Abstract:
An extender is used with a hole saw or other cutting or drilling bit to drill/saw a passageway, through thick or distant materials in a residential or commercial building, for installation of a fluid pipe, an electrical conduit, or other conduits or elongated members. The extender and methods of using the extender comprise a hollow pipe with only external threads at each end. After the passageway is created, the externally-threaded pipe may be left in place in the passageway for use in its plumbing capacity. No internal threads are present in the interior surface of the pipe, so that turbulent fluid flow through the pipe is prevented or minimized, and, as a result, pitting, damage, and disintegration of the interior wall of the pipe is prevented or minimized.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to extenders for hole saws or for other cutting tools that are used by plumbers in residential and commercial structures. The extender allows a plumber or other construction worker to provide a passageway through wood or other sawable materials for receiving a pipe. The preferred embodiments comprise an extender that comprises the pipe that the plumber wishes to install in the passageway, and methods that comprise disconnecting the pipe from the saw and power unit and optionally leaving it in place in the passageway for its intended plumbing use. 
         [0003]    2. Related Art 
         [0004]    Extenders for drilling or sawing at a distance from the user, by means of a hand-held drill power unit, have been developed in the past. For example, the following systems appear in the patent literature: Klein, et al. (U.S. Pat. No. 7,127,972, issued Oct. 31, 2006); DeBlasio (U.S. Pat. No. 6,558,089, issued May 6, 2003); Hanson (U.S. Pat. No. 6,601,478, issued Aug. 5, 2003); Carpinetti (U.S. Pat. No. 5,957,634, issued Sep. 28, 1999); and Carrol (U.S. Pat. No. 5,624,214, issued Apr. 29, 1997); Bowling (U.S. Pat. No. 4,906,146, issued Mar. 6, 1990); Salyers (U.S. Pat. No. 4,474,513, issued Oct. 2, 1984); Emmerich (U.S. Pat. No. 4,206,821, issued Jun. 10, 1980); and Siebrecht (U.S. Pat. No. 4,076,444, issued Feb. 28, 1978). 
       SUMMARY OF THE INVENTION 
       [0005]    The invention comprises an extender system for use with a hole saw or other hole-forming tool to allow drilling/sawing of holes to create a passageway through multiple or thick pieces of wood or other materials in a residential or commercial building structure. The passageway receives a fluid flow pipe that connects to fittings for other plumbing in the building structure. The extender system and methods of using the extender system comprise a hollow pipe with only external threads at each end. The preferred methods comprise using the extender system to drill through said multiple or thick wood or other materials, then disengaging the externally-threaded pipe from the any apparatus attached to its ends, and optionally leaving said externally-threaded pipe in place in the passageway that was created with the hole-forming tool, for use in its plumbing capacity. The externally-threaded pipe allows said use of the pipe in its plumbing capacity without the internal threads or other disruptions in the interior surface that typically cause turbulent fluid flow through the pipe and, as a result, the invented system reduces or prevents turbulence-caused pitting, damage, and disintegration of the interior, and, ultimately the entire wall, of the pipe. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0006]      FIG. 1A  portrays one embodiment of the invented extender system in use with a power unit and a hole saw bit, during drilling/sawing through multiple, spaced pieces of wood. 
           [0007]      FIG. 1B  portrays the externally-threaded pipe that is part of the extender system in  FIG. 1A , disconnected from the hole saw, the power unit, and the other portions of the extender system, and left in place in the passageway drilled/sawn through the pieces of wood. 
           [0008]      FIG. 2  is a perspective view of the extender system of  FIG. 1A , with hole saw attached, wherein the externally-threaded pipe is cut in two (and a substantial length of the pipe not shown) for ease of illustration of the opposing ends of the extender system. 
           [0009]      FIG. 3  is a side view of the extender system, attached to a hole saw bit, of  FIGS. 1A and 2 . 
           [0010]      FIG. 4  is a side view of the saw end of the system of  FIGS. 1A ,  2 , and  3 , with the pipe connection region shown in cross-section. 
           [0011]      FIG. 5  is a side view of the power unit end of the system of  FIGS. 1A   2 - 4 , partially shown in cross-section. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0012]    Referring to the Figures, there are shown two, but not the only, embodiments, of the invented extender system for drilling/sawing a passageway for a pipe intended for conducting fluids through a building. There is also shown in the Figures, one embodiment of a method for forming a passageway and installing an externally-threaded pipe in said passageway by using an externally-threaded standard fluid plumbing pipe as a portion of the extender system. The preferred forming and installing methods minimize the number of steps and apparatus that must be used to accomplish the plumbing task. While the preferred embodiment is described and drawn as including a hole saw, other cutting or drilling tools may be connected to the distal end of the extender system, for example, any auger-style or self-feeding bits, and/or a spade bit or other drill bit that makes a large hole. Said cutting or drilling tools preferably are selected from those that are capable of making a hole in the range of 1-6 inches. The term “hole-forming tool,” therefore, may be used to include a hole saw, spade bit, and/or other tools that may be installed at the distal end of the extender system for the methods described herein. 
         [0013]      FIG. 1A  portrays the preferred embodiment in use sawing through multiple, spaced-apart pieces of wood. In this portrayal, the wood pieces are studs S of a wood frame wall W, and the sawing is done in a horizontal direction to create a passageway comprising holes H in the studs and the spaces SP between the studs. A power unit  5  is connected to a proximal end of the preferred extender system  10 , and a hole saw  15  is connected to a distal end of the preferred extender system  10 . 
         [0014]    The extender system  10  is portrayed in  FIG. 1A  to be several feet long, so that it extends through and between several studs S. The extender system  10  may be of various lengths, but is typically in the range of 6 inches-21 feet long, as it is preferably used to reach 3-10 feet from the user, for example, through walls, from basements up through a floor and into the interior of a wall, and/or through a ceiling/floor- between floors of a multiple-story building. Longer extender systems may be possible, but may require more than a conventional hand-held power unit. The preferred embodiment is especially useful for drilling/sawing through structure into which the user cannot reach and/or see easily and through which a long, straight hole/passage must be formed. For example, such long, straight holes/passages may be required for plumbing, for electrical conduit, for various flexible electrical cables, or other elongated elements. The rigid, elongated extender system allows the user to begin the drilling/sawing in an area of relative comfort and room and to continue drilling/sawing “blind” through distant areas. 
         [0015]    The preferred embodiments allow the drilling/sawing of the passageway to be done straight and accurately, and the pipe, which is coaxial with the passageway as it is created, remains coaxial with the passageway during use. The pipe  20  is symmetric about its axis, as are, preferably, the bit connector  22  and the saw connector  24 , in order to prevent wobbling and/or inaccurate cutting/sawing. 
         [0016]    Upon completion of the passageway for plumbing applications, the user and/or assistant(s) may optionally disconnect the pipe  20  of the extender system  10  from the bit connection unit  22  (or “bit connector”), and from the saw connection unit  24  (or “saw connector”), to leave only the pipe  20  remaining in the passageway. The bit connector  22  and the saw connector  24  are removed by unscrewing them from the pipe  20 , and no fasteners, screws, set screws, or other fasteners (other than the threads) need be disconnected in order to disconnect the pipe  20  from this adjacent apparatus. No tools are needed to accomplish the disconnection except perhaps for a pipe wrench or other wrench/pliers to grip and turn the bit connector  22 /pipe  20  relative to each other, and to grip and turn the saw connector  24 /pipe  20  relative to each other. Thus, as best shown in  FIG. 1B , the pipe may be left in the intended position, installed properly for connection to other plumbing O for subsequent use. Note that, the pipe  20  is left in place, undamaged and unmarred, as no fasteners or connection means were used (other than the pipe threads) during its being connected and used as a drill/saw extender. 
         [0017]    Details of the preferred embodiment are shown to best advantage in  FIGS. 2-5 . Extender system  10  comprises externally-threaded pipe  20 , bit unit  22 , and saw connection unit  24 . 
         [0018]    The bit connector  22  has a bit end  26 , with a hexagonal exterior surface, for being received and locked into the power unit  5 , and an opposing female end  28  for threadably connecting to the proximal end  21  of the pipe  20 . Preferably, no screws, set screws, or other fasteners are used to connect the pipe  20  to the bit connector  22 . The female end  28  has internal threads  30  for connecting to the external threads  32  of the proximal end  21  of pipe  20  (see  FIG. 5 ). Pipe  20 , as discussed above, preferably extends for several feet to reach, and to allow cutting (drilling/sawing), entirely through the passageway with one length of pipe, that is, preferably only a single pipe is needed rather than multiple pipes connected together. Therefore, there are preferably no significant discontinuities in the internal surface of the pipe portion of the extender system  10  because the pipe portion is a single, continuous pipe length. 
         [0019]    The saw connector  24  has a proximal female end  38  with internal threads  40  that connect to the external threads  42  of the distal end  23  of the pipe  20  (see  FIG. 4 ). Preferably, no screws, set screws, or other fasteners are used to connect the pipe  20  to the saw connector  24 . The distal end  44  of the saw connector  24  preferably has a female hexagonal interior surface  46  for mating with the hexagonal exterior surface of bit end  48  of the hole saw  15 . One or more set screws  50  extend from the outside of distal end  44  through holes in the wall of the distal end  44 , for being screwed inward to abut against, and lock, the bit end  48  of the hole saw that is received inside the distal end  44 . Preferably, two of said screws  50  are spaced from each other and lie in an axial line on an axial surface of distal end  44 . Alternatively, other mechanical fasteners may be used to secure the bit end  48  of the hole saw  15  into the saw connector  24 , however, compact and light-weight fasteners are preferred so that the weight of the extender system  10  remains generally symmetric around the central axis of the extender system  10 . 
         [0020]    Alternatively, the extender system may have different bit styles, including different bit exterior surface shapes. For example, the bit end  26  of the bit connector  22  may be other polygonal shapes besides hexagonal, may be cylindrical, or may be any shape or style required for adaptation to alternative power units. The bit end  48  of the saw connector  24  also may be other polygonal shapes besides hexagonal, may be cylindrical, or may be any shape or style required for adaptation to alternative power units, and/or any shape or style for adaptation to the female, distal end  44  of the saw connector. For example, bit end  26  may be one shape/style to cooperate with a particular power unit, while the bit end  48  of the hole saw may be another shape/style to cooperate with a particular saw connector  24 , and the bit ends  26 ,  48 , therefore, do not necessarily need to be the same shape/style. Good gripping features, such as a polygonal shape are preferred, however, to provide secure and reliable connections during sawing. Note also, that keyed, keyless, or other types of chucks and/or power units may be used. 
         [0021]    It may be noted that the simple and durable construction of the preferred extender system  10 , and particularly the externally-threaded pipe  20  therein, provides for efficient creation of a passageway for a fluid pipe or for other elements of a building, particularly where at least a portion of the passageway is at a hard-to-reach distance or position relative to the person creating the passageway. In plumbing applications, the preferred extender system  10  allows efficient installation of said pipe in a minimum number of steps, because the pipe element of the extender may be left in place as the pipe for that section of plumbing. In such plumbing applications, a substantial portion of the extender system need not be removed from the holes and spaces through which the drilling/sawing has been done, but instead left there for the ultimate purpose of the project, that is, to have a fluid pipe extend through those holes/spaces for subsequent use when the building is completed/occupied. 
         [0022]    The above methods may all be accomplished with a pipe that is optimum for said subsequent use, by virtue of having only external threads (no internal threads), preferably external National Pipe Threads (according to U.S. NPT threaded pipe standards). The external threading provides superior surfaces for fluid flow, by maintaining a non-threaded internal surface inside the pipe that is smooth except for any natural texture or irregularities of the pipe metal, which natural texture or irregularities would be insignificant compared to the roughness created by threads. The externally-threaded pipe interior surface does not cause, or at least does not increase, turbulence in the fluid flow and consequent pitting and damage of the pipe wall, and, hence significantly extends the life of the pipe in its use as a fluid conduit. 
         [0023]    The preferred pipe  20  may be any type of metal pipe, typically ½ inch or ¾ inch diameter, with normal iron pipe size (IPS) thread. A ½ inch pipe is expected to be usable with any size drill bit without bending or striping the threads. Most preferably, black iron or galvanized schedule  40  or  80  pipe is used as pipe  20 . 
         [0024]    In preferred embodiments, therefore, the extender system comprises a bit connector  22  with both a male bit and a female threaded receptacle, and a saw connector  24  with two female ends, one with threads and one with a polygonal or other surface that mates with the hole-forming tool to discourage relative rotation. The saw connector  24  may include set screws to discourage axial movement of the hole-forming tool relative to the saw connector  24 . Each of the bit connector  22  and the saw connector  24  will typically be about 3-8 inches long (and more preferably 4-6 inches long). The bit connector  22  and the saw connector  24  may be adapted for use with a keyed chuck on a conventional power unit  5  such as a Jacobs™ power unit that has, for example, a ⅜ or ½ inch chuck. Alternatively, may be adapted for use with a keyless chuck on a conventional power unit such as a Dewalt™ power unit, for example. 
         [0025]    The pipe  20  is preferably is a single, continuous piece of pipe having a length in the range of 0.5-21 feet long, depending upon the application and user preference, wherein the bit connector  22  is preferably a single unitary piece with no disconnectable parts, and the saw connector is preferably a single unitary piece with two set screws as its only disconnectable parts. For many applications, a continuous piece of pipe in the range of 3-10 feet long will be effective, but special applications may find a shorter or longer pipe beneficial. All of said pipe, bit connector, and saw connector are preferably all metal. 
         [0026]    Although this invention has been described above with reference to particular means, materials and embodiments, it is to be understood that the invention is not limited to these disclosed particulars, but extends instead to all equivalents within the scope of the following claims.