  is operated is engaged to turn head  8  and blades  3  such that the blades cut away the plastic material of outer member  52 .  
         [0022]     Referring to  FIGS. 3A-3B , a cross-sectional and a top plan view of wedge  2  in accordance with the present invention are respectively shown.  FIG. 3A  illustrates conical section  32 , cylindrical section  33  with threads  38 , recess  11 , central opening  21  and pin opening  34 .  FIG. 3B  illustrates these features from above. Pin opening  34  may be used to receive a locking pin or the like that fits through the opening into a groove between collet fingers  12 , preventing the bushing from rotating when the bushing nut is turned.  
         [0023]      FIGS. 4A-4B  illustrate a side view and a top plan view of bushing  1  in accordance with the present invention, while  5 A- 5 B illustrate a cross-sectional side view and a top plan view of bushing nut  6  in accordance with the present invention.  FIG. 4A  illustrates that fingers  12  are conically shaped on the inside, approximating the conical shape of wedge  2 . The relative size and arrangement of fingers  12  and base  32  are shown in both figures.  
         [0024]      FIGS. 5A-5B  illustrates threaded section  37  and the central opening  36  of bushing nut  6 . Washer and a bushing contact surface  39  is also shown. The surface is smooth and flat to evenly distribute collet expanding force to bushing  1 .  
         [0025]      FIGS. 6A-6C  illustrates a cross-sectional, side elevation and a plan view of cutter head  8 . Head  8  may include a housing  42  having a plurality of recesses  43  and blade mounting areas  44 . A recess  45  for receiving a mounting screw or the like may be provided at each mounting area  44 . A recess  47  for shaft securing screw  10  is preferably provided.  
         [0026]      FIG. 7  is a perspective view of an alternative cutter head  108  and blade section  103  arrangement in accordance with the present invention. In the embodiment of  FIG. 7 , cutter head  108  is configured to receive an annularly configured blade section  103  that has a plurality of individual cutting blades  103 A configured in it and arranged to cut an outer pipe member in substantially the same manner as blades  3 . Cutter head  108  mounts to shaft  107 .  
         [0027]     Blades  3 , 103 A may have a concave face. Blade materials for cutting plastic are known in the art. Various other blade arrangements may be utilized without departing from the present invention.  
         [0028]     While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention and the limits of the appended claims.