Patent Publication Number: US-2010108441-A1

Title: Adjustable work platform for pipe and casing stabbing operations

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a handling board or platform and, more particularly, to a stabbing board assembly mountable on a well derrick for supporting a worker while stabbing joints of pipe or casing during running operations. 
     BACKGROUND OF THE INVENTION 
     It is common practice in the oil and gas well drilling art to provide some form of support or platform for accommodating an operator or worker at a position above the floor of the derrick, particularly during a running of pipe or tubulars into the well, in order to assist in properly axially aligning the tubulars during the stabbing operation. Typically this is accomplished through the use of casing stabbing boards, which are hung or suspended on wirelines held within the derrick or drilling rig. 
     Additionally, in the prior art, a number of devices have been developed to improve upon such hung or suspended stabbing boards. For example, U.S. Pat. No. 4,326,602 to Bryant, which is herein incorporated by reference in its entirety, teaches a portable stabbing board adapted to be attached to a rig which includes a frame member mountable with the rig and a platform adapted for vertical movement along the frame member for supporting a worker during running operations. However, the stabbing board of Bryant does not provide for any horizontal movement of the platform to allow an operator to be placed in sufficient proximity to the pipe or tubulars during stabbing operations and to easily and quickly allow the platform to move away from the pipe or tubulars when the operator has completed his task of stabbing the tubular. 
     U.S. Pat. No. 2,425,302 to Calhoun, which is herein incorporated by reference in its entirety, teaches a more permanently mounted stabbing board which can be adjusted in a horizontal manner. However, the stabbing board of Calhoun is designed to be kept or locked in a fixed horizontal relation through the use of bolts ( 55 ) positioned through aligned openings ( 53 ) in both the telescoping sleeve ( 42 ) and hanger rail ( 40 ), as well as through the use of a bar ( 58 ) the end of which are receivable in eyes ( 60 ) and ( 62 ). As such, the stabbing board of Calhoun cannot easily and quickly move the platform away from the pipe or tubulars when the operator has completed the stabbing operations so as to reduce the risk of the operator being hit or injured by to the moving blocks or other equipment within the derrick. 
     Accordingly, there still exists a need to for an improved stabbing board that will provide ease of platform movement in both the horizontal and vertical directions, that is stable and which is simple in design. 
     SUMMARY OF THE INVENTION 
     The present invention provides improvements to stabbing boards and stabbing baskets. 
     In one embodiment, the present invention provides a stabbing board for a rig and for supporting a worker while stabbing joints of tubular members together during running operations, comprising a frame member, a platform to support the worker, a carriage, vertical power means for moving the carriage vertically with respect to the frame member, a linkage to connect the platform to the carriage and to facilitate horizontal movement of the platform relative to the carriage and the frame member and horizontal power means for moving the platform horizontally with respect to the frame member. 
     In another aspect of the invention the linkage of the stabbing board is a scissors linkage and the vertical power means comprises a leadscrew mounted within the frame member, a motor to drive the leadscrew and a nut mounted on the carriage to receive the leadscrew. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: 
         FIG. 1  is a side perspective view of a stabbing board according to a preferred embodiment of the invention, shown with the linkage in an extended state, the platform moved away from the frame member and with the carriage and platform having moved some distance vertically up along the frame member; 
         FIG. 2   a  is a side perspective view of a stabbing board of  FIG. 1 , also shown with the linkage in an extended state, the platform moved away from the frame member, the carriage and platform having moved some distance vertically up along the frame member and further with a worker being supported by the platform; 
         FIG. 2   b  is a side perspective view of a stabbing board of  FIG. 1 , now shown with the linkage in a collapsed state, the platform moved adjacent the frame member, the carriage and platform having moved vertically down along the frame member and with a worker being supported by the platform; 
         FIG. 3  is a side perspective view of the carriage, linkage, platform (showing also the safety barrier assembly) and horizontal power means of the stabbing board of  FIG. 1 , shown with the linkage in an extended state; 
         FIG. 4  is a side perspective view of the carriage, linkage, platform and horizontal power means as shown in  FIG. 3 , but with the safety barrier assembly no longer being shown; 
         FIG. 5  is a side perspective view of the carriage, linkage, platform and horizontal power means as shown in  FIG. 4 , but with further components being hidden to more clearly illustrate certain other components thereof; 
         FIG. 6  is a side perspective view of the frame member, vertical power means and carriage, of the stabbing board of  FIG. 1 , shown with the carriage having moved some distance vertically up along the frame member; 
         FIG. 7  is a side perspective view the frame member, vertical power means and carriage as shown in  FIG. 6 , but with components being hidden to more clearly illustrate certain other components thereof; 
         FIG. 8  is a side perspective view of the stabbing board of  FIG. 1 , shown with the carriage at a lower most position along the frame member, with the linkage in a collapsed state, with the platform adjacent the frame member and with the platform floor being pivoted (upwardly) in a stowed position; 
         FIG. 9  is a side perspective view of the lower portion of the stabbing board as shown in  FIG. 8 ; and 
         FIG. 10  is another side perspective view of the stabbing board as shown in  FIG. 2   a.    
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description is of a preferred embodiment by way of example only and without limitation to the combination of features necessary for carrying the invention into effect. Reference is to be had to the Figures in which identical reference numbers identify similar components. The drawing figures are not necessarily to scale and certain features are shown in schematic form in the interest of clarity and conciseness. 
       FIGS. 1-10  illustrate the configuration of a preferred embodiment of the present invention. In this embodiment, stabbing board  10  is adapted to be removably attached to a rig (not shown) from the inside and for supporting a worker W in stabbing joints of tubular members (also not shown) together during running operations. 
     The stabbing board  10  of this embodiment includes generally a frame member  12 , rig attachment means  14  to attach or mount the stabbing board to the inside of a rig, a platform  16  to support the worker W, a carriage  22  to slidably mount the platform  16  to the frame member  12 , vertical power means  18  for moving the carriage  22  and platform  16  vertically with respect to the frame member  12 , a linkage  30  to interconnect the platform  16  with the carriage  22  and to facilitate horizontal movement of the platform  16  relative to the carriage  22  and frame member  12 , and horizontal power means  40  for moving the platform  16  horizontally with respect to the frame member  12 . Unless otherwise specified, it is preferred that the components of the invention be made of steel or other suitable high-strength materials capable of taking stresses and strains encumbent upon such a stabbing board  10  during its intended use during stabbing operations. 
     As is well known and preferred, the drilling rig has a plurality of horizontal girders or braces connecting its legs. Frame member  12  is adapted to be affixed with the rig, along the rig&#39;s inside periphery, using one or more of the rig&#39;s horizontal girders, in a vertical plane substantially parallel with the tubulars. The frame member  12  includes includes a pair of vertical, substantially parallel channel members  12   a,    12   b.  The channel members  12   a,    12   b  preferably are of a U-shaped channel having channel troughs  12   a ′,  12   b ′ formed within the U-shaped channel members with the channel troughs  12   a ′,  12   b ′ of the channel members  12   a,    12   b  facing inwardly with respect to the frame member  12 . Top frame member  12   c  and bottom frame member  12   d  separate and maintain the substantially parallel vertical relationship of the channel members  12   a,    12   b  and provide for the upper and lower strength of the frame member  12  of the present invention. A plurality of braces  12   e  provide further structural support for the frame member  12  and are mounted therewith adjacent the exterior surface of the vertical channel members  12   a,    12   b  and preferably not within the troughs  12   a ′,  12   b ′ of the channel members  12   a,    12   b.  The upper end  12   j  of the frame member  12  is formed by the top frame member  12   c  and the adjacent portions of channel members  12   a,    12   b  while the lower end  12   k  of the frame member  12  is formed by bottom frame member  12   d  and adjacent channel member  12   a,    12   b,  respectively. It is preferred that the frame member  12  be of a rigid construction, as noted above. 
     The stabbing board  10  of the present invention preferably comprises rig attachment means  14  with the frame member  12  for removably securing the frame member  12  with the inside of a rig. In the preferred embodiment, rig attachment means  14  includes a top support member  24  mounted with the upper end  12   j  of the frame member  12 . The top support member  24  may also be referred to as girder locking assembly and comprises a pair of top supports  24   a,  each substantially alike and having a suitable hook  24   b  formed adjacent one end thereof. Preferably, the top support  24   a  and hook  24   b  are an integral unit. The top support member  24  is adapted to supportably engage the rig for supporting the frame member  12 . The top support member  24  is mounted with the rig in such a fashion that the top support  24   a  may extend through the rig side with a portion thereof disposed on a girder of the drilling rig. Advantageously, the hook  24   b  is useful for engaging the girder of rig during installation procedures and to prevent the stabbing board  10  from falling from the rig during such preliminary placement procedures. 
     The rig attachment means  14  further comprises bottom locating means designated generally as  34 . The bottom locating means  34  comprises at least one arm  34   a  adapted to be mounted with the lower end  12   k  of the frame member  12 . Multiple arms  34   a  may be used, if desired. The arms  34   a  are preferably pivotally mounted to the lower end  12   k  at a pivot points P. More preferably, arms  34   a  are slidably mounted, using securable sliding means  34   s,  with and along the vertical channel members  12   a,    12   b  adjacent the lower end  12   k  thereof. This preferred arrangement of the bottom locating means  34  results in substantially universal mounting of the arm  34   a  with the frame member  12  such that the arm  34   a  may pivot and slide in a vertical plane with respect to the frame member  12 . 
     The bottom locating means  34  further includes a sleeve  34   c  slidably mounted with arm  34   a  and movable along the length thereof as desired. The sleeve  34   c  has projecting plate  34   e  depending therefrom. Appropriate securing means  34   d  which may include an screwable tee handle or the like threaded through a treadable opening within the sleeve  34   c.  As such, the bottom locating means  34  is for locating the lower end  12   k  of the frame member  12  an appropriate distance from the rig to insure a substantially vertical disposition of the frame member  12  within the rig. The arm  34   a  extends from the frame member  12  through the rig side of the drilling rig for engaging a girder thereof. More particularly, the sleeve  34   c  is positioned with the arm  34   a  such that the sleeve&#39;s plate  34   e  engages the girder of the rig and the securing means  34   d  secures the sleeve and consequently arm  34   a  to the drilling rig upon being suitably disposed against the girder, for ease in quick mounting. 
     In an alternate embodiment (not shown), the stabbing board  10  is permanently attached to the rig, such as by welding or bolting the frame member  12  directly to the rig. 
     The stabbing board  10  of the present invention further comprises platform  16  for supporting the worker W during running operations. The platform  16  comprises a floor  16   f  affixed to a rear platform support  16   r.  Rear platform support  16   r  comprises a pair of vertical, substantially parallel platform channel members  16   a,    16   b  mounted therewith and extending substantially upwardly from the floor  16   f.  Top and bottom support members  16   t,    16   bt  separate and maintain the substantially parallel vertical relationship of the platform channel members  16   a,    16   b  and provide for the upper and lower strength of the rear platform support  16   r.  The platform channel members  16   a,    16   b  preferably are of a U-shaped channel having channel troughs  16   a ′,  16   b ′ formed within the U-shaped channel members with the platform channel troughs  16   a ′,  16   b ′ of the platform channel members  16   a,    16   b  facing inwardly with respect to the rear platform support  16   r.    
     Preferably, the platform  16  further comprises a safety barrier assembly  17  to form the perimeter of a working cage for the worker W utilizing the stabbing board  10  of the present invention. The safety barrier assembly  17  has appropriate braces such as vertical posts  17   a,    17   b  and safety chain  17   c  for providing a suitable barrier to safely keep worker W on the stabbing board  10  during running operations. More preferably, the platform floor  16   f  further comprises a wire screen or metal grate (not shown) to prevent inadvertent slipping of the worker when standing on the floor  16   f.  It is preferred that the rear platform support  16   r  is sized such that it is of substantially the same width as the vertical channel members  12   a,    12   b  of the frame member  12 . 
     Even more preferably, the platform floor  16   f  is pivotally connected to the rear platform support  16   r,  using a securable pivot means  50 , to enable the platform to be folded up in a substantially vertical position, substantially paralled to the rear platform support  16   r,  when the platform  16  is not in use and requires to be stowed (see  FIGS. 8 and 9 ). 
     The stabbing board  10  of the present invention further comprises carriage  22  for supporting the platform  16  and capable of vertical movement V along the frame member  12 . Carriage  22  comprises a pair of vertical, substantially parallel carriage channel members  22   a,    22   b.  Top and bottom support members  22   t,    22   bt  separate and maintain the substantially parallel vertical relationship of the carriage channel members  22   a,    22   b  and provide for the upper and lower strength of the carriage  22 . The carriage channel members  22   a,    22   b  preferably are of a U-shaped channel having carriage channel troughs  22   a ′,  22   b ′ formed within the U-shaped channel members with the carriage channel troughs  22   a ′,  22   b ′ of the carriage channel members  22   a,    22   b  facing inwardly with respect to the carriage  22 . 
     Carriage  22  is slidably mounted to the frame member  12  for vertical movement V along said frame member  12 . Preferably, carriage  22  is disposed within the channel troughs  12   a ′,  12   b ′ formed within vertical channel members  12   a,    12   b  of the frame member  12 . More preferably, a plurality of carriage rollers  22   r  are provided to facilitate said slidable vertical movement V of the carriage  22  within the channel troughs  12   a ′,  12   b′.    
     The stabbing board  10  of the present invention further comprises vertical power means  18  to provide motive force for moving the carriage  22  vertically with respect to the frame member  12 . Preferably, vertical power means  18  is a leadscrew-based power means, further comprising a leadscrew  18   l  (threads not shown) mounted within the frame member  12  in a vertical plane substantially parallel with the frame member, a motor  18   m  to drive the leadscrew and a nut  18   n  mounted on the carriage  22  to receive and treadably mate with the leadscrew  18   l  (leadscrew  18   l  otherwise passing through carriage through appropriate sized openings, including openings in top and bottom support members  22   t,    22   bt ) and to translate the torque of the leadscrew  18   l  into linear vertical motive force on the carriage  22 . More preferably, the threads of the leadscrew  18   l  and nut  18   n  have an Acme profile. Even more preferably the motor  18   m  is an air motor or may alternatively be an electric, hydraulic or any other suitable type of motor. The carriage  22  (and the platform  16  mounted thereto) is movable vertically along the frame member  12  upon actuation of the vertical power means  18 . 
     Advantageously, the leadscrew-based power means is self-locking (i.e. when stopped, a linear force on the nut  18   n  will not apply a torque to the leadscrew  18   l ). More advantageously, the vertical power means  18  is therefore capable of holding vertical loads (such as the carriage  22 , platform  16  and any worker W positioned thereon) when the motor  18   m  is turned of, thereby providing significant safety advantages over a winch and cable based power means such as that disclosed in U.S. Pat. No. 4,326,602 to Bryant. 
     The stabbing board  10  of the present invention further comprises a linkage  30  to interconnect the platform  16  with the carriage  22  and to facilitate horizontal movement H of the platform  16  relative to the carriage  22  and the frame member  12 . Preferably, the linkage  30  is a scissors linkage  30   s  capable of moving in the horizontal plane only and comprising laterally off-set, side-by-side scissor linkages, each scissor linkage having one or more sets of lever arms. In this embodiment, scissors linkage  30   s  comprises two pairs of lever arms  31 ,  31 ′ and  32 ,  32 ′ each mounted scissor fashion, i.e. a pair of level arms pivoting about a pin  30   p  in their median part, respectively pivoting with the side edges of the platform  16  and carriage  22 . 
     One of the free ends  31   a,    32   a  of each of arms  31 ,  32  is pivotally mounted about a fixed pin  31   p,    32   p  secured to the carriage  22 , each to their respective carriage channel members  22   a,    22   b.  The other free ends  31   b,    32   b,  of each of the pairs of arms  31 ,  32 , each pivot about a roller or slider  31   r,    32   r  slidably mounted within their respective platform channel troughs  16   a ′,  16   b ′ of the platform channel members  16   a,    16   b  (see  FIG. 3 ). The other free ends  31   b,    32   b  are thereby confined to move in a rectilinear manner, that is, with straight line motion, relative to the platform channel members  16   a,    16   b  with which they are associated. Preferably, a pivoting cross-member  33  separates and maintains the substantially parallel relationship of free ends  31   b,    32   b  and provide for additional strength of the linkage  30 . 
     One of the free ends  31 ′ a,    32 ′ a  of each of arms  31 ′,  32 ′ is pivotally mounted about a fixed pin  31 ′ p,    32 ′ p  secured to the platform  16 , each to their respective platform channel members  16   a,    16   b.  The other free ends  31 ′ b,    32 ′ b,  of each of the pairs of arms  31 ′,  32 ′, each pivot about a roller or slider  31 &#39; s,    32 &#39; s  slidably mounted within their respective carriage channel troughs  22   a ′,  22   b ′ of the carriage channel members  22   a,    22   b  (see  FIG. 4 ). The other free ends  31 ′ b,    32 ′ b  are thereby confined to move in a rectilinear manner, that is, with straight line motion, relative to the carriage channel members  22   a,    22   b  with which they are associated. Preferably, a cross-member  34  separates and maintains the substantially parallel relationship of free ends  31 ′ b,    32 ′ b  and provide for additional strength of the linkage  30 . 
     The stabbing board  10  of the present invention further comprises horizontal power means  40  to provide motive force for actuating the linkage  30  between an extended state (see  FIG. 2   a ) and a collapsed state (see  FIG. 2   b ) and, hence, move the platform  16  horizontally with respect to the frame member  12  and, consequently, towards or away from the well center and any tubular members that may be present there. 
     Horizontal power means  40  may be a hydraulic ram-based means of conventional design. Preferably, however, horizontal power means  40  is a leadscrew-based power means, further comprising a leadscrew  40   l  (threads not shown) mounted within the rear platform support  16   r  in a vertical plane substantially parallel with platform channel members  16   a,    16   b,  a motor  40   m  to drive the leadscrew and a nut  40   n  mounted on the rear platform support  16   r  to receive and treadably mate with the leadscrew  40   l  and to translate the torque of the leadscrew  40   l  into actuating force on the linkage  30  to move it between an extended state and a collapsed state. More preferably, the nut  40   n  integral with the pivoting cross-member  33  and allows leadscrew  40   l  to pass therethrough. Advantageously, pivoting cross-member  33  pivots as scissors linkage actuates about free ends  31   b,    32   b,  thereby allowing leadscrew  40   l  to remain substantially parallel with platform channel members  16   a,    16   b  while also still maintaining the substantially parallel relationship of free ends  31   b,    32   b.  Even more preferably, the threads of the leadscrew  40   l  and nut  40   n  have an Acme profile. Yet even more preferably the motor  40   m  is an air motor or may alternatively be an electric, hydraulic or any other suitable type of motor. 
     During running operations the worker W preferably stands on the floor  16   f  of the platform  16  for stabbing the appropriate tubular members during such running operations. Should it be necessary that the platform  16  be raised or lowered, the worker merely actuates the vertical power means  18 . In the preferred embodiment, the worker W actuates motor  18   m  to turn in the appropriate direction, resulting in either upward or downward vertical movement of the carriage  22 , and hence the platform  16 , along the frame member  12  as may be required. Should it be necessary that the platform  16  be moved towards or away from the tubular members, the worker W merely actuates the horizontal power means  40 . In the preferred embodiment, the worker W actuates motor  40   m  to turn in the appropriate direction, resulting in actuating the linkage  30  between an extended state and a collapsed state and, hence, move the platform  16  horizontally with respect to the frame member  12  as may be required. 
     As will be appreciated, the stabbing board  10  of the present invention enables a worker W to efficiently and safely accomplish the stabbing of joints of tubular members during running operations. Advantageously, by having separate vertical and horizontal power means  18 ,  40 , and by having a scissors linkage  30   s  which operates in the horizontal plane only, the stabbing board  10  can efficiently move the worker W closer to, or farther away from, the tubular members during stabbing operations. 
     More advantageously, a worker W supported by the stabbing board can easily and quickly actuate the horizontal power means only, so as to swiftly move the platform  16  away from the pipe or tubulars when the worker W appears to be at risk of being hit or injured by the moving blocks, tubulars or other equipment within the center of derrick or rig. Such movement along the horizontal plane only is preferably, as compared to say the telescoping, luffing or slewing of a boom (where there is both horizontal and vertical movement), in situations of imminent danger when a worker quickly needs to be moved away from the central axis of the derrick and to a position of safety adjacent the derrick&#39;s inside periphery. Thus, the present invention comprehends a stabbing board  10  that is a new and useful concept not heretofore known. 
     Those of ordinary skill in the art will appreciate that various modifications to the invention as described herein will be possible without falling outside the scope of the invention.