Tunneling device including a rotary tunneling tool

Abstract

A tunneling assembly (144) for use with a tunneling device (102) includes a housing (160) and a piston (146) extending within the housing and configured for reciprocating motion relative to the housing along a first stroke length and a second stroke length. The tunneling assembly further includes a cam gear (150) coupling a tunneling tool (148) to the piston. The cam gear translates reciprocating motion of the piston into a reciprocating motion of the tunneling tool when the piston is reciprocated along each of the first stroke length and the second stroke length. The cam gear further pivots the tunneling tool relative to the housing when the piston is reciprocated along the first stroke length.

Description

(12764-1157)TUNNELING DEVICE INCLUDING A ROTARYTUNNELING TOOLSTATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

[0001] This invention was made with Government support under contract number N00014-22-C-2009, awarded by the United States Department of Defense. The Government has certain rights in this invention.TECHNICAL FIELD

[0002] The field of the disclosure relates to tunneling devices, and more particularly to tunneling devices including a rotary tunneling tool for steering the tunneling devices.BACKGROUND

[0003] Tunneling devices are used to travel through underground locations and displace material to form and shape tunnels through the underground locations. At least some tunneling devices include a drive system to propel the tunneling devices through underground locations. In addition, a tool may be positioned at the front of the tunneling devices to displace material and form an interior cavity of the tunnel as the tunneling devices travel through the underground locations. However, the underground locations may have varying conditions and obstacles that make travel and access difficult.

[0004] Some tunneling devices include horizontal directional drilling devices or impact moling which may allow for creation of tunnels without open-cut excavation. However, such devices are not typically configured to be steered when tunneling. That is, such tunneling devices may travel horizontally in a straight line, but have limited ability to turn for obstacle avoidance and build curved tunnels.

[0005] Accordingly, it is desirable to provide a system including a tunneling device with a simplified steering mechanism.(12764-1157)BRIEF DESCRIPTION

[0006] In one aspect, a tunneling assembly for use with a tunneling device is provided. The tunneling assembly includes a housing, a piston extending within the housing, configured for reciprocating motion relative to the housing along a first stroke length and a second stroke length, and a tunneling tool. The tunneling assembly further includes a cam gear coupling the tunneling tool to the piston. The cam gear translates reciprocating motion of the piston into a reciprocating motion of the tunneling tool when the piston is reciprocated along each of the first stroke length and the second stroke length. The cam gear further pivots the tunneling tool relative to the housing when the piston is reciprocated along the first stroke length.

[0007] In another aspect, a tunneling device is provided. The tunneling device includes a body including a plurality of rigid sections and a plurality of flexible sections and a tunneling assembly coupled to a leading end of the body. The tunneling device is configured as a percussive device generating a linear impact motion to penetrate ground, The tunneling device includes a piston configured for reciprocating motion relative to the body along a first stroke length and a second stroke length. The tunneling device further includes a tunneling tool and a cam gear coupling the tunneling tool to the piston. The cam gear cam gear translates reciprocating motion of the piston into a reciprocating motion of the tunneling tool when the piston is reciprocated along each of the first stroke length and the second stroke length, and wherein the cam gear pivots the tunneling tool relative to the body when the piston is reciprocated along the first stroke length.

[0008] In yet another aspect, a method for forming a tunnel using a tunneling device is provided. The method includes controlling a piston to reciprocate relative to a housing of the tunnelling device along a first stroke length, the piston being coupled to a tunneling tool by a cam gear. The method further includes controlling the piston to reciprocate relative to the housing along a second stroke length. The cam gear translates reciprocating motion of the piston into a reciprocating motion of the tunneling tool when the piston is reciprocated along each of the first stroke length and the second stroke length, and the cam gear pivots the tunneling tool relative to the housing when the piston is reciprocated along the second stroke length.(12764-1157)BRIEF DESCRIPTION OF THE DRAWINGS

[0009] These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0010] FIG. 1 is a schematic diagram of a system including one embodiment of a tunneling device traveling underground;

[0011] FIG. 2 is a side view of a tunneling assembly of the tunneling device shown in FIG. 1 ;

[0012] FIG. 3 is an enlarged side view of a portion of the tunneling assembly shown in FIG. 2, showing a cam gear of the tunneling assembly;

[0013] FIG. 4 is an enlarged side view of another portion of the tunneling assembly shown in FIG. 2, showing a piston rotation assembly of the tunneling assembly;

[0014] FIG. 5 is a side view of the tunneling assembly shown in FIG. 2, showing a piston stroke of the tunneling assembly with the piston in a retracted position;

[0015] FIG. 6 is a side view of the piston stroke shown in FIG. 5, showing the piston in an extended position;

[0016] FIG. 7 is a side view of the piston stroke shown in FIG. 5, showing the piston in an intermediate retracted position;

[0017] FIG. 8 is a side view of the piston stroke shown in FIG. 5, showing the piston in another retracted position;

[0018] FIG. 9 is a schematic of an alternative embodiment of a cam gear for use with the tunneling device of FIGS. 1-8;

[0019] FIG. 10 is a flow chart of an example method of forming a tunnel using the tunneling device shown in FIG. 1.

[0020] Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of this disclosure. These features are believed to be applicable in a wide variety of systems including one or more embodiments of this disclosure.(12764-1157)As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.DETAILED DESCRIPTION

[0021] In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings.

[0022] The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.

[0023] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

[0024] Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately”, and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and / or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.

[0025] As used herein, the terms “processor” and “computer,” and related terms, e.g., “processing device,” “computing device,” and “controller” are not limited to just those integrated circuits referred to in the art as a computer, but broadly refers to a microcontroller, a microcomputer, an analog computer, a programmable logic controller (PLC), and application specific integrated circuit (ASIC), and other programmable circuits, and these terms are used interchangeably herein. In the embodiments described herein, “memory” may include, but is not limited to, a computer-readable medium, such as a random access memory (RAM), a computer-readable non-volatile medium, such as a flash memory. Alternatively, a floppy disk, a compact disc - read only memory (CD-ROM), a magnetooptical disk (MOD), and / or a digital versatile disc (DVD) may also be used. Also, in the embodiments described herein, additional input channels may be, but are not limited to,(12764-1157) computer peripherals associated with an operator interface such as a touchscreen, a mouse, and a keyboard. Alternatively, other computer peripherals may also be used that may include, for example, but not be limited to, a scanner. Furthermore, in the example embodiment, additional output channels may include, but not be limited to, an operator interface monitor or heads-up display. Some embodiments involve the use of one or more electronic or computing devices. Such devices typically include a processor, processing device, or controller, such as a general purpose central processing unit (CPU), a graphics processing unit (GPU), a microcontroller, a reduced instruction set computer (RISC) processor, an ASIC, a PLC, a field programmable gate array (FPGA), a digital signal processing (DSP) device, and / or any other circuit or processing device capable of executing the functions described herein. The methods described herein may be encoded as executable instructions embodied in a computer readable medium, including, without limitation, a storage device and / or a memory device. Such instructions, when executed by a processing device, cause the processing device to perform at least a portion of the methods described herein. The above examples are exemplary only, and thus are not intended to limit in any way the definition and / or meaning of the term processor and processing device.

[0026] Embodiments described herein relate to a system including a tunneling device. The tunneling device includes a plurality of expandable sections. Each of the expandable sections are configured to expand and collapse in width and / or length during operation of the tunneling device. Additionally, the tunneling device includes a fluid line and a plurality of fluid valves coupled to the expandable sections. The fluid valves regulate and / or control when each section of the tunneling device is expanded and collapse during operation. The sequence of expanding and collapsing each section of the tunneling device facilitates the formation of a tunnel and / or allows the tunneling device to move while forming the tunnel. More specifically, the plurality of fluid valves are formed as passive microvalves that facilitate the expanding and collapsing of each of the expandable sections in a sequential order and / or in series, based on predetermined pressure thresholds specific to each passive fluid valve. Additionally, the combination of expandable sections and fluid valves allow the tunneling device to be operably to form the tunnel using a single fluid line fluidly coupled to each valve and expandable section.(12764-1157)

[0027] FIG. 1 is a schematic diagram of a system 100 including a tunneling device 102 traveling underground. For example, tunneling device 102 is configured to travel through a tunnel 104 and / or displace material to form tunnel 104. Tunnel 104 includes a sidewall 106 having an interior surface 108 extending around a central axis 110 and defining interior cavity 112. Tunneling device 102 is configured to fit within interior cavity 112 and travel along the length of tunnel 104. Accordingly, tunneling device 102 facilitates construction of tunnel 104. Additionally, tunneling device 102 can facilitate the inspection and / or repair of tunnel 104. Moreover, tunneling device 102 is self-propelled, meaning that tunneling device 102 moves within interior cavity 112 without an external force acting on tunneling device 102.

[0028] During operation, for example, tunneling device 102 may be positioned at a surface 114 proximate an underground location, and tunneling device 102 travels through surface 114 to form an opening into tunnel 104. In the illustrated embodiment, tunneling device 102 travels in a travel direction 115. In some embodiments, tunneling device 102 traverses transitions in tunnel 104 such as bends or size transitions. As tunneling device 102 travels through underground locations, tunneling device 102 is configured to form tunnel 104 and / or inspect and / or repair any portions of tunnel 104.

[0029] System 100 includes tunneling device 102, a controller 116 communicatively coupled to tunneling device 102, and a fluid supply system 118. Controller 116 is also communicatively coupled to fluid supply system 118 for controlling operation of fluid supply system 118, as discussed herein. Fluid supply system 118 includes a pressurized fluid source 120 that is coupled to tunneling device 102 via a fluid line 122. Fluid supply system 1 18 is configured to regulate pressurized fluid that is provided, supplied, and / or delivered to, and removed from tunneling device 102 for operation of tunneling device 102, as described further herein.

[0030] In an example embodiment, controller 1 16 is configured to provide instructions to move tunneling device 102 (e.g., tip) through tunnel 104 and / or to perform inspection or repair operations, as discussed herein. Controller 116 includes a transceiver 124, a processor 126, and a memory 128. In some embodiments, controller 116 is positioned remotely from tunneling device 102, e.g., controller 1 16 is located at a base station that(12764-1157) enables an operator on an exterior of tunnel 104 (shown in FIG. 1) to interact with tunneling device 102, and / or controller 116 can be at least partly incorporated into and located on board tunneling device 102. Transceiver 124 is communicatively coupled with tunneling device 102 and is configured to send information to and receive information from a transceiver of tunneling device 102. In some embodiments, transceiver 124 and a transceiver on tunneling device 102 communicate wirelessly. In alternative embodiments, tunneling device 102 and controller 116 communicate in any manner that enables system 100 to operate as described herein. For example, in some embodiments, controller 1 16 and tunneling device 102 exchange information through a wired link extending between tunneling device 102 and controller 116.

[0031] In addition, in some embodiments, controller 116 is at least partly located on board tunneling device 102 and is configured to execute instructions for controlling components of tunneling device 102, such as a maintenance device and drive systems. For example, controller 116 executes instructions that cause tunneling device 102 to move in a selected direction. In alternative embodiments, tunneling device 102 includes any controller that enables system 100 to operate as described herein. In some embodiments, controller 116 is not located on board tunneling device 102.

[0032] Also, in example embodiments, an operator interface 130 is configured to display information relating to the characteristics determined and / or detected by tunneling device 102 for interpretation by the operator. Operator interface 130 may be included on a remote computing device (not shown) and / or may be incorporated with controller 116. Operator interface 130 may include, among other possibilities, a web browser and / or a client application. For example, in some embodiments, operator interface 130 displays images of interior surface 108 based on received signals. In some embodiments, operator interface 130 allows an operator to input and / or view information relating to control of tunneling device 102. In the example embodiment, operator interface 130 is configured to display information relating to the state of one or more of a maintenance device and a power source for interpretation by the operator. For example, state information may include a position of tunneling device 102 along a length of tunnel 104 (shown in FIG. 1). State information may also include a charge status of a power source and / or a current draw for the various drive and positioning motors. In various embodiments, processor 126 translates(12764-1157) operator inputs into steering, tool motion, camera control, sensor control, sensor motion, and / or any other commands and sends information via transceiver 124 to tunneling device 102 via a transceiver of tunneling device 102. In some embodiments, operator control of tunneling device 102 is in real time, such as through a joystick, a keyboard, a touchscreen, a remote motion capture system, and / or a wearable motion capture system or other interface having similar function. In other embodiments, tunneling device 102 is controlled partially or wholly according to a pre-programmed routine. In further embodiments, tunneling device 102 is at least partially automated. In some embodiments, an operator inputs information such as operation goals or conditional directions. In further embodiments, information, such as information received by controller 116 from tunneling device 102, control data sent to tunneling device 102, and additional operator inputs or state information (e.g., location, time, orientation, datalink quality, battery levels, repair material levels, failure mode indicators), is logged into memory 128.

[0033] Moreover, in the example embodiment, controller 116 is positioned on the exterior of tunnel 104 and communicates with tunneling device 102 positioned within interior cavity 112 of tunnel 104. For example, controller 116 is configured to send information to tunneling device 102 relating to the propulsion and / or steering of tunneling device 102 while tunneling device 102 is moving within interior cavity 112 of tunnel 104 through a wireless connection and / or atether 132. In alternative embodiments, controller 116 and tunneling device 102 are configured in any manner that enables system 100 to operate as described herein.

[0034] Tunneling device 102 includes a body 140 and a tip 142 coupled to body 140. In the example embodiment, body 140 includes a plurality of components disposed along a length of tunneling device 102.

[0035] In the example embodiment, tunneling device 102 includes a tip 142 on a forward end 138 of tunneling device 102. Forward end 138 is a first portion of tunneling device 102 that may form tunnel 104 and / or is with reference to the forward travel direction 115 of tunneling device 102, as discussed herein. Tip 142 is shaped to engage material and displace material when tip 142 moves during operation. For example, tip 142 includes a tunnelling tool configured to displace material as tip 142 moves. As shown in FIG. 2, tip 142(12764-1157) is a cone tapering to a point that is configured to engage the material. In alternative embodiments, tip 142 is any shape that enables tunneling device 102 to operate as described herein. For example, in some embodiments, tip 142 includes a blade, a helix, a sphere, and / or any other suitable shape.

[0036] In the example embodiment, tip 142 may move in a direction parallel to a longitudinal axis 134 of tunneling device 102 and / or in a rotational direction about longitudinal axis 134 during operation. Additionally, or alternatively, tip 142 may also move in a direction perpendicular to longitudinal axis 134. In the example shown in FIG. 1, tip 142 may be controlled by controller 116. More specifically, and as discussed herein, controller 116 may be in operable communication with tip 142 to engage, provide instruction, and / or move tip 142 during the operation of tunneling device 102.

[0037] During operation, tunneling device 102 is positioned proximate surface 114 such that tip 142 engages material of the surface 114 (see, FIG. 1). Controller 1 16 provides instructions that cause tunneling device 102 to tunnel into surface 1 14 and through underground locations by moving tip 142. Tip 142 displaces material to form interior cavity 112 when tip 142 is moved. For example, tip 142 displaces the material in directions parallel and / or perpendicular to longitudinal axis 134. In the example embodiment, the cone shape of tip 142 causes material in front of tunneling device 102 to be compacted and directed at least partly in a direction perpendicular to longitudinal axis 134. A width of tip 142 defines an initial width of interior cavity 112 of tunnel 104 as tip 142 displaces material. In the example embodiment, system 100 does not require an apparatus to remove at least some of the displaced material because tunneling device 102 compacts the displaced material around tunnel 104.

[0038] FIG. 2 shows a tunneling assembly 144 for use with the tunneling device 102 shown in FIG. 1. Tunneling assembly 144 includes tip 142 and is coupled to body 140 at forward end 138 (shown in FIG. 1).

[0039] Tunneling device 102 includes a piston 146, a tunneling tool 148, and a cam gear 150 coupling piston 146 to tunneling tool 148. Piston 146 includes an anvil plate 152 at a first end 154 of tunneling assembly 144 and a piston shaft 156 extending from anvil plate 152. Piston shaft 156 defines longitudinal axis 134 extending through piston shaft(12764-1157)156. In the example embodiment, at least a portion of piston 146 extends through a housing cavity 158 defined in a housing 160 of body 140. Body housing 160 is attached to body 140 such that body housing 160 does not move relative to body 140 as piston 146 is reciprocated. In other embodiments, body housing 160 may extend any length relative to piston 146. For example, in some embodiments, piston 146 and at least a portion of tunneling tool 148 are positioned within body housing 160.

[0040] Piston 146 is operably coupled to an actuator (not shown) that applies a downward force on piston 146 to impart reciprocating motion of piston 146 relative to body housing 160. Specifically, piston 146 is configured to reciprocate along longitudinal axis 134 when the actuator is activated. A stroke return biasing device 163 is coupled to piston 146 and extends between anvil plate 152 and body housing 160. Stroke return biasing device 163 is a compression spring that is engaged with anvil plate 152 and housing 160 to bias piston 146 to a retracted position, as shown in FIG. 2.

[0041] Tunneling tool 148 includes tip 142 and a gear housing 162. Gear housing 162 has a cylindrical shape and defines a gear housing cavity 158 therein. Tip 142 defines a tip axis 136 that extends along a centerline of tip 142. In the example embodiment, in which tip 142 has a cone shape, tip axis 136 extends through a distal end (i.e., the apex) of tip 142 and is perpendicular to a base of tip 142. In other embodiments in which tip 142 has a different shape, tip axis 136 may extend through a distal burrowing end of tip 142. As shown in FIG. 2, tip axis 136 is oriented at an offset to longitudinal axis 134. The offset of tip axis 136 relative to longitudinal axis 134 enables tunneling assembly 144 to tunnel in a turning direction, as described in greater detail below. The offset of tip axis 136 relative to longitudinal axis may be any suitable angle that enables tunneling assembly 144 to operate as described herein. In other embodiments, gear housing 162 may include a bearing or any other suitable structure operable to pivot tip 142 in response to a torque as described herein.

[0042] Cam gear 150 couples tunneling tool 148 to piston 146. Cam gear 150 is configured to translate the linear motion of piston to tip 142, causing tip 142 to move along longitudinal axis 134. Cam gear 150 is further configured to rotate the tip 142 about the longitudinal axis 134. Cam gear 150 includes a plurality of pins 164 and a plurality of gear teeth 166 extending circumferentially around piston 146. In the example embodiment,(12764-1157) gear teeth 166 are positioned on an interior surface of gear housing 162 and extend fully circumferentially around gear housing cavity 158. Pins 164 are formed on piston shaft 156 and protrude radially outward therefrom. In other embodiments, gear teeth 166 may be positioned on piston shaft 156 and pins 164 are positioned on gear housing 162. In further embodiments, tunneling assembly 144 includes any suitable number of pins 164 and gear teeth 166. For example, and without limitation, in some embodiments, tunneling assembly 144 includes a single pin 164.

[0043] FIG. 3 is an enlarged view showing cam gear 150 of FIG. 2. In the example embodiment, gear teeth 166 are each spaced circumferentially substantially equidistant from one another and define gear tracks 168 therebetween. Gear tracks 168 are sized to receive pins 164 therein. Specifically, pins 164 protrude from piston 146 a sufficient distance such that pins 164 may be received within gear tracks 168, with gear tracks 168 guiding pins 164, and thereby piston 146, when piston 146 is moved.

[0044] In the example embodiment, gear teeth 166 each have a ‘'shark-fin” shape including a first convex edge 170 and a second concave edge 172. First edge 170 and second edge 172 intersect at an end tip 174 of gear teeth 166. When piston 146 is moved, pins 164 are guided by gear teeth 166 within gear tracks 168 to control an angular position of tip 142 relative to body 140. In the example embodiment, piston 146 is able to be moved along a first stroke length SLi during a first or “straight” drive mode of operation (also referred to herein as “straight drive mode”) and along a second stroke length SL2 during a second or “turning” drive mode of operation (also referred to herein as a “turning drive mode”). In the example embodiment, second stroke length SL2 is less than first stroke length SLi.

[0045] In the straight drive mode, tip 142 (shown in FIG. 2) is incrementally rotated relative to body housing 160 during each full stroke of piston 146 (i.e., each full extension and retraction of piston 146 along first stroke length SLi). The magnitude of rotation of tip 142 is based on the number and sizing of gear teeth 166. For example, in the example embodiment, tunneling assembly 144 includes six gear teeth 166 each positioned 60 degrees apart circumferentially about piston 146. As a result, tip axis 136 (shown in FIG. 2) is pivoted 60 degrees about longitudinal axis 134 during each full stroke of piston 146.(12764-1157)The consistent and constant rotation of tip 142 in the straight drive mode causes tunneling assembly 144 to tunnel in a generally straight direction (i.e., colinear with longitudinal axis 134) during operation.

[0046] In the straight drive mode, extension of piston 146 causes pins 164 to travel along first edges 170 of respective gear teeth 166. The downward force of pins 164 on curved first edges 170 causes gear housing 162 to rotate about longitudinal axis 134, thereby rotating tip 142 relative to body housing 160. Retraction of piston 146 along first stroke length SLi causes pins 164 to travel in contact along second edges 172 of and adjacent gear tooth 166 and clear gear teeth 166, such that pins 164 are positioned above end tips 174 of gear teeth 166. After pins 164 clear gear teeth 166, piston 146 is rotated relative to gear housing 162 by a piston rotation assembly 178 (shown in FIG. 4), such that pins 164 are aligned over first edge 170 of adjacent gear tooth 166, as shown in FIG. 3.

[0047] In the turning drive mode, piston 146 is moved along second stroke length SL2 such that pins 164 do not clear gear teeth 166 during retraction of piston 146. As a result, in the turning drive mode, tip 142 is moved longitudinally during each stroke of piston 146, and is not rotated about longitudinal axis 134. As shown in FIG. 2, because tip axis 136 is offset from longitudinal axis 134, the reciprocating linear motion of tip 142, without rotating tip 142 as in the straight drive mode, causes tip 142 to tunnel in a direction offset relative to longitudinal axis 134, thereby causing tunneling device 102 to tunnel out a turning path. In the example embodiment, second stroke length SL2 is less than first stroke length SLi. In other embodiments, first stroke length SLi and second stroke length SL2 may be any suitable length that enables tunneling device 102 to operate as described herein.

[0048] The actuator drives movement of piston 146 along first stroke length SLi or second stroke length SL2. In some embodiments, the stroke length of piston 146 is controlled by any one or more of an air valve, a mechanical stop, and electrical actuation (i.e., control of the actuator).

[0049] Referring back to FIGS. 1 and 2, tunneling device 102 is show n in the straight drive mode, having tunneled a generally straight tunnel along axis 110. During operation, tunneling device 102 may be turned in response to a command from controller 116 (e.g., input from the operating interface). For example, in response to a command to turn(12764-1157) downward relative to the position of FIG. 1, controller 116 may control tunneling device 102 to reciprocate piston in the straight drive mode until tip 142 is oriented at a downward offset corresponding to the drive command. Once tip 142 is in the downw ard offset, controller 116 controls tunneling device 102 to reciprocate piston 146 at the downward offset along second stroke length SL2, with tip 142 still reciprocating linearly but locked in the downward offset position. Tunneling device 102 may remain in the turn mode at the downward offset until a new command is received from controller 116 and / or a predetermined travel path has been tunneled. Controller 1 16 may further control tunneling device 102 to switch back to the straight drive mode by controlling piston 146 to reciprocate along first stroke length SLi.

[0050] In some embodiments, a turn radius of tunneling device 102 is controlled by intermittently combining the straight drive mode and the turn mode. For example, when turning solely in the turn mode, tunneling device 102 may turn at a minimum radius of curv ature (i.e., tightest turn) of tunneling device 102. The turn radius of tunneling device 102 may be increased by intermittently switching tunneling device 102 between the turn mode and the straight drive mode manually and / or according to a predetermined pattern.

[0051] FIG. 4 is an enlarged view' of tunneling assembly 144 showing a piston rotation assembly 178. Piston rotation assembly 178 rotates piston 146, after pins 164 clear gear teeth 166 in the straight drive mode, as shown in FIG. 3. Piston rotation assembly 178 includes an elongate piston key 180 that projects radially outward from an outer surface of piston 146. Body housing 160 defines a recess 182 defined on an interior edge of body housing 160 (i.e., within housing cavity 158) and which is recessed radially outward therefrom into body housing 160. Piston key 180 projects into recess 182. Piston rotation assembly 178 further includes a biasing device 184 which biases piston key 180 to a first position, as shown in FIG. 4, in which piston key 180 is positioned circumferentially against an end edge 186 of housing recess 182. In the example embodiment, biasing device 184 is a compression spring, though in other embodiments, any suitable biasing device 184 may be used. As shown in FIG. 4, piston key 180 is in contact with end edge 186. End edge 186 restricts clockwise rotation of piston key 180 beyond end edge 186 (i.e., rotation of piston key 180 to the left of the page in FIG. 4). In other embodiments, piston rotation assembly 178 includes any suitable device to limit rotation of piston 146 and guide pins 164 relative(12764-1157) to gear teeth 166 as described herein. For example, in some embodiments, piston rotation assembly 178 includes any one of a ratchet and a one-way gear housing.

[0052] Referring to FIGS. 3 and 4, in the straight drive mode, when piston 146 is retracted and pins 164 are moved upward along second edges 172, piston 146 is rotated in a counter-clockwise direction relative to body housing 160. Referring to FIG. 4, rotation of piston 146 in the counter-clockwise direction causes piston key 180 to rotate counterclockwise within recess 182 to a second position (e.g., as shown in FIG. 8), thereby compressing biasing device 184. After pins 164 have cleared gear teeth 166, compression of biasing device 184 is released, thereby causing piston key 180, and piston 146, to rotate back in the clockwise direction and into contact with end edge 186. Referring to FIG. 3, pins 164 are likewise rotated in the clockwise direction and moved over first edges 170 of gear teeth 166. As piston 146 is then extended, referring to FIG. 4, end edge 186 limits further clockwise rotation of piston 146. As a result, as show n in FIG. 3, the downw ard force of pins 164 on first edges 170 is converted to a torque rotating gear housing 162 and tip 142 (shown in FIG. 2) in the clockwise direction.

[0053] FIGS. 5-8 show' a stroke cycle of tunneling assembly 144 in the straight drive mode. Referring to FIG. 5. piston 146 is in the retracted position with pins 164 clear of gear teeth 166 and piston key 180 biased to the first position. In FIG. 5, a first pin 188 is positioned in circumferential alignment with a first gear tooth 190, and more specifically, with a first edge 170 of first gear tooth 190.

[0054] Referring to FIG. 6, piston 146 is extended along longitudinal axis 134, tip 142 is rotated, and pins 164 are positioned at base 165 of gear tracks 168. As shown in FIG. 6, piston 146 is extended within gear housing cavity 158 relative to the retracted position shown in FIG. 5. In the extended position of FIG. 6, first pin 188 is positioned in a first gear track 192 defined between first gear tooth 190 and a second gear tooth 192. As piston 146 is extended from the retracted position shown in FIG. 5 to the extended position shown in FIG. 6, first pin 188 is slid along first edge 170 of first gear tooth 190, thereby rotating gear housing 162 and tip 142 relative to piston 146.(12764-1157)

[0055] FIG. 7 shows tunneling assembly 144 with piston 146 in an intermediate retracted position, immediately before pins 164 clear gear teeth 166. In the intermediate retracted position, first pin 188 is slid along second edge 172 of second gear tooth 192 from the extended position shown in FIG. 6. At least in part due to the curvature of second edge 172, piston 146 is rotated relative to gear housing 162 and tip 142, such that piston key 180 compresses biasing device 184.

[0056] FIG. 8 shows tunneling assembly 144 in a second fully retracted position. In the second fully retracted position, piston 146 is retracted relative to the intermediate position shown in FIG. 7, such that pins 164 have cleared gear teeth 166 and biasing device 184 biases piston key 180 to the first position. As shown in FIG. 8. first pin 188 is circumferentially aligned over second gear tooth 192. Repeated strokes of piston 146 along first stroke length SLi continue to rotate gear housing 162 and tip 142 relative to piston 146 in substantially the same manner as shown in FIGS. 5-8.

[0057] FIG. 9 is a schematic showing an alternative embodiment of a cam gear 350 for use with tunneling device 102 of FIGS. 1-8. Cam gear 350 of FIG. 9 is substantially the same as cam gear 150 shown in FIG. 3 except that, in the example embodiment, the gear tracks 368 have a different shape from the gear tracks 168 of the cam gear 150. In the schematic of FIG. 9, gear track 368 is a continuously connected track and is illustrated in a plan view showing a partial portion of gear track 368. It should be understood that gear track 368 of FIG. 9 extends fully circumferentially around piston 146, similar to gear tracks 168 shown in FIG. 3. and that the view of FIG. 9 shows the circumferential gear track 368 in a flat map projection.

[0058] In the exemplary embodiment, gear tracks 368 include an elongate section 301 and an oblique section 303 extending from a distal end 305 of elongate sections and to an adjacent elongate section 301. In the straight drive mode, pins 364 are moved along first stroke length SLi from a proximal end 307 of elongate sections 301 to distal end 305. In the embodiment of FIG. 9, the extension of piston 146 (shown in FIG. 2) causes pins 164 to move counter-clockwise in gear tracks 368, such that pins 364 are positioned in oblique sections 303 during retraction. As a result, during each stroke, pins 364 are moved into an adjacent gear track 368 in substantially the same manner as cam gear 350. Gear track 368(12764-1157) and pins 364 may be positioned on any one of tunneling tool 148 and piston 146 (shown in FIG. 2).

[0059] In the exemplary embodiment, in the turning drive mode, piston 146 is moved along a second stroke length SL2 shorter than first stroke length SLi. Second stroke length SL2 is sized such that pins 364 do not reach distal ends 305 of elongate sections 301 and are not moved into oblique sections 303 during retraction of piston 146.

[0060] In other embodiments, gear tracks 368 may have any suitable shape that enables tunneling device to operate as described herein. For example, and without limitation, in some embodiments, gear tracks 368 include different stroke length sections (not shown) that cause tip 142 to move to a different offset to change a turn radius of tunneling device 102 (shown in FIG. 1).

[0061] FIG. 10 is a flow chart of an example method 400 for forming a tunnel using a tunneling device 102 (shown in FIG. 1). In reference to FIGS. 1 -9, method 400 includes controlling 402 a piston 146 to reciprocate relative to a housing 160 of the tunnelling device 102 along a first stroke length SLi. The piston 146 is coupled to a tunneling tool 148 by a cam gear 150. The method further includes controlling 404 the piston 146 to reciprocate relative to the housing 160 along a second stroke length SL2, wherein the cam gear 150 translates reciprocating motion of the piston 146 into a reciprocating motion of the tunneling tool 148 when the piston 146 is reciprocated along each of the first stroke length SLi and the second stroke length SL2. The cam gear 150 pivots the tunneling tool 148 relative to the housing 160 when the piston 146 is reciprocated along the first stroke length SLi.

[0062] An example technical effect of the methods, systems, and devices described herein includes at least one of: (a) increasing the complexity of tunnel geometry; (b) improved control over steering path of a tunneling device and shape of tunnel; (c) reduced size and lowered cost of steering mechanism on a tunneling device; (d) improved lifespan of tunneling device with steering mechanism; (e) reducing the power requirements for tunneling devices during tunneling operations.(12764-1157)

[0063] Example embodiments of devices, systems and methods for use in tunneling operations are described above in detail. The methods, devices, and systems are not limited to the specific embodiments described herein, but rather, components of devices, systems, and / or steps of the methods may be utilized independently and separately from other components and / or steps described herein. For example, the method may also be used in combination with other components, and are not limited to practice only with tunnels as described herein. Rather, the example embodiment can be implemented and utilized in connection with many other applications.

[0064] Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the disclosure, any feature of a drawing may be referenced and / or claimed in combination with any feature of any other drawing.

[0065] This written description uses examples to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

(12764-1157)WHAT IS CLAIMED IS:

1. A tunneling assembly for use with a tunneling device, said tunneling assembly comprising: a housing; a piston extending within said housing, said piston configured for reciprocating motion relative to said housing along a first stroke length and a second stroke length; a tunneling tool; and a cam gear coupling said tunneling tool to said piston, wherein said cam gear translates reciprocating motion of said piston into a reciprocating motion of said tunneling tool when said piston is reciprocated along each of the first stroke length and the second stroke length, and wherein said cam gear pivots said tunneling tool relative to said housing when said piston is reciprocated along the first stroke length.

2. The tunneling assembly of Claim 1, wherein said tunneling tool is configured to tunnel along a straight path when said piston is reciprocated along the first stroke length, and wherein said tunneling tool is configured to tunnel along a turning path when said piston is reciprocated along the second stroke length.

3. The tunneling assembly of Claim 1, wherein the first stroke length is greater than the second stroke length, and wherein said tunneling tool does not pivot relative to said housing when said piston is reciprocated along the second stroke length.

4. The tunneling assembly of Claim 1, wherein said piston reciprocates along a longitudinal axis and wherein said tunneling tool includes a tip defining a tip axis extending through a distal end of said tip, wherein the tip axis is oriented at an offset relative to the longitudinal axis.

5. The tunneling assembly of Claim 1, wherein said tunneling tool defines a cavity therein, and wherein said piston is at least partially received within the cavity.(12764-1157)6. The tunneling assembly of Claim 1, wherein said cam gear comprises a plurality of gear teeth and a pin, said plurality of gear teeth defining a plurality of gear tracks and said pin sized to extend into said gear tracks, wherein said pm moves longitudinally out of contact with said gear teeth when said piston is reciprocated along the first stroke length, and wherein said pin moves along a single gear tooth when said piston is reciprocated along the second stroke length.

7. The tunneling assembly of Claim 6, wherein said pin is positioned on said piston and projects radially outward therefrom, and wherein said gear tracks are positioned on said tunneling tool.

8. The tunneling assembly of Claim 6 further comprising a rotation assembly configured to rotate said pin relative to said gear teeth when said pin moves longitudinally out of contact with said gear teeth.

9. The tunneling assembly of Claim 8, wherein said rotation assembly comprises a key projecting radially outward from said piston into a recess of the housing, said rotation assembly further comprising a biasing device engaged with said key and biasing said key to a first position in the recess.

10. The tunneling assembly of Claim 6, wherein said gear teeth each comprise a first convex edge and a second concave edge, said first edge and said second edge intersecting at a distal tip of said gear tooth.

11. A tunneling device comprising: a body including a plurality of rigid sections and a plurality of flexible sections; and a tunneling assembly coupled to a leading end of said body, said tunneling assembly configured as a percussive device generating a linear impact motion to penetrate ground, said tunneling assembly comprising: a piston configured for reciprocating motion relative to said body along a first stroke length and a second stroke length;(12764-1157) a tunneling tool; and a cam gear coupling said tunneling tool to said piston, wherein said cam gear translates reciprocating motion of said piston into a reciprocating motion of said tunneling tool when said piston is reciprocated along each of the first stroke length and the second stroke length, and wherein said cam gear pivots said tunneling tool relative to said body when said piston is reciprocated along the first stroke length.

12. The tunneling device of Claim 11, wherein said tunneling tool is configured to tunnel along a straight path when said piston is reciprocated along the first stroke length, and wherein said tunneling tool is configured to tunnel along a turning path when said piston is reciprocated along the second stroke length.

13. The tunneling device of Claim 11. wherein the first stroke length is greater than the second stroke length, and wherein said tunneling tool does not pivot relative to said body when said piston is reciprocated along the second stroke length.

14. The tunneling device of Claim 11, wherein said piston reciprocates along a longitudinal axis and wherein said tunneling tool includes a tip defining a tip axis extending through a distal end of said tip, wherein the tip axis is oriented at an offset relative to the longitudinal axis.

15. The tunneling device of Claim 11, wherein said tunneling tool defines a cavity therein, and wherein said piston is at least partially received within the cavity.

16. The tunneling device of Claim 11, wherein said cam gear comprises a plurality of gear teeth and a pin, said plurality of gear teeth defining a plurality of gear tracks and said pin sized to extend into said gear tracks, wherein said pin moves longitudinally out of contact with said gear teeth when said piston is reciprocated along the first stroke length, and wherein said pin moves along a single gear tooth when said piston is reciprocated along the second stroke length.

17. The tunneling device of Claim 16, wherein said pin is positioned on said piston and projects radially outward therefrom, and wherein said gear tracks are positioned on said tunneling tool.(12764-1157)18. A method for forming a tunnel using a tunneling device, said method comprising: controlling a piston to reciprocate relative to a housing of the tunnelling device along a first stroke length, the piston being coupled to a tunneling tool by a cam gear; and controlling the piston to reciprocate relative to the housing along a second stroke length, wherein the cam gear translates reciprocating motion of the piston into a reciprocating motion of the tunneling tool when the piston is reciprocated along each of the first stroke length and the second stroke length, and wherein the cam gear pivots the tunneling tool relative to the housing when the piston is reciprocated along the second stroke length.

19. The method of Claim 18. wherein the tunneling tool tunnels along a straight path when the piston is reciprocated along the first stroke length, and wherein the tunneling tool tunnels along a turning path when the piston is reciprocated along the second stroke length.

20. The method of Claim 18, wherein the first stroke length is greater than the second stroke length, and wherein the tunneling tool does not pivot relative to the housing when the piston is reciprocated along the second stroke length.

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