Abstract:
An apparatus for handling tubular goods which includes an elongate tubular body having a peripheral sidewall and opposed ends. The peripheral sidewall has a plurality of axial slots arranged circumferentially around the tubular body parallel to an axis of the tubular body. An articulating coupling protrudes from at least one of the opposed ends. The articulated coupling includes an insert positioned within the tubular body with radial pins that engage the slots, the pins being axially movable along the slots. A gripping assembly is provided at one of the opposed ends for engaging a tubular good.

Description:
[0001]     This is a continuation-in-part of U.S. patent application Ser. No. 10/239,454, now U.S. Pat. No. 6,732,822, priority of the filing date of which is hereby claimed under 35 U.S.C. § 120. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The manufacture, assembly and use of tubular systems in drilling and constructing wells frequently involves operations where the tubular work piece must be gripped and handled to enable the application of axial and torsional loads.  
       BACKGROUND OF THE INVENTION  
       [0003]     In U.S. Pat. No. 6,732,822 there was described and claimed an apparatus for handling tubular goods having an internal gripping device for handling tubular work pieces. There was also described the use of articulated couplings. It has now been realized that the articulated couplings illustrated and described were equally important to the internal gripping device claimed, as they permit the transfer of torque with little or not moment or lateral resistance. Once the principles underlying the use of the articulated coupling are understood, beneficial results may be obtained even when other configurations of gripping devices (internal or external) are used to engage the tubular goods.  
       SUMMARY OF THE INVENTION  
       [0004]     According to this aspect of the present invention there is provided an apparatus for handling tubular goods which includes an elongate tubular body having a peripheral sidewall and opposed ends. The peripheral sidewall has a plurality of axial slots arranged circumferentially around the tubular body parallel to an axis of the tubular body. An articulating coupling protrudes from at least one of the opposed ends. The articulated coupling includes an insert positioned within the tubular body with radial pins that engage the slots, the pins being axially movable along the slots. Means are provided for engaging a tubular good at one of the opposed ends.  
         [0005]     The upper adapter is coupled to the grip assembly by means of a tube having upper and lower universal joints which enable lateral movement during transmission of torque, as is commonly employed in applications where torque is transmitted over some length, such as in automobile drive shafts flexibly coupled through universal joints. The grip assembly is further arranged to permit the grip to be activated, or set, by application of right hand torque and deactivated or released by application of left hand torque when a first operating mode is engaged. In a second operating mode, either left or right hand torque is transferred directly through the grip without changing the grip force. The first or setting mode is engaged by application of slight axial compressive load, or by setting the quill down. The second or direct torque mode is engaged by application of slight tension or by lifting the quill up once the grip is set. These simple, fast and direct means of gripping and releasing provide substantial operational improvements over the existing methods.  
         [0006]     A primary purpose of the present invention is to provide a method employing an internal gripping device for handling tubular work pieces in general and particularly suited to perform make up and break out of pipe joints being run in or out of a well with a top drive drilling rig, having as its gripping mechanism a sub-assembly comprised of: 
    1. a generally cylindrical expandable cage with upper and lower ends,     2. a structural member is provided in the form of a mandrel. Mandrel has upper and lower ends placed coaxially inside the cage where the lower ends of the mandrel and cage are attached, and where the external diameter of the cage is somewhat less than the internal diameter of the tubular work piece to be gripped, allowing the cage to be positioned within the tubular work piece,     3. a significant annular space between the inside surface of the cage and the outside surface of the mandrel,     4. a pressure member disposed in the lower interval of the annular space between the mandrel and cage as an expansion element, and     5. means to activate the expansion element to cause the cage to expand and frictionally engage the inside surface of the tubular work piece with sufficient radial force to enable the mobilization of friction to transfer significant torque and axial load from the upper end of the mandrel through the cage to the tubular.    
 
         [0012]     Said expandable cage of the gripping mechanism having a lower and upper end: 
        is preferably comprised of a plurality of flexible strips aligned largely axially along the body of the cage and attached to cylindrical sleeves at each end of the cage,     where the edges of adjacent strips are preferably profiled to provide interleaving tabs or fingers,     which fingers permit cage expansion or radial displacement of the strips but tend to prevent cage twist or shear displacement between strips under torsion loading.        
 
         [0016]     Said means to provide cage expansion is preferably provided by: 
        a largely incompressible elastomeric material disposed in the lower interval of the annular space between the mandrel and cage,     means to confine the ends of the elastomeric material and if necessary further means to confine the outer sides of the elastomeric material across gaps that may exist between adjacent edges of the cage strips to prevent excess extrusion of the elastomeric material when compressed, and     means to axially compress the annular elastomeric material with sufficient force to cause the cage to expand and frictionally engage the inner surface of the tubular enabling transfer of torque and axial load from the upper end of the mandrel through the cage to the tubular.        
 
         [0020]     An additional purpose of the present invention is to provide a tubular gripping and handling device having said gripping sub-assembly joined to an external load and torque application device, such as the quill of a top drive rig, through a load transfer member or drive shaft, flexibly coupled at each end where such flexible couplers function as universal joints enabling transfer of torque with little or no moment or lateral resistance.  
         [0021]     This purpose is preferably realized by: 
        providing a crossover sub configured to thread to the quill on its upper end and connect to a tubular or hollow drive shaft at its lower end,     by means of pins engaging slots in the upper end of the drive shaft thus providing the function of a universal joint, where     a similar slotted and pinned connection is provided to join the lower end of the drive shaft to the upper end of the gripping mechanism sub-assembly.        
 
         [0025]     A further purpose of the present invention is to provide a means to flow fluid and apply pressure through the top drive adapter and into the tubular work piece being gripped. This purpose is realized by providing a flow path through the crossover sub, drive shaft and tool mandrel and is preferably augmented by provision of an internal cup seal, such as a packer or swab cup, attached to the lower end of the mandrel to prevent leakage into the annular space between the mandrel and inside surface of the tubular work piece.  
         [0026]     In applications, where the lifting capacity of the frictional grip is insufficient to reliably support the hoisting loads required to run assembled tubular strings into or out of a well, the make up and break out functions provided by the tubular handling and gripping assembly, must be supplemented by the addition of hoisting equipment. In a manner well known to the industry, such hoisting equipment may be provided as elevators. However, to support applications where suitable elevators may not be available or convenient to use, it is a further purpose of the present invention to provide additional means to support hoisting loads, integral with the frictional grip device.  
         [0027]     This purpose is realized by providing an external hoisting sub-assembly, which sub-assembly is comprised of: 
        a largely cylindrical hoisting sleeve coaxially placed outside the internal gripping sub-assembly having an upper end attached to the upper end of the internal gripping sub-assembly, a lower end extending downward to overlap an interval of the tubular work piece, typically to the lower end of the collar typically attached to the upper end of casing or tubing joints, and lower end configured with internal grooves,     a plurality of jaw segments, preferably provided as a collet where the upper end of the collet fingers are attached, and the lower end of the collet fingers carry the jaw segments configured to mate on their interior with the outside surface of the tubular work piece and on their exterior with ribs engaging the internal grooves of the hoisting sleeve where the spring action of the collet is preferably arranged so the jaws tends to contact the work piece,     where the mating ribs and grooves of the jaw and hoisting sleeve surfaces respectively tend to force the jaws inward under application of hoisting load, in the manner of slips, well known to the industry as a method of providing load transfer between hoisting equipment and tubular goods, and     means to retract the jaws to facilitate disengaging from the tubular work piece, which means is preferably linked to the operation of the internal friction grip so that the jaws may only be retracted when the tool is not set or activated.       
 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0032]      FIG. 1  is an isometric view of the assembled top drive make up adapter tool.  
         [0033]      FIG. 2  is a longitudinal cross-sectional view through the centre of the top drive make up adapter tool as it appears prior to setting.  
         [0034]      FIG. 3  is a longitudinal cross-sectional view of the top drive make up adapter tool with the gripping assembly in setting mode showing exaggerated cage expansion gripping the tubular work piece.  
         [0035]      FIG. 4  is a longitudinal cross sectional view of the top drive make up adapter tool with gripping assembly in torque mode showing exaggerated cage expansion gripping the tubular work piece.  
         [0036]      FIG. 5  is a schematic showing the general shape of a single ‘dovetailed’ tooth as they may be employed on the setting nut face with matching grooves in the actuator sleeve.  
         [0037]      FIG. 6  is an isometric view of the assembled top drive make up adaptor tool configured with externally latching, integral hoisting sub-assembly.  
         [0038]      FIG. 7  is a longitudinal cross-sectional view along the axis of the top drive make up adapter tool with hoisting sub-assembly showing position of components with tool in hoisting mode engaging the collar on the upper end of a typical tubular work piece.  
         [0039]      FIG. 8  is a longitudinal cross-sectional view of hoisting sub-assembly showing position of components with the tool in hoisting mode, engaging the collar on the upper end of tubular work piece.  
         [0040]      FIG. 9  is a longitudinal cross-sectional view of hoisting sub-assembly showing position of components with tool in retract mode.  
         [0041]      FIG. 10  is an isometric view of the assembled casing drive tool.  
         [0042]      FIG. 11  is a longitudinal cross-sectional view through the centre of the casing drive tool as it appears stabbed into the tubular work piece prior to setting.  
         [0043]      FIG. 12  is a view of a mandrel showing exterior profiled intervals.  
         [0044]      FIG. 13  is an isometric view of the casing drive tool with cage removed showing helical spring expansion assembly.  
         [0045]      FIG. 14  is a longitudinal cross-sectional view through the casing drive tool centre with the gripping assembly in setting mode showing cage expansion gripping the tubular work piece.  
         [0046]      FIG. 15  is a longitudinal cross sectional view through the casing drive tool centre with gripping assembly in torque mode showing cage expansion gripping the tubular work piece.  
         [0047]      FIG. 16  is a longitudinal cross sectional view through the centre of the casing drive tool with tool set and in torque mode showing tool position hoisting the tubular work piece.  
         [0048]     The aspect ratio of the drawings shown in  FIGS. 14, 15  and  16  has been adjusted to exaggerate the width.  
         [0049]      FIG. 17  is an isometric view of the articulating coupler as it would appear retracted.  
         [0050]      FIG. 18  is an isometric view of the articulating coupler as it would appear with both upper and lower adaptors fully articulated in the same direction as required to accommodate a drive line axis shift.  
         [0051]      FIG. 19  is a longitudinal cross sectional view through the articulating coupler with the coupler straight and fully extended.  
         [0052]      FIG. 20  Longitudinal cross sectional view through the articulating coupler with the coupler straight and fully retracted (same configuration as shown in  FIG. 17 ).  
         [0053]      FIG. 21  is a longitudinal cross sectional view through the articulating coupler with the coupler fully articulated to accommodate axial axis shift (same configuration as shown in  FIG. 18 ). 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0054]     In its preferred embodiment, the tubular internal gripping and handling device of the present invention is configured as a top drive make up adapter tool, which tool connects a crossover sub  1  to an internal gripping assembly through a flexibly coupled tubular drive shaft  2 .  FIG. 1  is an isometric view of the assembled tool with the grip in its unexpanded state, as it would appear preparatory to insertion into a tubular joint.  
         [0055]     The crossover sub  1  is generally cylindrical and made from a suitably strong and rigid material. Referring to  FIG. 2 , crossover sub  1  has an upper end  10  configured with internal threads  21  suitable for connection to the quill of a top drive and a lower end  22  configured to allow insertion into an upper end  23  of tubular drive shaft  2 . In the preferred embodiment it is also provided with a centre bore  24  to allow passage of pumped fluid through the quill as a convenient and desirable means for filling the tubular string.  
         [0056]     Referring to  FIG. 1 , tubular drive shaft  2  is provided with sets of through-wall closed L-shaped slots  25  at each of its upper and lower ends. Slots  25  are distributed equidistantly about the circumference and aligned axially. Tubular drive shaft,  2  is fastened to lower end  22  of crossover sub  1  by means of pins  26  placed through the upper set of slots  25  in tubular drive shaft  2 . This provides a flexible connection. The pin positions and outside diameter of the lower end of the crossover sub  1  in the interval of overlap with the tubular drive shaft  2  are so arranged that said flexible connection is free to bend or flex through several degrees in any direction when the pins  26  are in the axial ‘leg’  25   a  of the L-shaped slots  25  but prevent such flexibility when the pins  26  are in the lower circumferential leg  25   b  of the L-shaped slots  25 . The lower end of the drive shaft  2  is similarly connected by means of pins  26  within L-shaped slots  25  that are inverted and reversed relative to the upper end of the actuator sleeve,  9 , comprising the top element of the grip assembly. When the pins  26  are in the axial legs  25   a  of the slots  25 , this method of coupling both ends of the drive shaft,  2 , to the crossover sub  1  and grip assembly respectively not only provides for lateral translation of the top of the joint with respect to the quill axis but also allows some axial length variation, or stroking, since the pins may ride up and down in their slots, thus enabling the make up adapter tool to provide the function of a floating cushion sub during make up and break out. When the pins  26  are in the circumferential legs  25   b  of the slots  25 , this method of coupling allows the tool to be moved and positioned with the lateral flexibility fully disabled, thus providing advantages in handling, particularly valuable in slant rig operations, where the tool would otherwise droop with difficulty then being encountered when attempting to stab into the top of the tubular joint.  
         [0057]      FIG. 2  is a cross sectional view along the axis of the tool showing the relation of components in the grip assembly portion of the tool. In its preferred embodiment the grip assembly is comprised of several interacting components, those being: 
        an expandable generally cylindrical cage  3  with provided with an upper end  27  and a lower end  29 . Cage  3  has an outer diameter slightly less than the inside diameter of a tubular work piece  13  except at its upper end  27  where a stop ring  28  with increased diameter over a short distance is provided to create a shoulder sufficient to engage the end of the tubular work piece  13 ;     a mandrel  4  is provided having an upper end  30  and a lower end  31 . Mandrel  104  has an outside diameter significantly less than the cage  3  internal diameter and placed coaxially inside the cage,  3 , with its lower end  31  attached to lower end  29  of cage  3 , in a manner enabling transfer of axial load and torque and upper end extended beyond the upper end of the cage  3 ;     cylindrical lower spacer sleeve  5  and upper spacer sleeve  7 , separated by a generally cylindrical elastomeric setting element  6 , or series of elements, to form an element stack, which sleeves and element stack are placed coaxially in the annular space between the cage  3  and mandrel  4 , and where the length of the sleeves and element stack is somewhat less than the cage length;     a largely cylindrical setting nut  8  internally threaded to engage matching threads provided on the mandrel  4  over an interval starting at a position covered by the upper spacer sleeve  7  and having the face of its upper end configured as a dog nut with teeth  32  distributed equidistantly about the circumference, which teeth are preferably shaped as illustrated in  FIG. 5 ;     an actuator sleeve  9  sliding on the upper interval of the mandrel  4 , as illustrated in  FIG. 2 . Sleeve  9  has notches  33  on its lower end face matching teeth  32  provided on the upper end face of the setting nut  8 . Referring to  FIG. 2 , sleeve  9  has internal splines  34  on its lower end  36  matching external splines  35  provided on upper end  30  of mandrel  4 , and having threads on its external surface to accommodate jam nut  12 ;     a jam nut  12 , internally threaded to fit the actuator sleeve  9  and provided with set screws to lock its position on the actuator sleeve  9  and;     a swab cup  10 , or similar annular seal element such as a packer cup, retained with a nut  11  to the extreme lower end of the mandrel  4 .          
         [0065]     Referring to  FIG. 1 , the expandable cage,  3 , is generally cylindrical in its body, and in its preferred embodiment is formed from a thin smooth walled vessel of steel or other suitably strong and flexible material by cutting a series of largely square wave slits  78  along a mid length interval of the vessel at several circumferential locations. Although a smooth walled vessel is preferred to avoid surface marking of tubular goods; in some applications cage  3  may be made with a friction enhancing surface to improve its friction coefficient with respect to the tubular good. This forms a series of largely axially aligned strips  80  having their ends  82  attached by the non-slit upper and lower ends of the cylinder but having their edges  84  interlocked by the ‘tabs’  86  resulting from the largely square wave cutting pattern. Even though interlocked, there is some space or a gap between the strip edges, the magnitude of which is dependent on the method of manufacturing and tolerancing thereof. It will be evident to one skilled in the art that torsional loading applied along the axis of such a cage will tend to generate twisting distortion with associated shear displacement along the strip edges until any gaps between faces of the tabs are closed. Once these gaps are closed they begin to bear and transfer shear load along the strip length causing the torsional stiffness and strength of the cage  3  to increase dramatically and greatly enhancing it&#39;s overall ability to transmit torque. It is therefore desirable to keep the axial gap spacing as small as possible to limit the twist required to engage the tabs. It has been determined that laser cutting offers an efficient means to form slits narrow enough to sufficiently limit the angle of twist before tab contact; however, alternative manufacturing methods may be employed as indeed the cage  3  may built up from individual pieces suitably attached. The square wave amplitude or tab height must further be arranged to ensure sufficient overlap exists to achieve satisfactory shear load transfer when the cage  3  is in its expanded position within the tubular work piece  13 . It should also be apparent to one skilled in the art that numerous variations of the slitting geometry may be employed to enhance the fatigue and strength performance of the cage  3 , which rely on some form of interlocking to achieve maximum torque transfer capacity while retaining the ability to expand significantly as disclosed herein. Upper end  27  of the cage  3 , is provided with an upset diameter forming a stop ring  28  greater than the inside diameter of the tubular work piece  13  end to be gripped. Lower end  29  of cage  3  is typically provided with an internally upset diameter internally splined for attachment to the lower end  31  of mandrel  4 .  
         [0066]     The generally cylindrical mandrel  4  is formed from a suitably strong and rigid material to enable its function of axial load and torque transfer into the lower end of the cage  3  and in its preferred embodiment is provided with a centre bore  37  to enable fluids to be passed in or out of the tubular work piece  13  if desired. Lower end  31  of mandrel  4  is typically threaded and splined to attach the splined lower end  29  of cage  3  retained by nut  11 . The splined engagement being generally indicated by reference numeral  38 . In the preferred embodiment the lower threaded interval of the mandrel  4  may also be used to attach the swab cup  10  to provide sealing between the inside of the tubular work piece  13  and the mandrel bore, which method of sealing is well known to the oil field industry. The main body diameter of the mandrel, is selected with respect to the inside diameter of the cage  3  to provide an annular space sufficiently large to accommodate the elastomeric setting element  6 . Right hand threads are provided along the mandrel length over an interval where the load nut travel is desired. The upper end of the mandrel  4  is splined where the splines are open downward but have closed or blind upper ends. To facilitate and simplify assembly, the mandrel diameter at each of the intervals described generally increases from the lower to upper end, as needed to accommodate the functions of the threads, splines or controlled diameters. The upper end of the mandrel inside bore is provided with threads suitable for attachment to a hose or similar fluid conduit.  
         [0067]     The lower spacer sleeve  5  is a rigid cylinder of sufficient length to extend from the closed end of the cage  3  to a point somewhat above the ends of the cage strips  80  to provide a transition interval over which the strips of cage  3  can expand without being additionally radially loaded by application of expansion pressure by the elastomer. The inside and outside diameters of the lower sleeve are selected to fit inside the annular space between the mandrel  4  and cage  3  while minimizing the elastomer extrusion gaps.  
         [0068]     The upper spacer sleeve  7  is similar to the lower spacer sleeve  5  where its length is selected relative to the setting nut  8  and upper end of the cage slots  78  to also provide an interval where cage expansion can occur in the absence of radial expansion pressure.  
         [0069]     The setting element  6 , or element stack, is largely cylindrical and may be comprised of several separate components including specialized end elements or devices to control extrusion, such as is well known in the well bore packer and bridge plug art, but is generally formed of hydrostatically incompressible and highly deformable elastomeric materials and is dimensioned to largely fill the annular space between the upper spacer sleeve  7  and lower spacer sleeve  5 . This annular space and hence element stack must be of sufficient annular thickness and initial length so that the shortening under axial displacement required for expanding the cage  3  and setting, still provides an adequate interval length over which radial displacement and the consequent radial load are sufficient to mobilize the friction grip capacity as required by the application.  
         [0070]     The setting nut  8  is a largely cylindrical internally threaded nut with lower end smooth faced to allow sliding contact with the upper end of the upper spacer sleeve  7 . The upper face of setting nut  8  is configured with dog nut teeth  32  to enable torque coupling with the actuator sleeve  9 . To further facilitate engagement in applications requiring some ‘locking’, the tooth shape may be dovetailed and oriented so that the narrow portion of the dovetail is attached to the face of the nut as shown in  FIG. 5 .  
         [0071]     The actuator sleeve  9  is largely cylindrical and rigid with internal diameter slightly greater than the upper end of the mandrel  4  on which it slides. The face of its lower end is provided with evenly distributed notches  33  to engage the matching notches in the upper end of the setting nut  8  which notches may be dovetailed as required to match the setting nut  8  geometry as shown in  FIG. 5 . The inside surface of the lower end of the actuator sleeve  9  is provided with splines  34  to match the splines  35  on the upper end of the mandrel  4 . When assembled, the actuator sleeve  9  is able to slide on the mandrel  4  but is constrained in its lower position by the top of the setting nut  8 , referred to as setting mode position, and in its upper position by the blind ends of the spline grooves  35  on the mandrel  4  referred to as torque mode position. The various interacting component lengths are arranged so that the actuator has sufficient travel between these two positions to create a range of motion where neither the setting nut  8  nor the upper mandrel splines are engaged, which intermediate position is referred to as neutral because the actuator sleeve  9  is free to rotate about the mandrel  4 . The upper end of the actuator sleeve  9  has an external diameter somewhat less than the internal diameter of the drive shaft  2 , and has several holes distributed equidistantly around its circumference to accept pins  6  which provide attachment to the drive shaft  2 .  
         [0072]     In operation, with the crossover sub  1 , of the top drive adapter tool made up to the quill of a top drive rig, the grip assembly is lowered into the top end of a tubular joint until the cage stop ring engages the top end surface of the joint. The top drive is then further lowered or set down on the tool which causes the actuator sleeve  9  to displace downward until its notched lower end  33  engages the teeth  32  on the upper face of setting nut  8 . This position is referred to as setting mode. Right hand rotation of the top drive then drives the nut downward against the upper spacer sleeve  7  which acts as an annular piston, compressing the elastomeric element and causing it to expand radially thus forcing the cage  3  outward and into contact with the inside surface of the tubular work piece  13 . Continued right hand rotation causes largely hydrostatic compression of the elastomer with consequent development of significant contact stress between the cage  3  and the inner surface of the tubular over the length of the elastomeric setting element  6 . Frictional resistance to the compressive axial load is developed in the setting nut threads and end face and is manifest as torque at the top drive. It will be apparent that this torque is reacted through the tool into the tubular joint. Until the cage  3  is expanded, this reaction is provided by incidental friction of the cage strips, the swab cup  10  and contact with the stop ring  28 . Once activated the cage expansion ‘self reacts’ the increasing setting torque, a measurement of which is available to the top drive control system and may be used to limit the amount of setting force applied. As a further means to limit the amount of setting force applied, the position of the jam nut  12  may be adjusted up or down on the actuator sleeve by rotation, and locked with the set screws provided in the jam nut  12 . When thus positioned and locked the jam nut will engage the top of the cage and ‘jam’ during setting with consequent dramatic torque increase and thus limit the downward travel of the actuator sleeve and hence setting nut. When sufficient setting torque has been applied, the tool is considered set.  FIG. 3  shows a cross section of the tool in setting mode with the cage,  3 , expanded into contact with the tubular work piece  13 .  
         [0073]     Once set, the top drive is raised which disengages the lower face of the actuator sleeve  9  from the setting nut  8  and upon being further raised engages the actuator sleeve splines  34  and mandrel splines  35  at the upper extent of the actuator range of travel where the closed ends of the mandrel spline  35  grooves prevent the actuator sleeve  9  from sliding off the top of the mandrel  4 . This position is referred to as torque mode and either right or left hand torque may by transferred through the actuator sleeve  9 , directly to the mandrel  4 .  
         [0074]     As is apparent in  FIG. 1 , the application of right hand torque during setting will move the pins out of the circumferential leg  25   b  of the L-shaped slots  25  so that when the quill is raised to engage torque mode, the pins will tend to slide up the axial legs  25   a  of the L-shaped slots and re-establish the flexibility of the drive shaft coupling.  
         [0075]     If the joint is to be broken out, the top drive is positioned to allow the drive shaft  2  to ‘float’, i.e. with the pins positioned approximately mid-way in the slots, and reverse torque applied. Once broken out, the joint weight may be supported by the tool and raised out of the connection until gripped by separate pipe handling tools. Once gripped by the pipe handlers, the top drive is set down on the tool, engaging the set mode. Left hand torque is then applied and the setting nut  8  rotated a sufficient number of turns to release the tool. The amount of rotation required to release will in general be equal to the number of turns required for setting.  
         [0076]     If the joint is to be made up, its weight may be supported by the tool while being positioned and stabbed into the connection to be made up. Once stabbed, and with the joint weight still largely supported by the tool, the connection may be made up. As for break out, the tool is released by setting down the top drive to engage set mode and applying sufficient left hand rotation to release the tool.  
         [0077]     For either make up or break out, it will be evident from  FIG. 1 , that setting down and applying left hand torque will cause the pins  26  to move into the circumferential legs  25   b  of the L-shaped slots. Upon withdrawal from the tubular work piece  13 , the tool will be more or less rigidly coupled to the quill, facilitating stabbing into the top of the next joint of tubular goods to be handled.  
         [0078]      FIG. 4  shows the tool in torque mode set inside a tubular work piece  13 . It will be evident to one skilled in the art that loads (torque or tension) applied to the mandrel  4  with the tool set and in torque mode are reacted in part into the tubular work piece  13  by shear coupling through the annular thickness of the elastomer and cage material compressed between the mandrel  4  and tubular work piece  13 . However the greater part of any applied loads are reacted through the lower end of the mandrel  4  into the lower end of the cage  3 , and from there, are shed into the tubular work piece  13  over the interval along which it is in contact with the expanded cage  3 . The axial or torsional load required to initiate slippage is therefore determined by the area in contact, the effective friction coefficient acting between the two surfaces and the normal stress acting in the interfacial region between the cage  3  and work piece  13 . It will be further evident to one skilled in the art that to provide sufficient torque and axial load capacity, these variables may be manipulated in numerous ways including: lengthening the expanded interval of the grip; coating, knurling or otherwise roughening the cage exterior to enhance the effective friction coefficient; increasing the axial stress that may be applied to the elastomer through improved materials and extrusion protection (within the limits imposed by the allowable stress state (e.g., burst capacity) of the tubular work piece,  13 ), and; reduced friction loss along the setting element  6  by disposing lubricants on the mandrel and cage surfaces contacted by the setting element  6 , perhaps in combination with friction reducing coatings such as Teflon®.  
         [0079]     It will be apparent to one skilled in the art that as the elastomer is compressed from the top, sliding resistance will tend to cause the hydrostatic stress to decrease from top to bottom over the elastomer length. It has been found in practice that lubrication of the elastomer surfaces can be employed to reduce this effect if required to either improve the ‘self starting’ response or the relationship between setting torque and axial or torsional grip capacity.  
         [0080]     To provide further functionality in applications where it is desired to apply fluid pressure or flow fluids into or out of the tubular work piece  13 , as often occurs when running casing which must be filled from the top, in its preferred embodiment the top drive adapter tool is configured with a hose connected between the bottom end of the crossover sub bore and the top of the mandrel bore. The hose length and positioning must be arranged to accommodate the length change between the hose end attachment points occurring during operation as allowed by the axial stroke of the drive shaft slots and the movement of the actuator sleeve,  9 . Positioning the hose as a coil inside the drive shaft,  2 , provides one means to accommodate the required length change during operation. The hose and connections must also accommodate rotation of the cross over sub  1  with respect to the mandrel  4  during setting and unsetting or if rotating in neutral. A swivel coupling, or other suitable means, may be used to provide this function.  
         [0081]     To further enhance the operational and handling characteristics of the tool, springs may be provided between the drive shaft  2 , crossover sub  1  and grip assembly. A compression spring may be provided between the drive shaft  2  and actuator sleeve  9  to reduce the tendency for the actuator sleeve  9  to become disengaged from the setting nut,  8 , while rotating in setting mode without downward travel of the quill. A tension spring may be provided between the crossover sub  1  and the drive shaft  2  to similarly reduce the tendency of the actuator sleeve spline to disengage from the mandrel  4  while rotating in torque mode to break out a joint, which break out tends to push the joint upward. As the joint moves upward in the absence of quill travel, sliding will tend to occur in the tool either within the slots of the drive shaft  2  or by sliding between the engaged actuator sleeve and mandrel splines. It will be seen that the tension spring biases the pins in the upper end of the drive shaft  2  to slide in favour of the engaged spline. It will be evident to one skilled in the art that various other biasing strategies may be similarly employed such as control of friction coefficient in the pinned flexible couplings relative to the engaged components to simplify operating procedures. Alternatively, details of the engagement mechanisms may be varied to accomplish similar purposes such as lengthening the overlapped splined interval or modifying the tooth and notch profile between the setting nut  8  and actuator sleeve  9  to obtain a more preferential friction angle. One such configuration is shown in  FIG. 5 .  
         [0082]     In the preferred embodiment, expansion of the cage  3  is accomplished by elastomeric material that comprises the setting element  6  making direct contact against the cage, so that under setting stresses, elastomer extrusion into the gaps between cage strip edges is possible. If the combination of applied stress and gap size required for certain applications results in excessive extrusion, the cage gaps may be bridged by provision of individual thin solid strips placed on the inside surface of the cage  3  so as to cover the gaps over the interval where elastomer load occurs. To facilitate assembly, said strips may be fastened to one or the other of the strips forming the gap to be bridged.  
         [heading-0083]     Preferred Embodiment Incorporating Additional Integral Hoisting  
         [0084]     In its preferred embodiment as a top drive make up adaptor tool, the method of the present invention readily accommodates the axial and torsional loads required to handle, make up and break out single joints of pipe as required to run casing or tubing strings in and out of well bores. However, to support applications where the hoisting loads associated with running such strings may exceed the ability of the internal friction grip of the make up adaptor tool to reliably support the string weight, the tool may be provided with an externally gripping, integral hoisting sub-assembly.  
         [0085]      FIG. 6  shows an isometric view of a tool configured with such a hoisting sub-assembly, showing the general location of the components supporting the hoisting function relative to the cage  3  and drive shaft  2 . The components comprising the hoisting sub-assembly may be described with reference to  FIG. 7 , which shows an entire longitudinal cross section along the tool axis, and  FIG. 8 , which shows a close up view of the tool centre interval. In these figures the hoisting components are shown in relation to the tubular work piece  13  having a threaded collar  41  forming its upper end as is typical of oil field casing or tubing. The components are shown as they would appear when hoisting.  
         [0086]     A largely cylindrical hoist tube  40 , is attached at its upper end to the actuator sleeve  9  and at is lower end to the upper end of a largely axisymmetric hoist collar  42 , having an internal diameter somewhat greater than the outside diameter of the work piece collar  41  and having a length extending below the lower face of the work piece collar  41 . The lower end of the hoist collar,  42 , is provided with one or more relatively deep grooves, forming teeth having a shape similar to buttress threads, where the load flank is sloping downward and the stab flank is relatively flat. The latch segments  44  are configured as the lower ends of fingers on the hoist collet  46  having an interior profile closely matching the work piece  13  diameter, below the work piece collar  41  when the collet is in its relaxed state. The exterior surface of the latch segments  44  are profiled to form ribs loosely engaging and generally matching the buttress profile of the grooves provided in the lower end of the hoist collar  42 . The root and crest diameters, and other dimensions of the buttress profiled grooves and ribs, are selected to ensure the engagement of the load flanks when the latch segments  44  are positioned against the pipe is sufficient to carry the hoisting load and that the latch segments  44  may displace outward a sufficient distance so that the bore formed by the expanded segments is greater than the outside diameter of the work piece collar  41 . The upper end of the latch segments are arranged to align with the lower face of the work piece collar  41  when the actuator sleeve  9  is near the upper extent of its travel in torque mode.  
         [0087]     The body of the hoist collet  46  extends upward passed the latch control collet  48  attached to the upper end of the cage  3 . The fingers of the latch control collet  48  open upward having ends which form an internal upset conical surface and external upset rounded surface. In its relaxed state, the external diameter defined by the latch control collet  48  fingers, is slightly less than the internal diameter of the relaxed hoist collet  46  body. The setting nut indicator sleeve  50  has a relatively thin cylindrical lower end extending downward and engaging the setting nut  8  at the outside edge of its upper end. The upper end of the setting nut indicator sleeve  50  is provided with an externally upset conical end, dimensioned to engage the internally upset conical end of the latch control collet  48 .  
         [0088]     To further support the hoisting load capacity of the tool, externally threaded split rings  52  are provided to mate with internal threads on the upper and lower ends of the drive shaft  2 . When the slotted and pinned connections between the drive shaft  2  and the crossover sub  1  and actuator sleeve  9  are fully extended, the externally threaded split rings  52  engage shoulders provided in the crossover sub  1  and actuator sleeve  9 , which shoulder engagement reacts the hoisting load instead of the pinned connection.  
         [0089]     In operation the hoisting sub-assembly may be placed in one of two modes depending on the position of the setting nut  8 . When the tool is set, the setting nut  8  will be in its lower position compressing the setting element  6 . In this position the hoist collet  46  tends to hold the latch segments against the work piece  13  placing the hoisting sub-assembly in hoisting mode as shown in  FIG. 8 . Application of hoisting load tending to lift the tool, will be transferred through the hoist collar and carry the latch segments upward until their upper ends begin to bear on the lower face of the work piece  13  collar. Upon application of additional hoisting load, engagement of the conical load flank surfaces provided by the buttress shaped hoist collar  42  grooves, and latch segment  44  ribs, tend to create a radial force, in the manner of slips, which radial force ensures positive engagement between the work piece  13  and tool.  
         [0090]     To disengage the tool from the work piece  13 , collar the latch segments  44  must be retracted to place the tool in release mode as shown in  FIG. 9 . To retract the latch segments, the hoisting load must be removed and the tool un-set by left hand rotation of the setting nut  8 , which as described above, raises the setting nut  8  and simultaneously raises the setting nut indicator sleeve  50 . Continued left hand rotation brings the upper cone of the setting indicator sleeve into contact with the mating internal conical surface on the inside of the latch control collet  48 , forcing the fingers outward and into contact with the interior of the hoisting collet  46  body, expanding the hoisting collet  46  and retracting the latch segments  44  carried on the ends of the hoisting collet  46  fingers, thus enabling the tool to be disengaged from the work piece  13 .  
         [heading-0091]     Preferred Embodiment Incorporating Additional Axial Load and Fatigue Capacity  
         [0092]     As discussed above, advances in drilling rig technology have resulted in increased use of top drive rigs. Top drives are primarily used to apply drilling loads to drill pipe, however they also allow application of handling, make up and break out loads required for running tubulars, referred to as casing and tubing, typically used to case or complete the well. To run casing or tubing requires a method of coupling the quill to the tubular capable of transmitting full make up or break out torque, and at least some axial load, without risking damage to the threaded connections of these tubulars which are less robust than those used to connect joints of drill pipe.  
         [0093]     The embodiment of the present invention described to this point, specifically address this need for a tool to support running tubing or casing. However the emerging use of top drives to perform drilling using casing, referred to in the industry as Casing Drilling™, has resulted in the further need for a method to grip casing to perform drilling operations. The preferred embodiment described above, while suited to the needs of make up and break out of casing and tubing for running operations, does not provide the axial load and fatigue capacity required for drilling with casing.  
         [0094]     The embodiment which will now be described, with reference to  FIGS. 10 through 16 , was therefore conceived specifically as a means to couple the top drive quill to casing with a device having sufficient axial and torsional fatigue capacity to support drilling with the casing while preserving the advantages of a friction grip provided by the earlier casing running tool.  
         [0095]     To meet these objectives, the method of the present invention makes use of a device having an upper end provided with a cross-over sub to attach to the quill of a top drive and having a lower end provided with a grip assembly, which may be inserted into the top end of a tubular work piece and expanded to engage or grip the inside surface of the tubular work piece. The grip method and contacting element preferably frictionally engage the inside wall of the tubular with symmetric radial loading, virtually eliminating the risk of marking or distorting the pipe or connection. The method of expansion employed in the grip assembly further provides means whereby the application of axial load tends to increase the gripping force applied by the device to the work piece, better enabling hoisting loads to be reliably transferred from the quill into the tubular joint. It will be understood that such attachment to the top drive quill may be direct or indirect to other intermediate components of the drill string such as a ‘thread saver sub’ essentially forming an extension of the quill.  
         [0096]     The cross over sub is coupled to the grip assembly by means of a sliding, splined and sealing connection, providing the function of a ‘cushion sub’ to facilitate management of load during make-up, transmission of axial and torque loads and containment of fluids. The grip assembly is further arranged to permit the grip to be activated, or set, by application of right hand torque and deactivated or released by application of left hand torque when a first operating mode is engaged. In a second operating mode, either left or right hand torque is transferred directly through the grip without changing the grip force. The first or setting mode is engaged by application of slight downward axial movement, or setting the quill down. The second or direct torque mode is engaged by lifting the quill up once the grip is set, i.e., application of upward movement until slight tensile resistance occurs. These simple, fast and direct means of gripping and releasing provide substantial operational improvements over the existing methods.  
         [heading-0097]     Summary of Preferred Embodiment Incorporating Additional Axial Load and Fatigue Capacity  
         [0098]     An additional purpose of the present invention is to provide a method employing an internal gripping device for handling tubular work pieces in general and particularly suited for connecting between a top drive quill and upper joint of casing in a string used for Casing Drilling™, having as its gripping mechanism a sub-assembly comprised of: 
    1. a generally cylindrical expandable cage with upper and lower ends,     2. a structural member in the form of a mandrel is provided. The mandrel has upper and lower ends placed coaxially inside the cage where the lower ends of the mandrel and cage are attached in a manner allowing torque transfer and some relative axial movement, and where the external diameter of the cage is somewhat less than the internal diameter of the tubular work piece to be gripped, allowing the cage to be placed inside the tubular work piece,     3. a significant annular space between the inside surface of the cage and the outside surface of the mandrel,     4. a pressure member disposed in the lower interval of the annular space between the mandrel and cage as a spring expansion element,     5. means to activate the spring expansion element to cause the cage to expand and frictionally engage the inside surface of the tubular work piece with sufficient radial force to enable transfer of significant torque and axial load from the upper end of the mandrel through the cage to the tubular, and     6. further means to increase the radial force applied by the spring expansion element, beyond that provided by the activation means, upon application of sufficient axial load as may be required to support some portion of the string weight while conducting running or drilling operations.    
 
         [0105]     Said cylindrical cage of the gripping mechanism having a lower and upper end: 
        is preferably comprised of a plurality of strips aligned largely axially along the body of the cage and attached to cylindrical sleeves at each end of the cage,     where the edges of adjacent strips are preferably profiled to provide interlocking tabs or fingers, and     which fingers permit cage expansion or radial displacement of the strips but tend to prevent cage twist or shear displacement between strips under torsion loading.        
 
         [0109]     Said means to provide cage expansion is preferably provided by: 
        a generally cylindrical helical spring expansion assembly disposed in the central interval of the annular space between the mandrel and cage,     which helical spring expansion assembly is formed by a plurality of structural, coaxial, helically parallel coils having co-terminal upper and lower ends and side edges, and by upper and lower spring end sleeves structurally engaging the upper and lower co-terminal ends of the coils,     means to axially compress the cylindrical helical spring assembly with sufficient force to cause the cage to expand and frictionally engage the tubular work piece enabling transfer of torque and axial load from the upper end of the mandrel through the cage to the tubular,     which structural engagement between the coil ends and sleeves preferably using a pivoting connection formed by providing said coil ends with a curved profile to mate with sockets placed in the upper and lower spring end sleeves where the axis of rotation for each pivoting connection is largely radially aligned to thus facilitate rotation as the helix angle increases under deformation imposed by axial compression causing expansion of the cylindrical helical spring assembly,     helix angle of the helically parallel coils chosen so that under compression the spring assembly expands significantly and preferably chosen to be slightly less than 45° with respect to the pipe axis in their expanded configuration,     where contact between side edges of helically parallel coils is preferably allowed, but if not allowed a means is provided to react the torque required to prevent edge contact, and     which means to react torque to prevent edge contact is preferably obtained largely by providing the cylindrical spring assembly in two co-axial layers having their helixes wound in opposite directions and sleeve elements at their ends connected.        
 
         [0117]     Said means to increase the radial force applied by the expansion element upon application of axial load provided by reacting the lower spring end sleeve into the mandrel and the upper spring end sleeve into the upper end of the cage. Thus configured, lifting load, applied to the upper end of the mandrel, is reacted into the lower end of the cylindrical spring assembly and thence partially reacted by frictional contact through the cage wall into the tubular work piece and partially as tension applied to the top of the cage and resisted by frictional contact between the cage and work piece.  
         [0118]     An additional purpose of the present invention is to provide a tubular gripping and handling device having its cross-over sub joined to said gripping sub-assembly by an appropriately splined and dogged connection allowing sufficient free sliding axial movement to facilitate control of axial load during make up required to perform what is known as a ‘floating make up’, i.e., make up under conditions where at most the weight of the single joint being made up is allowed to be born by the threaded connection undergoing make up.  
         [0119]     A further purpose of the present invention is to provide a means to flow fluid and apply pressure through the casing drive tool and into the tubular work piece being gripped. This purpose is realized by providing a flow path through the crossover sub and tool mandrel and is preferably augmented by provision of an internal annular seal, such as a packer or swab cup, attached to the lower end of the mandrel preventing leakage in the annulus between the mandrel and inside surface of the tubular work piece.  
         [heading-0120]     Description of Preferred Embodiment Incorporating Additional Axial Load and Fatigue Capacity  
         [0121]     In the preferred embodiment of the present invention incorporating additional axial load and fatigue capacity, the tubular internal gripping and handling device of the present invention, generally referred to as gripping assembly  100 , is configured as a casing drive tool. Referring to  FIG. 10 , gripping assembly  100  connects to a crossover sub  101 . Referring to  FIG. 11 , crossover sub  101 , is generally axisymmetric and made from a suitably strong and rigid material. Crossover sub  101  has an upper end  140  configured with threads suitable for connection to the quill of a top drive rig and a lower end  142  configured with threads to engage an upper end  146  of an actuator sleeve of gripping assembly  100 . In the preferred embodiment it is also provided with a centre bore  148  to allow passage of fluid pumped through the quill to facilitate various drilling and running operations such as mud circulation.  
         [0122]      FIG. 11  is a cross sectional view of the casing drive tool showing the relation of components in the gripping assembly  100  as they would appear stabbed into a tubular work piece  113 . Tubular work piece  113  is shown as the top interval of a joint of casing having a collar  150  at its upper end  152 . In its preferred embodiment grip assembly  100  is comprised of several interacting components, those being: 
        an expandable generally cylindrical cage  103  is provided having an upper end  154  and a lower end  156 . Cage  103  has an outer diameter slightly less than the inside diameter of tubular work piece  113 , except at its upper end  154  where a stop ring  157  with increased diameter over a short distance is provided to create a shoulder sufficient to engage collar  150  at upper end  152  of tubular work piece  113 ;     a mandrel  104  is provided having an upper end  158  and a lower end  160 . Mandrel  104  has an outside diameter significantly less than an internal diameter of cage  103  and is placed co-axially inside cage  103 . Upper end  158  of mandrel  104  extends beyond upper end  154  of cage  103 . Lower end  160  of mandrel  104  is splined to lower end  156  of the cage  103 . This splined interval, indicated by reference numeral  162 , enables torque transfer and allows some relative axial movement tending to prevent transfer of axial lifting load from mandrel  104  to lower end  156  of cage  103  and;     there is also provided a cylindrical lower spring end sleeve  105 , and an upper spring end sleeve  107 , separated by a plurality of coaxial closely spaced helical coils forming a generally cylindrical helical spring element  106 . Helical spring element  106  together with the spring end sleeves  105  and  107  form a helical spring expansion assembly, generally indicated by reference numeral  164 . Helical spring expansion assembly  164  is placed co-axially in the annular space between cage  103  and mandrel  104 . The length of helical spring expansion assembly  164  is somewhat less than the length of cage  103 . Lower spring end sleeve  105  is attached to lower end  160  of mandrel  104  directly above splined interval  162  traversed by mating lower end  156  of cage  103 ;     a largely cylindrical setting nut  108  is provided which is externally threaded to engage matching threads provided in upper end  154  of cage  103 . Setting nut  108  has an external spline over a portion of its upper interval, this splined interval being indicated by reference numeral  168 ;     an actuator sleeve  109  is provided which slides on upper end  158  of mandrel  104 . Actuator sleeve  109  has an internal splined interval  170  on its lower cylindrical end  172  that mates with external splined interval  168  on the upper end of setting nut  108 . Actuator sleeve  109  also has internal splines  174  matching external splines  176  provided on upper end  158  of mandrel  104 , and     a packer cup  110 , or similar annular seal element, is fastened with a nut  111 , to the extreme lower end  160  of mandrel  104 . Packer cup  110  and nut  111  also constrain the lower travel limit of cage  103 , which engages splined interval  162  of mandrel  104 .          
         [0129]     Referring to  FIG. 10 , the expandable cage  103  is generally cylindrical and is, preferably, formed from a generally smooth walled vessel of steel or other suitably strong and flexible material. Cage  103  has a series of largely square wave slits  178  along the cylindrical interval of the vessel body at several circumferential locations, thus forming a series of largely axially aligned strips  180 . Strips  180  have their ends  182  attached by the non-slit upper and lower ends of the cylinder and have their edges  184  interlocked by the ‘tabs’  186  resulting from the largely square wave cutting pattern. Even though interlocked, there is some space or a gap between the strip edges, the magnitude of which is dependent on the method of manufacturing and tolerances thereof. It will be evident to one skilled in the art that torsional loading applied along the axis of such a cage will tend to generate twisting distortion with associated shear displacement along the strip edges until any gaps between faces of the tabs are closed. Once these gaps are closed they begin to bear and transfer shear load along the strip length causing the torsional stiffness and strength of the cage  103  to increase dramatically and greatly enhancing it&#39;s overall ability to transmit torque. It is therefore desirable to keep the axial gap spacing as small as possible to limit the twist required to engage the tabs. It has been determined that laser cutting offers an efficient means to form slits narrow enough to sufficiently limit the angle of twist before tab contact; however, alternative manufacturing methods may be employed as indeed the cage  103  may built up from individual pieces suitably attached. The square wave amplitude or tab height must further be arranged to ensure sufficient overlap exists to achieve satisfactory shear load transfer when the cage  103  is in its expanded position within the tubular work piece. It should also be apparent to one skilled in the art that numerous variations of the slitting geometry may be employed to enhance the fatigue and strength performance of the cage  103  that rely on some form of interlocking to achieve maximum torque transfer capacity while retaining the ability to expand significantly as disclosed herein. The non-slit upper end  154  of the cage  103  is provided with a stop ring  157  having an upset diameter greater than the inside diameter of the upper end  152  tubular work piece end  113  to be gripped and internal threads mating with the external threads of the setting nut  108 . The lower end of the cage  103  is typically provided with an internally upset diameter internally splined over interval  162  for attachment to the lower end of the mandrel  104 .  
         [0130]     Referring to  FIG. 11 , the generally cylindrical mandrel  104  is formed from a suitably strong and rigid material to enable its function of axial load and torque transfer. In its preferred embodiment, it is provided with a centre bore  188  to enable fluids to be passed in or out of tubular work piece  113 , if desired. An upper end  190  of bore  188  is enlarged and threaded to attach a flow tube,  112 . A lower end  192  is similarly enlarged and threaded to attach the nut  111 . An outer surface  194  of the mandrel is shaped as shown in  FIG. 12  to accommodate connection to and interaction with various sub-components of the system and has the following intervals described in order from its lower to upper end. 
        Outer surface  194  on lower end  160  of the mandrel  104  is smooth to form a packer seal interval  196 . The packer cup,  110 , provides annular sealing between the inside of the tubular work piece and the mandrel bore, which method of sealing is well known to the oil field industry.     Directly above the packer seal interval  196  is lower splined interval  162  that engages the internally splined lower end  156  of the cage  103 , which splined interval is of sufficient length to allow cage  103  to slide axially.     Above lower splined interval  162  is an upper threaded interval  200  that engages the internally threaded lower spring end sleeve  105 , which threads are tapered in the preferred embodiment to maximize the axial load transfer efficiency of the connection.     Extending upward from the upper threaded interval  200  is the central body interval  202  having a diameter slightly less than the internal diameter of the unloaded helical spring expansion assembly  164 .     Central body interval  202  extends upward from upper threaded interval  200  and ends abruptly at a shoulder  204  forming the lower limit of a stop shoulder upset interval  206  having a diameter slightly less than the crest diameter of the actuator sleeve  109  internal splines  174  and length somewhat greater than the actuator sleeve  109  mid-section splined interval  170 . Shoulder  204  acts as a stop, limiting the range of relative upward travel allowed to setting nut  108 , with respect to the mandrel  104 .     Directly above stop shoulder upset interval  206  is the upper splined interval  176  which splines are open downward and configured to facilitate engagement with internal splines  174  of actuator sleeve  109 .     A shoulder  208  forming the lower limit of hoisting shoulder upset interval  210 , closes the upper end of upper splined interval  176 . Shoulder  208  engages a matching internal shoulder  212  in actuator sleeve  109 , enabling transfer of hoisting loads from actuator sleeve  109  to mandrel  104 .        
 
         [0138]     It will thus be apparent that to facilitate and simplify assembly, the mandrel diameter at each of the intervals described generally increases from its lower to upper end, as needed to accommodate the functions of the threads, splines, shoulders or controlled diameters.  
         [0139]     The lower spring end sleeve,  105 , is a rigid cylinder, internally threaded to engage the mandrel  105  as described above. It is of sufficient length to extend from the cylindrical end of the cage  103  to a point somewhat above the ends of cage strips  180 . This provides a transition interval over which the strips of cage  103  can expand without being additionally radially loaded by application of expansion pressure by the helical spring element  106 . The outside diameter of the lower spring end sleeve  105  is selected to fit just inside the cage  103 . Referring to  FIG. 13 , its lower end  214  is contoured or scalloped to form sockets  216  mating with the rounded ends of the helical coils constituting the helical spring element  106 . Its lower end  218  is configured as a dog nut to mate with dogs provided in lower end  156  of internally upset splined interval  162  of cage  103 . The dog teeth are configured to be engaged over the range of motion allowed to the cage  103  with respect to the mandrel  104 . This prevents lower spring end sleeve  105  from rotating on the mandrel  104 , enabling transfer of torque from the mandrel  104  into the helical spring assembly  164 .  
         [0140]     The upper spring end sleeve  107  is similar to the lower spring end sleeve  105 , having its lower end  220  contoured or scalloped. Its length is selected relative to the setting nut  108  and upper end of cage slits  178  to also provide an interval where cage expansion can occur in the absence of radial expansion pressure. However its internal bore is smooth to facilitate sliding relative to the mandrel.  
         [0141]     Referring to  FIGS. 11 and 13 , the helical spring element  106  is largely cylindrical and comprised of a plurality of coaxial closely spaced coils formed with a helix angle slightly less than 45° with respect to the cylinder axis. In its preferred embodiment, the coils of the helical spring element  106 , have a rectangular cross-section with smooth edges nearly touching when unloaded. When assembled between the upper spring end sleeve  107  and lower spring end sleeve  105  to form a helical spring expansion assembly  164 , the coil ends and sockets  216  form pivoting connections as shown in  FIG. 13 . In operation, axial compression applied to the helical spring expansion assembly initially brings the coil edges into contact. Further application of load tends to cause the entire helical spring element to expand radially. Confined by the cage  103 , which is in turn confined by the tubular work piece  113 , the application of sufficient axial load results in a radial or pressure load being transferred through cage  103  and reacted by work piece  113 . The presence of such radial load at both the inner and outer surfaces of cage  103  enables frictional transfer of axial and radial loads from upper end  158  of mandrel  104  to work piece  113  both through helical spring element  106  and through cage ends  154  and  156 . Spring element  106  must be of sufficient length so that the radially loaded interval provides an adequate area over which to mobilize the friction grip capacity required by the application. The thickness of spring element  106 , and mating lower and upper spring end sleeves,  106  and  107 , are selected to ensure sufficient contact area exists across the pivoting connections to transfer the required axial load when spring  106  is expanded.  
         [0142]     The setting nut  108 , is a largely cylindrical externally threaded nut with internal diameter slightly greater than the mandrel  104  main body interval  202  and lower end smooth faced to allow sliding contact with the upper end of the upper spring end sleeve  107 , which sliding contact may be enhanced by the addition of a thrust washer or other means generally known in the industry to manage wear and promote consistent frictional resistance. The upper end of the setting nut  108  is upset and carries external spline  168  engaging internal spline  170  on lower end  172  of actuator sleeve  109 , which splined connection enables torque coupling while allowing relative axial sliding movement.  
         [0143]     The actuator sleeve  109  is largely axisymmetric and rigid, with a generally uniform diameter external surface. Its internal surface is profiled to mate with three components as follows. Its lower end  172  forms an internally splined cylindrical sleeve  170  to engage the matching exterior splines  168  in the upper end of the setting nut  108 , which splined connection is loose fitting providing a significant amount of rotational back-lash, and sufficiently long to accommodate the full travel of the setting nut  108 . Directly above the splined sleeve interval  170  is a relatively short internally upset mid-section splined interval  174  engaging the mandrel  104  upper splined interval  176 . Above the mid-section splined interval  174  the bore increases to accommodate hoisting shoulder upset interval  210  of mandrel  104 , with shoulder  212  of actuator sleeve  109  engaging shoulder  208  of mandrel  104 . The bore extends to the upper end of the actuator sleeve  109 , where it is provided with threads to connect with the crossover sub  101 .  
         [0144]     When assembled, the actuator sleeve  109  is able to slide on the mandrel  104 , and is constrained in its upper position by hoisting shoulder  208  on mandrel  104 , enabling transfer of hoisting load from the mandrel  104  into the actuator sleeve  109 . The range of motion from this upper position downward to the point where the actuator sleeve and mandrel splines disengage is referred to as torque mode, and is illustrated in  FIGS. 15 and 16 . The interval between the position where actuator sleeve  109  is lowered a sufficient distance to first disengage the mandrel splines  176  and its lowest position constrained by contact with the top of setting nut  108 , is referred to as setting mode position and is illustrated in  FIGS. 11 and 14 . The various interacting component lengths are preferably arranged so that the actuator has sufficient travel in both torque and setting modes to provide the function of a ‘floating cushion’, where no significant axial load may be transferred between the tool and work piece.  
         [0145]     In its preferred embodiment a flow tube  112  is provided between the interior bores  188  and  148 , respectively, of mandrel,  104 , and crossover sub,  101 . A lower end  224  of flow tube,  112 , is sealingly threaded to upper end  190  of the mandrel bore  188 . An upper end  226  of flow tube  112  extends telescopically into the lower end of the crossover sub bore  148  through an annular seal  228  carried in the lower end of the crossover sub bore  148 . This configuration readily accommodates the required range of sliding between the crossover sub  101  and mandrel  104  while minimizing the fluid end load that would otherwise occur if sealing were provided between the mandrel  104  and actuator sleeve  109 .  
         [0146]     In its preferred embodiment the nut  111  is provided with a lower conical end  230  to facilitate stabbing into the tubular work piece  113 . Where upper end  152  of tubular work piece  113  carries an interior box thread, as is typical for casing and tubing joints, the conical end surface is preferably coated with an elastomer or similar relatively soft material to mitigate the potential for damage to the threads.  
         [0147]     In operation, with crossover sub  101  of the casing drive tool made up to the quill of a top drive rig, the grip assembly is lowered into the top end of a tubular joint until the cage stop ring  157  engages the top end surface, illustrated as collar  150 , of the joint. The top drive is then further lowered or set down on the tool which causes the actuator sleeve  109  to displace downward until it disengages from spline  176  on mandrel  104  and simultaneously causes cage  103  to slide up lower splined interval  162  of mandrel  104  until stopped by contact between lower spring end sleeve,  105  and lower end  156  of cage  103 . This position is referred to as setting mode, as illustrated in  FIG. 11 . Right hand rotation of the top drive then drives nut  108  downward against upper spring end sleeve  107 , which acts as an annular piston, compressing helical spring  106  causing it to expand radially, thus forcing cage  103  outward and into contact with the inside surface of the tubular work piece, as illustrated in  FIG. 14 . Continued right hand rotation causes largely biaxial compression of the helical spring element,  106 , with consequent development of significant contact stress between the cage  103  and the inner surface of the tubular over the length of the spring element. Frictional resistance to the compressive axial load is developed in the setting nut threads and end face and is manifest as torque at the top drive. It will be apparent that this torque is reacted through the tool into the tubular joint. Until the cage  103 , is expanded, this reaction is provided by incidental friction of the cage strips  180 , the packer cup  110  and contact with the stop ring  157 . Once activated the cage expansion ‘self reacts’ the increasing setting torque, a measurement of which is available to the top drive control system and may be used to limit the amount of setting force applied. When sufficient setting torque has been applied, the tool is considered set.  FIG. 14  shows a cross section of the tool in setting mode with the cage  103  expanded into contact with the tubular work piece. Once set, the top drive may be raised to engage the torque mode position, where the upward movement causes the actuator sleeve  109  to slide up relative to the mandrel and engage the splines  174  and  176 , respectively, between the actuator sleeve  109  and mandrel  104 . At the upper extent of the actuator range of travel the actuator sleeve shoulder  212  engages the mandrel shoulder  208  to prevent the actuator sleeve  109  from sliding off the top of the mandrel  104  and enable transfer of hoisting loads. To facilitate engagement of this spline, the mating spline tooth ends on both the mandrel  104  and actuator sleeve  109  are appropriately tapered. Engagement is further facilitated by the relatively loose fitting spline engagement between the actuator sleeve  109 , and setting nut  108  allowing some relatively free rotation. Thus in torque mode either right or left hand torque may by transferred through the actuator sleeve  109  directly to the mandrel  104 .  FIG. 15  shows the tool in torque mode, set inside a tubular work piece as it might appear prior to making up or breaking out a joint.  
         [0148]     Thus set, if the joint is to be broken out, the top drive is positioned to place the actuator sleeve  109  at or near the upper limit of the ‘float’ provided in torque mode, and reverse torque applied. Once broken out, the joint weight may be supported by the tool and raised out of the connection until gripped by separate pipe handling tools. Once gripped by the pipe handlers, the top drive is set down on the tool to a position near the upper limit of the float provided in set mode. Left hand torque is then applied and the setting nut,  108 , rotated a sufficient number of turns to release the tool. The amount of rotation required to release will in general be equal to the number of turns required for setting.  
         [0149]     Alternately, if the joint is to be made up after the tool is set, the joint weight may be supported by the tool while being positioned and stabbed into the connection to be made up. Once stabbed, and with the top drive is positioned to place the actuator sleeve,  109 , at or near the lower limit of the ‘float’ provided in torque mode, the connection may be made up. As for break out, the tool is released by setting down the top drive to engage set mode and applying sufficient left hand rotation to release the tool.  
         [0150]      FIG. 16  shows the tool in torque mode, set inside a tubular work piece  113  as it would appear while carrying hoisting load. Based on the teachings given herein describing the load transfer behaviour of the helical spring assembly interacting with the cage  103  and tubular work piece  113 , it will be evident to one skilled in the art that loads (axial and torque) applied to the mandrel  104  with the tool set and in torque mode, are reacted in part into the tubular work piece by coupling through the helical spring assembly and in part through the upper and lower ends of the cage. The relatively stiff connection between the mandrel  104  and the helical spring element  106  provided by the lower spring end sleeve  105  ensures that only torque loads exceeding the frictional capacity of the interfacial region of contact between the helical spring element  106  and cage  103  tend to be transferred to lower splined connection between the cage  103  and mandrel  104 . This greatly reduces the magnitude of cyclic torsional load transferred through the lower interval of the cage  103 , and hence substantially improves its operational fatigue life. Axial hoisting load is reacted through the lower spring end sleeve  105  and if it exceeds the setting load tends to cause sliding in the interval of travel allowed by the lower splined connection between the mandrel  104  and the cage  103  which movement is evident as gap between the cage and lower spring end sleeve as shown in  FIG. 16  and allows an increase in the radial pressure applied by the helical spring element  106  and hence the frictional lifting capacity of the grip assembly. This ‘self energizing’ tendency is highly valuable as a means to ensure sufficient frictional force is available to prevent slippage when hoisting. It will be further apparent that a portion of the axial load is reacted through the upper spring end sleeve  107  and into the top of the cage,  103 , as tension, which tension for large lifting loads will tend to increase above that required for setting. However it will only tend to decrease significantly upon a substantial reduction in axial hoisting load due, to the reversal in direction the friction vectors must undergo when the direction of sliding is reversed. This behaviour has an advantageous effect on the fatigue life of the cage,  103 , upper end similar to the manner in which the grip assembly responds to fluctuations in torque load.  
         [0151]     Among other variables, the axial or torsional load required to initiate slippage is determined by the area in contact, the effective friction coefficient acting between the two surfaces, and the normal stress acting in the interfacial region between the cage,  103 , and work piece. It will be further evident to one skilled in the art that to provide sufficient torque and axial load capacity, these variables may be manipulated in numerous ways including: lengthening the expanded interval of the grip; coating, knurling or otherwise roughening the cage exterior to enhance the effective friction coefficient; and increasing the axial stress that may be applied to the helical spring assembly.  
         [0152]     It will be apparent to one skilled in the art, that as the helical spring element,  106 , is compressed from the top, sliding resistance will tend to cause the axial and radial contact stress to decrease from top to bottom over the element length. It has been found in practice that lubrication of the contacting surfaces can be employed to reduce this effect if required to either improve the ‘self starting’ response or the relationship between setting torque and axial or torsional grip capacity.  
         [0153]     The casing drive tool also provides a fluid conduit from the top drive quill into the tubular joint in which it is set. This is necessary in Casing Drilling™ applications where it is desired to apply fluid pressure or flow fluids into or out of the tubular work piece  113  and often occurs when running casing that must be filled from the top. In its preferred embodiment, the flow tube  112  connecting the internal bores of the cross over sub  101  and actuator sleeve  109 , and the packer cup  110 , support this function.  
         [heading-0154]     Alternative Embodiments  
         [0155]     Sensors to provide measurements of torque and axial load may be incorporated into the actuator sleeve or other member of the load train or provided as separate devices and incorporated into the tool load train.  
         [0156]     A hydraulic actuator may be used to provide the axial setting load on the helical spring element that causes expansion of the cage in place of the mechanical system of the preferred embodiment using a torque driven setting nut to apply the setting load.  
         [0157]     A stronger yet still readily expandable cage wall may be constructed by joining at the ends two or more individual layers of coaxial close fitting thin wall tubes, each slit with interlocking tabs in the manner of the single wall cage described for the preferred embodiment.  
         [0158]     In a further aspect of the preferred embodiment, we believe the helical spring element may be provided in two close fitting concentric layers having their helix angles wound in opposite directions, and the upper spring end sleeve keyed to the mandrel so that relative axial sliding movement is allowed but not rotation. This arrangement allows the helical spring elements to be loaded without contact between the edges of individual coils by reacting the torsion required to prevent edge contact under application of axial load. By adjusting the helix angle along the length of the helical spring element, this arrangement allows the relationship between axial load and radial pressure to be favourably adjusted to increase the overall grip capacity in a given length.  
         [0159]     The method of internally gripping a work piece using a cage to enable torque and axial load transfer may be applied to applications where external gripping is required by inverting the grip architecture presented in the preferred embodiment. For such an inverted architecture the function of the mandrel is provided by a rigid outer sleeve, where the cage is coaxially positioned inside the outer sleeve and attached at one end, and the tubular work piece placed inside the cage. The helical spring element is disposed in the annular space between the mandrel and cage and means provided to activate the helical spring element with tension to cause the cage to contract inward and frictionally engage the outside surface of the tubular work piece with sufficient radial force to enable the mobilization of friction to transfer significant torque and axial load from the outer sleeve through the cage to the tubular.  
         [heading-0160]     Additional Detail Regarding Articulation Coupling  
         [0161]     Referring to  FIG. 1 , the articulating drive portion of the casing drive tool, including flexibly coupled tubular drive shaft  2 , may be provided separately to enable connection to various configurations of hoist or drive heads.  
         [0162]     Referring now to  FIG. 17 , such an independent articulating coupler  200  is shown providing the functions of a flexible torque transmitting coupling, accommodating both axis angle change, axis translation and length variation or stroking. In addition, the coupler can be provided with a fluid conduit to enable transport of pressure contained fluid through the body of the coupler and can be provided with a load compensation spring or springs.  
         [0163]     Similar to the tubular internal gripping and handling device shown in  FIG. 1  and described in the preferred embodiment, the articulating coupler  200  shown in  FIG. 17  is provided with an upper adaptor  201  having internal threads  221 , placed in its upper end  210 , suitable for connection to the quill of a top drive and a lower adaptor  209  also suitably provided with threads or other means to attach to various hoisting or gripping tools. The upper adaptor  201  is connected to lower adaptor  209  by tubular drive shaft  202  through upper and lower pairs of pins  226  slidingly engaged in matching upper and lower axial (longitudinal) slots  225 . As described, this arrangement enables articulation of the coupling to allow for axis translation as shown in  FIG. 18 . It will also be apparent that the articulation thus provided can also accommodate changes of angle. As in the earlier description, the slots  225  may be provided with other configurations, such as L-slots to facilitate locking out the articulation for certain operations. The axial or longitudinal configuration shown in this embodiment is well suited to normal vertical well operations.  
         [0164]     Lower adaptor  209  may be configured to connect to various casing running or drive tools, such as the top drive make up adaptor tool shown in  FIG. 6 . However it is an express purpose of the present invention that this includes such simple devices as thread adaptors, commonly known as nubbins, to directly engage casing or drill pipe threads. In fact, such thread geometries may be directly provided on lower adaptor  209 .  
         [0165]     Referring now to  FIG. 19 , showing the coupler in cross-section as it would appear extended, the interior space of tubular drive shaft  202  accommodates both telescopic flow line  250  and pneumatic spring  280 . Tubular drive shaft  202  is provided with upper and lower tension support rings  203  attached, which support rings engage the upper and lower adaptors  201  and  209  respectively to transfer axial tension load. Similarly tubular drive shaft  202  is provided with compression support sleeve  204  also attached, which sleeve engages upper and lower adaptors  201  and  209  respectively when the tool is retracted to transfer axial compressive load.  
         [0166]     Telescopic flow line  250  is sealingly connected to upper adaptor  201  and lower adaptor  209  by means of upper and lower ball socket connectors  251  and  252  respectively. Telescopic flow line  250  is comprised of flow line piston  253  which sealing slides inside flowline cylinder  254  in contact with flowline seal  255 .  
         [0167]     Pneumatic spring  280  is attached to the upper end  256  of flow line cylinder  254  by spring cap  281  in sealing engagement with the outer surface of flow line piston  253  thus forming oil chamber  282 . Spring cylinder  283  is attached to spring cap  281  and flow line cylinder  254  thus enclosing gas chamber  284  between spring cap  281  and the outer surface of flow line cylinder  254 . Oil is placed in oil chamber  282  and in the bottom of gas chamber  284  forming fluid level  286 . Fluid communication in between these two chambers is provided by flow tube  285  and connecting ports in spring cap  281 . Pressured gas, typically compressed air, is placed in gas chamber  284  acting as a ‘gas cap drive’ where gravity separation ensures the oil is top pressured by the gas cap thus providing a spring action by means of the piston effect of the pressured oil in oil chamber  282  acting between flow line piston  253  and spring cap  281 . Flow tube  285  is arranged to extend below fluid level  286  and thus draw from the bottom of gas chamber  284  where the oil is placed, thus tending to preferentially move oil into and out of oil chamber  282  as the articulating coupler  200  is stroked during operation.  
         [0168]     Referring now to  FIG. 20 , a cross section of the articulating coupler is shown as it would appear retracted under the action of the spring force of pneumatic spring  250 . The volume of oil chamber  282  increases, fluid level  286  decreases, while the length of telescopic flow tube  250  decreases, all relative to the extended configuration shown in  FIG. 19 . It will be apparent that this volume expansion tends to allow the gas cap to expand by movement of oil between the gas and oil chambers  284  and  282  respectively. This arrangement of pneumatic spring advantageously allows the spring characteristics of stiffness and force to be adjusted by controlling both the gas pressure and oil level in gas chamber  284 , in a manner known to the art, when for example sizing accumulators, and ensures the sliding seal remains oil wet promoting seal life and improved sealing over a gas contact seal. Such adjustment enables control of the coupler&#39;s ‘cushion sub’ characteristics when handling different weights of pipe and requiring stroking to accommodate stabbing of threads as is often desirable when running casing to avoid thread damage and other operational problems. However other spring arrangements, such as mechanical coil strings, can be used to provide axial load compensation between upper adaptor  201  and lower adaptor  209  without departing from the purpose of the present invention.  
         [0169]     Referring now to  FIG. 21 , the articulating coupler is shown in cross section as it would appear articulated to accommodate an axis shift in the drive line. It is evident from this figure that the arrangement of upper and lower ball socket connectors  251  and  252  respectively accommodates the movement of articulation by being placed at the rotation centre of the pins  226  as they travel in slots  225 . While other arrangements to provide the functions of flow through the articulating coupling may be employed without departing from the purpose of the present invention, this configuration enjoys the advantages of functional simplicity and spatial economy, reducing the length requirements for the articulating coupling. This is highly advantageous in many applications where rig hoisting height is limited.