Abstract:
An apparatus and method for removing a fitting from a pipe having a central axis. The apparatus includes a guide member which defines a guide passage and a means for supporting the guide member within at least a portion of the pipe with the longitudinal axis of the guide passage in a coaxial relationship with the central axis of the pipe. The apparatus also includes a rotary hole saw having a cylindrical wall provided with a plurality of cutting teeth on an open end thereof and a central axis of rotation. The cylindrical wall defines a cylindrical chamber. A guide rod is connected to the rotary hole saw such that the guide rod extends through the cylindrical chamber of the hole saw and beyond the open end thereof in coaxial alignment with the central axis of rotation. The guide rod is slidingly receivable in the guide passage of the guide member.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional application No. 61/215,584, filed May 7, 2009, the entire contents of which are herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to a cutting apparatus. More particularly, but not by way of limitation, the present invention relates to a method and apparatus for removing a fitting from a pipe. 
     2. Brief Description of the Related Art 
     A number of prior art devices have been suggested for removing a fitting from a pipe. However, these devices suffer from a number of limitations and deficiencies. One such device is disclosed in U.S. Pat. No. 6,929,430, issued to Dever. Dever discloses a water closet flange removal tool that includes an axial shaft, a cylindrical guide body attached to a lower end of the shaft, and a cylindrical wall cutter mounted above the guide body and on the axial shaft. The Dever tool uses a single component wherein the cylindrical guide body is intended to guide the cylindrical wall cutter along the interior surface of the pipe to thereby position the cylindrical wall cutter along the outside of the pipe to remove the fitting. 
     However, the Dever tool suffers from a number of problems with the design and operation thereof. For example, the diameter of the cylindrical guide body is fixed such that it can only be used with a pipe having a specific diameter. The cylindrical guide body cannot be adjusted to fit properly in a number of different pipes having different diameters. Using the Dever tool to remove a fitting from a pipe having an inside diameter that varies because of, for example, differences in manufacturing tolerances, wear and tear associated with normal use, or the like, would limit the accuracy or reliability of the Dever tool. For example, if the Dever tool were to be used to remove the fitting from a pipe wherein the interior dimension of the pipe had been expanded through normal wear and tear and differing manufacturing tolerances, the cylindrical guide body would not form a secure fit within the interior pipe wall and there may be sufficient room within the pipe for the cylindrical guide body to move laterally with respect to the central axis of the pipe. As would be understood, in this situation, the excess movement of the cylindrical guide body within the interior of the pipe would result in the cylindrical wall cutter being misaligned with the central axis of the pipe. In such a case, the cylindrical wall cutter would likely contact the pipe, thereby destroying or otherwise damaging the pipe. 
     In addition, the Dever tool could not be used with a pipe that has an interior dimension smaller than specified due to, for example, different manufacturing tolerances and/or obstructions within the pipe. In such a situation where the interior dimension of the pipe is less than that of the outer dimension of the cylindrical guide body, Devers cylindrical guide body would be too large to be inserted into the pipe and thereby could not be used at all. 
     Another limitation of the Dever tool is the cylindrical guide body and cylindrical wall cutter being axially attached to a single rod. As would be understood in the art, an individual using the Dever tool with, for example, a drill, wherein the individual did not maintain substantially perfect alignment of the rod axis with the central axis of the pipe could thereby twist and alter the angle where the cylindrical wall cutter contacts the pipe and/or the fitting. In this instance, the cylindrical wall cutter could likely contact the pipe in addition to the fitting, thereby causing damage to the pipe. That is, an individual using the Dever tool would be required to maintain almost perfect alignment throughout the operation of the system to prevent damage to the pipe. In the instant described above wherein the interior dimension of the pipe was enlarged such that the cylindrical guide body did not maintain a consistent fit, the individual using the Dever tool could more likely misalign the single rod with the central axis of the pipe and thereby damage or destroy the pipe. 
     Yet another limitation of the Dever tool is presented wherein the interior of the pipe is blocked or configured such that the cylindrical guide body could not be extended downward therein for the length necessary for the cylindrical wall cutter to remove the exterior fitting. That is, because the Dever tool relies on the cylindrical wall cutter and the cylindrical guide body to be fixed on the axial rod, in an instance where the interior of the pipe is obstructed or is configured, for example, with an elbow positioned near the entrance to the pipe, the user would not be able to extend the cylindrical guide body into the pipe a sufficient length for the cylindrical wall cutter to remove the fitting. 
     Thus, the Dever system suffers from a number of limitations wherein it could not be used for certain configurations of a pipe and/or it could not be used in a situation in which the interior dimension of the pipe was larger than the exterior diameter of the cylindrical guide body. 
     To this end, a need exists for an improved apparatus and method for removing a fitting from a pipe with minimal or no damage to the pipe. It is to such an apparatus and method that the present invention is directed. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a sectional view of a fitting removal apparatus with a guide assembly positioned inside a pipe and a cutter assembly shown in a pre-cutting position. 
         FIG. 2  is an elevational view of the fitting removal apparatus of the present invention. 
         FIG. 3  is a sectional view taken along line  3 - 3  of  FIG. 2 . 
         FIG. 4  is a sectional view taken along line  4 - 4  of  FIG. 2 . 
         FIG. 5  is a sectional view of the fitting removal apparatus illustrating the cutter assembly having cut through a fitting. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Referring now to the drawings, and in particular to  FIGS. 1-2 , shown therein and designated by reference, numeral  10  is a fitting removal apparatus  10  constructed in accordance with the present invention. Broadly, the apparatus  10  includes a cutter assembly  12  and a guide assembly  14 . The guide assembly  14  includes a guide member  16  and a support assembly  18  for supporting the guide member  16 . The cutter assembly  12  includes a rotary hole saw  20 , a mandrel  22 , and a guide rod  24 . 
     In  FIG. 1 , the apparatus  10  is shown with the guide assembly  14  positioned inside a pipe  26  having a fitting  28  attached thereto. The cutter assembly  12  is shown in a pre-cutting position. In general, the guide member  16  is secured inside the pipe  26  via the support assembly  18  such that the guide member  16  is securely positioned in a coaxial relationship with a central axis of the pipe  26 . The guide rod  24  of the cutter assembly  12  is then partially inserted into the guide member  16  wherein a rotational force is then applied to the cutter assembly  12  via, for example, a drill (not shown). The guide rod  24  is then further inserted into the guide member  16  such that the cutter assembly  12  is thereby lowered onto the pipe  26  having the fitting  28  attached thereto. The guide member  16  being securely positioned in coaxial relationship with the pipe  26  maintains substantial alignment of the central axis of the pipe  26  with the central axis of the guide rod  24  of the cutter assembly  12 . Thus, the central axis of cutter assembly  12  is substantially aligned with the central axis of the pipe  26 , via the guide member  16  and the support assembly  18 , permitting the cutter assembly  12  to be lowered about the pipe  26  in an aligned manner. Further, the rotary hole saw  20  is sized to have an interior diameter  30  which substantially corresponds to an outer diameter  31  of the pipe  26 . Therefore, when the cutter assembly  12  is lowered about the pipe  26 , rotary hole saw  20  thereby removes the fitting  28  without contacting or otherwise damaging the pipe  26 . Once the apparatus  10  has been used to remove the fitting  28  from the pipe  26 , the guide assembly  14  can then be removed and the pipe  26  can then be reused, or a new fitting can be attached thereto without requiring replacement or repair of the pipe  26 . 
     Referring now to  FIG. 3 , shown therein in more detail is a sectional view of a preferred embodiment of the guide assembly  14  constructed in accordance with the present invention. The guide assembly  14  includes the guide member  16  and the support assembly  18  discussed above. The guide member  16  is embodied as a circular tube or pipe having an axial opening therein so as to define a guide passage  32  having a central axis. The guide member  16  can be constructed of a rigid material such as, for example, steel, iron, or the like. The guide passage  32  slidingly receives the guide rod  24  of the cutter assembly  12 . Further, as will be described in more detail below, the guide member  16  includes a plurality of threads  34  extending along at least a portion of the exterior surface which permit the guide member  16  to be secured to, and adjusted relative to the support assembly  18 . 
     The support assembly  18  includes a top member  36 , a bottom member  38 , and an expandable gripping member  40 . The support assembly  18  secures the guide member  16  within at least a portion of the pipe  26  such that the central axis of the guide passage  32  is in a coaxial relationship with the central axis of the pipe  26 . The guide member  16  is adjustable by a user of the apparatus  10  to change the outside diameter of the gripping member  40  wherein the guide assembly  14  is thereby securable inside the pipe  26 . In particular, the guide assembly  14  is constructed such that, in a relaxed state, the gripping member  40  has a diameter smaller than the diameter when the member  40  is in a compressed state, or otherwise acted upon by the top member  36  and the bottom member  38 , and caused to expand. 
     One such example of a support assembly can be found in U.S. Pat. No. 4,493,344, issued to Mathison, the entire contents of which are herein incorporated by reference. However, other embodiments of a support assembly would become apparent to one having ordinary skill in the art. 
     The bottom member  38  is affixed to, or otherwise positioned on the guide member  16  such that the bottom member  38  is stationary, i.e., the bottom member  38  is not adjustable or otherwise movable in relation to the guide member  16 . The gripping member  40  is positioned on top of the bottom member  38  and the top member  36  is positioned on top of the gripping member  40 . The guide assembly  14  further includes a top fastener  42  adapted to adjust the pressure on the top member  36 , i.e., apply an axial force to the top member  36  to move the top member  36  towards the bottom member  38 . As should be understood, as the top member  36  is moved towards the bottom member  38 , the gripping member  40  is compressed which causes the member  40  to expand. As the gripping member  40  expands, its outside diameter increases which then causes it to contact the interior surface of the pipe  26 . Increased pressure applied to the gripping member  40  by the top member  36  provides added radial force on the gripping member  40  so as to secure the gripping member  40  against the interior surface of the pipe  26 . Thus, the support assembly  18  securely supports the guide member  16  within at least a portion of the pipe  26  while maintaining axial alignment of the central axis of the guide passage  32  with the central axis of the pipe  26 . 
     The top member  36  includes a top angled face  44  and the bottom member  38  includes a bottom angled face  46 , which cooperate to act on or otherwise apply pressure to the gripping member  40  thereby compressing the gripping member  40 . As the gripping member  40  is compressed, or otherwise acted upon, it is thereby forced outward causing the gripping member  40  to expand in a radial direction. It should be understood that, although shown as angled faces, the top angled face  44  and the bottom angled face  46  can be configured in any number of shapes and/or configurations to thereby perform similar functions without departing from the scope and intent of the present invention. Examples of such alternative configurations include a stepped face, rounded face, and the like. 
     Referring again to  FIG. 3 , the bottom member  38  is fastened to or otherwise affixed to the guide member  16  via a bottom fastener  48  which permits adjustment of the bottom member  38  along the axial direction of the guide member  16 . For example, as discussed above, the guide member  16  includes a plurality of threads  34  along at least a portion of its exterior length. The bottom member  38  is affixed to the guide member  16  using the bottom fastener  48  wherein the bottom fastener  48  includes a plurality of threads adapted to cooperate with the plurality of threads  34  to thereby secure the bottom member  38  to the guide member  16 . As would be understood in the art, when the bottom fastener  48  is affixed to the guide member  16  via the plurality of threads  34 , the bottom member  38  would then be stationarily affixed to the guide member  16  when in use, for example, when the guide assembly  14  is affixed inside the pipe  26 . However, when not in use, the bottom member  38  may be adjustable along the axial direction of the guide member  16 . That is, the bottom member  38  may be rotated around the guide member  16  via the plurality of threads to raise or lower the bottom member  38  along the axial length of the guide member  16 . As would be further appreciated in the art, adjustment of the bottom member  38  would be accomplished prior to operational use of the apparatus  10  (i.e., before the guide assembly  14  is inserted into the pipe  26 ). The bottom member  38  could be adjusted along the axial length of the guide member  16  prior to use wherein the user of the apparatus  10  ensures that the guide assembly  14  is configured to fit within the pipe  26 . 
     The top member  36  is positioned on the guide member  16  to secure the gripping member  40  between the bottom member  38  and the top member  36 . The top member  36  includes a central passage  50  for receiving the guide member  16 . The top member  36  is secured to the guide member  16  using the top fastener  42 . The top fastener  42  can be embodied as a nut or other fastening device known in the art. However, the top fastener  42  can be embodied as other fasteners which achieve similar functionality. For example, the top fastener  42  can be embodied as a wing-nut, a spring loaded tensioning device, a quick release device, and the like. The top fastener  42  can be embodied as a variety of mechanisms which operate on the top member  36  to apply force thereon to move the top member  36  towards bottom member  38  or release force from the top member  36 , thereby releasing pressure on the gripping member  40 . 
     Alternatively, the top member  36  may be affixed to the guide member  16  in a manner similar to which the bottom member  38  is affixed to the guide member  16  (i.e., using a fastener similar to the bottom fastener  48 ). In this embodiment, the top member  36  includes a fastener with a plurality of threads whereby a user can manually rotate the top member  36  along the thread  28  of the guide member  16  to adjust the position of the top member  36  relative to the bottom member  38 . For example, the top member  36  can include holes, wings, or other configurations whereby the user of the apparatus  10  can rotate the top member  36  to move the top member  36  towards or away from bottom member  38 . 
     The gripping member  40  can be constructed using any malleable material capable of expanding in a radial direction when a compressive force is applied thereto, and retracting when the force is released. Examples of such materials include rubber or other polymeric materials which are known in the art. The gripping member  40  permits use of the guide assembly  14  in the pipe  26  when the interior dimension of the pipe  26  varies outside of predefined parameters. That is, the gripping member  40  permits use of the apparatus  10  in the pipe  26  when the interior dimension of the pipe  26  varies because of, for example, differences in manufacturing tolerances, normal wear and tear associated with use, and the like. A user of the apparatus  10  can adjust the top member  36  to apply pressure to the gripping member  40  to cause the member  40  to expand radially and conform to the contour of the interior of the pipe  26 . Similarly, in the case where the interior dimension of the pipe  26  is smaller than anticipated, the user could manually restrict the gripping member  40  to ensure that the guide assembly  14  is positionable within the pipe  26 . 
     In use, the guide assembly  14  is positioned and secured inside the pipe  26 , as shown in  FIGS. 1 and 5 . Initially, the distance between the top member  36  and the bottom member  38  would be such that little or no pressure is applied to the gripping member  40 . That is, the guide assembly  14  is configured such that the outside diameter of the gripping member  40  is at its smallest to allow the guide assembly  14  to be positioned inside the pipe  26 . The user then adjusts the top member  36 , in the manner described above, along the axial length of guide member  16  (e.g., towards the bottom member  38 ). As the top member  36  is adjusted towards the bottom member  38 , the top member  36  and the bottom member  38  apply pressure to the gripping member  40 . As the pressure applied to the gripping member  40  increases, the member  40  expands outwardly (radially) so as to contact the interior walls of the pipe  26  and secure the guide assembly  14  inside the pipe  26 . 
     Referring now to  FIG. 4 , shown therein is a sectional view of the cutter assembly  12  constructed in accordance with the present invention. The cutter assembly  12  includes the rotary hole saw  20  and the guide rod  24 . Guide rod  24  can be embodied as a solid rod constructed using metal, steel, or other rigid material known in the art. The guide rod  24  is sized and shaped to be slidingly and rotatably received in the guide passage  32 . The rotary hole saw  20  has a cylindrical wall  52  defining an open end and having a plurality of cutting teeth  54  on the open end. The cylindrical wall  52  can optionally include one or more relief ports  56  which operate to dissipate heat or otherwise reduce the heat of the cutter assembly  12  when in use. Additionally, the relief port  56  can be used to eject or otherwise remove debris generated when the apparatus  10  is in use. 
     The Cutter assembly  12  further includes the mandrel  22  to which the guide rod  24  is connected. The guide rod  24  can be either permanently affixed to mandrel  22 , or can be detachable. The mandrel  22  has a shank  58  for attachment to a rotary device such as a drill. 
     The rotary hole saw  20  has an interior diameter  30  which substantially corresponds to the outer diameter  31  of the pipe  26  such that the interior diameter  30  is substantially sized so as to remove the fitting  28  without contacting or damaging the outside of the pipe  26 . 
     Referring now to  FIGS. 1 and 5 , shown therein is the apparatus  10  as it would be used in operation. As shown in  FIG. 1 , the guide assembly  14  has been secured inside the pipe  26  such that the guide member  16 , including the guide passage  32 , is securely fixed in a coaxial relationship with the central axis of the pipe  26 , and the guide passage  32  of the guide member  16  is substantially parallel to the central axis of the pipe  26 . As was discussed above, the guide assembly  14  is secured inside the pipe  26  using, for example, the top fastener  42  to apply a force to the top member  36  so as to apply pressure to the gripping member  40 , causing the gripping member  40  to expand and thereby engage the inside wall of the pipe  26 . With the guide assembly  14  secured inside the pipe  26 , the guide rod  24  of the cutter assembly  12  is then inserted at least partially inside the guide passage  32  of the guide assembly  14 . With the guide rod  24  inserted into at least a portion of the guide passage  32 , rotational force can be applied to the cutter assembly  12 , and the guide rod  24  can be further inserted into the guide passage  32  so as to cause the cutting teeth  54  to engage the fitting  28 . The cutter assembly  12  is lowered until the cutting teeth pass through the fitting  28 , as shown in  FIG. 5 . 
     From the above description it is clear that the present invention is well adapted to carry out the disclosed aspects, and to attain the advantages mentioned herein as well as those inherent in the invention. While presently preferred implementations of the invention have been described for purposes of disclosure, it will be understood that numerous changes may be made which readily suggest themselves to those skilled in the art and which are accomplished within the spirit of the invention disclosed.