Abstract:
An apparatus for mounting a cutting tool or grinding tool in substantially perpendicular orientation with a pipe is provided. The apparatus comprises a support arm with a clamp for engaging the pipe; a pivot means on the support arm; and a tool mounting arm with a tool mount means for engaging the pivot. The clamp is positioned to grip the pipe, with the pivot means extending generally parallel to the pipe; the tool mounting arm is engaged with the support arm; then the cutting or grinding tool is mounted on the tool arm. A tool so mounted may then be swivelled in a generally arcuate path towards and away from the pipe to be cut in a plane generally perpendicular to the orientation of the pipe. A method for severing a service tee with the mounting apparatus is also provided.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention generally relates to pipe tools and maintenance, and in particular to a method and apparatus for service tee abandonment. 
       BACKGROUND OF THE INVENTION 
       [0002]    Natural gas is distributed to commercial and residential buildings using underground gas mains which are connected and tapped to smaller service lines. 
         [0003]    Typically, the service lines that provide gas to individual industrial and residential customers are connected to the gas main by service tees. A service tee comprises a generally cylindrical body with a threaded exterior surface, two open ends, and a service outlet provided in the body between the two ends. One end of the service tee is welded to the gas service main in more or less perpendicular orientation to the main; the service line, which may be formed of metal or plastic piping, is joined at the service outlet; the remaining end is used to enable access to the service main. 
         [0004]    For example, when a half-inch service tee is connected to a steel main, the main body is welded to the main, and a cutter is turned down through the main body of the tee until it impinges the service main. The cutter is turned until it cuts a coupon out of the service main wall, then is retracted through the main body to allow gas to flow into the tee and out through the tee service outlet. The cutter remains in the tee body and access to it is capped. When the tee is to be abandoned, the gas technician blocks the opening in the main wall using the internal cutter, and purges and removes the service connection leading from the service tee to the service site. The tee may then be severed below the service outlet, and a cap welded over the tee opening to permanently seal the tee. The steps of severing the tee and welding the cap require a welder. 
         [0005]    This process, because it requires welding, is inefficient. Typically the gas technician qualified to disconnect the gas service is not qualified as a welder; if a welder is not immediately available, then the crew carrying out the service abandonment must wait until a welder is available to cut and weld the service tee so that the technician may complete the abandonment process. It is therefore desirable to provide an apparatus and method for overcoming the foregoing disadvantages. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    In drawings which illustrate by way of example only a preferred embodiment of the invention, 
           [0007]      FIG. 1  is an exploded perspective view of the mounting apparatus. 
           [0008]      FIG. 2  is a cross-sectional view of a support plate in position at a service tee. 
           [0009]      FIG. 3  is a perspective view of a mounting plate, bearing, and shield of the mounting apparatus of  FIG. 1  with a grinder mounted thereon. 
           [0010]      FIG. 4   a  is a front elevation of a pilot die. 
           [0011]      FIG. 4   b  is a front elevation of a cap. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    In accordance with a preferred embodiment, a mounting apparatus is provided for mounting a grinder or cutter in relation to a pipe to be ground or cut. 
         [0013]    The mounting apparatus  10  is shown generally in exploded view in  FIG. 1 . Preferably, the components of the mounting apparatus  10  described herein are manufactured from suitable metals and finished in any appropriate method; for example, some components such as the support plate  20 , described below, may be machined from aluminum and anodized; other components may be formed from bronze or steel. The following description describes suitable materials for manufacturing the components of the assembly, but those skilled in the art will appreciate that substitute materials of suitable hardness, finish, and density may be selected according to the component&#39;s function. 
         [0014]    Referring to  FIG. 1 , a support  20  is provided. The support  20  is generally elongated, preferably a generally rectangular plate of anodized aluminum. A cutout  22  may be provided in the support  20  to reduce the weight of the component, provided that the support  20  remains sufficiently rigid to withstand the forces applied to the support  20  in use. At a first end of the support  20 , a first clamp member  50  is provided. While the first clamp member  50  may be machined from aluminum, preferably the first clamp member  50  is manufactured from a suitable tool steel. If the first clamp member  50  is manufactured as a separate component, means are provided on the support  20  and the first clamp member  50  for fixing the first clamp member  50  to the support  20 ; as shown in  FIG. 1 , preferably a plurality of screw bores  54 ,  54 ′ are provided for attaching the two components by means of screws (not shown). The first clamp member  50  may be welded to the support  20 . Alternatively, the first clamp member  50  may be formed integrally with the support  20 . 
         [0015]    The first clamp member  50  comprises a first clamp face  52 , which cooperates with a second clamp face  62  provided on a second clamp member  60  to accommodate a pipe. Preferably, each of the first clamp face  52  and the second clamp face  62  is shaped to fit a variety of pipe diameters; as shown in  FIG. 1 , the first and second clamp members  50 ,  60  may fit a range of diameters by adjusting the distance between the first and second clamp faces  52 ,  62 . 
         [0016]    The second clamp member  60  is preferably manufactured of the same material as the first clamp member  50 . In the embodiment shown in  FIG. 1 , the second clamp member  60  is provided with bores  64  extending from an outer face  66  through the inner face  67 , and the first clamp member  50  is provided with corresponding bores  64 ′ at its outer face  57 . Bolts may be provided (not shown) to removably and adjustably fasten the second clamp member  60  to the first clamp member  50 . The embodiment depicted in the figures is a two-part clamp that is fixed around a service tee by means of bolts inserted on either side of the first and second clamp faces  52 ,  62 ; in a further embodiment, other clamp means fixed to the support  20  may be provided, for example a C-clamp type clamp. 
         [0017]    At the distal end of the support  20 , a shaft  40  is provided extending substantially perpendicularly from a surface  21  of the support  20 . In the preferred embodiment, the shaft is formed of steel and is fixed to the support  20  by means of bolts (not shown) through corresponding bores  42 . These bores  42  are preferably provided in a flange  44  around the base of the shaft  40 . Again, in an alternate embodiment, the shaft  40  may be formed integrally with the support  20 , or the shaft  40  may be welded to the support  20 . 
         [0018]    There is also provided a cap  75 . The cap  75  is preferably formed from steel, and is removable from the shaft  40 ; as can be seen from  FIG. 1 , the shaft  40  is provided with a threaded bore  46 , and the cap  75  is provided with a screw member  77 . 
         [0019]    A mounting plate  30  is further provided. The mounting plate  30 , like the support  20 , is preferably formed of anodized aluminum; although persons skilled in the art will appreciate that alternative materials may be used. The mounting plate  30 , like the support  20 , is an elongated member and is preferably substantially rectangular. A first end comprises a tool mount  38 . The tool mount  38 , in the embodiment shown in  FIG. 1 , is a slightly enlarged portion comprising screw bores  37  and an aperture  35  for removably mounting a grinding or cutting tool  100 , shown in  FIG. 2 . The aperture  35  is preferably circular, although it may be another shape. With reference to  FIG. 4 , a preferred cutter or grinder  100 , such as the Heavy Duty Vertical Grinder Model No. 1410006 sold by Superior Pneumatic &amp; Manufacturing, Inc. of Cleveland, Ohio, is provided with a cutting or grinding disc  104  that is removably mounted on a drive shaft connected to the body  110 , and with a handle  112  extending from the body  110 , preferably generally perpendicularly to the axis of the drive shaft. The cutter or grinder  100  may be placed on the tool mount  38  such that the drive shaft is generally coaxial or otherwise aligned with the aperture  35 . The slight enlargement at the first end of the mounting plate  30 , if provided, adds additional support for the grinding or cutting tool  100 . The tool mount  38  may be adapted as necessary to accommodate the grinding or cutting tool  100 , preferably so that the angle of the grinder or cutter with respect to the mounting plate  30  may be adjusted. The tool mount  38  may even be provided as a separate component from the mounting plate  30 , and attached to the mounting plate  30  by suitable means, including screws or welding. The mounting plate  30  further comprises an optional cutout  31  for reducing the weight of the component. 
         [0020]    At the distal end, the mounting plate  30  is provided with a bushing  34  that extends generally perpendicularly from the mounting plate  30 . Preferably, the bushing  34  is machined separately and then welded to the mounting plate  30 , being inserted in an aperture  36  provided in the mounting plate  30 . As shown in  FIG. 3 , the bushing  34  may also be provided with a flange. This flange and the mounting plate  30  may be provided with corresponding threaded bores, such that the bushing  34  may be bolted to the mounting plate  30  in a manner similar to that described for the shaft  40  and the support  20 , above. In an alternative, the bushing  34  may be formed integrally with the mounting plate  30 , although it is generally easier to machine the bushing  34  and the mounting plate  30  separately and then fix them together. The bushing  34  is provided with bores  32 ,  33 ; bore  32  is sized to accommodate a pin, preferably a metal pin (not shown) and is disposed longitudinally in the bushing  34 , while the other bore  33  is disposed radially through the bushing  34 . In a preferred embodiment, the mounting plate  30  is further provided with a further threaded bore  80  near the bushing  34 , for receiving a height adjustment screw  81  (shown in  FIG. 3 ). 
         [0021]    A bearing  70  is further provided. The bearing  70  is preferably manufactured of bronze, and is sized with an outer diameter D 1  to cooperate with the diameter D 2  of the bushing  34 , such that the bearing  70  may be inserted through the bushing  34  and allow the bushing  34  to be supported and rotate on the bearing  70 . The inner diameter D 3  of the bearing  70  is sized to cooperate with the outer diameter D 4  of the shaft  40 , such that the shaft  40  may be supported and rotate inside the bearing  70 . The bearing  70  is preferably provided with a flange  72  at one end of the bearing  70 , the flange  72  generally extended perpendicularly from the surface of the bearing  70 . A pin bore  74  is provided in the flange  72 , aligned generally longitudinally along the bearing  70 . 
         [0022]    A guard  90  is preferably provided. The guard  90  is preferably a generally truncated circular shield  96 , formed of aluminum, with an aperture  92  and screw bores  94  generally corresponding to the aperture  35  and the screw bores  37  provided in the tool mount  38 . A skirt  95  depends from the shield  96 . The shield  90  may therefore be fixed to the tool mount  38  by means of screws through the screw bores  94 ,  37 . 
         [0023]    To assemble and mount to a service tee, reference is also made to  FIG. 2  and to  FIG. 3 . The guard  90  is affixed to the tool mount  38 . The shaft  40  is fixed to the support  20 , if it is not already affixed. 
         [0024]    The support  20  is preferably placed on a surface, such as a service main  200  adjacent a service tee  300 . The first clamp face  52  is placed in contact with the service tee  300 , as shown. The alignment of the service outlet  330  and the support  20  is preferably as shown, although the support  20  may be aligned in a different orientation with respect to the service outlet  330  as necessary such that the apparatus  10  and grinder will function as described below. The second clamp face  62  is placed on the other side of the service tee  300 , and fastened to the first clamp member  50  using bolts screwed into the bores  64 ,  64 ′. Tightening the bolts in this embodiment reduces the area defined by the first and second clamp faces  52 ,  62 , thus gripping the service tee  300 . It will be appreciated by those skilled in the art that alternate clamp means may be provided, such as a C-clamp style clamp, provided the clamp secures the support  20  in place on the service tee  300  to generally hold the support  20  in fixed relation to the service tee  300 . 
         [0025]    The bearing  70  is placed on the shaft  40 . The bushing  34  is then placed on the bearing  70 . The mounting plate  30  may thus pivot around the shaft  40 ; suitable metal lubricants may be applied as necessary to reduce friction between the shaft  40 , bearing  70 , and bushing  34 . Preferably, the cap  75  is mounted on the shaft  40  after assembly to prevent the shaft  40 , bearing  70 , and bushing  34  from vertically separating when in use. The bushing  34  and the bearing  70  may be oriented such that the pin bores  32 ,  74  are aligned, and a pin (not shown) may be inserted into the pin bores  32 ,  74  to temporarily secure the bushing  34  and the bearing  70  in fixed relation with each other. The bushing  34 , provided on the mounting plate  30 , and the bearing  70  may therefore pivot as a unit on the shaft  40 . The grinder or cutter  100  is then mounted on the tool mount  38  on the face opposite the guard  90  such that the drive shaft (not shown) is aligned with the aperture  35 . The cutting or grinding disc  104  is mounted on the drive shaft and secured as necessary; the shield  96  generally corresponds in shape with the disc  104 , and the shield  96  and skirt  95  protect the operator from the rotating disc  104  while exposing a portion of the disc edge for use when cutting or grinding. 
         [0026]    Preferably, the grinder or cutter is of sufficient weight that simply setting the grinder or cutter  100  in the aperture  35  will provide sufficient support. It can be seen that once assembled in this manner, the grinder or cutter  100  may be swiveled away and towards the service tee  300 , and preferably the grinder or cutter  100  may be rotated in the tool mount  38 . Those skilled in the art will appreciate that the lengths of the support  20  and the mounting plate  30  will be selected to enable the grinder or cutter disc  104  to contact and sever the service tee. The truncated portion of the shield  96  is preferably oriented opposite any power or pneumatic connection provided on the cutter or grinder  100 . 
         [0027]    It will be appreciated that the mounting assembly  10  thus effectively provides a jointed arm, secured at one end to the service tee and provided at the other end with a cutting or grinding means for severing the service tee. It will also be appreciated that the mounting assembly  10  maintains the cutting or grinding disc  104  in substantially perpendicular relation to the service tee. The jointed arm of the mounting assembly  10  may thus be used to guide the disc  104  to the service tee; when the disc  104  severs the tee  300 , the tee will be cut off at a substantially right angle to its axis. While the service tee  300  is preferably mounted vertically on the service main  200 , even if the service tee  300  is connected to the service main  200  at an angle the mounting assembly  10  will enable the grinder or cutter  100  to sever the service tee  300  at a substantially right angle to the axis of the tee. 
         [0028]    The support  20 , which preferably rests on the service main  200 , may be oriented at an angle from the service main  200 , provided the clamping means is sufficiently secure to hold the disc  104  in substantially perpendicular relation to the tee  300 . 
         [0029]    In a preferred embodiment, the height of the disc  104  may be adjusted so that the service tee  300  is severed by the grinder or cutter  100  at a desirable height. A preferred height, for example, is immediately below the service outlet  330 , as shown in  FIG. 2 . The height adjustment may be effected by providing a support  20  or a mounting plate  30  of a different thickness, or by providing a spacer (not shown) between the shaft  40  and the bearing  70 . In the most preferred embodiment, a height adjustment may be effected by placing a height adjustment screw  81  in the bore  80 , as shown in  FIG. 3 . The end of the screw  81  bears on the bearing flange  72 . By tightening the screw  81  (usually by turning it counter-clockwise), the distance between the mounting arm  30  and the bearing flange  72  is increased, thereby raising the mounting plate  30  in relation to the support  20 . By turning the screw  81  clockwise, the mounting plate  30  may be lowered. 
         [0030]    Once the service tee  300  is severed, the portion of the tee comprising the service outlet  330  may be discarded. At this point, the top of the tee is preferably cleaned to remove rough edges, and with reference to  FIG. 4   a , a pilot die  370  is placed on the severed tee and turned down to tap the outer surface of the tee  300 . Once the severed tee  300  is tapped, the threads may be cleaned with a wire brush or the like for removing metal shavings, and a cap  380  threaded to fit the threads cut by the pilot die is installed, as shown in  FIG. 4   b . Preferably a suitable thread sealing compound (pipe dope) is applied to the threads on the tapped tee  300  and the threads in the cap  380  prior to installing the cap. 
         [0031]    Thus, if a service tee  300  previously in use is to be abandoned and removed, it may be disconnected from a service main  200  and severed in accordance with the following procedure: 
         [0032]    First, the gas supply from the main  200  to the service outlet  330  is cut off in a manner known in the prior art. In the case of a self-tapping service tee, likely the service cap  320  would be removed, the cutter  325  would be screwed down into the main body of the tee  330  until it came in contact with the main  200 , thereby substantially arresting gas flow through the service outlet  330 . The service connection  340  would then preferably be purged to remove any residual gas. 
         [0033]    Next, the mounting apparatus  10  would be assembled and installed on the main  200 , as generally described above, and the grinder or cutter  100  would be moved into position on the mounting apparatus  10  for severing the service tee  300 . The grinder or cutter  100  can then be activated to sever the service tee  300 ; the operator may swivel the grinder or cutter  100  on the shaft  40  to enable the disc  104  to progressively cut through the pipe. 
         [0034]    Preferably, the severed tee  300  is then filed down as necessary using hand tools to provide a relatively smooth surface. To seal the severed tee  300 , as described above a pilot die  370  may be used to cut a thread into the outer surface of the tee  300 , the newly cut threads may be cleaned as necessary with a wire brush, and a cap  380  may then be installed with a sufficient amount of torque and preferably with pipe dope applied to the mating threads to reliably seal the service tee  300  against gas leaks. 
         [0035]    Thus, the mounting apparatus  10  provides a means for reliably severing the service tee, or any similar generally vertically oriented pipe, at a right angle. In particular, by clamping a support  20  to the service tee  300 , and by providing a pivot means on the support  20  for supporting a mounting plate  30  for supporting the grinder or cutter  100 , the operator will be able to accurately and stably position the grinder or cutter  100  to make a perpendicular cut through the pipe. By enabling personnel to sever the service tee  300  in this manner, abandonment of a gas service tee  300  may be effected more efficiently; if the service tee  300  in question is a self-tapping tee with a suitable cutter  325 , there is no longer a need for a seal to be welded onto the severed tee  300  because it may be threaded and capped without requiring the services of a welder. This mounting apparatus  10  therefore presents a savings in time and personnel. 
         [0036]    If the service tee  300  to be abandoned does not comprise a cutter that may be used as a plug means for blocking gas flow from the service main  200 , then other means may be required to cut off the gas supply to the service outlet  330 . 
         [0037]    It will be understood by those skilled in the art that this procedure may be adapted as necessary to conform to safety requirements; for example, after the cap  380  is installed, a leak test is preferably conducted to determine if there is a gas leak. It is also preferable to eliminate any static charge buildup during the abandonment process to reduce the risk of ignition. Such steps may be conducted using practices known in the art. 
         [0038]    Typically, the service tee  300  is buried, and may be located underneath a paved surface. In those situations, excavation is necessary to expose the service tee  300  in order to proceed with cutting, maintenance, or abandonment. In an alternative embodiment, the mounting apparatus  10  may be adapted for use in a keyhole excavation environment by providing a clamping means  50 ,  60  that can be operated from a distance. For example, a pneumatically-driven jaw or clamp may be provided on the support  20 , and a pneumatically-driven rotating brush may be provided for cleaning the severed tee  300  during the abandonment process. 
         [0039]    Various embodiments of the present invention having been thus described in detail by way of example, it will be apparent to those skilled in the art that variations and modifications may be made without departing from the invention. For example, the present invention may be used to sever pipes other than gas service tees. The invention includes all such variations and modifications as fall within the scope of the appended claims.