Drill bit for use with micro tunneling equipment

Abstract

The invention relates to a drill bit (4) for use with a micro-tunneling apparatus (1) for producing cuttings in a working area (13) of a drill hole. The drill bit (4) comprises a cutterhead beam (12) having at least one injection outlet configured to inject fluid towards a radial member (36) of the drill bit (4).

Description

Technical Field

[0001] The present invention relates to a drill bit for use with a microtunneling machine and a microtunneling machine comprising such a drill bit. More specifically, the drill bit is used at the end of a drill string of a microtunneling machine. The drill bit has a particular application in producing a substantially straight hole from a working well, and the invention will be described below with reference to this particular application. However, it should be understood that the invention may have other applications, such as producing a curved hole from the ground. Background Art

[0002] The term "microtunneling" as used in this specification refers to the drilling or boring of non-vertical holes without the operator having to enter the hole. The diameter of the hole produced will generally not exceed 1500 mm, but this value may change over time according to the perception of the microtunneling industry. However, it will be convenient to describe the invention hereinafter within these reference values.

[0003] The provision of services such as telecommunications, gas, water, stormwater, sewerage, data and electricity typically involves trench excavation, laying of service facilities and backfilling of the trench. This approach can be convenient if the trench is relatively shallow and no infrastructure exists, such as on a "greenfield" site. However, as trench depth increases, it becomes difficult to cost-effectively provide machinery to excavate the required depth. Additionally, if other existing infrastructure would be adversely affected by trench excavation, such as major roads or existing services being destroyed or damaged, other methods of conduit creation must be considered.

[0004] Another such method is microtunnelling, which typically involves a drilling apparatus having a drill bit with a cutterhead beam at the end of a drill string that rotates across the face to drill a borehole in the ground. The drill string is composed of a plurality of sections, each of which includes a drive shaft that transmits torque from a drive device located at the face or at the bottom of a vertical drive pit to the drill bit underground. The drill string may also include passages to accommodate operating lines (e.g., hydraulic pipes and communications cables) or to supply fluids from the drive pit to the working area where the cutterhead is located during operation. The drill string may also include a discharge conduit through which cuttings and fluids from the working area may be pumped back to the drive pit and ultimately to the ground. As the drill bit is launched from the well, a laser may be aimed along the drill string as a reference point to facilitate maintaining a straight drill string.

[0005] When ground conditions are perfectly uniform, it is fairly simple to operate a microtunnel boring machine to produce a satisfactory borehole. Unfortunately, perfectly uniform ground conditions are extremely rare and the drill bit will always gravitate towards the ground that offers the least resistance. While attempts have been made to produce steerable drill bits, such as the drill bit described in the inventor's earlier application WO2007 / 143772, the inventor has realised that such drill bits have their limitations in producing straight holes when the drill bit tip is steered.

[0006] The inventors have also realised that when operating in unconsolidated or flowing ground, chip extraction may outstrip the operation of the cutterhead beam, resulting in uneven collapse of the work surface. This will make it difficult for the operator to achieve a straight hole, even with a steerable drill head. Excessive chips may block further access to the discharge duct, especially if the cutterhead beam is not capable of handling the chips removed from the work surface. Access to the discharge duct may become blocked and it may not be clear to the operator whether the cause of the blockage is in the work area or in the discharge duct itself.

[0007] The present invention is directed to solving one or more of the above problems.

[0008] The reference herein to a patent document or other matter cited as prior art is not to be taken as an admission that the document or matter is known in Australia or that the information it contains was part of the common general knowledge at the priority date of any claim. Summary of the invention

[0009] According to one aspect of the present invention, there is provided a drill bit for use with a micro-tunnel boring device to produce a borehole, the drill bit comprising: a housing having an annular shell and a radial member adjacent to the distal end of the housing; a cutterhead beam having at least one cutting element positioned for front cutting, the cutterhead beam being capable of rotating in a working zone of the borehole in a manner straddling the radial member to produce chips; an air cavity extending in the longitudinal direction of the housing and leading to an air hole in the radial member for supplying air to the working zone, the radial member having a discharge hole leading to a discharge cavity extending in the longitudinal direction of the housing for extracting chips from the working zone, the air cavity, the working zone and the discharge cavity defining an air flow path; a pressure regulating mechanism capable of operating at the distal end of the housing and for regulating the air pressure in the working zone so as to regulate the extraction of chips from the working zone.

[0010] The pressure regulating mechanism can take any suitable form, and in a preferred form, it includes a throat member positioned between the air hole and the extraction hole to generate a venturi flow between them, and the throat member is adjustable to control the venturi flow of the air in the working area. The throat member may include a curved surface positioned in the airflow path. The curved surface is configured to interact with the airflow in a manner similar to a venturi tube. Preferably, the throat can be moved between an extended position and a retracted position relative to the radial member. In this way, the throat can be adjusted similar to the throat of the venturi tube. Preferably, the throat member is configured so that when in the extended position, a maximum negative pressure is generated in the working area, and when in the retracted position, a minimum negative pressure is generated in the working area.

[0011] According to another aspect of the present invention, there is provided a drill bit for use with a micro-tunnel boring device to produce a borehole, comprising: a housing having an annular shell and a radial member adjacent a distal end of the housing; a cutterhead beam having at least one cutting element positioned for front cutting, the cutterhead beam being rotatable within a working area in a manner straddling the radial member to produce drill cuttings; and a movable imaging device configured to capture images within the working area and being movable between a retracted position within the housing and an extended position outside the housing.

[0012] The radial member preferably includes an imaging aperture that is obscured by the cover when the movable imaging device is in the retracted position and is not obscured by the cover when the movable imaging device is in the extended position. It is further preferred that the drill head includes another imaging device located within the housing, the other imaging device configured to capture an image on the rear surface of the radial member. The other imaging device is configured to interact with a target on the rear surface of the radial member, the target configured to interact with the laser. In this way, the laser can be projected onto the drill head along the drill string and inform the operator whether the drill head is moving along a straight path.

[0013] According to another aspect of the present invention, there is provided a drill bit for use with a micro-tunnel boring device to produce a borehole, comprising: a housing having an annular shell and a radial member adjacent to the distal end of the housing; a cutterhead beam having at least one cutting element positioned for front cutting, the cutterhead beam being capable of rotating within a working area of ​​the borehole in a manner straddling the radial member to produce chips, the cutterhead beam having at least one injection outlet (hereinafter referred to as a beam injection portion), the beam injection portion being configured to inject a fluid toward the radial member.

[0014] The drill bit may include an air cavity extending in the longitudinal direction of the housing, the air cavity leading to the air hole in the radial member for supplying air to the working area, the radial member having a discharge hole leading to the discharge cavity extending in the longitudinal direction of the housing for removing chips from the working area, the housing having at least one jet outlet (hereinafter referred to as the discharge jet portion), the discharge jet portion being configured to spray fluid toward the discharge hole. The housing has at least one jet outlet (hereinafter referred to as the housing jet portion), the housing jet portion spraying fluid toward the cutterhead beam.

[0015] According to another aspect of the present invention, there is provided a drill bit for use with micro-tunnel boring equipment to produce a borehole, comprising: a housing having an annular shell and a radial member adjacent to the distal end of the housing; a cutterhead beam having at least one cutting element positioned for front cutting, the cutterhead beam being capable of rotating within a working area of ​​the borehole in a manner straddling the radial member to produce chips; an air cavity extending in the longitudinal direction of the housing and leading to an air hole in the radial member for supplying air to the working area, the radial member having a discharge hole leading to a discharge cavity extending in the longitudinal direction of the housing for removing chips from the working area, the housing having at least an ejection outlet (hereinafter referred to as an ejection jet portion), the ejection jet portion being configured to eject fluid toward the discharge hole.

[0016] The cutterhead beam may have at least one spray outlet (hereinafter referred to as a beam spray portion) configured to spray fluid toward the radial member. The housing may also have at least one spray outlet (hereinafter referred to as a housing spray portion) configured to spray fluid toward the cutterhead beam.

[0017] According to another aspect of the present invention, there is provided a drill bit for use with a micro-tunnel boring device to produce a borehole, comprising: a housing having an annular shell and a radial member adjacent to the distal end of the housing; a cutterhead beam having at least one cutting element positioned for front cutting, the cutterhead beam being capable of rotating within a working area of ​​the borehole in a manner straddling the radial member to produce chips, the housing having an annular body configured to be hinged.

[0018] The drill head preferably includes an articulated coupling configured to enable adjustment of up to 3° relative to the drive axis. The articulated coupling may include a drive gear shaft, a driven gear shaft, and a gear sleeve, the drive gear shaft, the driven gear shaft, and the gear sleeve configured to allow adjustment of the articulated coupling. The drill head preferably includes a plurality of radially mounted actuators positioned around the articulated joint, the plurality of actuators being used to adjust the articulation angle.

[0019] The actuator may take any suitable form and in a preferred arrangement the actuator is a hydraulic ram (hereinafter referred to as articulation rams), each articulation ram comprising a piston (hereinafter referred to as an articulation piston) arranged to move longitudinally along the annular body, each articulation piston having a part spherical surface configured to interact with a socket to allow axial movement of the articulation piston while allowing angular adjustment of the articulation coupling.

[0020] The annular housing is preferably configured to move radially relative to the annular body to adjust the orientation of the annular housing within the borehole when in use. This radial movement may be achieved in any suitable manner, and in one preferred arrangement, the drill head comprises a plurality of radially mounted hydraulic push rods (hereinafter referred to as housing push rods), each housing push rod comprising a piston (hereinafter referred to as housing piston) arranged to engage the inner surface of the annular housing and configured to move in a radial direction to adjust the position of the annular housing relative to the annular body.

[0021] According to another aspect of the present invention, there is provided a micro-tunnel boring device for producing a borehole, comprising: a driving device for positioning in a working shaft; a drill string for connecting to the driving device, the drill string having a transmission shaft rotatable under the operation of the driving device; and the aforementioned drill bit, which is used to be connected to the drill string so that rotation of the transmission shaft causes rotation of the cutter head beam.

[0022] The microtunneling apparatus preferably includes a pair of elongated members at the proximal end of the housing for interacting with a latch connection at the distal end of the drill string, each elongated member being configured to be adjustable so as to vary the tolerance between the proximal end of the housing and the distal end of the drill string. This may also include a drill string formed of a plurality of connected drill string sections, each drill string section including a latch connection for manually connecting adjacent drill string sections. Preferably, the drill string includes a first cavity configured to supply air from a drive device to a working area and a second cavity for extracting cuttings from the working area to the drive device. More preferably, the first cavity is also configured to aim a laser along the first cavity to a rear surface of the radial member.

[0023] The invention will be described in more detail below by reference to the accompanying drawings of preferred embodiments of the drill bit according to the invention. The particularity of these drawings and the accompanying detailed description should not be understood as superseding the generality of the foregoing definition of the invention in accordance with its various aspects. Although some of the drawings are provided in a vertical / longitudinal orientation, it should be understood that the microtunneling machine is intended to operate in a horizontal or substantially horizontal orientation. These drawings are provided in a longitudinal vertical / longitudinal orientation to increase the level of detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order that the present invention can be more fully understood, some embodiments will now be described with reference to the accompanying drawings.

[0025] Figure 1 is a side elevation view of a preferred embodiment of a microtunneling apparatus according to the present invention.

[0026] Figure 2 It's from the first person perspective Figure 1 An isometric view of a drill string portion of a drill string is shown.

[0027] Figure 3 From a second perspective Figure 2 Isometric view of the drill string section.

[0028] Figure 4 is an isometric view of a preferred embodiment of a drill bit according to one aspect of the present invention.

[0029] Figure 5 From a second perspective Figure 4 Isometric view of a drill bit.

[0030] Figure 6 yes Figure 4 An isometric view of the drill bit in FIG. 1 with the casing of the annular body removed to show the air cavity and the exhaust cavity.

[0031] Figure 7 It is an elevation view of the far end of the drill bit.

[0032] Figure 8 yes Figure 7 Isometric view of the far end of the drill bit in .

[0033] Fig. 9 is a cross-sectional view of the distal end of the drill with the movable imaging device in a retracted position.

[0034] Fig.10 yes Fig. 9 A cross-sectional view of the distal end of the drill bit in FIG. 1 with the movable imaging device in an extended position.

[0035] Fig.11 is an isometric view of the distal end of the drill bit with the throat member in the extended position.

[0036] Fig.12 yes Fig.11 An isometric view of the distal end of the drill bit in FIG. 1 with the throat member in the retracted position.

[0037] Fig.13 is a cross-sectional view of the drill bit showing the air flow path.

[0038] Fig.14 is a cross-sectional view of the drill bit showing the articulation within the annular body.

[0039] Fig.15 is an isometric view of a preferred embodiment of an articulated joint from a first perspective.

[0040] Fig.16 Seen from the second angle Fig.15 Isometric view of an articulated joint in . Fig.16 is a cross-sectional view of the annular housing, which also shows the rear surface of the radial member. DETAILED DESCRIPTION

[0041] Reference now Figure 1 , which shows an example of a microtunnel boring device 1 in use. In summary, the microtunnel boring device 1 includes a drive device 2, a drill string 3 and a drill bit 4. The drive device 2 includes a drive 5 positioned on a platform 6, the drive being configured to be able to move along the platform. The platform is positioned at the bottom of a working pit 7 so that the drive 5 can be moved horizontally to produce a horizontal borehole 8. In this way, it differs from a HDD system in that it is located at the bottom of the working pit 7, rather than being located on the ground like a HDD system.

[0042] Figure 1 The drill string 3 is shown to be formed of two drill string sections 9, wherein the proximal end of the first drill string section 9 is engaged with the driver 5 and the distal end of the second drill string section 9 is engaged with the drill bit 4. The distal end of the drill bit 4 is engaged with the working surface 10 of the borehole 8. The drill bit 4 comprises Figure 4 The annular housing 11 and the cutterhead beam 12 are more clearly shown in the figure, wherein the cutterhead beam 12 can rotate relative to the annular housing 11 under the operation of the drive 5. The cutterhead beam 12 rotates in a working area 13 which is the area between the annular housing 11 and the working surface 10.

[0043] Figure 1 Also shown is a discharge outlet 14 which can be connected by a conduit (not shown) to a vacuum extraction facility (not shown) on the ground surface in order to extract the cuttings from the working area 13 in a manner which will be described in more detail with reference to the following figures.

[0044] Figure 2 and 3 A preferred embodiment of each drill string section 9 is shown, the drill string section 9 includes a drive shaft 15, which is formed at the proximal end of each drill string section 9 as shown in FIG. Figure 2 The protrusion shown in FIG. 1 and the distal end of each drill string section 9 are formed with a protrusion such as Figure 3 In this way, the drive shafts 15 of adjacent drill string sections 9 can be connected to create a substantially continuous drive shaft from the driver 5 to the drill bit 4. The driver 5 is configured to rotate the drive shaft 15 around a working axis extending at the center of the drill string 3.

[0045] Figure 2 Each drill string section 9 is shown having a pair of elongated pins 16, and Figure 3 Each drill string section 9 is shown formed with a pair of holes located on either side of the drive shaft 15. A locking mechanism 18 is arranged at each hole 17, which is configured to lock each elongate pin 16 when a pair of drill string sections 9 are located adjacent to each other. Figure 2 and 3 Also shown is a nut 19 positioned at the rear of each elongated pin 14, which can be rotated relative to the pin 16 to adjust the length of each pin 16 extending from the proximal end of the drill string section 9. In this way, the connection between adjacent drill string sections 9 can be tightened or loosened depending on the direction of rotation of the nut 19.

[0046] Figure 2 and 3 Also shown are a first conduit 20, a second conduit 21 and an open passage 22, which extend longitudinally from the proximal end to the distal end of each drill string section 9, respectively. In addition, the first conduit 20 and the second conduit 21 are provided with a first seal 23 and a second seal 24, respectively, at least at the proximal end of the drill string section 9, which surround the inlets of the first conduit 20 and the second conduit 21. The first conduit 20 is configured for supplying air to the working area, while the second conduit 21 is configured to draw air and cuttings in the working area 10 back to the discharge outlet 14 (see Figure 1 ). The first seal 23 and the second seal 24 are configured to inhibit the flow of air or chips from the first conduit 20 and the second conduit 21, respectively. The channel 22 is configured to receive a cable (not shown) extending from the driver 5 to the drill bit 4 therein. The cable may include hydraulic fluid, cleaning fluid, and communications to operate the drill bit 4 in a manner more clearly described with reference to the following figures.

[0047] Reference now Figure 4 and Figure 5 , they show a drill head 4 having a cutterhead beam 12 positioned in front of an annular housing 11, and an annular body 25 located behind the annular housing 11. The annular body 25 shown comprises three casings 26, of which a cover 27 (see Figure 1 ) is removed to reveal the internal features of the drill bit 4. Figure 5 It can be seen that the proximal end of the annular body 25 includes a pair of elongated pins 27 and a nut 28 positioned at the rear of the elongated pins 27, which are configured to be aligned with the reference Figure 3 The drill string section 9 shown illustrates the interaction of the hole 17 and the locking mechanism 18. In addition, Figure 5 Also shown is an input shaft 29, which is configured to be connected to the Figure 3 The illustrated drive shaft 15 interacts. In addition, the proximal end of the illustrated annular body 25 also includes an air cavity 30 and a drain cavity 31, the air cavity 30 and the drain cavity 31 having a third seal 32 and a fourth seal 33, respectively, so as to connect with the first pipe 20 and the second pipe 21 when the drill bit 4 is attached to the adjacent drill string section 9. The air cavity 30 may include a pressure sensor inside it for comparison with atmospheric pressure to detect airflow obstruction. Figure 5 Also shown is a slot 34 adjacent the air cavity 30 , which slot 34 may accommodate a cable (not shown) to provide access for the cable to internal features of the drill bit 4 .

[0048] See now Figure 6 , which shows the drill bit 4, wherein the shell 26 is removed to expose the air cavity 30 and the exhaust cavity 31, each of which extends in the longitudinal direction of the housing. Fig.13 As will be appreciated, the air cavity 30 provides an air flow path that extends along the annular body 25, through the annular housing 11 and outwardly through the air holes 35 formed in the radial plate member 36. The radial plate 36 also includes a discharge hole 37 through which air and chips can be drawn along the discharge cavity 31 and returned to the drive device 2 (see Figure 1 ).

[0049] Figure 7 A spray outlet (hereinafter referred to as discharge spray 38 ) is shown through which a cleaning fluid can be sprayed from within the annular housing 11 towards the discharge aperture 37 in order to facilitate extraction of chips from the working area 13 . Fig.11 The housing spray outlet (hereinafter referred to as the housing spray portion 39) is shown, which is configured to spray the cleaning fluid toward the blade beam 12. At the same time, the blade beam 12 is formed with a cavity 40 (see Fig.13 ), the cavity extends in the longitudinal direction of the cutter head beam and terminates in a plurality of ejection outlets (hereinafter referred to as the beam ejection portion 41), which are configured to face the working surface 10 (see Figure 7 ) and return toward a radial plate 36 (obscured in the illustration provided) located at the rear side of the cutterhead beam 12. The jets 38, 39 and 41 can be used purely for cleaning (cleaning mode) or operated in conjunction with the cutterhead beam 12 (extraction mode), which can be determined by the operator.

[0050] Figure 7 While the cutterhead beam is shown as being formed with a plurality of cutting elements 42 positioned along the cutterhead beam, the number and location of the cutting elements may vary from that shown. Figure 7 Also shown is an annular ring 43 attached to the annular housing 11 by a plurality of bolts 44. Fig.13As can be seen, the annular ring 43 includes a frustoconical surface 45. It is contemplated that the annular ring 43 is interchangeable so as to be selected to include a frustoconical surface 45 having an angle and length suitable for ground conditions. Figure 7 Also shown is a removable imaging device 46 which may take the form of a digital camera. Figure 8 It can be seen that the radial plate 36 has an imaging hole 47 formed in the radial plate and can be in the closed position ( Figure 6 ) and open position ( Figure 8 ) between which the cover 48 (see Figure 6 ). Brief reference Fig. 9 and 10 , which show that the movable imaging device 46 can be Fig. 9 The retracted position shown and Fig.10 Adjust between the extended positions shown. Fig. 9 The movable imaging device 46 is shown at the end of the tube 64, wherein the ball valve 65 is also in a closed position, thereby providing further protection for the movable imaging device 46. Fig.10 In this way, when the cutter head beam 12 is stopped, the movable imaging device 46 can capture images in the working area 13, especially the images in front of the radial plate 36, while when the cutter head beam 12 rotates, the movable imaging device 46 can be protected from the working area 13.

[0051] The drill bit according to one aspect of the present invention includes a pressure regulating mechanism located at the distal end of the annular housing 11, which is used to regulate the gas pressure in the working area 13. Fig.13 As explained above, an air flow path is established between the air cavity 30 and the discharge cavity 31, so that the air flow enters and leaves the working area 13 through the air holes 35 and the discharge holes 37 on the radial plate 36, respectively. The throat member 49 is positioned near the air holes 35 and the discharge holes 37 and provides a curved surface 50 through which the air flows between the air holes 35 and the discharge holes 37. The position of the throat member 49 is Fig.11 Extended position shown and Fig.12The retracted positions shown are adjustable to adjust the characteristics of the airflow path between the air holes 35 and the exhaust holes 37 through the work zone 13. The inventors have realized that when the throat member 49 is in the extended position, it creates a maximum negative pressure in the work zone, and when the throat member 49 is in the retracted position, it creates a minimum negative pressure in the work zone 13. In this way, when the throat member 49 is in the extended position, chips are more actively extracted from the work zone through the exhaust holes 37, and when the throat member 49 is in the retracted position, chips are less actively extracted from the work zone 13. This allows the cutterhead beam 12 to properly process chips on the entire work surface 10 of the borehole 8, rather than extracting chips from the lower portion of the work surface 10 through excessive negative pressure.

[0052] Fig.13 Also shown is a fixed imaging device 51 positioned in the air cavity 30 , which is configured to project an image taken from the rear surface of the radial plate 36 . Fig.17 A radial plate 36 is shown formed with a target 52 so that in use, a laser beam (not shown) can be projected along the first conduit 20 and the air cavity 30 toward the target 52, and a fixed imaging device 51 provides an image to the operator to enable them to determine whether the drill bit is moving on a straight path. When the operator realizes that the drill bit 4 deviates from the straight path, the position of the annular housing 11 relative to the annular body 25 can be adjusted by operating any one or more radially mounted push rods (hereinafter referred to as housing push rods 53). Each housing push rod 53 includes a housing piston configured to engage the inner surface of the annular housing 11, so that adjustment of the position of each housing piston 54 results in adjustment of the position of the annular housing 11 relative to the annular body 25.

[0053] The inventors have realised that while a degree of steering is indeed provided by adjusting the position of the annular housing 11 relative to the annular body 25 , the steering capability can be enhanced by providing the annular body 25 with a degree of articulation. Fig.14 A preferred embodiment of an articulated joint 55 according to another aspect of the invention is shown. The preferred degree of articulation is up to three degrees relative to the axis of the input shaft 29, but this degree of articulation may vary. Fig.14 The input shaft 29 and the output shaft 56 are shown positioned on either side of the articulated joint 55. The output shaft 56 extends directly or indirectly to the cutterhead beam 12 such that rotation of the input shaft 29 results in rotation of the output shaft 56 and rotation of the cutterhead beam 12.

[0054] Fig.15 and 16A preferred embodiment of an articulated joint 55 is shown, wherein the input shaft 29 is formed with a driving gear 57, the output shaft 56 is formed with a driven gear 58, and a gear sleeve 59 connects the driving gear 57 with the driven gear 58. Each tooth on the driving gear 57 and the driven gear 58 is preferably crescent-shaped to allow the desired articulation angle to be achieved by the gear sleeve 59.

[0055] Fig.15 An articulated joint 55 is shown, which includes four hydraulic push rods (hereinafter referred to as articulated push rods 60), each of which has an articulated piston 61. Each articulated piston 61 is provided with a part spherical surface 62, which is configured to be seated in a hole seat 63 located on the opposite side of the articulated joint 55, so that the axial movement of each articulated piston 61 will still allow angular adjustment through the articulated joint 55. In addition, a concave surface 66 (see FIG. 6 ) on one side of the articulated joint is provided. Fig.15 ) is supported on the convex surface 67 on the opposite side of the hinge joint 55 (see Fig.16 ) on the hinge joint 55, thereby allowing thrust to be transmitted through the hinge joint 55. It is also preferred that a seal 68 is included between adjacent shells 26 (see Fig.14 ). Due to the use of the articulated push rods 60 in this manner and their positioning at the rear of the annular housing 11 within the annular body 25, further steering capabilities are provided to the operator in addition to the steering capabilities achieved by the housing push rods 53.

[0056] Various changes and / or additions may be made to the reamer bit assembly described above without departing from the spirit and scope of the invention.

Claims

1. A drill bit for use with a microtunneling apparatus to produce a borehole, comprising: shell, It has an annular housing and a radial member adjacent to the distal end of the housing; A cutterhead beam having at least one cutting element positioned for front cutting, the cutterhead beam being rotatable in a working area of ​​the borehole in a manner straddling the radial member to produce chips, the cutterhead beam having at least one jet outlet (hereinafter referred to as a beam jet portion), the beam jet portion being configured to jet a fluid toward the radial member.

2. The drill bit according to claim 1 comprises an air cavity extending in the longitudinal direction of the housing and leading to an air hole in the radial member for supplying air to the working area, the radial member having a discharge hole leading to a discharge cavity extending in the longitudinal direction of the housing for removing chips from the working area, the housing having at least one ejection outlet (hereinafter referred to as an ejection ejection portion), the ejection ejection portion being configured to eject fluid toward the ejection hole.

3. The drill bit according to claim 12, wherein: The housing has at least one spray outlet (hereinafter referred to as a housing spray portion), and the housing spray portion sprays a fluid toward the cutter beam.

4. A drill bit for use with a microtunneling apparatus to produce a borehole, comprising: shell, It has an annular housing and a radial member adjacent to the distal end of the housing; A cutterhead beam having at least one cutting element positioned for front cutting, the cutterhead beam being rotatable in a working area of ​​the borehole in a manner straddling the radial member to produce chips; an air cavity extending in the longitudinal direction of the housing and leading to an air hole in the radial member for supplying air to the working area, the radial member having a discharge hole leading to a discharge cavity extending in the longitudinal direction of the housing for removing chips from the working area, the housing having at least a jet outlet (hereinafter referred to as a discharge jet portion), the discharge jet portion being configured to spray a fluid toward the discharge hole.

5. The drill bit according to claim 4, wherein: The cutter head beam has at least a spray outlet (hereinafter referred to as a beam spray portion) configured to spray a fluid toward the radial member.

6. The drill bit according to claim 4 or 5, wherein: The housing has at least one spray outlet (hereinafter referred to as a housing spray portion), and the housing spray portion is configured to spray a fluid toward the cutter beam.

7. A drill bit according to any one of the preceding claims, comprising: an annular body, which is located behind the annular shell; an input shaft located at a proximal end of the annular body and rotatable about a transmission axis; an output shaft extending toward a distal end of the annular housing associated with the cutter beam so that the cutter beam rotates about an output axis; an articulated coupling located within the housing between the input shaft and the output shaft, the articulated coupling being adjustable so as to adjust an articulation angle between the input shaft and the output shaft.

8. The drill bit according to claim 7, wherein: The articulated coupling includes a drive gear associated with the input shaft, a driven gear associated with the output shaft, and a gear sleeve, wherein the drive gear, the driven gear, and the gear sleeve are configured to allow adjustment of the articulated coupling.

9. The drill bit according to claim 7, wherein: The driving gear shaft and the driven gear shaft each include crescent-shaped gear teeth configured to interact with the gear sleeve to achieve an adjustment of the articulation angle of up to 3°.

10. The drill bit of claim 10, comprising a plurality of radially mounted actuators positioned about the articulation joint, the plurality of actuators being used to adjust the articulation angle, wherein: The actuator is a hydraulic push rod (hereinafter referred to as an articulated push rod), each of which includes a piston (hereinafter referred to as an articulated piston), which is arranged to move longitudinally along the housing, and each of which has a partial spherical surface, which is configured to interact with a hole seat to allow the articulated piston to move axially while allowing the articulated coupling to be angularly adjusted.

11. A drill bit according to any one of the preceding claims, wherein The annular housing is configured to move radially relative to the annular body to adjust the orientation of the annular housing within the borehole in use.

12. The drill bit according to claim 11 comprises a plurality of radially mounted hydraulic push rods (hereinafter referred to as housing push rods), each of the housing push rods comprising a piston (hereinafter referred to as housing piston), the housing piston being arranged to engage with the inner surface of the annular housing and configured to move in a radial direction to adjust the position of the annular housing relative to the annular body.

13. A drill bit according to any one of the preceding claims, comprising: an air cavity extending in the longitudinal direction of the housing and leading to the air holes in the radial member for supplying air to the working area, the radial member having a discharge hole leading to a discharge cavity extending in the longitudinal direction of the housing for extracting chips from the working area, the air cavity, the working area and the discharge cavity defining an air flow path; A pressure regulating mechanism is operable at the distal end of the housing and is used to regulate the gas pressure in the working zone to regulate the extraction of chips from the working zone.

14. The drill bit according to claim 13, wherein: The pressure regulating mechanism includes a throat member positioned between the air aperture and the extraction aperture to generate a venturi flow therebetween, the throat member being adjustable to control the venturi flow of air in the working zone.

15. The drill bit according to claim 14, wherein The throat member includes a curved surface positioned in the air flow path.

16. The drill bit according to claim 15, wherein: The throat member is movable relative to the radial member between an extended position and a retracted position. 5 17. The drill bit according to claim 16, wherein: The throat member is configured to generate a maximum negative pressure in the working volume when in the extended position and to generate a minimum negative pressure in the working volume when in the retracted position.

18. A microtunneling apparatus for producing a borehole, comprising: A drive device for positioning in a working pit; a drill string for connection to the drive device, the drill string having a drive shaft capable of rotating under operation of the drive device; ； A drill bit according to any preceding claim, adapted to be connected to the drill string such that rotation of the drive shaft causes rotation of the cutterhead beam.

19. A microtunnel boring device according to claim 18, comprising a pair of slender members located at the proximal end of the housing, the slender members are used to interact with the latch connector at the distal end of the drill string, and each of the slender members is configured to be adjustable to change the tolerance between the proximal end of the housing and the distal end of the drill string.

20. A microtunnel boring machine according to any one of claims 18 or 19, wherein: The drill string is formed of a plurality of connected drill string sections, each of the drill string sections including a latch connection for manually connecting adjacent drill string sections.

21. A microtunneling apparatus according to any one of claims 18 to 20, wherein: The drill string includes a first chamber configured to supply air from the drive device to the working area and a second chamber for extracting cuttings from the working area to the drive device.

22. The microtunneling apparatus of claim 21, wherein: The first lumen is also configured to aim the laser along the first lumen to the rear surface of the radial member.

23. A microtunneling apparatus according to any one of claims 18 to 22, wherein: The drill string includes a passage extending longitudinally thereof to accommodate a cable extending between the drive device and the drill bit, thereby allowing an operator remote from the work area to operate the drill bit, including at least supplying fluid to the cutterhead beam in the work area.

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