Abstract:
A portable beveling tool that is attached to a power tool having a rotary cutter for beveling pipe. The beveling tool includes a base, two rollers extending away from the base, and a tool mount that rotatably mounts the power tool to the base. The rollers and the cutter cooperate to locate the beveling tool on the pipe and to guide movement of the beveling tool around the pipe. The position of one of the rollers is adjustable to accommodate pipes of different diameters and wall thicknesses. An operator can move the beveling tool around the end of the pipe without changing his or her grip on the power tool.

Description:
This application claims the benefit of our pending U.S. provisional patent App. No. 60/955,045 filed Aug. 10, 2007, which provisional application is incorporated by reference as if fully set forth herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to tools for beveling pipe, and in particular to tools intended for attachment to a power tool that drives a cutter that bevels the pipe. 
     BACKGROUND OF THE INVENTION 
     The portable beveling tool of the present invention was developed for use by excavators and contractors when installing plastic sewer and drainage pipe. An example of such pipe is SDR 35 PVC (Poly Vinyl Chloride) Sewer and Drainage Pipe. 
     Lengths of SDR 35 PVC Sewer and Drainage Pipe are manufactured with a bell end and a spigot end, with the spigot end including a bevel. The bell end of the pipe has a neoprene/rubber seal inside the periphery of the bell. When the pipe is installed in the field, the beveled spigot end is inserted into the bell end of the preceding pipe. The bevel allows for proper assembly of the pipe lengths and eliminates tearing or disturbing the neoprene/rubber seal. 
     The integrity of the seal must be maintained as each length of pipe is assembled. This seal is critical as the integrity of each pipe joint is tested after assembly with air pressure. 
     When a standard length of pipe is cut to a specific length, the cut end of the pipe no longer has the factory-beveled end. The pipe must have the correct bevel cut each time a standard length pipe is cut to size to maintain the integrity of the seal. 
     Portable tools have been developed to bevel the end of a pipe with a power tool carrying a cutter. Uribe, U.S. Pat. No. 4,180,358 and Nybo, US Published Patent Application No. 2004/0206218 each disclose a pipe beveling tool that attaches to a power tool such as a drill, router, or the like. The beveling tool includes a datum plate that attaches to the power tool. The plate has a through-hole or aperture that enables a cutter carried by the power tool to extend through the beveling tool and cut the bevel. 
     The plate is placed against the end of the pipe, and at least three rollers mounted on the plate locate the beveling tool on the end of the pipe. The rollers abut the inner or outer pipe walls, allowing the pipe to rotate and enabling the cutter to cut a bevel around the entire circumference of the pipe. 
     Although the above beveling tools are useful, there is room for improvement in both the initial cost of the beveling tool and operator convenience when using the beveling tool. 
     Simplifying construction would reduce the number of components, thereby reducing cost. 
     A more ergonomic design of the beveling tool would increase operator convenience and improve the quality of the bevels made by the beveling tool. 
     When beveling a pipe in place that cannot rotate, the beveling tool itself must instead revolve around the pipe. The handle of the power tool is used to move the beveling tool around the pipe. The beveling tool and its attached power tool must each make one complete rotation with a complete revolution around the pipe, which can cause the operator to change his or her grip on the handle as the bevel is being cut. 
     Changing grip while the bevel is being cut can affect the quality and accuracy of the resulting bevel. If the operator could maintain the same grip on the power tool as the beveling tool moves around the periphery of the pipe, operator convenience as well as bevel quality and accuracy increases. 
     Thus there is a need for a beveling tool having a simpler construction and a more ergonomic design. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention is an improved portable beveling tool that includes a simplified construction to locate the beveling tool on the end of a pipe and an ergonomic design for attaching a power tool to the beveling tool. The simplified construction helps minimize the cost of the beveling tool, while the ergonomic design enables the operator to maintain the same grip on the power tool as the beveling tool moves around the periphery of the pipe. 
     The simplified construction results from the beveling tool having only two rollers that each extend along a respective axis of rotation. The power tool is attached to the beveling tool with the cutter extending along a third axis spaced from the first and second axes. The two rollers and the cutter cooperate to locate and guide the beveling tool around the end of the pipe. 
     The beveling tool is ergonomically designed and includes a tool mount friction swivel that rotatably attaches the power tool to the beveling tool. The power tool is free to rotate or pivot about the cutter axis with respect to the beveling tool. This enables the operator to maintain the same grip on the power tool as the beveling tool moves around the periphery of the pipe when cutting the bevel. 
     The portable beveling tool of the present invention includes a plate or base having a datum surface that rides on the pipe end perpendicular to the longitudinal axis of the pipe. The datum surface is preferably machined from flat aluminum plate. The first and second guide rollers are attached to the base and extend on a perpendicular line from one side of the base. The first roller is attached to the plate for rotation about a fixed first axis and the second roller rotates about a second axis spaced from the first axis. The second roller is preferably adjustable and mounted to the plate for locating the second axis with respect to the first axis. This enables the operator to selectively adjust the position of the second roller for different diameters or wall thicknesses of pipe. 
     The plate includes an opening that extends through the plate and a tool mount that attaches the power tool onto the other side of the plate. The tool mount locates the power tool with the cutter extending along the third axis. The cutter extends through the opening and extends away from the one side of the base. 
     The power tool is preferably a router or rotary trimmer that holds a cutter having an angled cutting edge shaped to cut the bevel. The cutter preferably includes a pilot roller or pilot bearing that cooperates with the other two rollers to locate the beveling tool on the pipe. The beveling tool also preferably includes a clear Lexan shield to protect the operator from the shavings coming off the cutter. 
     The tool mount preferably rotatably mounts the power tool on the base for rotation about the third axis. 
     The portable beveling tool of the present invention has fewer rollers than conventional beveling tools to reduce cost and to simplify adjusting the beveling tool for different pipe diameters. The portable beveling tool also enables the operator to maintain the same grip on the power tool as the beveling tool moves around a pipe, increasing operator comfort and improving the quality and accuracy of the bevels. 
     Other objects and features of the present invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying three drawing sheets illustrating an embodiment of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a portable beveling tool in accordance with the present invention; 
         FIG. 2  is a sectional view taken along line A-A with the portable beveling tool attached to a router; 
         FIG. 3  is a side view of the portable beveling tool; 
         FIGS. 4 and 5  are side and front views respectively of the baseplate of the portable beveling tool; 
         FIG. 6  is a sectional view similar to  FIG. 2  but illustrating only the friction swivel assembly; 
         FIGS. 7 and 8  are side and front views of the retaining nut of the friction swivel assembly; 
         FIGS. 9 and 10  are side and front views of the spacer of the friction swivel assembly; 
         FIGS. 11 and 12  are side and front views of the attachment plate of the friction swivel assembly; and 
         FIG. 13  is a front view illustrating the portable beveling tool mounted on an end of a pipe for beveling the end of the pipe. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIGS. 1-12  illustrate a portable beveling tool  10  in accordance with the present invention. Beveling tool  10  is shown in  FIGS. 1 and 2  attached to a power tool  12  that carries a rotary cutter  14 . In the illustrated embodiment tool  12  is a router or rotary trimmer  12 . Trimmer  12  can be a Ryobi P600 cordless trimmer or equivalent. The illustrated cutter  14  is a conventional carbide-tipped piloted router bit  14  that cuts the pipe bevel. Router bit  14  includes a pilot bearing or pilot roller  16  that locates the router bit  14  against the object to be cut by the bit. Router bit  14  can be a WOODTEK Catalog No. 115-571 router bit or equivalent, or can be a bit specifically designed for the portable beveling tool  10 . 
     Beveling tool  10  includes a base machined as a flat baseplate  18 , and a friction swivel assembly  20  that mounts the router  12  to the baseplate  18 . A fixed guide roller  22  and an adjustable guide roller  24  are located on one side of the baseplate  18 . Guide rollers  22 ,  24  can each be a Fafnir KP4 FS428 MS27640-AG bearing or equivalent. A clear plastic Lexan shield  26  is attached to an outer peripheral edge of the baseplate by screws (see  FIG. 13 ) and extends outwardly beyond the guide rollers  22 ,  24 . 
     Fixed guide roller  22  is attached to a shaft  28  that extends through a closely-sized circular hole  30  in the baseplate  18 . A bushing  32  carried on the shaft  28  spaces the guide roller  22  from the one side of the baseplate  18 . 
     Adjustable guide roller  24  is attached to a shaft  34  that extends through an elongate, arcuate slot  36  in the baseplate  18 . A bushing  38 , like bushing  32 , spaces the guide roller  24  from the one side of the baseplate  18 . Shaft  34  is preferably a carriage bolt that includes a threaded shaft portion  39  that extends beyond the guide roller  24 . An adjustable handle  40  is threaded on the end of the shaft portion  39 . Handle  40  can be a Reid Supply Company Part No. JCL-303 handle or equivalent. The handle  40  acts as a clamping lever that is tightened to clamp the shaft  34  against the baseplate  18  and hold the shaft  34  at a selected position along the slot  36 , or released and loosened to enable the shaft  34  to be repositioned along the slot  36 . 
     Baseplate  18  is machined from aluminum plate and includes a flat datum surface  42  on the one side of the baseplate that locates an end of a pipe to be beveled. A central circular through hole or opening  44  having a counterbore  46  on the one side of the baseplate is located between the baseplate hole  30  and the baseplate slot  36 . 
     Friction swivel assembly  20  includes a retaining nut  48 , a spacer  50 , and a router attachment plate  52 . Swivel assembly  20  is mounted in baseplate opening  44  and permits the router  12  to rotate about the axis of the opening  44  when the beveling tool  10  is attached to the router  12 . 
     Retaining nut  48  includes a circular, annular flange  54  and a tubular body  56  extending from the flange  54 . Flange  54  is sized to fit closely within baseplate counterbore  46  and flush with the datum surface  42 . Body  56  has an outer diameter less than the diameter of the baseplate opening  46  and includes an externally threaded end portion  58 . Retaining nut  48  is preferably made from HDPE or Teflon. 
     Spacer  50  has a circular, annular flange  60  and a tubular collar  62 . The outside diameter of the collar  62  is closely received within baseplate opening  44 . Spacer  50  is preferably made from Ultra-High Molecular Weight plastic (UHMW). 
     Attachment plate  52  is a flat annular washer or disk preferably machined from aluminum plate. The outer diameter of the attachment plate  52  preferably equals the outer diameter of the baseplate of the router to be attached to the beveling tool  10 . The inner wall  64  of the attachment plate  52  is sized and threaded to permit the attachment plate to be threaded onto the retaining nut threaded end portion  58 . Countersunk through holes receive screws that attach the attachment plate  52  to the router. Different attachment plates  52  can be provided to adapt the beveling tool  10  for use with other routers or other types of power tools. 
     Retaining nut  48  is installed in the baseplate  18  with flange  54  within counterbore  46  and body  56  extending through baseplate opening  44 . Spacer  50  is fitted on body  56  with spacer collar  60  in baseplate opening  44 . Attachment plate  52  with the router  12  attached is threaded onto nut threaded portion  58  and sandwiches the spacer  50  between the plate  52  and the baseplate  18 . Router bit  14  is installed in the router  12 . 
     Beveling of an end of a pipe is described next. The router  12  is turned off. The router bit  14  is positioned so that the upper end of the cutting edges of the bit is even with the baseplate surface  42  as shown in  FIG. 2 . The length of the bushings  32 ,  36  preferably space the guide rollers  22  and  24  the same distance from the baseplate surface  42  as the bit pilot bearing  16  when the router bit  14  is properly positioned with respect to the baseplate. 
     Adjustable handle  40  is loosened to enable shaft  34  to move along slot  36 . The end of a pipe is placed between the fixed guide roller  22  and the router bit pilot bearing  16  and abuts the stationary, non-rotating router bit  14 . The fixed guide roller  22  is placed against the pipe interior wall  68  and the bit pilot  16  is against the pipe outer wall  70 . See  FIG. 13 , in which the interior and exterior pipe walls  68  and  70  are shown as hidden lines. Adjustable guide roller  24  is pressed against the interior pipe wall  68  and handle  40  is tightened by rotation indicated by arc  72  to hold shaft  34  in place with the guide roller  24  against pipe wall  68 . The handle  40  is shown in  FIG. 13  in both its loosened and clamped positions. The end of the pipe is now against the three circumferentially spaced rollers  16 ,  22  and  24 . 
     With the beveling tool away from the pipe, router  12  is turned on to rotate the bit  14  at high speed. The end of the pipe is moved against the baseplate datum surface  42 . The router bit  14  cuts into the pipe as the end of the pipe moves axially towards the baseplate  18 . With the end of the pipe kept against the baseplate  18 , the beveling tool  10  is rotated about the outside periphery of the pipe. The end of the pipe is kept against the datum surface  42  and the rollers  16 ,  22  and  24  remain in contact with the pipe walls to maintain correct alignment of the pipe with the router bit  14  so that the a smooth, accurate bevel is cut at the correct bevel angle. The shield  26  overlays the outside of the pipe across from the router bit  14  to help limit operator exposure to chips or shavings produced by the router bit  14 . 
     The friction swivel assembly  20  permits the router  12  to rotate with respect to the baseplate  18 . The retaining nut  48  and the spacer  50  are preferably made of low friction materials to permit relative motion between the baseplate  18  and the attachment plate  52  with low or essentially no drag or frictional resistance. An operator can hold the router  12  and move the beveling tool  10  around the end of a stationary pipe without changing his or her grip on the router  12 . The friction swivel assembly  20  enables the beveling tool  10  to rotate with respect to the router  12  as the beveling tool  10  moves around the end of the pipe so that the operator&#39;s hands do not have to twist or turn to follow the rotation of the beveling tool  10 . 
       FIG. 13  illustrates beveling tool  10  used in cutting a bevel on the outer pipe wall, that is, the bevel is being cut on the outer diameter of the pipe. The beveling tool would be used essentially rotated 360 degrees as shown in  FIG. 13  to locate the rollers on the inside wall of the pipe and the bit pilot on the outside wall of the pipe. 
     While we have illustrated and described a preferred embodiment of our invention, it is understood that this is capable of modification, and we therefore do not wish to be limited to the precise details set forth, but desire to avail ourselves of such changes and alterations as fall within the purview of the following claims.