Patent Publication Number: US-11649685-B2

Title: Mechanical shuttle pipe gripper

Description:
SUMMARY 
     The present invention is directed to a pipe shuttle. The pipe shuttle comprises a linear shuttle track, a shuttle body, a shuttle drive system, a gripper, and a cam-follower arrangement. The shuttle body is supported by the shuttle track and constrained to move therealong. The drive system is configured to power movement of the shuttle body. The gripper is rotatably supported by the shuttle body and conformable to a pipe. The cam-follower arrangement is capable of causing rotation of the gripper in response to linear motion of the shuttle body. 
     The present invention is also directed to a drilling machine. The drilling machine comprises a machine frame, a pipe box, a carriage, and a pipe shuttle. The pipe box is supported on the machine frame and contains a plurality of pipe sections. The carriage is movable along the machine frame in a first direction and connectable to each of the plurality of pipe sections. The pipe shuttle comprises a guide plate, a support frame, and a gripper. The guide plate is fixed in position relative to the machine frame. The support frame is supported by the guide plate and movable relative thereto in a second direction. The gripper is disposed on the support frame. The gripper is engageable with the guide plate. The gripper is movable between an open position and a closed position, and configured to conform to a pipe section held by the support frame when in the closed position. The gripper is maintained in the open position when the gripper engages the guide plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an illustration of a horizontal boring operation 
         FIG.  2    is a perspective view of a horizontal boring machine of the present invention. 
         FIG.  3    is a perspective view of a pipe handling assembly removed from the horizontal boring machine of  FIG.  2   . The shuttle arms are shown in the operating position. 
         FIG.  4    is a perspective view of the pipe handling assembly of  FIG.  3   . The shuttle arms are shown under a pipe box column. 
         FIG.  5    is a perspective view of a shuttle arm of the pipe handling assembly of  FIG.  3   . The cradle is shown in the open position. 
         FIG.  6 A  is a first side view of the shuttle arm of  FIG.  5   . The cradle is shown in the closed position. 
         FIG.  6 B  is a second side view of the shuttle arm of  FIG.  5   . The cradle is shown in the closed position. 
         FIG.  7 A  is a first side view of the shuttle arm of  FIG.  5   . The cradle is shown in the open position. 
         FIG.  7 B  is a second side view of the shuttle arm of  FIG.  5   . The cradle is shown in the open position. 
         FIG.  8 A  is the first side view of the shuttle arm of  FIG.  5    with the side plate removed. 
         FIG.  8 B  is a cross-sectional view of the first side view of the shuttle arm of  FIG.  5   . 
         FIG.  9 A  is the second side view of the shuttle arm of  FIG.  5    with a pipe held in the cradle. The cradle is shown in the open position. 
         FIG.  9 B  is the second side view of the shuttle arm of  FIG.  5    with a pipe held in the cradle. The cradle is shown in the closed position. 
         FIG.  10    is a top right perspective view of an embodiment of a shuttle arm. 
         FIG.  11    is a top left perspective view of the shuttle arm of  FIG.  10   . 
         FIG.  12 A  is a side view of the shuttle arm of  FIG.  10    with the cradle shown in the closed position and the side plate removed. 
         FIG.  12 B  is the view of  FIG.  12 A  with the cradle shown in the open position. 
         FIG.  13 A  is a detail side view of a pipe section being held within the cradle, showing the compression spring and spring block in phantom. 
         FIG.  13 B  is the detail view of  FIG.  13 A  with the pipe section causing the compression springs and pad to tilt. 
         FIG.  14    is a front view of the shuttle arm of  FIGS.  10 - 11   . 
     
    
    
     DETAILED DESCRIPTION 
     Many utility pipelines are installed underground by boring a borehole in a generally-horizontal direction rather than by digging a trench. This type of construction is typically referred to as “horizontal boring” or “horizontal directional drilling” (“HDD”). A horizontal borehole is created by using a drilling machine to drive rotation of a drill bit attached to a drill string. The drill string is made of up of a plurality of pipe sections connected together. The pipe sections are stacked in columns within a pipe box attached to the drilling machine. A carriage included within the drilling machine connects the pipe sections together and pushes or pulls the drill string through the ground surface. 
     In operation, a pipe handling assembly uses a pair of shuttle arms to transport each pipe section between the pipe box and the carriage. The shuttle arms are stopped beneath each column using a pipe column selection assembly. 
     Shuttle arms often comprise an open socket or a catchment for supporting a pipe section as it is moved from beneath a pipe box to the carriage. Securing the pipe section so that sudden stops or jolts do not dislodge them from the shuttle arms is advantageous. In addition, the precise location of a pipe section in the shuttle arm enables faster and better pairing of the pipe section to the carriage and the drill string. 
     With reference now to the figures,  FIG.  1    shows a drilling machine  10  sitting on a ground surface  12 . Extending from the drilling machine  10  is a drill string  14 . The drill string  14  is made up of a plurality of pipe sections  200  attached end to end. The drill string  14  is connected to a downhole tool  16  at its first end and the drilling machine  10  at its second end. 
     The downhole tool  16  comprises a drill bit  18  and a beacon contained within a beacon housing  20 . An above ground operator uses a tracking device (not shown) to confirm the location of the beacon housing  20  underground. 
     In operation, the drill string  14  is rotated by the drilling machine  10 , causing the drill bit  18  to displace underground material and create a borehole. The drilling machine  10  adds pipe sections  200  to the drill string  14  as the downhole tool  16  advances underground. 
     As shown in  FIG.  2   , the drilling machine  10  comprises an engine housed within an engine cowl  30 , an operator station  32 , a pipe handling assembly  100 , a wrench assembly  33  and a carriage  34 . The components of drilling machine  10  are supported on a frame that is in turn supported on a pair of endless tracks  36 . The tracks  36  move the machine  10  from location to location. 
     The carriage  34  connects pipe sections  200  to or removes pipe sections  200  from the drill string  14  ( FIG.  1   ). The wrench assembly  33  provides torque to this connection or removal process, and may hold the drill string  14  while a new pipe section is threaded by the carriage  34 . The carriage  34  also moves back and forth along the frame to push and pull the drill string through the ground. The carriage  34  moves along the frame of the drilling machine  10  in a first direction to provide thrust to the drill string  14  and to return to its starting location for connection to a new drill section  200 . 
     The present invention is directed to a pipe handling assembly  100  that provides for reliable transfer of pipe into and out of the carriage  34  using a mechanical cam-follower arrangement rather than hydraulics. 
     With reference to  FIGS.  2 - 3   , a pipe handling assembly  100  stores the pipe segments  200  and provides a mechanism for moving stored pipe sections in a second direction along the frame of the drilling machine  10  for connection to the drill string  14 . The pipe handling assembly  100  comprises a pipe box  102 , a pair of shuttle arms  104 , and a pipe column stop assembly  150  ( FIG.  10   ). The pipe box  102  contains four columns  106  for storing pipe sections  200 . The columns  106  are created by dividers  108  formed at opposite ends inside the pipe box  102 . The shuttle arms  104  are positioned such that they are parallel to and spaced apart from one another on the frame underneath the pipe box  102 . 
     In operation, the shuttle arms  104  retrieve pipe sections from each of the columns  106  and deliver the pipe sections to the carriage  34  ( FIG.  2   ) to be added to the drill string  14  ( FIG.  1   ). If a drill string is being removed from the borehole, the shuttle arms  104  will remove pipe sections from the carriage  34  and return the pipe sections to the pipe box  102 . The pipe sections are held in a cradle  110  formed at the end of each of the arms  104 . 
     With reference to  FIGS.  3 - 9 B , the shuttle arms  104  are moved using a drive system, such as a rack and pinion gear. The rack  112  is secured to a bottom of each of the shuttle arms  104  and has a forward and rearward end. Each rack  112  mates with a corresponding pinion gear (not shown) mounted on the frame via brackets. The rotating pinion gears engage the racks causing the shuttle arms  104  to move back and forth on the frame. Other means for translating the shuttle arms  104  may include a linear actuator like a hydraulic cylinder or jackscrew. 
     The shuttle arms  104  move between guides  114  mounted to the frame and brackets. The shuttle arm  104  is mounted between guides  114  in which it may move longitudinally via the rack  112  and pinion. The shuttle arms  104  in  FIG.  3    are shown in the operating position. In the operating position the cradle  110  is closed, such that a pipe section  200  is secured inside. As the shuttle arms  104  move away from the carriage  34  and towards the pipe box  102  the cradle  110  is opened through a pair of rollers  116  which engage the guide  114 . The rollers  116  allow the cradle  110  to open and the shuttle arm  104  is positioned underneath one of four columns  106  ( FIG.  4   ). The shuttle arms  104  may then either return or retrieve a pipe section from the column  106  while the cradle  110  is in the open position. 
     The shuttle arm  104  comprises the cradle no, a bottom plate  118 , a pair of side plates  120 , and the rack  112  and a top plate  122 . The bottom plate  118 , side plates  120  and top plate  122  generally form a support frame for supporting the cradle and allowing the movement relative to the drilling machine. The bottom plate  118  is situated within a slot in the guide  114  ( FIG.  14   ) and allows for single-axis movement of the shuttle arm  104  in the second direction along this linear track. Preferably, the second direction is transverse to the first direction. 
     The cradle no comprises a pad  126 , a pair of grippers  128 , the rollers  116 , a compression spring  130 , and an extension spring  132 . The extension spring  132  ( FIGS.  8 A- 8 B ) biases the grippers  128  in a closed position by maintaining pressure on a bushing  134  that is attached to the lower end of each of the grippers  128 . The tension on the extension spring  132  may be adjusted with a tensioner  138 . Tension is primarily adjusted during assembly. As shown, the tensioner  138  is a screw for adjusting the distance between the ends of the extension spring  132 . While the grippers  128  are in the closed position, the cradle no is closed such that pipe sections cannot be added or removed from the pipe box. 
     The bushing  134  is situated between a first set of slots  140  in the side plates  120 . ( FIGS.  8 A- 8 B ). The grippers  128  rotate between an open and closed position as the bushing  134  slides back and forth within the first set of slots  140  in a cam-follower arrangement. However, when the shuttle arm  104  is in an operating position such that a pipe segment  200  held within would be near the carriage  34 , the cam-follower does not function. As a result, when the shuttle arm  104  is in the operating position the extension spring  132  holds the grippers  128  in the closed position. As the shuttle arm  104  moves under the pipe box  102  and the rollers  116  engage the guide  114 , the extension spring  132  expands and the grippers  128  are pushed to the open position ( FIGS.  7 A- 7 B ), opening the cradle  110 . 
     After the shuttle arm  104  returns or retrieves a pipe section  200  ( FIGS.  9 A- 9 B ) from the pipe box  102  the shuttle arm is reversed and moves back towards the operating position. When the rollers  116  disengage the guide  114  the extension spring  132  retracts and the grippers  128  move to the closed position. The cam-follower arrangement and extension spring  132  ensures that movement from the open position to the closed position only occurs when the shuttle arm  104  moves from the pipe box to the operating position. Likewise, movement from the closed position to the open position occurs only when the shuttle arm  104  is moved in the opposite linear direction, back towards the pipe box  102 . 
     In the embodiment of  FIGS.  5 - 9 B , the grippers  128  include a first gripper  142  and a second gripper  144  situated on either side of the pad  126 . Both grippers  142 ,  144  comprise an upper end  146  to hold the pipe between the gripper and the pad  126  when the gripper  128  is in the closed position. The second gripper  144 , as shown, has a lower end  148  that serves as a retainer for a pipe section being returned or retrieved from the pipe box  102  while the cradle no is in the open position ( FIG.  9 A ). In an alternative embodiment, both grippers  128  could comprise an upper  146  and lower end  148 . Each gripper  128  is conformable to the pipe, and is in opposed relationship to the concave surface of the pad  126 . 
     When the cradle  110  is in the closed position with a pipe section  200  held by the grippers  128 , force is applied to the pipe section  200  by the pad  126 . The pad  126  is attached to the side plates  120 . The front side of the gripper pad  126  sits on the compression spring  130 . The compression spring  130  exerts an upward force on the pad  126  and the pipe section  200  ( FIGS.  8 A- 9 B ). The amount of tension on the compression spring  130  can be adjusted by turning the compression spring bolt  131 . 
     When the shuttle arm  104  is in the operating position, the carriage  34  will connect a pipe section  200  to the drill string  14  or remove a pipe section from the drill string. As the carriage  34  connects a pipe section  200  to the drill string  14  the shuttle arm  104  will move away from the operating position. At this point, the pipe segment  200  is held fast by its connection to the drill string  14  and the carriage  34 . 
     With reference to  FIGS.  13 A- 14   , as the shuttle arm  104  moves away from the operating position, the pipe section  200  will force the pad  126  to press down on the compression spring  130 . As shown in  FIG.  13 B , the pad will move down and around the pipe section  200  enough to allow the shuttle arm  104  to pull away from the pipe section. Likewise, when the shuttle arm  104  is moving towards the carriage  34  to retrieve a pipe section from the carriage, the gripper pad  126  will press down on the compression spring  130  under the force of the pipe section  200  enough to allow the cradle no to envelop the pipe section, as shown in  FIG.  12 A . 
     The compression spring  130  is attached to a spring block  131 . The spring block  131  is pinned to the shuttle arm  104  and may tilt relative to it about a bolt  133 . This range of movement allows the pad  126  to react to forces imparted by the pipe section  200 . 
     With reference to  FIG.  10   , an embodiment of the shuttle arm  104  is shown. The shuttle arm  104  has a column stop assembly  150  comprising one stop  152  for each column  106  ( FIG.  3   ). The stops  152  are disposed along the side wall  120 . A column stop actuator (not shown) is provided on the drill frame. A stop bar is disposed on the rod end of the actuator. The actuator is configured to move the stop bar along a vertical axis so that the stop bar may intersect a selected stop  152 . Each stop  152  corresponds to a matching column  106  when it intersects the stop bar and aids in location of the cradle  110  beneath the proper pipe column. A back stop  154  may be utilized to indicate that the shuttle is aligned with the spindle. Alternatively, a spring or cushioned stop  154  may be utilized to reduce jolting on the shuttle arm  104  when a pipe section is within the cradle  110 . 
     In  FIGS.  10 - 11   , the cradle  110  comprises a magnet  161  located near the second gripper  144  which may provide a magnetic grip on a pipe section  200 . The magnet  161 , used in conjunction with grippers  128 , the concave surface of pad  126 , and lower tong  148  provide for coaxial alignment of a pipe section  200  and the spindle  34 . 
     In the embodiment of  FIGS.  10 - 11   , the grippers  128  may be attached to extension plates  160 . The extension plates are then attached to rollers  116  to aid in the spacing of the grippers  128 . As shown in  FIG.  10   , the first gripper  142  has both upper  146  and lower  148  ends. 
     With reference to  FIGS.  12 A- 12 B , the shuttle arm  104  utilizes a compression spring  170  rather than the extension spring  132  to bias the grippers  128  to the closed position. Because the bushing  134  is not co-axial with the roller  116  (as in  FIGS.  3 - 9 B ), the grippers  128  are closed when the bushing  134  is at a furthest back position relative to the slot  140 , as shown in  FIG.  12 A . When the rollers  116  engage the guide plate  114 , the bushing is moved forward in the slot  140 , overcoming the bias of the compression spring  170 , as shown in  FIG.  12 B . 
     Changes may be made in the construction, operation and arrangement of the various parts, elements, steps and procedures described herein without departing from the spirit and scope of the invention as described in the following claims.