Patent Publication Number: US-2009235532-A1

Title: Pipe Cutting And Bevelling Tool

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     THIS INVENTION relates to a pipe cutting and bevelling tool. 
     The invention is particularly suitable for, but not limited to, a cutting and bevelling tool for pipes used in civil construction and other infrastructure areas, including mechanical, and electrical and gas installations/pipes. 
     Throughout the specification, the term “pipe” shall include pipes, conduits and other tubular bodies. 
     2. Prior Art 
     The ends of pipes typically have to be bevelled so as to pass the rubber seals used in joints or fittings used to connect adjacent sections of pipe together. 
     Current practice, although officially not approved, is to cut the pipes with a cut-off saw and then bevel the ends of the pipes by using the side of the cut-off saw blade. 
     The cut-off saw is responsible for many incidents and injuries; and the disc/blade which has been weakened by using the side, instead of the cutting edge, which can be damaged by impact in handling or transport, and when shattered can be lethal. Furthermore, this process produces fine dust and smoke which may be inhaled; and it also produces heat which can damage the plastics or metal at the circumferential zone at the pipe ends being bevelled. 
     It is important that the depth of bevelling is adjustable (and can be accurately controlled) to accommodate different wall thicknesses. Good pipe laying practice requires there be a “landing” face on the ends of the pipes, and not a feather edge (which can damage the rubber seals). 
     The landing faces must be square to the longitudinal axes of their-pipes to minimize damage to the rubber seals. 
     While the bevelling can be produced by hand tools, this is slow and requires the use of an accurate cut-off tool to cut the pipes to length. 
     Over the years, many proposals have been put forward for tools which simultaneously cut and bevel the pipe ends and examples are disclosed in (i) AU-2003231625 A1 (AMEC SERVICES PTY LTD); JP-606307, (iii) U.S. Pat. No. 4,180,358 (URIBE); (iv) U.S. Pat. No. 4,625,464 (KUBO); (v) U.S. Pat. No. 4,689,883 (DENT); (vi) U.S. Pat. No. 6,129,488 (FAHR); (vii) US 20050022353 (VIOLA et al); (viii) International Publication WO 98/16342 (CHINN et al). 
     All of these machines have features which limit their application. For example, U.S. Pat. No. 4,689,883 (DENT) requires the provision of a guide around the pipe to be cut and a cutting head which only has a single point of contact with the external wall of the pipe and so cannot ensure an accurate line of cut, or bevel, around the pipe. 
     U.S. Pat. No. 6,129,488 (FAHR) requires the use of an extremely complex cutting head to enable the pipes to be cut to length and bevelled. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a pipe cutting and bevelling tool which can be used with pipes having a range of external diameters. 
     It is a preferred object of the present invention to provide a tool which can cut a range of bevel depths for a given pipe diameter. 
     It is a further preferred object of the present invention to provide a tool which is easy and safe to use. 
     It is a still further preferred object of the present invention to provide a tool which can be self-contained, or which can be powered from a remote power source. 
     Other preferred objects will become apparent from the following description. 
     In one aspect, the present invention resides in a pipe cutting and bevelling tool including: 
     a first guide plate; 
     at least one cutting tool and at least one bevelling tool extending through the first guide plate; 
     drive means to drive the cutting tool(s) and bevelling tool(s); and 
     a second guide plate pivotally mounted relative to the first guide plate, so arranged that: 
     by a single adjustment of an angular relationship between the first and second guide plates, the tool can cut and bevel pipes of different diameters, or can bevel ends of pipes of a single diameter to different bevel depths. 
     Preferably, the tool has a main frame, to which the first guide plate is mounted, and the cutting tool(s) and bevelling tool(s) are detachably mounted on a drive shaft journalled (in bushes or bearings) on the main frame. 
     Preferably, a cutting tool comprising a single saw blade or abrasive disc is interposed between a pair of bevelling tools, e.g., of the types known as dovetail or milling cutters or abrasive-coated drums, where the saw blade or abrasive disc extends through the first guide plate to a depth at least just greater than the wall thickness of the pipes to be cut and beveled. 
     Preferably, the bevelling cutters or abrasive-coated drums extend through the guide plate a reduced distance relative to the saw blade or abrasive disc, the reduced distance being preferably not less than the minimum thickness of landing faces at the ends of the pipes, after bevelling has been effected. 
     The drive means may include an internal combustion engine, an electric motor, a hydraulic motor, a pneumatic motor or other suitable power source, which may be self-contained, or connected to a remote power source, e.g., a hydraulic pump; and the engine or motor may be operably connected directly, or via a transmission, to the drive shaft. 
     Preferably, the second guide plate extends through a transverse slot or recess in the first guide plate and is pivotally mounted on the main frame or first guide plate. 
     Preferably, a screw-type adjuster interconnects the second guide plate to the main frame to enable the angular adjustment of the second guide plate to the first guide plate. 
     In a second aspect, the present invention resides in pipes cut and bevelled by the tool of the first aspect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To enable the invention to be fully understood, preferred embodiments will now be described with reference to the accompanying drawings, in which: 
         FIG. 1  is an isometric view of one side of a first embodiment of the tool; 
         FIG. 2  is a similar view from the opposite side; 
         FIG. 3  is a similar view of the underside of the tool; 
         FIG. 4  is a bottom plan view thereof; 
         FIG. 5  is a side elevational view of the tool, with parts omitted for clarity; 
         FIG. 6  is a similar view, showing the tool in use with pipes of different diameters; 
         FIG. 7  is a similar view, showing the tool cutting bevels of different sizes for a single pipe diameter; 
         FIGS. 8 and 9  show the alternative bevels cut by the tool in  FIG. 7 ; 
         FIG. 10  is a schematic side elevational view of a second embodiment of the tool; and 
         FIGS. 11 and 12  are respective schematic side and end elevational views of cutting and bevelling tools for metal pipes. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1 to 9 , the pipe bevelling and cutting tool  10  of the first embodiment has a main frame  11  with a pair of spaced, parallel, side plates  12  and  13 , to which is adjustably mounted a housing  14  for a small internal combustion engine  15 . 
     The housing  14  is provided with respective handles or grips  16 ,  17 . 
     A first guide plate  20  with an upturned front portion  21 , is fixed to the side plates  12 ,  13  of the main frame  11  by suitable fasteners  22 . 
     A hexagonally shaped slot  23 , as shown in more detail in  FIG. 3 , is provided in the first guide plate  20  to allow the saw blade and bevelling cutters (to be hereinafter described in more detail) to extend therethrough. 
     A drive shaft  30  received within a tubular housing  31  is rotatably journalled in suitable bearings or bushes  32  mounted on the side plates  12 ,  13 . 
     A drive chain or belt  33  is driven by a driving sprocket or pulley  34  fixed to the output shaft  18  of the engine  15 . 
     While the drive chain or belt  33  passes around a guide plate  35  and drives a driven sprocket or pulley (not shown) on the drive shaft  30  (adjacent the side plate  12 ). 
     While the drive chain or belt  33  may be tensioned by a tensioning roller rotatably journalled on the side plate  12 , in this embodiment, the guiding plate  35  has an elongate slot  37 , engageable by a bolt or stud  19  in the housing  14 , to allow the guiding plate  35  to be moved relative to the housing  14  so that the distance between the shafts  18 ,  30  to be selectively adjusted to maintain the correct tension in the drive chain or belt  33 . 
     A second guide plate  50 , of substantially L-shape in front view, has a top portion  51  extending through a slot  40  defined between a rear end wall  41  of the first guide plate  30  and the front wall  14 A of the housing  14 . The top portion  51  is pivotally connected to the side walls  12 ,  13 , adjacent their upwardly rearward corners, by suitable pivot studs  52 ,  53 . 
     The second guide plate  50  has a lower portion  54 , with a pair of holes  55  therethrough, the lower portion  54  extending laterally relative to the upper portion  51  to extend across the full width of the first guide plate  20 . 
     It will be noted that the pivotal axis of the second guide plate  50 , defined by the pivot studs  52 ,  53 , is perpendicular other cutting direction of the tool  10  as shown in  FIGS. 6 and 7 . The first and second guide plates  20 ,  50  co-operate to engage respective portions of the pipes to be cut to maintain the longitudinal axis of the pipes parallel to the drive shaft  30  and thereby perpendicular to the axes of the saw-blade and bevelling cutters to be hereinafter described. 
     A saw blade  60  is interposed between a pair of bevelling cutters  61 ,  62 , which are provided on the drive shaft  30  and extend through the slot  23  in the first guide plate  20 . 
     The saw blade  60  has teeth  63  appropriate to the cutting of the material, e.g., plastics or metal, of the pipes to be cut. Similarly, the bevelling cutters  61 ,  62 , e.g., of the dovetail or milling cutter types, have respective cutting teeth  64 ,  65  profiled to cut the desired profile on the ends of the pipes. It will be noted that the cutting teeth  63  of the saw blade  60  extend further through the slot  23  than the teeth  64 ,  65  of the bevelling cutters  61 ,  62 , preferably to a depth substantially equal to, or greater than, the thickness of the landing faces to remain on the pipes after the ends of the pipes have been cut and bevelled. 
     Removable covers  70 ,  71  are provided over the saw blade  60 , bevelling cutters  61  and  62  and the driving chain or belt  33  to protect the operator of the tool  10 . 
     Pivotal adjustment of the second guide plate  50  relative to the first guide plate  20  is effected by an adjustment nut  80  on a screw threaded rod  81  connected to the upper portion  51  of the second guide plate  50 , the adjustment nut  80  bearing against a flange  82  on the tubular housing  31  for the drive shaft  30 . 
     A water nozzle  83  is provided adjacent the saw blade  60  and bevelling cutters  61  and  62 , to direct water or other liquid coolant from a coolant source  84  onto the saw blade  60  and the bevelling cutters  61 ,  62  when the pipes are being cut. Coolant is usually only required when cutting/bevelling metal pipes. 
     As shown in  FIG. 6 , by adjusting the angular relationship of the second guide plate  50  to the first guide plate  20 , via adjustment nut  80 , the tool  10  can cut and bevel pipes  90  with a wide range of diameters, e.g., 50 mm to 500 mm. 
     As shown schematically in  FIG. 7 , for pipes  90  of a given diameter, adjustment of the angular relationship, e.g., from the angle α (where the second guide plate  50  is shown in solid lines) to the angle β (where the second guide plate  50  is shown in dashed lines), different bevel profiles can be applied to the pipes  90  as shown in  FIGS. 8 and 9 . 
     In addition, for a given pipe diameter, but different pipe wall thicknesses T 1 , T 2 , the thickness t 1 , t 2  of the land faces  91 ,  92  can be varied by selected angular adjustment of the second guide plate  50  relative to the first guide plate  20 . 
     As the guide plates  20 ,  50  provide two, spaced, lines of contact with the walls of the pipes  90 , the saw blade  60  will always cut the ends of the adjacent sections of the pipes  90  square to the longitudinal axis of the pipes  90  and the respective adjacent ends of the pipes  90  will be evenly bevelled by the respective bevelling cutters  61 ,  62 . 
     The homing ability of the tool  10  to end the cuts of the pipes  90  where the cuts start, which results in the high quality of the cuts/bevels produced, is due to the feature that the guide plates  20 ,  50  provide parallel lines of contact with the pipes  90 . The second guide plate  50  is already parallel to the drive shaft  30 , and the drive shaft  30  and first guide plate are also always parallel. By maintaining the guide plates  20 ,  50  in contact with the pipes  90  as the cuts/bevels are formed, accuracy is ensured. 
     Where the pipes  90  are subject to variations in wall thicknesses due to manufacturing tolerances, the bevel depths cut will remain constant, as these start from the outer faces of the pipes  90  in contact with the guide plates  20 ,  50 . (Any variation will be in the thickness of the land faces  91 ,  92 .) 
     The pipes  90  may also be out-of-round, again due to manufacturing tolerances or localised damage during handling. 
     By having the line of contact between the pipes  90  and the first guide plate  20  aligned as close as possible to the axis of the drive shaft  30 , any effects of the out-of-roundness of the pipes  90  is minimised, especially if the line of contact is directly under the output shaft  30 . 
     Greater accuracy in the cutting/bevelling of the pipes  90  is possible with the present tool, than with previous machines where the pipes are cut at 360°, e.g., supported by rollers/wheels at 60° and 300°. 
     In addition, the lines of contact between the pipes  90  and the guide plates  20 ,  50 , minimise the adverse effects of any localised deformations or variations in the outer faces of the pipes, where the rollers/wheels of the previous machines which may run into, e.g., recesses in the outer faces. 
     It will be readily apparent to the skilled addressee that the present invention provides simple, efficient, safe cutting and bevelling of the ends of the pipes using the tool  10  of the present invention. 
     In a second embodiment illustrated in  FIG. 10 , the tool  110  may be used to cut pipes  90  in situ in trenches or other locations where limited access is available. In this embodiment, the internal combustion engine  14  is replaced by a hydraulic motor  114  connected to a remote hydraulic pump HP by suitable hydraulic lines HL. The hydraulic motor  114  can be directly connected to, or provide, the drive shaft  130 , for the saw blades  160  and bevelling cutters  161 . 
     It will be readily apparent to the skilled addressee that the hydraulic motor  114  can be replaced by a pneumatic motor or electric motor, each connected to a respective remote power source. 
     To assist in maintaining the pipes  90  in contact with the first and second guide plates  120 ,  150  of the tool  110 , a flexible restraint or clamp C may be mounted on, or connected to, the main frame  111  of the tool  110 . 
     The relatively compact nature of the tool  110  enables it to be used on pipes  90  in situ, where the tool  110  is moved around the pipes  90  to accurately cut and bevel the pipe ends. 
     As illustrated in  FIGS. 11 and 12 , the saw blades  60 ,  160  and bevelling cutters  61 ,  62 ,  161  may be replaced with abrasive discs  260  and drums  261 ,  262 , with appropriate abrasive coatings, to cut and bevel metal pipes  290 . The abrasive coatings for iron pipes are preferably diamonds; while the preferred abrasive coatings for steel pipes are CBN or Ambercite. Other suitable abrasive coatings, e.g., tungsten carbide, may be used. 
     The present invention provides a simple, efficient tool for cutting and bevelling the ends of pipes; where accuracy is ensured; and safety of the operators is important. 
     Unlike prior tools, a single adjustment of the second guide plate  50 ,  150  relative to the first guide plate  20 ,  120 , enables pipes  90  of a wide range of diameters to be cut and bevelled, or different bevelled profiles be applied to pipes  90  of a single diameter. 
     Various changes and modifications may be made to the embodiments described and illustrated without departing from the present invention.