Patent Publication Number: US-11391100-B2

Title: Pipe storage box

Description:
SUMMARY 
     The present invention is directed to a system comprising a magazine having internal structure defining a plurality of vertical columns, each column having opposed ends, and a sensor assembly having a non-unitary relationship with the magazine. The sensor assembly comprises a plurality of proximity sensors having one-to-one correspondence with the plurality of columns. Each sensor is positionable adjacent an end of its corresponding column. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a representative 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 the horizontal boring machine of  FIG. 2  with several components removed to more clearly show the pipe handling assembly of the invention. 
         FIG. 4  is a view of an end of the magazine shown in  FIGS. 2 and 3 . 
         FIG. 5  is a partial end view of the horizontal boring machine of  FIG. 2 . 
         FIG. 6  is a cross-section view of the magazine filled with pipe sections. 
         FIG. 7  is a cross-section view of the magazine having one column empty. 
         FIG. 8  shows a proximity sensor assembly. 
         FIG. 9  shows a representative pipe indicator of  FIGS. 6 and 7  of the present invention. 
         FIG. 10  shows a shuttle arm of the pipe handling assembly shown in  FIG. 3 . 
         FIG. 11  is a perspective view of an alternative embodiment of the pipe indicators attached to the end of a magazine. 
         FIG. 12  is a perspective view of the end of the magazine shown in  FIG. 11 . 
         FIG. 13  is a perspective view of one of the pipe indicators shown in  FIG. 11 . 
         FIG. 14  is a side view of  FIG. 13 . 
         FIG. 15  is a second perspective view of the end of the magazine shown in  FIG. 11 . 
         FIG. 16  is a cross-section view of the magazine of  FIG. 11  filled with pipe sections. 
         FIG. 17  is the view of  FIG. 16 , but having one column empty. 
         FIG. 18  is a straight on view of an alternative embodiment of the proximity sensor assembly. 
         FIG. 19  is a perspective view of the end of the magazine shown in  FIG. 11  with the alternative embodiment of the proximity sensor assembly attached to the machine. 
         FIG. 20  is a side view of  FIG. 19 . 
         FIG. 21  is an end perspective view of  FIG. 19 . 
         FIG. 22  is a perspective view of an alternative embodiment of the pipe indicators attached to the end of a magazine. 
         FIG. 23  is a top perspective view of another alternative embodiment of the pipe indicators attached to the end of a magazine. 
         FIG. 24  is a perspective view of one of the pipe indicators of  FIG. 22 . 
         FIG. 25  is a side view of  FIG. 23 . 
         FIG. 26  is a perspective view of the alternative embodiment of the pipe indicators and proximity sensor assembly attached to the end of a magazine. 
         FIG. 27  is a rear perspective view of an alternative embodiment of a sensor assembly supported on a drill frame adjacent a magazine. A portion of the drill frame and magazine are cut away. 
         FIG. 28  is a front perspective view of the sensor assembly, drill frame and magazine shown in  FIG. 27 . 
         FIG. 29  is a side elevational view of the sensor assembly, drill frame and magazine shown in  FIG. 27 . 
         FIG. 30  is a bottom plan view of the rigid support assembly of the sensor assembly shown in  FIG. 27 . 
         FIG. 31  is a rear perspective view of an alternative embodiment of a sensor assembly supported on the drill frame adjacent the magazine. A portion of the drill frame and magazine are cut away. 
         FIG. 32  is a front perspective view of the sensor assembly, drill frame and magazine shown in  FIG. 31 . 
         FIG. 33  is a side elevational view of the sensor assembly, drill frame and magazine shown in  FIG. 31 . 
     
    
    
     DETAILED DESCRIPTION 
     Turning now to the figures, and specifically to  FIG. 1 , a horizontal directional drilling operation is shown. Horizontal directional drilling (“HDD”) or boring permits the installation of utility services or other underground products in an essentially “trenchless” manner, minimizing surface disruption along the length of the project and reducing the likelihood of damaging previously buried products or surface obstructions  5 . The typical HDD borepath begins from the ground as an inclined segment that is gradually leveled off as the desired depth is neared by the drill bit  1 . This depth is maintained, or a near horizontal path is followed, for the specified length of the product installation. As a drill string  2  is pushed into the ground behind the drill bit  1  new sections of pipe  3  are added to the uphole end of the drill string. The pipe section  3  may range from three (3) feet long to over ten (10) feet. Thus, as the boring operation progresses to drill a pilot bore  4  new sections of drill pipe must be added to the uphole end of the drill string  2 . Likewise, when the drill string  2  is pulled from the ground, such as during backreaming, pipe sections  3  are removed from the drill string  2 . The pipe sections  3  are typically stored for use in a magazine  40  that is supported on the boring machine  10  and moved between the magazine and a spindle  34  ( FIG. 2 ) during the boring operation. The process of adding or removing pipe sections from the drill string may be labor intensive and time consuming. Quick make-up and break-out of pipe sections with the drill string is important to operators to maintain an efficient and profitable boring operation. 
     The present invention provides an unproved HDD machine  10  having a magazine  40  that is easily connected to and removed from the boring machine yet secured in place when in use. The HDD machine  10  of the present invention also comprises an improved pipe handling system designed to speed-up the make-up and break-out of pipe sections  3  with the drill string  2  and movement of such pipe sections between the spindle  34  and the magazine  40 . 
     Turning now to  FIG. 2 , shown therein is the horizontal boring machine  10  constructed in accordance with the present invention. The machine  10  comprises an engine (not shown) housed within an engine cowl  12 . The engine may comprise an internal combustion engine or an electric engine and hydraulic motors used to power the various functions of the machine. An operator station  14  may be disposed near the engine and comprises controls used by the operator to control the various functions of the machine. The engine and operator station  14  may be supported on a frame  16  having a first end  18  disposed at the front of the machine  10  and a second end  20  disposed at the rear of the machine. The frame  16  is supported on a pair of endless tracks  22  that are useful for moving the machine from location to location. A stabilizer  24  is positioned at the rear  20  of the machine  10  and may be actuated by a hydraulic cylinder  26 . At the front  18  of the machine  10 , a pair of earth screw assemblies  28  are attached to the frame  16  and used to anchor the machine to the ground during the horizontal boring operation. 
     A carriage  30  is supported on the frame  16  and is movable along the frame between the first end  18  and the second end  20 . A rotary drive  32  is supported on the carriage  30  and transmits torque to the spindle  34  supported on the carriage for movement therewith. The spindle  34  is threadably connectable to a drill pipe section  3  ( FIG. 1 ) at a first end  35  ( FIG. 1 ) of a drill string  2 . The spindle  34  transmits torque along the plurality of drill pipe sections  3  comprising the drill string  2  to the downhole tool  1  at a second end  37  of the drill string. The carriage  30  moves back and forth on the frame  16  along a rack  36  to push and pull the drill string  2  through the ground. A pinion (not shown) disposed on the underside of the carriage  30  engages the rack  36  and drives the carriage along the frame  16 . 
     A pipe handling device  38  for storing and supplying pipe sections  3  ( FIG. 1 ) for use with the machine  10  is shown supported on the frame  16 . The device  38  comprises a magazine  40  within which a pipe section  3  may be received and stored and a pipe sensor  42 . The pipe sensor  42  is disposed to detect the presence and absence of a pipe section  3  within the magazine  40 . A pipe handling assembly  44  is disposed under the magazine  40  and transports a pipe section  3  on a delivery path between the magazine and the spindle  34 . 
     Turning now to  FIG. 3 , the machine  10  is shown with several components such as the engine and operator station removed to more clearly show the frame  16 , carriage  30 , and pipe handling device  38 . As shown in  FIG. 3 , the carriage  30  is disposed at the second end  20  of the frame  16 . When in this position the spindle  34  is prepared to receive a pipe section  3  ( FIG. 1 ) from the magazine  40 . A make-up and breakout assembly  46  is disposed at the first end  18  of the frame  16 . The make-up and break-out assembly  46  comprises wrenches  45  used to partially thread and unthread a pipe section from the drill sting  2 . The rack  36  is disposed along the length of the frame  16  and provides a track for the carriage  30  to travel along as the pipe section  3  is pushed into the ground or pulled out of the ground. 
     The pipe handling assembly  44  comprises a pair of shuffle arms  48  that are used to transport the pipe section  3  between the magazine  40  and the spindle  34 . The shuttle arms  48  receive the pipe section  3  through a lower portion of the magazine comprising a discharge outlet  50 . The pipe section  3  may be stored in the magazine in a plurality of columns  51  within each of which a plurality of pipe sections may be received and stored. The columns  51  are defined by dividers  52  disposed at both a first end  54  and a second end  56  of the magazine  40 . The pipe sensor  42  is disposed at the first end  54  of the magazine  40  near the top of the magazine. The pipe sensor  42  is able to detect the presence or absence of a pipe section within the magazine and the movement of a pipe section through the discharge outlet  50  to or from the spindle axis  58  of the machine  10 . Specifically, the pipe sensor  42  monitors the removal of a pipe section  3  from a column  51  or the addition of a pipe section to a column. 
     The magazine  40  is generally rectangular and has am open bottom comprising the discharge outlet  50 , two elongate side walls  60  and  62 , a first end plate or  64 , and a second end plate  66 . The top of the magazine is generally open and may comprise a center cross bar  68  and lift points  70  for lifting the magazine to move it to is and from the frame  16 . The side walls  60  and  62  may be defined by a support brace  72  extending between a top rail  74  and bottom rail  76 . 
     Turning now to  FIG. 4 , the second end  56  of the magazine  40  is shown in close-up. While the second end  56  is shown in  FIG. 4  and will be discussed in detail herein, the end of the magazine shown in  FIG. 4  may be either the first end  54  or the second end  56  of the magazine  40  because both ends are identical. Having a magazine with identical ends such that there is no distinction between the ends except for the direction of the pipe held within the magazine permits the magazine to be supported on the frame for “pin-up” or “pin-down” threading by the spindle. 
     The top rails  74  are connected to a vertical second endplate  66 . The end plate  66  comprises a plurality of slots  78 . The slots  78  are configured to receive tabs  80  formed on the dividers  52  to help secure the dividers to the end plate  66 . Dividers  52  are also supported on a crossbar  82  that spans the distance between the top rails  74  and passes through a hole  84  formed in each divider. Grenade pins  86  may be used with tabs  88  to further secure the end plate  66  and dividers  52  to the tops rails  74  and bottom rails  76 . 
     The end plate  66  also comprises a plurality of pipe slots  90 . The pipe slots  90  are arranged in columns and rows on the end plate  66  to correspond to the number of columns  51  and rows of pipe sections that may be stored within the magazine  40  when the magazine is full. The pipe slots  90  generally align with a fluid passage of a pipe section  3  stored within the magazine. A pin  92  having a generally T-shaped configuration may be inserted into the pipe slots  90  and the fluid passage of the pipe section on both ends of the magazine  40  to secure the pipe section within the magazine and prevent the pipe section from falling out through the discharge outlet of the magazine. 
     Continuing with reference to  FIG. 4 , the bottom of the end plate  66  bends outward to form a flange  94 . The flange  94  may comprise a plate and supports a locating pin receiver  96  supported on the end plate  66 . Of course, because the first end  54  and second end  56  of the magazine may be identical, another locating pin receiver may be supported by the first end plate  64 . The pin receiver  96  is configured to receive a locating pin  98  disposed proximate the second end of the frame, while the first pin receiver at the first end  54  of the magazine (not shown) receives a locating pin  98  disposed proximate the first end of the frame  16 . The pin receiver  96  comprises a pair of parallel vertical plates  100  and  102  supported on a base  104  that is secured to the end plate  64 . The base  104  and flange  94  both comprise corresponding holes (not shown) configured to receive the locating pin  98  so that it aligns with holes  106  formed in the vertical plates  100  and  102 . An end cap  108  provides support for vertical plates  100  and  102  and also may be configured to support T-shaped pin  92  with a grenade pin  110  when the pin is not in use. 
     A locking pin  112  passes through the holes  106  formed in the vertical plates  100  and  102  and a hole  114  ( FIG. 5 ) formed in the locating pin  98 . The locking pin  112  comprises an arm  116  that may be pinned to the end plate  108  to secure the locking pin  112  to the pin receiver  96 . The magazine  40  is securely supported on the frame  16  when the locating pins  98  are disposed within the locating pin receivers  96  and secured therein by the locking pins  112 . 
     Turning now to  FIG. 5 , a partial side view of the back end of the machine  10  is shown with the magazine  40  removed from the machine. The rack  36  of the rack and pinion carriage drive is shown supported on the frame  16  along with stabilizer  24 . Fluid cylinder  26 , used to actuate stabilizer  24 , is shown connected to the frame  16  at one end and the stabilizer at the other end of the cylinder. The cylinder  26  receives fluid and/or releases fluid through inlet  118  and hose  120  to drive operation of the cylinder. A mud pump motor  122  is shown supported on the frame  16  and is used to pump drilling fluid downhole through the fluid passage of the drill string  2  to the drill bit  1  or backreaming tool. 
     With the magazine removed from the machine  10  the locating pin  98  is more clearly visible because the locating pin receiver  96  is not blocking the view of the pin. The pin  98  is supported on the frame  16  by an L-shaped bracket  124 . The L-shaped bracket  124  may comprise a pair of supports  126  disposed on either side of the pin  98 . 
     Both locating pills  98  comprise a base  127  and a tapered top portion  128  configured to guide the locating pins into the pin receiver  96 . A hole  114  may be formed in the top portion  128  of each of the locating pins  98  to receive lock pin  112  ( FIG. 4 ) within the hole and corresponding holes  106  formed in the locating pin receivers  96  to secure the magazine  40  to the frame  16 . The base portion  127  of the locating pin  98  passes through a hole (not shown) in the shorter leg of the L-shaped bracket  124  and may be secured to the bracket and supports  126  by welding or other methods of fastening the pin  98  to the frame  16 . 
     Continuing with  FIG. 5 , a proximity sensor assembly  129  is shown supported on the frame  16 . The proximity sensor assembly  129  comprises a pipe sensor  42  to detect the presence or absence of a pipe section  3  within the magazine. The pipe sensor  42  may comprise sensor array  130 . Sensor array  130  may comprise a plurality of proximity sensors  170  ( FIG. 8 ) each disposed to detect the presence or absence of a pipe section  3  within a column  51  of the magazine  40 . The proximity sensor assembly  129  is pivotally connected to the frame  16  at pivot point  131  and comprises a post  132 , a biasing member  134 , and an arm  136 . Post  132  is used to support the plurality of proximity sensors  170 . The post  132  comprises a bottom member  138  and a top member  140 . The top member  140  may telescope from within the bottom member  138  to allow adjustment of the height of the proximity sensor assembly  129  to the height of the magazine supported on the frame. When the desired height is reached, locking member  142  may be engaged to lock the top member  140  relative the bottom member  138 . 
     The biasing member  134  comprises a spring connected at one end to the bottom of the post  132  and a support member  144  at the other end to bias the plurality of proximity sensors  170  supported on the post away from the magazine. The arm  136  is connected to the post  132  and disposed for engagement with the bottom of the magazine  40  as the magazine is lowered onto the frame  16  and guided into position by the locating pins  98 . The weight of the magazine is able to overcome the biasing force of the spring  134  and the proximity sensor assembly  129  pivots about pivot point  131  to move the plurality of proximity sensors  170  in direction A to a position proximate the magazine. 
     Turning now to  FIGS. 6 and 7 , the magazine  40  is shown in cross-section having a plurality of drill pipe sections  3  disposed in columns  51  defined by dividers  52 . The view shown in  FIGS. 6 and 7  is looking from the front  18  of the machine near the earth screw assemblies  28  ( FIG. 1 ) toward the rear  20  of the machine. The sensor array  130  is shown disposed at the top of, and behind the magazine  40 . The sensor array  130  may comprise a plurality of pipe sensors comprising proximity sensors  170  ( FIG. 8 ), each proximity sensor corresponding to an individual column. A plurality of pipe indicators  148 , are disposed proximate a single proximity sensor to communicate the presence and absence of pipe sections  3  within a column  51 . For example, when an individual column is full the pipe level indicator  148  is in the position shown in  FIG. 6 . However, when a pipe section  3  has been removed from a column, or as shown in  FIG. 7  when a column is empty, the pipe level indicator  148  will move to the position shown in  FIG. 7 . Each of the plurality of pipe indicators  148  may comprise a pipe engaging member  150  and a flag  152  detectable by the proximity sensor. A pivot point  154  is disposed between the pipe engaging member  150  and the flag  152 . Each pipe indicator  148  is supported on a pivot bar  156  about which the pipe indicator is allowed to rock about the pivot point  154 . Thus, the pipe engaging member  150  moves down when a pipe section  3  is removed from the bottom of the column and flag  152  is raised upward and away from the proximity sensor  130 . 
     With reference now to  FIG. 8 , the proximity sensor assembly  129  of  FIG. 5  is shown in more detail. A sensor housing  158  is shown supported at the top of post  132 . Post  132  comprises the top member  140  and bottom member  138 . Locking member  142  is configured to engage predrilled holes  160  in the top member  140  to lock the height of the post  132  relative to the magazine  40  ( FIG. 1 ). The bottom member  138  is supported on a generally triangular bracket member  162 . The arm  136  extends from an apex of the bracket  162  to position the arm for engagement with the magazine  40  when the magazine is supported on the frame. Pivot  131  and biasing member connection point  164  are also shown in  FIG. 7 . An assembly lock  166  may be supported on the bracket  162  and used to secure the assembly  129  to the magazine  40  to decrease movement of the assembly during operation of the machine  10  ( FIG. 1 ). 
     The housing  158  supports the sensor array  130 . The sensor array  130  may be connected to the housing with a plurality of fasteners  168 . Fasteners  168  may comprise bolts that allow easy removal of the senor array  130  for replacement or service. Additionally, a retention bar  169  may be positioned to help secure and align the sensor array  130  within the housing  158 . The sensor array  130  may comprise a plurality of pipe sensors  170  comprising proximity sensors positioned to detect the presence or absence of a pipe section  3  within a respective column  51  by detecting the presence or absence of the flag  152  as discussed with reference to  FIGS. 6 and 7 . When the flag  152  is in the position shown in  FIG. 6  the sensor  170  detects the presence of the flag  152  in front of the sensor. When a pipe section is removed from a column the proximity sensor  170  cannot detect the flag  152  as it has pivoted upward (as shown in  FIG. 7 ). The sensor  130  sends a signal to a processor at the operator station indicating a pipe section has been removed from the column. The processor uses this data to determine which column the pipe handling assembly should remove pipe sections from or which column to place pipe sections into. Likewise, when the column is full the proximity sensor  170  detects the presence of the flag  152  and sends a signal to the processor indicating the column is full. The processor uses this data from the sensor to fill a column that is not yet full when pipe sections are being added to the magazine. 
     Turning now to  FIG. 9 , a representative pipe indicator  148  of  FIGS. 6 and 7  is shown in greater detail. The pipe indicator comprises a body  172 , a pipe engaging member  150  at a first end of the body, and a flag  152  disposed at a second end of the body. As shown, the body  172  and pipe engaging member  150  may be constructed from a single piece of metal. However, one skilled in the art will appreciate that the pipe indicator  148  may be constructed from component pieces attachable and detachable from the body  172  to permit the use of pipe engaging members  150  and flags  152  of different sizes and configurations. While the flag  152  is shown in a substantially vertical orientation, one skilled in the art will appreciate the flag  152  may be disposed in a horizontal or other orientation to make contact with the proximity sensor  170 . Likewise, pipe engaging member  150 , shown in a generally horizontal orientation, may be oriented in a variety of configurations to engage pipe sections stored within the magazine. 
     The pivot point  154  is disposed between the flag  152  and the pipe engaging member  150 . The pivot point is defined by a cylindrical housing  174  that is configured to receive pivot bar  156  ( FIGS. 6 and 7 ). A bearing (not shown) may be disposed within housing  174  to assist in the pivotal movement of the pipe indicator relative to the pivot bar  156 . The housing  174  is positioned on the body  172  so that the pipe engaging member is supported on pivot bar  156  to bias the pipe engaging member  150  to pivot downward and the flag  152  upward when a pipe section has been removed from the selected column. Thus, if the body is divided by the pivot point  154 , there is a greater amount of weight on the pipe engaging member  150  side of the pivot point than on the flag  152  side of the pivot point. Weighting the pipe indicators in this manner causes the default position of the flag  152  to be upright so that the flags do not contact the proximity sensor  170  when the column  51  is not full. This causes a “not full” signal to be transmitted to the operator or the processor used to control the pipe handling assembly. 
     Continuing with  FIG. 9 , the flag  152  is supported on a flag support  176  portion of the body  172  and may be secured to the support with a fastener disposed in a hole  178 . Numbers  180  on flag  152  may be used to indicate the type or size of pipe stored within magazine  40 . For example, the number “ 32 ” shown on flag  152  may be used to indicate the presence of ten (10) foot pipe in the magazine. When the operator desires to use pipe of a different length or size the flag may be turned around on support  176  so that the number “ 40 ” is correctly read to indicate the use of pipe section of a different length. 
     With reference now to  FIGS. 3 and 10 , the pipe handling assembly  44  is discussed in more detail. The pipe handling assembly  44  is situated directly beneath the discharge outlet  50  of the magazine  40 . The pipe handling assembly  44  comprises a pair of shuttle arms  48  movably supported on the frame  16 , and a drive assembly (not shown) for driving the movement of the arms  48 . 
     In  FIG. 10  one of the two shuttle arms  48  is shown. The arms  48  comprise a pipe holding member  182  formed in the end of the arm proximal the horizontal boring machine  10 . The pipe holding member  182  is adapted to receive and support the pipe section  3 . The pipe holding member  182  may further comprise a retaining structure  184  for retaining the pipe section  3  in the pipe holding member. In a preferred embodiment, each retaining structure  184  is actuated by a cylinder  186  operatively connected to the arm  48  at one end and the retainer structure at the other end. The cylinder moves the retaining structure  184  about pivot point  188 . Retaining structure  184  retains the pipe section  3  in pipe holding member  182  until the pipe section  3  is aligned with the spindle axis  58 . 
     The arms  48  are positioned on the frame  16  generally parallel with each other. The arms are advanced and retracted laterally and generally perpendicular to spindle axis  58  of the horizontal boring machine  10  in such a manner as to shuttle pipe sections  3  between the horizontal boring machine and the magazine  40 . The extension and retraction of the arms  48  is powered by a drive assembly supported on the frame. 
     The drive assembly may comprise a rack  190  and pinion gear (not shown) mounted on the frame  16 . The rack  190  is operatively connected to each arm  48  and mates with a corresponding pinion gear. The rack and pinion gears are mounted in parallel on the frame  16 . 
     Operation of a hydraulic motor causes the pinion gears to rotate. The rotating pinion gears engage the gears on racks  190 . When the pinion gears rotate in a first direction, the arms  48  extend laterally in the direction of the horizontal boring machine  14  thereby transporting a pipe section  3  to the spindle axis  58 . The pinion gears may be rotated in a second direction to cause the pipe holding member  182  to retract away from the horizontal boring machine, thereby enabling return of a pipe section  3  to the magazine  40 . 
     To receive a pipe section  3  from the magazine  40 , the arms  48  of the pipe handling assembly  44  are retracted to position the pipe holding member  182  beneath the selected column  51  from which a pipe is to be received. Generally, pipe sections  3  are first retrieved from the column  51  proximal the horizontal boring machine  10  until this column is empty. Thereafter, pipe sections  3  will be retrieved from the immediately adjacent column  51  until it also is empty. Retrieval of pipe sections  3  will proceed in the same fashion until all columns  51  are empty or until the boring operation is completed. 
     After selecting the desired column  51 , the arms  48  are retracted to position the pipe holding member  182  beneath the selected column. As the blocking member  192  of arms  48  recedes from beneath the selected column  51 , the pipe section  3  positioned at the discharge outlet  50  of the selected column  51  falls into the pipe holding member  182 . The retaining structure  184  is moved in direction X by actuation of the cylinder  186  to grip the pipe section  3  and prevent the pipe section from rolling off of the pipe holding member  182 . A proximity switch  194  may be positioned proximate the pipe holding member  182  to detect the presence and/or absence of a pipe section within the holding member. Wear pads  196  may be disposed on the pipe holding member  182  and the retaining structure  184  to protect the holding member and retaining structure. 
     The arms  48  are then advanced to the spindle axis  58  for connection of the pipe section  3  in the pipe holding member  182  with the drill string of the horizontal boring machine  10 . The horizontal boring machine  10  is operated to connect pipe section  3  to the drill string. 
     To receive a pipe section  3  from the horizontal boring machine  10  the arms  48  are advanced toward the spindle axis  58 . As the arms  48  advance, the cylinder  186  retracts to open the pipe retainer  184 . The pipe holding member  182  is aligned with the pipe section  3  to be received. After alignment with the pipe section  3 , the cylinder  186  extends to move the retaining structure in direction X to the support position and retains the pipe section  3  in the pipe holding member  182  during transport back to the magazine. The pipe section  3  is unthreaded from the drill string and is supported solely by the pipe holding member  182 . The arms  48  are then retracted in direction Y for return of the pipe section  3  to the magazine  40 . Pipe sections  3  are replaced in the magazine  40 . 
     The present invention includes a method for handling a plurality of pipe sections  3  at a horizontal boring machine  10 . In the method a plurality of pipe sections  3  are stored in plural columns  51  of a multiple-column magazine  40 . A single pipe section  3  is discharged from a first selected magazine column and transported to the spindle  34 . Removal of a pipe section from the first selected column is visually indicated. In one embodiment, visual indication is accomplished by raising flag  152 . The pipe section  3  is transported to the spindle  34  by the pipe handling assembly and added to the drill string  2  of the horizontal boring machine. The steps of removing a pipe section  3  from the magazine may be repeated until all pipe sections have been emptied from the first selected column. Removal of all pipe sections  3  from the first selected column may be visually indicated to the operator. Visual indication may be accomplished by further raising the flag  152  or by illumination of an indicator at the operator station. The steps of emptying a column may be repeated for one or more additional columns and may be repeated until all of the columns of the magazine have been emptied. 
     During a backreaming operation or when the drill string is simply pulled back through the borehole, a pipe section  3  may be removed from the drill string  2  of the horizontal boring machine and transported from the spindle  34  to a last emptied magazine column by the pipe handling assembly  44 . The pipe handling assembly  44  uses arms  48  to transport the pipe section  3  along a delivery path between the spindle axis  58  and the discharge outlet  50  of the magazine. The pipe handling assembly  44  is also configured to lift the pipe section  3  into the column. As the drill string  2  is withdrawn from the borehole  4  and pipe sections  3  are removed from the drill string, the pipe handling assembly  44  transports the pipe sections to the magazine and places the pipe sections in a selected column until all pipe sections have been replaced in the selected column. The pipe indicators  148  are connected to the proximity sensors to indicate the presence or absence of pipe sections within each respective column. When the selected column is full again the pipe engaging member  150  of the pipe indicator  148  will be pushed up causing the flag  152  to pivot downward in front of the proximity sensor  170 . The proximity sensor  170  will generate a signal that is communicated to the processor. Operation of the pipe handling assembly  48  is managed by the processor. In operation, data from the proximity sensors  170  is processed and used to determine which column to remove pipe sections from or which column to place pipe sections into. 
     With reference now to  FIGS. 11-26 , an alternative embodiment of the proximity sensor assembly  200  and corresponding pipe indicators or signal elements  202  are shown. An overview of the alternative embodiment of the proximity sensor assembly  200  and signal elements  202  is shown in  FIG. 26 . The proximity sensor  200  is best shown with reference to  FIGS. 18-20 . The signal elements  202  are best shown with reference to  FIGS. 11-17 . 
     Starting with  FIG. 11 , the signal elements  202  are attached to a first end  204  of a magazine  206 . Alternatively, the signal elements  202  may be attached to an opposed second end  208  of the magazine  206 . The magazine  206  is identical to the magazine  40  described with reference to  FIGS. 1-10 , except that the alternative signal elements  202  and proximity sensor assembly  200  are used with the magazine  206 . The magazine  206  also has an alternative embodiment of a locating pin receiver  284  attached to each end  204  and  208 . 
     The magazine  206 , shown in  FIG. 11 , has sidewalls  210  formed between a first external face  212  and a second external face  214 , such that the magazine forms the shape of a right rectangular prism. The signal elements  202  are attached to the magazine  206  adjacent its first external face  212 . A plurality of dividers  218  are formed inside of the magazine  206  adjacent both its first end  204  and its second end  208 . The dividers  218  create a plurality of rectilinear columns  220  within the magazine  206  that extend between the first external face  212  and the second external face  214 . The columns  220  are each capable of holding a plurality of pipe sections  222  stacked on top of each other, as shown in  FIGS. 16-17 . The second external face  214  may be open and serve as a discharge conduit  216  for the pipe sections  222  held within the magazine  206 . The dividers  218 , columns  220 , and pipe sections  222  are similar to those described with reference to  FIGS. 1-10 . 
     Referring now to  FIGS. 12-17 , the signal elements  202  are shown in more detail. The signal elements  202  each comprise a frame  224  having a partially arcuate portion. A target element  226  is attached to a first end  228  of the frame  224  and a first ballast element  230  is attached to its opposite second end  232 . The arcuate portion of the frame  224  is situated immediately adjacent the first ballast element  230 . A series of holes  234  are formed along the frame  224 . The holes  234  decrease the weight of the frame  224 . 
     The first ballast element  230  is heavier than the target element  226 , because the first ballast element comprises a weight. The weight may be cylindrical in shape and have a cut-out  252  ( FIGS. 13-14 ) formed on its outer surface along its horizontal axis. The cut-out is configured to receive a magnet  254 . The magnet  254  helps the first ballast element  230  engage with the pipe sections  22  within the magazine  206 . Additional ballast elements  230  may be attached to the second end  232  of the signal element  202  if needed to increase its weight or stability. 
     The target elements  226  comprise a plate  256  that is attached orthogonally to the first end  228  of the planar frame  224 . The plate  256  is preferably rectangular in shape. The plate  256  has a top bolt hole  258  and a bottom bolt hole  260 . The bolt holes  258  and  260  may hold a bolt  262 . The target elements  226  serve as a target for the proximity sensor assembly  200  to detect during operation. 
     A pivot point  236  is formed between the target element  226  and the first ballast element  230 . The pivot point  236  is in-line with the target element  226 , as shown in  FIGS. 13-14 . The pivot point  236  is defined by a cylindrical housing  238  that is configured to receive a pivot bar  240 . The signal elements  202  are attached to the first end  204  of the magazine  206  via the pivot bar  240 . 
     The pivot bar  240  is attached to the first end  204  of the magazine  206  via a set of pivot bar holders  242 , shown in  FIG. 12 . The pivot bar holders  242  each have an opening for receiving the pivot bar  240 . The pivot bar  240  is secured in place on the first end  204  of the magazine  206  via a grenade pin  244 . Multiple signal elements  202  may be pivotally supported on the pivot bar  240 , as shown in  FIGS. 12 and 15 . A cover  243 , shown in  FIG. 15 , may be placed on top of the dividers  218 . The cover  243  helps maintain the spacing of the signal elements  202  on the pivot bar  240 . The cover  243  is also helps protect and maintain the signal elements  202  within the magazine  206 , if the magazine is tilted to extreme angles. 
     There are preferably the same number of signal elements  202  as columns  220  formed in the magazine  206 . The signal elements  202  are supported on the pivot bar  240  such that each first ballast element  230  extends at least partially within a footprint of each column  220 . The center of mass of the signal elements  202  is offset from its pivot point  236 . The signal elements  202  are movable about the pivot bar  240  between a first position and a second position, as shown in  FIGS. 16-17 . The first and second positions are vertically offset from one another. 
     When each column  220  is full of pipe sections  222 , the first ballast elements  230  will rest on or engage with the pipe section at the top of each column. This is considered the first position of the signal element  202 . Therefore, if a column  220  is full of pipe sections  222 , the corresponding signal element  202  is in the first position, as shown in  FIG. 16 . 
     When a pipe section  222  is removed from one of the columns  220 , gravity will cause the first ballast element  230  to pivot more deeply within the footprint of the corresponding column. This is because the first ballast element  230  is heavier than the target element  226  and the first ballast element  230  can no longer rest on the pipe section  222  at the top of the column  220 . This is considered the second position of the signal element  202 . Therefore, if a column  220  is not full of pipe sections  222 , the corresponding signal element  202  is in the second position, as shown in  FIG. 17 . 
     Referring now to  FIGS. 18-21 , the proximity sensor assembly  200  is shown in more detail. The proximity sensor assembly  200  comprises a plurality of sensors  264 . The proximity sensor assembly  200  is attached to the frame  16  of machine  10  so that the sensors  264  line up with each target element  226 , as shown in  FIGS. 19-20 and 26 . Preferably, the bolt  262  of each target element  226  is directly in-line with each sensor  264 . The bolt  262  may be moved between the top bolt hole  258  and bottom bolt hole  260 , depending on which position better aligns the bolt with each sensor  264 . The bolt  262  is used to bring the target element  226  closer to each sensor  264 , as shown in  FIG. 20 . 
     A target element  226  is in-line with a sensor  264  when the signal element  202  is in the first position  246 . Thus, when a sensor  264  detects the presence of a target element  226 , the corresponding column  220  is full of pipe sections  222 . Alternatively, when the signal element  202  is in the second position  248 , the target element  226  will pivot upwards and away from the sensor  264 , such that the target element  226  is above the first ballast element  230 . When this occurs, the sensor  264  will no longer detect the corresponding target element  226 . Thus, when a sensor  264  does not detect a target element  226 , the corresponding column  220  is not full of pipe sections  222 . The proximity sensor assembly  220  will signal the processor on the machine  10  whether it detects the presence of the target element  226 . The signals indicate whether or not a given column is full of pipe sections. 
     The proximity sensor assembly  200  comprises one sensor  264  for each signal elements  202 . The sensors  264  are secured in a row to a sensor housing  266  via a plurality of fasteners  265 , as shown in  FIG. 18 . The sensor housing  266  is rectangular in shape and is supported on a first end  267  of a post  268 . The post  268  is a solid piece that cannot be adjusted in height. This provides stability to the proximity sensor assembly  200 . 
     A mounting assembly  270  is attached to a second end  269  of the post  268  opposite the sensor housing  266 . The mounting assembly  270  is best shown with reference to  FIGS. 19-21 . The mounting assembly  270  comprises a locking member  272 , a mounting plate  274 , and a bracket  276 . The locking member  272  is disposed below the second end  269  of the post  268 . The bracket  276  and the mounting plate  274  are attached to opposite ends of both the post  268  and the locking member  272 . 
     A planar mount  280  is attached to the frame  16  of the machine  10 , as shown in  FIGS. 19-20 . The mount  280  sits underneath the magazine  206  and extends out past the first end  204  of the magazine. The mount  280  has a vertical plate  282 . The vertical plate  282  has four bolt holes  281  for receiving bolts  278 . A second mounting plate  279  may be attached to the vertical plate  282 . The second mounting plate  279  has four bolt holes  277  ( FIG. 18 ) that correspond with bolt holes  281 . The second mounting plate  279  is attached to the vertical plate  282  via bolts  278 . 
     The locking member  272  has a bore formed therein for holding a fastener  273 . The fastener  273  passes through the locking member  272  and threads into the mounting plate  274  and the second mounting plate  279 . This secures the proximity sensor assembly  200  to the planar mount  280 . 
     Referring now to  FIG. 21 , the mounting plate  274  also contains a series of round pins  285  that engage with corresponding holes on the second mounting plate  279 . The round pins  285  may prevent the proximity sensor assembly  200  from rotating on the second mounting plate  279 . 
     When the proximity sensor assembly  200  is installed on the machine  10 , the fastener  273  may be loosened from the second mounting plate  279 . This allows round pins  285  to back off of the second mounting plate  279  and allows the proximity sensor assembly  200  to pivot about the second mounting plate  279 . This moves the assembly  200  out of the way, if needed. For example, the assembly  200  may be pivoted 90 degrees while the magazine  206  is secured to the frame  16  of the machine  10 . 
     Once the proximity sensor assembly  200  has been pivoted as desired, the is fastener  273  may be re-tightened to retain the proximity sensor assembly  200  in place. The mounting plate  274  also has a series of slots  287  that correspond with the bolts  278 . The slots  287  are big enough so that the bolts  278  may fit within the slots  287  when the proximity sensor assembly  200  is pivoted. The fastener  283  may also be completely unthreaded from the second mounting plate  285  to remove the proximity sensor assembly  200  from the machine  10 , if needed. 
     Turning back to  FIG. 15 , the magazine  206  is secured to the frame  16  of the machine  10  via the locating pin receiver  284 . Identical locating pin receivers  284  are each attached to the first end  204  and second end  208  of the magazine  206 . The locating pin receiver  284  is substantially identical to the locating pin receiver  96 , described with reference to  FIGS. 1-10 . The pin receiver  284  is supported on a flange  286  extending out from the first end  204  of the magazine  206 . The pin receiver  284  comprises a pair of parallel vertical plates  288 . A top plate  290  and an end plate  300  are secured to the vertical plates  288  to form a box-like structure. A hole  302  is formed in the flange  286  for receiving a locating pin  98 , shown in  FIG. 5 . 
     The vertical plates  288  each have a hole  304  formed in them. The locating pin  98  has a hole  114 , shown in  FIG. 5 , that aligns with the holes  304  when the locating pin  98  is in the pin receiver  284 . A locking pin  306  may pass through the holes  304  and  114  to secure the locating pin  98  to the locating pin receiver  284 . A grenade pin  308  may be used to secure the locking pin  306  in place. 
     In the embodiment of the proximity sensor assembly  129 , shown with reference to  FIGS. 1-10 , the proximity sensor assembly is supported on the locating pin  98  prior to installation of the magazine  40 . Installation of the magazine  40  on the locating pin  98  holds the proximity sensor  129  in position. In the embodiment shown with reference to  FIGS. 11-20 , the proximity sensor assembly  200  is attached to the frame  16  of the machine  10  rather than the locating pin  98 . This provides more stability to the sensor assembly  200 . 
     The magazine  206  shown in  FIG. 11  has five columns  220 . However, the magazine  206  may have more or less columns  220  depending on the size or number of pipe sections  222  filled within the magazine. For example, a magazine  309 , shown in  FIG. 22 , only has four columns  220 . This is because the magazine  309  may be used to hold larger pipe sections. Because there are fewer columns  220  within the magazine  309 , the position of the target elements  226  relative the sensors  264  may be changed. Due to this, a tab  310  may be added to the target element  226 . The tab  310  provides additional surface area to align the signal elements  202  with the sensors  264 . 
     Referring now to  FIGS. 23-25 , an alternative embodiment of a signal element  312  is shown. The signal element  312  may be used with a shorter magazine  314 . The signal element  312  comprises a frame  316  that is more linear in shape than the frame  224 , shown in  FIGS. 13-14 . The frame  316  still has holes  234  to decrease the weight of the frame. The signal element  312  is also smaller in size than the signal element  202 . 
     The signal elements  312  each comprise a target element  318  attached to its first end  320  and a first ballast element  322  attached to its opposite second end  324 . A pivot point  326  is formed on the frame  316  between the target element  318  and the first ballast element  322 . The pivot point  326  comprises a cylindrical housing  328  for receiving a pivot bar  330 . The height of the pivot bar  330  on the magazine  314  is the substantially the same as the height of the pivot bar  240  on the magazine  206 . This allows the same proximity sensor assembly  200  to be used with magazines of varying size. 
     The target element  318  comprises a plate  332 . The plate  332  is a generally square shape and comprises a top bolt hole  334  and a bottom bolt hole  336 . The bolt holes  334  and  336  are horizontally and vertically spaced on the plate  332 . This provides multiple spacing options to position the bolt  262  so that it aligns with the sensors  264 . The plate  256  may also be used with this embodiment. The tab  310  array also be used with the target element  318 , as shown in  FIG. 23 . 
     The first ballast element  322 , shown in  FIGS. 23-25 , comprises a weight  338  and a planar shoe  340  that projects out past the weight. The weight  338  is a generally cylindrical shape, but is smaller than the weight attached to the signal element  202 . The weight  338  helps guide the signal elements  312  between the first and second position and keep appropriate spacing within the dividers  218 . The shoe  340  may be used to provide additional surface area to the first ballast element  322  to better engage with the pipe sections  222  in the magazine  314 . The size and shape of the shoe may vary as needed. 
     Turning to  FIGS. 27-30 , an alternative embodiment of a sensor assembly  400  is shown. The sensor assembly  400  has a non-unitary relationship with a magazine  404 . The magazine  404  is constructed the same as the magazine  40  or  206 , described with reference to  FIGS. 3 and 11 . The magazine  404  is supported on a drill frame  408  and has internal structure defining a plurality of vertical columns  406 , as shown in  FIG. 28 . Each column  406  includes opposed upper and lower ends that correspond with opposed upper and lower ends  405  and  407  of the magazine  404 , as shown in  FIG. 29 . 
     The sensor assembly  400  comprises an elongate tower  432  and a rigid support structure  409 . The tower  432  has opposed upper and lower ends  440  and  441 , as shown in  FIG. 29 . The tower  432  is supported on the drill frame  408  at its lower end  441  and is secured to the drill frame  408  in the same manner as the post  268 , shown in  FIGS. 18-21 . The rigid support structure  409  is attached to the upper end  440  of the tower  432  such that a portion of the structure is suspended above the upper end  405  of the magazine  404 . 
     Continuing with  FIGS. 27-30 , the rigid support structure  409  comprises an arm  430  attached to a sensor housing  402 . A first end of the arm  430  is attached to the upper end  440  of the tower  432  such that the arm  430  and the tower  432  are orthogonal to one another. A second end of the arm  430  carries an attachment plate  434  used to attach the arm  430  to the sensor housing  402 , as shown in  FIG. 27 . A plurality of fasteners may be used to secure the attachment plate  434  to the sensor housing  402 . 
     The sensor housing  402  is preferably made of metal and comprises a top plate  410  attached to a rear and front plate  412  and  414 . The top plate  410  has an external surface  416 , shown in  FIGS. 27 and 28 , and an internal surface  418 , shown in  FIG. 30 . The top plate  410  bends proximate the edges of the rear and front plates  412  and  414  to form side plates  420  and  422 . In alternative embodiments, the side plates may be separate pieces attached to the top plate. In further alternative embodiments, the rear and front plates may be integral with the top plate. 
     The sensor housing  402  supports a plurality of sensors  424 . Each sensor  424  corresponds with a single column  406  in a one-to-one relationship, as shown in  FIG. 28 . The sensors  424  are each proximity sensors. Specifically, each sensor  424  may be an ultrasonic sensor. Alternatively, each sensor may be an optical sensor. 
     The sensors  424  each comprise a top cap  426 , shown in  FIGS. 27-29 , joined to a sensing face  428 , shown in  FIG. 30 . Each sensor  424  is installed within the housing  402  such that the top cap  426  is positioned adjacent the external surface  416  of the top plate  410  and the sensing face  428  is positioned adjacent the internal surface  418  of the top plate  410 . The sensor housing  402  is positioned so that it extends wholly within a footprint of the magazine  404  and each sensing face  428  looks down upon each corresponding column  406 . 
     A screen  444  is positioned between each sensor  424  within the sensor housing  402 . The screens  444  are each plates attached to the inner surfaces of the front and rear plates  412  and  414 , as shown in  FIG. 30 . The size and shape of each screen  444  corresponds with the size and shape of the side plates  420  and  422 . The screens  444  isolate adjacent sensors  424  and prevent a sensor  424  from sensing objects in an adjacent column  406 . 
     In operation, each sensor  424  monitors its corresponding column  406  and senses the presence or absence of a pipe section within that column  406 . Each sensor  424  also determines the exact number of pipe sections within each column  406 . The sensors  424  are each configured to sense the distance between the sensing face  428  and the top most pipe section. Such distance can be correlated with a known distance between the sensing face  428  and each pipe within each column  406 . For example, the distance between the sensing face  428  and the top pipe section may be 6 inches. If each pipe section has a diameter of 3 inches and there are 8 pipe sections within each column, a measured distance of 6 inches will equal 8 pipe sections, 9 inches will equal 7 pipe sections, 12 inches will equal 6 pipe sections, etc. 
     The values measured by the sensors  424  are transmitted to the processor on the drilling machine  10 , shown in  FIG. 1 . The processor analyzes the values and communicates the number of pipe sections within each column to an operator. The processor may be programmed to recognize values corresponding to differently sized pipe sections or magazines. 
     The measured values may be transmitted to the processor via a wire (not shown) that interconnects each sensor  424  to the processor. Individual wires attached to each sensor  424  may be joined together as a single wire that is routed through the interior of the arm  430  and tower  432 . From the tower  432 , the wire is routed through the drill frame  408  to the processor. 
     Continuing with  FIGS. 27-29 , the first end of the arm  430  carries a cylindrical pin housing  435 . The pin housing  435  allows the arm  430  to be pivotally attached to the upper end  440  of the tower  432 . The pin housing  435  is hollow and configured to receive a pin  437 , as shown in  FIGS. 27 and 28 . The pin housing  435  supported on a connection plate  436 . The connection plate  436  provides a surface to attach the arm  430  to the tower  432 . A corresponding connection plate  438  is formed on the upper end  440  of the tower  432 , as shown in  FIG. 29 . 
     In order to attach the arm  430  to the tower  432 , the connection plates  436  and  438  are placed on top of one another and the pin  437  is disposed within the pin housing  435  and the interior of the tower  432 . The arm  430  may rotate about the pin  437  so that the arm  430  pivots about an axis that is parallel to a longitudinal axis of the tower  432 . The arm  430  is held stationary on the tower  432  by installing a removable pin  442  within a pin hole formed within both connection plates  436  and  438 . If the arm  430  is rotated relative to the tower  432 , the removable pin  442  may be installed within a side pin hole  439 , as shown in  FIGS. 27, 28, and 30 . Installing the pin  442  within the side pin hole  439  holds the arm  430  in the rotated position. For example, the arm  430  may be rotated 90 degrees from as original position so that the sensor housing  402  is clear of the magazine  404 . 
     The pin  437  is preferably configured so that the pin housing  435  is not removable from the pin  437 . For example, the top of the pin  437  may be larger than the opening of the pin housing  435 . In alternative embodiments, the pin housing  435  may be easily removed from the pin  437  so that the arm  430  may be detached from the tower  432 . 
     Turning to  FIGS. 31-33 , an alternative embodiment of a sensor assembly  500  is shown. The sensor assembly  500  is identical to the sensor assembly  400 , with the exception of its arm  502  and tower  504 . A sensor housing  503  attached to the arm  502  is identical to the sensor housing  402 . 
     The arm  502  is secured to the tower  504  via a hinge  506 . The arm  502  is pivotable relative to the tower  504  at the hinge  506  along an axis that is perpendicular to the longitudinal axis of the tower  504 . The arm  502  is supported on the tower  504  by resting on a plate  508  supported on an upper end  510  of the tower  504 . The tower  504  attaches to the drill frame  408  in the same manner as the post  132 , shown in  FIGS. 5 and 8 . Like the post  132 , the height of the tower  504  is adjustable telescopically. 
     In another embodiment, the housing may be configured to support only a single sensor. An actuator may be attached to the housing to move the housing over each of the columns. The operator may direct the linear actuator to move the housing and sensor over the column the operator is currently directing pipe sections to be loaded into or unloaded from. Once the operator has finished with that column, the processor will automatically direct the linear actuator to move the housing to the next column, and so on. Alternatively, the operator may manually direct the linear actuator to move the housing to a desired column. 
     It should be appreciated by those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention. It is intended that the present invention cover such modifications and variations as come within the scope and spirit of the appended claims and their equivalents.