Abstract:
A work station having a number of tools used to prepare pipe stock for accepting mechanical pipe couplings is disclosed. The work station has a chuck for rotating the pipe. A movable carriage on which the tools are pivotally mounted is mounted adjacent to the chuck. The tools include a pipe cutter, a reamer and a grooving tool. The grooving tool is for forming circumferential grooves externally around the pipe. The grooving tool has a grooving roll which cooperates with an oppositely disposed back-up roll to deform the pipe and create the groove. The grooving tool is pivotally mounted on the carriage via a spring-biased pivot arm having longitudinal slots engaging set screws which permit the position of the grooving tool to be adjusted to engage pipes of various diameters.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention concerns a pipe grooving tool for the preparation of pipe stock to be used with a mechanical pipe coupling system, and especially a grooving tool which is adapted to be used in combination with other tools on a single work station at which all steps necessary for pipe stock preparation can be performed.  
         BACKGROUND OF THE INVENTION  
         [0002]    Mechanical pipe coupling systems which do not require welding, brazing or soldering for joining piping, find widespread use throughout industry, especially in petroleum and chemical applications where it may be hazardous and/or forbidden to use an open flame or an electrical arc. Such mechanical coupling systems are also more conveniently employable in the field or in remote locations where primitive environmental conditions and a lack of access to services and supplies such as electricity or acetylene gas and oxygen inhibit traditional arc or gas welding techniques.  
           [0003]    [0003]FIG. 1 shows an example of one mechanical pipe coupling system wherein pipes  20  and  22  are joined together by a coupling  24 . Coupling  24  comprises segmented semi-circular collar segments  26  and  28  which are clamped together around the pipe ends. Each collar segment is roughly U-shaped in cross section as shown, the ends of the “U” forming a pair of flanges  30  and  32  which engage grooves  36  formed circumferentially in the pipe wall  38  on each pipe end. A pressure energized elastomeric seal  40  is positioned within the coupling to effect a fluid tight joint between the pipe ends.  
           [0004]    Before pipes are joined together using a mechanical coupling system as exemplified above, pipe stock of a particular diameter must be prepared to receive the couplings. The preparation steps include, at a minimum, cutting the pipe stock to a desired length, reaming the cut pipe stock to remove burrs or sharp edges formed by the cutting step, and forming circumferential grooves  36  at the proper distance from the ends of the pipe stock.  
           [0005]    Throughout industry, these steps are usually performed by separate tools mounted on different work stations. For example, the pipe cutter and the reamer might be mounted on a first work station and the pipe grooving tool on a second, separate work station. This separation of tools among different work stations in the preparation of pipe stock requires that extra steps be performed because, after the stock has been cut and reamed at the first work station, it must be removed from this station, brought to the second work station, mounted on the second work station and engaged with the grooving tool. These extra steps lead to inefficiencies which become significant when large quantities of pipe stock must be prepared for joining.  
           [0006]    There clearly is a need for a grooving tool which can be readily mounted on a work station having other tools, such as a pipe cutter and a reamer, thereby providing a single work station having a combination of tools which can be used to efficiently perform all of the necessary steps required for the preparation of pipe stock to be joined by a mechanical coupling system.  
         SUMMARY AND OBJECTS OF THE INVENTION  
         [0007]    The invention concerns a grooving tool for forming an external circumferential groove of a desired outer diameter in a pipe, the grooving tool being mountable on a work station with other tools used to prepare the pipe to accept mechanical couplings for joining lengths of pipe together.  
           [0008]    The grooving tool has a body portion and a jaw portion mounted on the body portion and movable relatively thereto. A grooving roll is preferably mounted on the jaw portion and rotatable about a first axis of rotation. The grooving roll has a circumferential surface engageable with the external surface of the pipe. A back-up roll is mounted on the body portion and rotatable about a second axis, preferably parallel to the first axis of rotation of the grooving roll. The back-up roll has a circumferential surface engageable with the internal surface of the pipe opposite to the grooving roll. The tool has means for moving the grooving roll and the back-up roll relatively toward one another for yieldably deforming the pipe therebetween and forming the external circumferential groove in the pipe upon rotation of the pipe about its longitudinal axis. Preferably, the moving means comprises a jack screw which is mounted in the body portion and operatively associated with the jaw portion to move the jaw relatively to the body portion when the jack screw is rotated. Other moving means, such as hydraulic or pneumatic actuators are also feasible.  
           [0009]    The grooving tool also has an elongated pivot arm for mounting it on the work station. The pivot arm has one end attached to the body portion and another end pivotally attachable to the work station for pivotally mounting the grooving tool thereto. Preferably, the pivot arm has an elongated slot arranged lengthwise to it and positioned proximate to the end attached to the body portion of the tool. The slot receives a set screw, which extends through the slot to engage the body portion. The set screw has an enlarged head engageable with the pivot arm for retaining the body portion to it. The set screw is movable lengthwise within the slot, allowing the body portion to move lengthwise relatively to the pivot arm to permit motion of the tool substantially perpendicular to its pivot axis.  
           [0010]    The pivot arm also has means for biasing it toward the pivot axis. The biasing means preferably comprises a spring located at the end of the pivot arm which is attachable to the carriage. The spring is located within a slotted aperture through the pivot arm, the slotted aperture being adapted to receive a pin for rotatably mounting the pivot arm to the carriage. The pin is mounted on the carriage and arranged coaxially with the pivot axis of the pivot arm. The slotted aperture is oriented substantially lengthwise to the pivot arm and allows it to move on the pin lengthwise perpendicularly to the pivot axis. The spring is located within the slotted aperture between the pin and the end of the pivot arm.  
           [0011]    The invention also concerns a work station for performing all of the steps required to prepare pipe stock for receiving mechanical couplings. The preparation steps include cutting the pipe, reaming the pipe, and forming an external circumferential groove of a desired outer diameter in the pipe.  
           [0012]    The work station has a chuck adapted to receive the pipe. The chuck is rotatable about an axis of rotation coincident with the longitudinal axis of the pipe when the pipe is received within the chuck. There is also a means, such as an electric motor, for rotating the chuck.  
           [0013]    Preferably, a carriage is positioned adjacent to the chuck, the carriage being slidably movable toward and away from the chuck in a direction substantially parallel to the axis of rotation of the chuck. The carriage provides a mounting platform for the tools necessary to pipe preparation. The tools include a pipe cutter, a reamer, and a grooving tool, each of which is described below.  
           [0014]    The pipe cutter is pivotally mounted on the carriage for rotation about a first pivot axis substantially parallel to the axis of rotation of the chuck. The pipe cutter is pivotally movable toward the axis of rotation for positioning the pipe cutter in engagement with the pipe for cutting the pipe when the pipe is received within the chuck and rotated. Preferably the pipe cutter has a circular cutting blade arranged opposite to a pair of support rollers. The pipe is positioned between the blade and the rollers and the blade is advanced into the pipe as it is rotated by the chuck to effect the cut at a desired location along the length of the pipe.  
           [0015]    The reamer is also pivotally mounted on the carriage for rotation about a second pivot axis substantially parallel to the axis of rotation of the chuck. This allows the reamer to be pivotally movable into coaxial alignment with the axis of rotation of the chuck. The reamer is also slidably movable toward the chuck for positioning it in engagement with the internal edge of the pipe when the pipe is received within the chuck. The reamer preferably has a conical surface on which cutting edges are positioned. The cutting edges engage the internal edge of the pipe and remove burrs and sharp edges caused by the cutting process.  
           [0016]    The grooving tool is used to form the circumferential groove in the pipe. The grooving tool is pivotally mounted on the carriage for rotation about a third pivot axis substantially parallel to the axis of rotation of the chuck. This allows the grooving tool to engage the pipe when the pipe is received within the chuck. Preferably, the grooving tool is as described above and is mounted to the work station by means of the aforementioned pivot arm.  
           [0017]    It is an object of the invention to provide a grooving tool which may be mounted on a work station and used in combination with other tools to efficiently perform the steps necessary for preparing pipe stock to accept mechanical couplings.  
           [0018]    It is another object of the invention to provide a grooving tool which may be adapted for use on pipe stock of various materials, diameters and wall thicknesses.  
           [0019]    It is again another object of the invention to provide a work station having a plurality of tools for preparing pipe stock to accept mechanical couplings.  
           [0020]    It is yet another object of the invention to provide a single work station wherein all of the steps required to prepare pipe stock to accept mechanical couplings may be efficiently performed.  
           [0021]    These and other objects and advantages of the invention may be discerned upon consideration of the following drawings and detailed description of preferred embodiments of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]    [0022]FIG. 1 is a partial sectional longitudinal view of a pipe joint formed by a mechanical coupling system;  
         [0023]    [0023]FIG. 2 is a perspective view of a work station according to the invention;  
         [0024]    [0024]FIG. 3 is a partial side view of the work station shown in FIG. 2 on an enlarged scale;  
         [0025]    [0025]FIG. 4 is a partial view of the work station taken along lines  4 - 4  in FIG. 3;  
         [0026]    [0026]FIG. 5 is a partial view of the work station taken along line  5 - 5  in FIG. 3;  
         [0027]    [0027]FIG. 6 is a partial side view of the work station shown in FIG. 2 on an enlarged scale;  
         [0028]    [0028]FIG. 7 is a partial view of the work station taken along lines  7 - 7  in FIG. 3;  
         [0029]    [0029]FIG. 8 is a sectional view taken along lines  8 - 8  of FIG. 2;  
         [0030]    [0030]FIGS. 9 and 10 are partial sectional views showing portions of FIG. 8 in detail;  
         [0031]    [0031]FIG. 11 is a perspective view of a pipe prepared for use with the mechanical pipe coupling system of FIG. 1; and  
         [0032]    [0032]FIG. 12 is a side view of a grooving tool mountable on the work station shown in FIG. 2. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0033]    [0033]FIG. 2 shows a work station  50  according to the invention having a pipe cutter  52 , a reamer  54  and a grooving tool  56 . As described in detail below, the grooving tool  56  is adapted for mounting on the station  50  to be used in combination with the other tools to efficiently process pipe stock by performing, at one work station, all steps necessary to prepare the pipe stock for use with a mechanical coupling system.  
         [0034]    Work station  50  includes a chuck  58  mounted for rotation about an axis  60 . Chuck  58  has radially adjustable jaws  62  which allow the chuck to be adapted to receive pipe stock  20  having various diameters. When pipe stock  20  is received within chuck  58 , the chuck axis of rotation  60  is coaxial with the longitudinal axis  64  of the pipe stock, and the pipe stock is rotatable with the chuck about these axes.  
         [0035]    Preferably, chuck  58  is mounted on a housing  66  which encloses an electric motor (not shown) or other means operatively associated with the chuck to effect its rotation about axis  60 . The housing may be mounted on a tripod  68  for convenience of use of the work station by an operator.  
         [0036]    A carriage  70  is mounted on housing  66  adjacent to chuck  58  on a pair of elongated arms  72  which extend from the housing in spaced relation to one another substantially parallel to the chuck axis of rotation  60 . Carriage  70  is slidable lengthwise along arms  72  toward and away from chuck  58  as illustrated by the double headed arrow  74 . A handle  76  is provided which facilitates manual adjustment of the carriage&#39;s position relatively to the chuck  58  for processing of the pipe stock  20  as described below.  
         [0037]    The following tools are preferably mounted on the carriage  70 : the pipe cutter  52 ; the reamer  54 ; and the pipe grooving tool  56 . As best shown in FIG. 3, each tool is pivotally mounted on the carriage  70  for pivoting motion about a respective pivot axis  78 ,  80  and  82 . Pivot axes  78 ,  80 , and  82  are preferably parallel to the chuck axis of rotation  60 , and, as shown respectively in FIGS. 4, 5, and  7 , allow each tool to pivot through a respective arc  84 ,  86 , and  88  as needed to bring the particular tool to bear on the pipe stock  20 .  
       Work Station Operation  
       [0038]    Work station  50  is operated to efficiently cut pipe stock  20  to a desired length, ream the cut pipe to remove burrs or sharp edges which result from the cutting process, and form an external groove  36  (see FIG. 11) of a desired outer diameter in the wall  38  of the pipe without having to remove the pipe from the work station.  
         [0039]    In operation, as shown in FIG. 2, the pipe  20  is received in chuck  58  and the jaws  62  of the chuck are adjusted by means well known in the art to hold the pipe with its longitudinal axis  64  coaxial with chuck axis of rotation  60 . using handle  76 , carriage  70  is moved along arms  72  in the direction of arrow  74  toward or away from the chuck  58  to position pipe cutter  52  at a point along pipe  20  where it is desired to effect a cut. As shown in FIG. 4, pipe cutter  52  is pivoted through arc  84  about its respective pivot axis  78  from its original position (shown in phantom line) into engagement with pipe  20 . Preferably the pipe cutter is of the variety having a circular cutting blade  90  arranged opposite to a pair of support rollers  92 , the blade and rollers being movable toward each other by a jack screw  94 . With the pipe positioned between the blade  90  and the rollers  92 , the chuck  58  is rotated by the aforementioned electric motor, also rotating the pipe  20 . The jack screw  94  is turned to force the blade  90  into the pipe  20  effecting the cut. Preferably, the pipe cutter is slidably movable relatively to carriage  70  along a line of motion indicated by arrow  96  which pivots with the pipe cutter and is, thus, always substantially perpendicular to pivot axis  78 . Sliding motion of pipe cutter  52  is enabled by a sleeve  98  positioned at the base of the tool which receives a shaft  100  which projects from the pivot axis  78 , the sleeve  98  sliding relatively to the shaft  100 . Motion along line  96  allows the pipe cutter  52  to be readily adjusted for engaging different diameter pipes and also allows the cutting blade  90  to move relatively to the support rollers  92 , as well as pivot axis  78 , while the cutting circle of the cutter remains centered on the chuck axis of rotation  60 .  
         [0040]    After the cut has been completed, the cut piece of the pipe falls away and the pipe cutter  52  is pivoted away from the pipe to its original position shown in phantom line in FIG. 4. Next, as shown in FIGS. 5 and 6, the reamer  54  is brought into action. Reamer  54  includes a conical reamer head  102  having cutting edges  104  arranged along its surface. Reamer head  102  is mounted on the end of a shaft  106  which is slidably mounted on an arm  108  and movable in the direction of double headed arrow  110  parallel to the chuck axis of rotation  60 . Arm  108  pivots through arc  86  about pivot axis  80  allowing the reamer to be moved from its original position shown in phantom line in FIG. 5 to a position coaxially aligned with the longitudinal axis  64  of the pipe  20  as shown in FIG. 6. Once coaxially aligned, reamer head  102  is moved toward the pipe by sliding shaft  106  over the full extent of its travel relatively to arm  108 . The reamer may be temporarily fixed in this fully extended position by a detent mechanism (not shown). Next, using handle  76 , carriage  70  is moved toward the chuck  58  to move the reamer head  102  into engagement with the rotating pipe  20 . As shown in FIG. 6, the cutting edges  104  on the reamer head engage the internal edge  21  of pipe  20 , removing any burrs or sharp edges as is common practice in the art. After reaming, the reamer is moved out of engagement with the pipe and the arm  108  is pivoted back into the original position shown in phantom line in FIG. 5.  
         [0041]    With the pipe  20  cut and reamed, the groove  36  (see FIG. 11) may next be formed. Grooves such as  36  are preferably formed by cold working the material comprising the pipe wall  38  beyond the yield point. Such grooves are most advantageously formed in the pipes by means of the grooving tool  56 , shown in FIGS. 7 and 8.  
         [0042]    Grooving tool  56  has a body portion  112  on which is mounted a relatively movable jaw portion  114 . Preferably a grooving roll  116 , having a circumferential surface  117 , is mounted on the movable jaw portion  114  and is rotatable about an axis  118  substantially parallel to the chuck axis of rotation  60 . A back-up roll  120  having a circumferential surface  121  is mounted on the body portion  112  and is rotatable about an axis  122  also substantially parallel to the chuck axis of rotation  60 . Motion of the movable jaw portion  114  relatively to the body portion  112  is effected by means of a jack screw  124 . Rotation of jack screw  124  allows the grooving roll  116  and the back-up roll  120  to cooperate as described below to form the groove  36  in the pipe  20 .  
         [0043]    Grooving tool  56  is pivotally mounted on carriage  70  by means of a pivot arm  126  designed to adapt the grooving tool for mounting on the work station  50 . One end of the pivot arm, denoted  126   a , is attached to the body portion  112 , the other end, denoted  126   b , is pivotally attached to the carriage  70  for pivoting motion about pivot axis  82 , allowing the grooving tool  56  to pivot through arc  88  as described below.  
         [0044]    As shown in FIG. 12, end  126   a  of pivot arm  126  is adjustably attached to body portion  112  preferably by means of slots  127  which receive set screws  129  extending outwardly from body portion  112 . Slots  127  are arranged lengthwise along the pivot arm, and screws  129  are movable lengthwise along slots  127  thereby allowing the grooving tool  56  to move relatively perpendicularly to the pivot axis  82  in the direction indicated by arrow  130  in FIG. 7. The position of the grooving tool  56  relative to the pivot axis, and also the pipe end  20 , may be fixed by tightening the set screws  129 , the set screws each having an enlarged head  131  which retains the pivot arm  126  to the body portion  112  by clamping action. Preferably, as shown in FIG. 12, there is an alignment mark  133  on the pivot arm  126  and a plurality of alignment indices  134  positioned on the body portion  112  adjacent to the pivot arm. The alignment marks and indices allow the position of the grooving tool  56  to be conveniently preset to properly receive a pipe end  20  of a particular diameter as described below.  
         [0045]    To form the groove  36  in the pipe end  20 , the position of grooving tool  56  relatively to its pivot axis  82  is set by loosening set screws  129  and sliding the grooving tool lengthwise along the pivot arm  126  until the alignment mark  133  is adjacent to one of the indices  134  appropriate for the particular diameter pipe which is to be grooved (see FIG. 12). The set screws are then tightened to fix the grooving tool at that position relatively to the pivot arm. Presetting the position of the grooving tool positions the back-up roll  120  in the proper location adjacent to the pipe inside surface  128  when the grooving tool  56  is moved into engagement with the pipe  20  as described below.  
         [0046]    Using jack screw  124 , the grooving roll  116  is spaced from the back-up roll  120  by a distance greater than the thickness of pipe wall  38 . As shown in FIG. 7, the pipe grooving tool  56  is then pivoted through arc  88  about its pivot axis  82  to position the grooving tool  56  against a support stop  48  and in alignment with pipe  20 . The support stop is pivotally mounted on carriage  70  to properly position and support the grooving tool relative to the pipe.  
         [0047]    The grooving tool is then moved toward pipe  20  using handle  76  to slide carriage  70  to position the back-up roll  120  within the pipe  20  abutting pipe stop surface  119 , as shown in FIG. 8. The back-up roll  120  clears the internal edge  21  of pipe end  20  (see FIG. 9) due to the fact that its position relative to the pipe end was preset using the alignment mark  133  and indices  134  as described above. Preferably, the preset initially positions the back-up roll within about an eighth of an inch of the pipe inside surface  128 .  
         [0048]    Next, the jack screw  124  is rotated to bring the circumferential surface  117  of grooving roll  116  into contact with pipe  20 . Once the grooving roll and pipe are in contact, continued rotation of the jack screw tends to draw the circumferential surface  121  of the back-up roll  120  into contact with the inside surface  128  of pipe  20 . As shown in FIG. 7, this motion of the back-up roll toward pipe  20  is enabled by mounting end  126   b  of pivot arm  126  on a pin  138  in a slotted aperture  140  arranged lengthwise along the pivot arm. The pin  138  is fixed to the carriage  70  and allows the pivot arm  126  to pivot about axis  82 , and the slotted aperture  140  allows a limited degree of motion of the pivot arm relatively to the axis  82 , permitting the jack screw to draw the back-up roll into engagement with the pipe as shown in FIG. 9. Preferably, the pivot arm  126  along with grooving tool  56  is biased toward the pivot axis  82  by a spring  142  arranged within a slot  141  positioned between the end of the pivot arm and slotted aperture  140 . Spring biasing eliminates the sloppiness in the joint which would otherwise cause misalignment between the back-up roll and the pipe, and yet allows a limited range of motion of the pivot arm relatively to the pin  138  to place the back-up roll in contact with the pipe.  
         [0049]    Once back-up roll  120  engages the inside surface  128  of pipe  20 , the pipe is rotated by the chuck  58 , and the grooving roll  116  is advanced toward back-up roll  120  by rotating jack screw  124 . Pipe rotation is clockwise when viewed in FIG. 7 to ensure that the grooving tool  56  is forced against support stop  48 . As shown in FIG. 10, the circumferential surface  117  of grooving roll  116  engages and deforms pipe wall  38 , thereby forming groove  36 . Preferably, the grooving roll is advanced gradually in stages as the pipe is rotated. Once the groove has the desired outer diameter appropriate for the particular coupling to be used, rotation of the pipe  20  is stopped and the jack screw  124  is rotated to move movable portion  114  away from pipe  20  along the direction indicated by arrow  130  in FIG. 7. Initially, due to this motion of movable portion  114  and the biasing action of spring  142 , pivot arm  126  moves relatively to pin  138 , drawing back-up roll  120  away from the pipe inside surface  128 , thus, allowing the back-up roll to clear the bump  37  of the groove  36  (see FIG. 10). Once the pivot arm  126  reaches the end of its travel as permitted by slotted aperture  140 , further rotation of jack screw  124  draws the grooving roll  116  out of engagement with groove  36 . Once the back-up roll is clear of the bump  37  and the grooving roll is clear of the groove  36 , the grooving tool  56  is then moved away from pipe  20  by sliding carriage  70  away from the pipe via handle  76 . The grooving tool is then pivoted through arc  88  back to the position shown in phantom line in FIG. 7 and the pipe is removed from the chuck.  
         [0050]    The grooving tool and work station according to the invention allow pipe stock to be prepared for accepting mechanical couplings efficiently by performing all of the necessary preparatory steps at one station, and eliminating the extra steps of mounting and dismounting the pipe stock onto and off of multiple stations. Significant time and cost savings are foreseen with the use of the invention, especially when large quantities of pipe stock are to be processed.