CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial

No. 62/054,796, filed September 24, 2014, the entire contents of which are incoiporated herein by reference.

FIELD

[0002] This invention relates generally to the field of horizontal boring and in particular to machines used in horizontal boring.

SUMMARY OF THE INVENTION

[Θ003] The present invention is directed to a pipe handling device for storing and supplying pipe sections for use in a horizontal boring machine. The device comprises a magazine within which a pipe section may be received and stored and a pipe sensor disposed to detect the presence and absence of a pipe section within the magazine.

[0004] The invention is likewise directed to a method for handling a plurality of pipe sections at a horizontal boring machine. The method comprises storing the plurality of pipe sections in plural columns of a multiple-column magazine and discharging a single pipe section from a first selected magazine column and transporting that pipe section to the spindle axis. Removal of the pipe section from the first selected column is visually indicated and the transported pipe section is added to the drill string of a horizontal boring machine.

[0005] The present invention is also directed to a horizontal boring machine comprising a frame, a carriage, a first locating pin, a second locating pin, a spindle, a magazine, a first locating pin receiver, and a second locating pin receiver. The frame has a first end and a second end. The carriage is supported on the frame and movable between the first end of the frame and the second end of the frame. The first locating pin is disposed proximate the first end of the frame and the second locating pin disposed proximate the second end of the frame. The magazine may receive and store a pipe section. The magazine comprises a first plate and a second plate. The first locating pin receiver is supported on the first plate and the second locating pin receiver is supported on the second plate. The magazine is supported on the frame when the first locating pin is disposed within the first, locating pin receiver and the second locating pin is disposed within the second locating pin receiver.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a representative illustration of a horizontal boring operation.

Figure 2 is a perspective view of a horizontal boring machine of the present invention.

[0008] Figure 3 perspective view of the horizontal boring machine of Figure 2 with several components removed to more clearly show the pipe handling assembly of the invention.

[0009] Figure 4 is a view of an end of the magazine shown in Figures 2 and 3.

[0010] Figure 5 is a partial end view of the horizontal boring machine of Figure 2.

[0011] Figure 6 is a cross-section view of the magazine filled with pipe sections.

[0012] Figure 7 is a cross-section view of the magazine having one column empty.

[0013] Figure 8 shows a proximity sensor assembly.

[0014] Figure 9 shows a representative pipe indicator of Figures 6 and 7 of the present invention.

[0015] Figure 10 shows a shuttle arm of the pipe handling assembly shown in Figure 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Turning now to the figures, and specifically to Figure 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 upho!e end of the drill siring. 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.

[0017] The present invention provides an improved 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.

[0018} Turning now to Figure 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. [0019] 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 conneetahle 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.

[Θ020] 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 deliver}' path between the magazine and the spindle 34.

[ΘΘ21] Turning now to Figure 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 Figure 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.

[ΘΘ22] The pipe handling assembly 44 comprises a pair of shuttle amis 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 sections 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.

[0023] The magazine 40 is generally rectangular and has an open bottom comprising the discharge outlet 50, two elongate side walls 60 and 62, a first end plate 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 and from the frame 16, The side walls 60 and 62 may be defined by a support braces 72 extending between a top rail 74 and bottom rail 76. [Θ024] Turning now to Figure 4, the second end 56 of the magazine 40 is shown in close- up. While the second end 56 is shown in Figure 4 and will be discussed in detail herein, the end of the magazine shown in Figure 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.

[ΘΘ25] The top rails 74 are connected to a vertical second endpiate 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, |0Θ26] 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.

[0027] Continuing with reference to Figure 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.

[0028] 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 1 2 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. [0029] Turning now to Figure 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 througli 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.

[ΘΘ30] 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.

[0031] Both locating pins 98 comprise a base 127 and a tapered top portion 128 configured to guide the locating pins into the pin receiver 96. A hole 1 14 may be formed in the top portion 128 of each of the locating pins 98 to receive lock pin 1 12 (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.

[0032] Continuing with Figure 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.

[8033] 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,

[0034] Turning now to Figures 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 Figures 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 cornrnunicate 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 Figure 6, However, when a pipe section 3 has been removed from a column, or as shown in Figure 7 when a column is empty, the pipe level indicator 148 will move to the position shown in Figure 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.

[0Θ35] With reference now to Figure 8, the proximity sensor assembly 129 of Figure 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 Figure 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).

[0036] 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 sendee. 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 Figures 6 and 7, When the flag 152 is in the position shown in Figure 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 Figure 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 section 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.

[0037] Turning now to Figure 9, a representative pipe indicator 148 of Figures 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 he 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.

[0038] 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 & 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 52 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 foil" signal to be transmitted to the operator or the processor used to control the pipe handling assembly. [ΘΘ39] Continuing with Figure 9, the flag 152 is supported on a flag support 176 portion of the body 172 and may he 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.

[0040] With reference now to Figures 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.

[0041] In Figure 10 one of the two shuttle anus 48 is shown. The aims 48 comprise a pipe holding member 182 formed in the end of the arm proximal the horizontal boring machine 1 , 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 operative!}' connected to the ami 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.

[0042] The am s 48 are positioned on the frame 16 generally parallel with each other.

The am s 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 anus 48 is powered by a drive assembly supported on the frame. [§§43] The drive assembly may comprise a rack 1 0 and pinion gear (not shown) mounted on the frame 16. The rack 1 0 is operaiively 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.

[0044] 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 he 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.

[0045] 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 he 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.

[ΘΘ46] After selecting the desired column 51 , the anus 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 5 L the pipe section 3 positioned at the discharge outlet 50 of the selected column 51 falls into the pipe holding memher 1 S2. 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 1 82 to detect the presence and/or absence of a pipe section within the holding member. Wear pads 1 6 may be disposed on the pipe holding member 182 and the retaining structure 184 to protect the holding member and retaining structure. [0047] 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. [ΘΘ48] To receive a pipe section 3 from the horizontal boring machine 10 the arms 48 are advanced toward the spindle axis 58. As the amis 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 hack 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.

[0(149] 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 plnral 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 ail 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.

[0050] During a backreaming operation or when the drill string is simply pulled back thorough 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 section 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.

[0051] 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.