An under-reaming bit

Abstract

This application relates to the field of under-reaming bits. The under-reaming bit includes: a drill pipe, a blade, and a pushing member. The drill pipe is provided with an axial groove and a sliding groove. At least a part of the blade is disposed in the sliding groove and moves along the sliding groove to protrude from or retract into the drill pipe. The pushing member is disposed below the blade, and the pushing member is slidably connected to the drill pipe so as to be able to move along the axial groove. A first guiding member is disposed on the blade, and a second guiding member is disposed on the drill pipe. The blade and the drill pipe cooperate through the first guiding member and the second guiding member to limit the displacement of the blade protruding from the drill pipe, so that the blade cannot completely separate from the drill pipe, preventing the blade from slipping out and falling off in a non-working state.

Description

Technical Field

[0001] This application relates to the field of hole - enlarging tools, and particularly to a under - reaming bit. Background Art

[0002] Due to its advantages such as economy, speed, and ease of construction, the post - anchoring technology of concrete is widely used in many engineering fields. The post - anchoring technology refers to the anchoring on the existing concrete structure through relevant means, which includes mechanical anchor bolts, chemical anchor bolts, chemical rebar planting, etc. Among them, the mechanical anchor bolt realizes the anchoring of the structural fastener through the mechanical interlock between the grooving and hole - enlarging at the bottom of the concrete drill hole and the expansion head of the anchor bolt. The grooving and hole - enlarging need to be completed by a special under - reaming bit.

[0003] The related under - reaming bits generally adopt the transmission mode of gears and racks to realize the expansion and contraction of the blades at the end of the bit. The hole - enlarging bit of this form has a relatively complex structure and high cost; there is also an under - reaming bit that uses the limiting mode of the drill pipe and the pushing part to make the blade slide to realize the expansion and contraction of the blade. The under - reaming bit of this form has a simple structure, is easy to install, and has a low cost. However, the sliding connection mode of the blade makes the blade easy to slide away from the drill pipe when not in use, affecting the working efficiency and increasing the cost of the instrument when replacing the blade. Summary of the Invention

[0004] In view of this, this application provides an under - reaming bit to solve the technical problem of preventing the blade from slipping away from the drill pipe and falling when not in use.

[0005] An under - reaming bit provided by an embodiment of this application includes: a drill pipe, an axial groove extending along the axis of the drill pipe is opened upward from the bottom end of the drill pipe, and the axial groove penetrates the diameter of the drill pipe; a chute is opened on the outer side surface of the drill pipe and extends obliquely downward to the axial groove; a blade, at least part of the blade is arranged in the chute and can move along the chute to protrude or retract into the drill pipe; wherein, a first guiding part is arranged on the blade, a second guiding part is arranged on the drill pipe, and the first guiding part and the second guiding part cooperate to slidably connect the blade and the drill pipe; a pushing part, the pushing part is arranged below the blade, and the pushing part is slidably connected with the drill pipe to be able to move along the axial groove.

[0006] Further, the upper end of the second guiding part is closed, and the lower end of the second guiding part extends to the bottom end of the drill pipe.

[0007] Further, the first guiding member is a protrusion protruding from the blade, and the second guiding member is a guiding groove formed on the wall surface of the sliding groove. The protrusion and the guiding groove are slidably engaged; wherein, the guiding groove includes: a first sub-groove inclined downward from the upper end of the second guiding member toward the axis direction, and a second sub-groove communicating with the lower end of the second guiding member of the first sub-groove; the extending direction of the second sub-groove forms a preset angle with the extending direction of the first sub-groove.

[0008] Further, the extending direction of the second sub-groove is substantially parallel to the axis direction of the drill pipe.

[0009] Further, the first guiding member is a groove formed on the surface of the blade, and the second guiding member is a guiding platform protruding from the wall surface of the sliding groove. The groove and the guiding platform are slidably engaged.

[0010] Further, the pushing member includes: a connecting portion connected to the drill pipe and capable of moving along the axial groove to protrude or retract into the axial groove; a base disposed below the connecting portion and fixedly connected to the connecting portion.

[0011] Further, the connecting portion is provided with a long through hole with both ends closed, and the extending direction of the through hole is substantially parallel to the axis of the drill pipe; the under-reaming bit further includes a connecting member passing through the through hole and the axial groove to slidably connect the connecting portion and the drill pipe.

[0012] Further, the base is a cone with the cone top located below, and the bottom of the cone is fixed to the connecting portion; the base is coaxially arranged with the drill pipe.

[0013] Further, the blade includes: a cutting edge located on the outer edge of the blade on the side away from the axis of the drill pipe; a back of the blade located on the side of the blade close to the axis of the drill pipe; an upper sliding surface connecting the upper end of the cutting edge and the upper end of the back of the blade, and the upper sliding surface abuts against the sliding groove; a lower sliding surface connecting the lower end of the cutting edge and the lower end of the back of the blade, and the lower sliding surface abuts against the connecting portion.

[0014] Further, the connecting portion is provided with an inclined surface abutting against the lower sliding surface of the blade, and the inclined surface is away from the axis of the drill pipe from top to bottom.

[0015] The under-reaming bit provided by the embodiment of the present application includes: a drill pipe, a blade and a pushing member. The drill pipe is provided with an axial groove and a sliding groove. At least part of the blade is arranged in the sliding groove and moves along the sliding groove to protrude from or retract into the drill pipe. The pushing member is arranged below the blade, and the pushing member is slidably connected to the drill pipe so as to be able to move along the axial groove. A first guiding member is arranged on the blade, and a second guiding member is arranged on the drill pipe. The first guiding member and the second guiding member are engaged with each other. Through the cooperation of the first guiding member and the second guiding member between the blade and the drill pipe, the blade is limited during the sliding process along the sliding groove and cannot completely separate from the drill pipe, preventing the blade from sliding out and falling off in the non-working state. Description of the Drawings

[0016] Figure 1 It is a schematic cross-sectional structure diagram of the under-reaming bit provided by the embodiment of the present application in one state;

[0017] Figure 2 It is a schematic cross-sectional structure diagram of the under-reaming bit provided by the embodiment of the present application in another state;

[0018] Figure 3 It is a schematic structure diagram of a pushing member provided by the embodiment of the present application;

[0019] Figure 4 It is an exploded view of the under-reaming bit provided by the embodiment of the present application;

[0020] Figure 5 Provided by the embodiment of the present application Figure 4 The cross-sectional view of the drill pipe in

[0021] Figure 6 It is an exploded view of another under-reaming bit provided by the embodiment of the present application;

[0022] Figure 7 It is a schematic structure diagram of the blade provided by the embodiment of the present application;

[0023] Figure 8 It is a schematic structure diagram of another pushing member provided by the embodiment of the present application;

[0024] Figure 9 Provided by the embodiment of the present application Figure 8 The side view of the pushing member in

[0025] Description of the Reference Numerals:

[0026] 10 - Drill pipe; 11 - Axial groove; 12 - Slide groove; 13 - Second guiding member; 131 - First sub - groove; 132 - Second sub - groove; 20 - Thrust member; 21 - Connecting portion; 211 - Through hole; 212 - Boss; 22 - Base; 30 - Blade; 31 - Cutting edge; 32 - Back of the knife; 33 - Upper sliding surface; 34 - Lower sliding surface; 35 - First guiding member; 40 - Connecting piece. Detailed implementation manner

[0027] In order to make the purpose, technical solutions and advantages of the present application clearer, the following further elaborates on the present application in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present application.

[0028] For the various specific technical features in each of the embodiments described in the detailed implementation manner, various combinations can be made without conflict. For example, different embodiments can be formed through combinations of different specific technical features. To avoid unnecessary repetition, various possible combination methods of the various specific technical features in the present application will not be described separately.

[0029] In the following description, the terms "first / second / ..." only distinguish different objects and do not indicate any same or related relationships between the objects. It should be understood that the orientation descriptions "above" and "below" refer to the orientations in the normal use state.

[0030] It should be noted that the term "comprising" or any other variant thereof is intended to cover non - exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, the elements defined by the statement "comprising..." do not exclude the existence of additional identical elements in the process, method, article or device including such elements. The term "connection" includes both direct connection and indirect connection unless otherwise specified.

[0031] The under - reaming bit is used in the field of post - anchoring technology. The working principle of the under - reaming bit is briefly described as follows. First, a straight hole with a fixed hole diameter is drilled and the bit is taken out; then, the under - reaming bit extends into the bottom of the pre - drilled straight hole, and the blades of the under - reaming bit extend out of the under - reaming drill pipe to perform the operation of cutting the wall of the straight hole, thereby enlarging the bottom hole; when the bottom hole is enlarged, the blades retract into the drill pipe and the bit is lifted out. If the blades fall off during the cutting process or during the process of lifting out the bit, it is difficult to retrieve them, so the blades need to be replaced, increasing the cost of the instrument.

[0032] As Figure 1As shown in the figure, an under-reaming bit provided by an embodiment of the present application includes: a drill pipe 10, a pushing member 20, and a blade 30. An axial groove 11 extending along the axis of the drill pipe 10 is provided upward from the bottom end of the drill pipe 10. Specifically, the drill pipe 10 is generally cylindrical, and the axis of the drill pipe 10 refers to the rotation center axis of the drill pipe 10. The bottom end of the drill pipe 10 refers to the lower boundary of the drill pipe 10 in the normal working state. The axial groove 11 is opened from the lowermost boundary of the drill pipe 10 and extends upward along the axis of the drill pipe 10. The axial groove 11 penetrates the radial direction of the drill pipe 10. Specifically, the radial direction of the drill pipe 10 refers to the diameter direction of the drill pipe 10, which is perpendicular to the axis direction of the drill pipe 10. The radial direction is the left-right direction as shown in Figure 1. The axial groove 11 penetrating the radial direction of the drill pipe 10 means that the cross-section of the drill pipe 10 is separated into two parts, and along the radial direction of the drill pipe 10, the axial groove 11 communicates with the outside.

[0033] As Figure 1 shown, the drill pipe 10 is provided with a chute 12 extending obliquely downward from the outer side surface of the drill pipe 10 to the axial groove 11. Specifically, the drill pipe 10 is generally cylindrical, and its outer side surface is the side surface of the cylinder. The number of chutes 12 is set to two, located on both sides of the axis of the drill pipe 10. Each chute 12 extends from the outer side surface of the drill pipe 10 to the axial groove 11. Looking at the chute 12 from the end located on the outer side surface of the drill pipe 10 to the end located in the axial groove 11, the extending direction of the chute 12 is inclined downward and inward. Specifically, the two chutes 12 symmetrically arranged relative to the axis of the drill pipe 10 penetrate the radial direction of the drill pipe 10, and the radial direction penetrated by the chute 12 is perpendicular to the radial direction penetrated by the axial groove 11.

[0034] Optionally, the chutes 12 are symmetrically arranged along the axis of the drill pipe 10, so that the intersection points of the two chutes 12 on both sides are on the axis of the drill pipe 10, forming a V-shaped chute, which is beneficial for the blade 30 to protrude or retract into the drill pipe 10 evenly on both sides. That is to say, one end of the chute 12 is located on the axis of the drill pipe 10 and communicates with the axial groove 11, and the other end is located on the outer side surface of the drill pipe 10.

[0035] As Figure 2 shown, at least a part of the blade 30 is arranged in the chute 12 and can move along the chute 12 to protrude or retract into the drill pipe 10. Specifically, protruding means that the blade 30 is far from the axis of the drill pipe 10, and the outermost edge of the blade 30 extends out of the edge of the drill pipe 10; the outermost edge of the blade 30 refers to the side of the blade 30 that is farthest from the axis of the drill pipe 10. Retracting means that the outermost edge of the blade 30 is closer to the axis of the drill pipe 10 or flush with the edge of the drill pipe 10 than the edge of the drill pipe 10. As Figure 1 shown is the state where the blade retracts into the drill pipe 10. As Figure 2The state shown is that the blade 30 protrudes from the drill pipe 10. At least partially disposed within the chute 12 means that necessarily a part of the blade 30 is disposed within the chute 12 for movement along the chute 12; in some states, the blade 30 can be entirely located within the chute 12.

[0036] As Figure 2 As shown, the blade 30 is provided with a first guide member 35. Specifically, the chute 12 has two opposite side walls and a bottom wall disposed between the two side walls, and the side walls and the bottom wall enclose the chute 12 to form a space for accommodating the blade 30; the first guide member 35 is disposed on the surface of the blade 30 facing the side wall of the chute 12.

[0037] Optionally, the first guide member 35 can be disposed on one of the surfaces of the blade 30 facing the side wall of the chute 12, or can be disposed on both surfaces of the blade 30 facing the side wall of the chute 12.

[0038] As Figure 2 As shown, the drill pipe 10 is provided with a second guide member 13. Specifically, the second guide member 13 is disposed on the side wall of the chute 12 or penetrates the side wall of the chute 12; penetrating means not being disposed on the wall surface of the side wall of the chute 12 but passing through the wall surface. The first guide member 35 cooperates with the second guide member 13 to slidably connect the blade 30 and the drill pipe 10. Specifically, the first guide member 35 cooperates with the second guide member 13 such that the blade 30 and the drill pipe 10 can relatively slide within a certain range, and the blade 30 slides between the displacements defined by the first guide member 35 and the second guide member 13.

[0039] As Figure 2 As shown, the pusher 20 is disposed below the blade 30. Specifically, below means below in the normal working state, as Figure 2 As shown below. As Figure 1 And Figure 2 As shown, the pusher 20 is slidably connected to the drill pipe 10 to be able to move along the axial groove 11. Specifically, a part of the pusher 20 can slide within the axial groove 11 such that the pusher 20 and the drill pipe 10 can relatively slide.

[0040] In some embodiments, as Figure 1 And Figure 3As shown, the pusher 30 includes a connecting portion 21 and a base 22. The connecting portion 21 is connected to the drill pipe 10 and can move along the axial groove 11 to protrude or retract into the axial groove 11. Specifically, the connecting portion 21 is in the shape of a sheet with a certain thickness, and the thickness refers to the distance between the two relatively larger-area faces of the sheet-like object. The thickness of the connecting portion 21 is slightly smaller than the width of the axial groove 11, so that the connecting portion 21 can extend upward into the axial groove 11 and move up and down therein; the width of the axial groove 11 refers to the distance between the two opposite walls of the axial groove 11. Protruding means that at least part of the connecting portion 21 extends out of the axial groove 11; retracting means that the connecting portion 21 is completely extended into the axial groove 11.

[0041] As Figure 1 and Figure 3 shown, the base 22 is provided below the connecting portion 21 and fixedly connected to the connecting portion 21. Specifically, one end of the connecting portion 21 away from the blade 30 is fixedly connected to the base 22, so that the base 22 and the connecting portion 21 can move synchronously; fixedly connected means that the connecting portion 21 and the base can be connected by threads, or by mortise and tenon joints, or by bonding and other means.

[0042] In some embodiments, as Figure 1 and Figure 3 shown, the base 22 is in the shape of a cone with the apex at the bottom, and the bottom of the cone is fixed to the connecting portion 21. Specifically. The base 22 is a cone with the apex at the bottom, that is, an inverted cone, and the apex faces the bottom of the hole to be reamed in the working state, which is beneficial to reducing the friction between the pusher 20 and the bottom reamed substrate during the rotation of the drill pipe 10. The base 22 is coaxially arranged with the drill pipe 10. Specifically, the base 22 is in the shape of an inverted cone, and its rotation center axis can coincide with the axis of the drill pipe 10 in the same direction.

[0043] In some embodiments, as Figure 3 shown, the connecting portion 21 is provided with a long strip through hole 211 with both ends closed. Specifically, closed means tightly closed and not passable; both ends refer to the two tops or ends of things; the through hole 211 with both ends closed means that both ends of the through hole 211 are adjacent to the entity in the length direction of the through hole 211 and are not directly connected to the external space.

[0044] Optionally, the through hole 211 can be generally rectangular or generally elliptical. As Figure 3 shown, the top of the through hole 211 in the length direction is arc-shaped, which is beneficial to increasing the contact area between the connecting member and the connecting portion 21 when the connecting member is at the uppermost position of the connecting portion 21, reducing the force per unit area between the connecting member and the connecting portion 21, thereby avoiding damage to the connecting portion 21 and avoiding breakage of the connecting member. As Figure 1 and Figure 3As shown, the extending direction of the through hole 211 is substantially parallel to the axis of the drill pipe 10. Specifically, the extending direction of the through hole 211 refers to the length direction of the through hole 211, and its length direction is parallel to the axis direction of the drill pipe 10, that is, the directions are the same.

[0045] In some embodiments, as Figure 4 shown, the under-reaming bit further includes a connecting member 40 that penetrates the through hole 211 and the axial groove 11 and slidably connects the connecting portion 21 and the drill pipe. Specifically, the connecting member 40 is strip-shaped and penetrates the axial groove 11 along the width direction of the axial groove 11 ( Figure 4 shown as the direction perpendicular to the paper surface), and this width direction is perpendicular to the radial direction of the drill pipe 10 through which the axial groove penetrates. The connecting portion 21 extends into the axial groove 11, and the connecting member 40 penetrates the axial groove 11 and the through hole 211 to complete the connection between the connecting portion 21 and the drill pipe 10.

[0046] Optionally, the cross-section of the connecting member 40 can be circular, square, diamond or other shapes.

[0047] When the under-reaming bit provided by the embodiment of the present application is working, the under-reaming bit is inserted into a pre-drilled straight hole. The pushing member 20 first touches the bottom of the hole, and the bottom of the hole applies an upward acting force on the pushing member 20. The pushing member 20 moves to the uppermost position along the axial groove 11. The pushing member 20 contacts the blade 30 and pushes the blade 30 upward so that the blade 30 moves upward and outward along the chute, thereby protruding from the drill pipe 10. The protruding blade 30 of the drill pipe 10 performs under-reaming cutting under the rotation of the drill head. When the under-reaming is completed and the drill bit is withdrawn, the drill pipe 10 is subjected to an upward acting force, and correspondingly, an upward acting force is applied to the blade 30 through the connection with the blade 30, so that the blade 30 moves upward along the chute 12 and is received into the drill pipe. The cooperation between the first guiding member 35 and the second guiding member 13 of the blade 30 and the drill pipe 10 limits the movement direction of the blade 30 and prevents the blade 30 from slipping out and falling off in the non-working state when the drill bit is withdrawn.

[0048] In some embodiments, as Figure 4 shown, the upper end of the second guiding member 13 is closed, and the lower end of the second guiding member 13 extends to the bottom end of the drill pipe 10. Specifically, "closed" means not communicating with the external space, and the upper end refers to the upward end of the second guiding member 13. The upper end of the second guiding member 13 being closed means that along the extending direction of the second guiding member 13, the upper end of the second guiding member 13 is not communicating with the external space, but is in adjacent contact with the drill pipe 10, that is, the upward displacement of the first guiding member 35 is limited by the upper end of the second guiding member 13.

[0049] In some embodiments, as Figure 4As shown, the first guide member 35 is a protrusion protruding from the blade 30. Specifically, the protrusion is arranged on the surface of the side wall of the blade 30 facing the chute 12, which can be one of the surfaces or both surfaces. The protrusion can be spherical, cylindrical, or gourd-shaped. The second guide member 13 is a guide groove opened on the wall surface of the chute 12. Specifically, the guide groove is arranged on the wall surface of the side wall of the chute 12, which can be arranged on only one of the surfaces or on both surfaces. There are at least two guide grooves, and the two guide grooves are symmetrically arranged along the axis of the drill rod 10. The protrusion and the guide groove can be slidably engaged. Specifically, the engagement refers to the formation of a snap-fit relationship between the protruding first guide member 35 and the second guide member 13 of the guide groove, so that the first guide member 35 will not be separated from the second guide member 13, thereby preventing the blade 30 from being separated from the connection with the drill rod 10.

[0050] In some embodiments, Figure 5 As shown, the guide groove includes: a first sub-groove 131 at the upper end of the second guide member 13 tilted downward toward the axis direction, and a second sub-groove 132 at the lower end of the second guide member 13 connected to the first sub-groove 131. Specifically, the first sub-groove 131 is tilted, and its tilting direction is parallel to the tilting direction of the slide groove 12 on the same side. The guide groove consists of the first sub-groove 131 and the second sub-groove 132. The first sub-groove 131 is connected to the second sub-groove 132. The first sub-groove 131 is located above the second sub-groove 132. The width of the first sub-groove 131 is substantially the same as the width of the second sub-groove 132, which is conducive to the first guide member 35 being able to move back and forth in the first sub-groove 131 and the second sub-groove 132. The extension direction of the second sub-groove 132 is at a preset angle to the extension direction of the first sub-groove 131. Specifically, the extension directions of the first sub-groove 131 and the second sub-groove 132 do not overlap, that is, the extension directions of the two can intersect. The preset angle refers to a predefined angle, which may be an obtuse angle, such as 120°, 135°, 150°, etc.

[0051] In some embodiments, Figure 4 and Figure 5 As shown in FIG. 5 , the extension direction of the second sub-groove 132 is substantially parallel to the axial direction of the drill rod 10. Specifically, the extension direction of the second sub-groove 132 can be substantially the same as the axial direction of the drill rod 10. The so-called substantially means that processing and assembly errors are taken into account, and absolute parallelism and sameness are not required. The blade 30 is assembled to the drill rod 10 from the bottom end of the drill rod 10, and the second sub-groove 132 is arranged along the vertical direction as shown in FIG. 5 for convenience of processing and for convenience of assembling the blade 30 to the drill rod 10.

[0052] In some embodiments, Figure 6As shown, the first guide member 35 is a groove provided on the surface of the blade 30. Specifically, the groove is provided on the surface of the blade 30 facing the wall of the chute 12, and can be provided on one surface or on two surfaces. The two ends of the groove are closed, and the groove is tilted upward and outward along the length direction of the blade 30, and its tilt angle is the same as the tilt angle of the matching chute 12. The second guide member 13 is a guide platform protruding from the wall of the chute 12. Specifically, the guide platform can be spherical, cylindrical, or gourd-shaped. The guide platform protruding from the wall of the chute 12 means that the guide platform and the wall of the chute 12 are not on the same plane, and the guide platform does not extend to the bottom end of the drill rod 10. The groove and the guide platform are slidably engaged. Specifically, the groove and the guide platform are matched, and the guide platform can slide up and down in the groove. The engagement means that a locking relationship is formed between the guide platform and the groove, so that the guide platform will not be separated from the groove. The radial width of the guide platform and the groove wall on the same plane is not greater than the width of the guide groove, which is conducive to reducing the friction between the guide platform and the groove.

[0053] Optionally, a through hole is provided on the drill rod 10, and the guide platform passes through the through hole and protrudes from the wall surface of the slide groove 12. The portion of the guide platform protruding from the wall surface of the slide groove 12 is used to engage with the groove on the blade 30, so that the blade 30 moves within the range defined by the groove. Figure 6 and Figure 7 As shown, the blade 30 includes: a blade 31, which is located at the outer edge of the blade 30, away from the axis of the drill rod. Specifically, the outer edge refers to the outer edge of the blade 30 on the side away from the axis of the drill rod 10, which is used for reaming. A back 32 is located on the side of the blade 30 close to the axis of the drill rod 10. Specifically, the back 32 is arranged on the side of the blade 30 close to the axis of the drill rod 10, and is used to abut against the back 32 when the blade 30 is retracted into the drill rod 10. An upper sliding surface 33 connects the upper end of the blade 31 and the upper end of the back 32, and the upper sliding surface 33 abuts against the wall of the slide groove 12. Specifically, the upper end refers to the upward end point of the blade 31 and the back 32 along the axis of the drill rod 10, and the upper sliding surface 33 formed by the upper end connecting line of the blade 31 and the back 32 abuts against the wall of the slide groove 12, and abutment refers to the contact and abutment between the two abutting parts to form a close contact. The upper sliding surface 33 moves obliquely upward and downward along the slide groove 12. The lower sliding surface 34 connects the lower end of the blade 31 and the lower end of the blade back 32, and the lower sliding surface 34 abuts against the connecting portion 21. Specifically, the lower end refers to the end point of the blade 31 and the blade back 32 pointing downward along the axis of the drill rod 10. The lower end connecting line of the blade 31 and the blade back 32 forms the lower sliding surface 34. The lower sliding surface 34 abuts against the upper end surface of the connecting portion 21. The upper end surface of the connecting portion 21 refers to the side of the connecting portion 21 pointing upward along the axis of the drill rod 10. Upward and downward are like this. Figure 1The vertical direction shown. The lower sliding surface 34 moves away from and closer to the axis of the drill pipe 10 on the upper end surface of the connecting portion 21.

[0054] It should be noted that the connecting portion 21 pushes against the lower sliding surface 34 of the blade 30, causing the entire blade 30 to move upward along the axis of the drill pipe 10. When the upper sliding surface 33 abuts against the sliding groove 12, due to the upward thrust of the connecting portion 21 along the axis of the drill pipe 10 on the blade 30, the upper sliding surface 33 moves away from the axis of the drill pipe 10 along the sliding groove 12, so that the blade 30 can protrude or retract into the drill pipe 10.

[0055] Optionally, the number of blades 30 is two, and the blades 30 are symmetrically arranged with respect to the axis of the drill pipe 10. When the two blades 30 are retracted into the drill pipe 10, the backs 32 of the two blades 30 abut against each other, restricting the lateral displacement of the blades 30 and providing better positioning.

[0056] In some embodiments, as Figure 8 shown, the connecting portion 21 is provided with an inclined surface that abuts against the lower sliding surface 34 of the blade 30, and the inclined surface moves away from the axis of the drill pipe 10 from top to bottom. Specifically, the blade 30 is arranged above the connecting portion 21, and the lower sliding surface 34 of the blade 30 abuts against the upper end surface of the connecting portion 21. The upper end surface is an inclined surface that cooperates with the upper sliding surface 33, which is beneficial to the close contact between the connecting portion 21 and the blade 30 and facilitates the blade 30 to receive force.

[0057] Optionally, as Figure 4 and Figure 9 shown, the connecting portion 21 may be provided with elongated bosses 212, and the bosses 212 are symmetrically arranged along the axis. The width of each boss 212 is slightly smaller than the width of the guiding groove, which is beneficial for the bosses 212 to slide up and down in the second sub-groove 132 of the guiding groove and avoid the accumulation of sand and soil in the guiding groove.

[0058] The above is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. Any equivalent structural transformation made using the content of the specification and drawings of the present application under the inventive concept of the present application, or any direct / indirect application in other related technical fields, is included in the patent protection scope of the present application.

Claims

1. An under-reaming bit, characterized in that, Comprising: A drill pipe, an axial groove extending along the axis of the drill pipe is provided upward from the bottom end of the drill pipe, and the axial groove penetrates the radial direction of the drill pipe; a chute is provided on the outer side surface of the drill pipe and extends obliquely downward to the axial groove. A blade, at least part of the blade is arranged in the chute and can move along the chute to protrude from or retract into the drill pipe; wherein, a first guide is provided on the blade, a second guide is provided on the drill pipe, and the first guide cooperates with the second guide to slidably connect the blade and the drill pipe. A pushing member, the pushing member is arranged below the blade, and the pushing member is slidably connected to the drill pipe to be able to move along the axial groove. The first guide is a protrusion protruding from the blade, and the second guide is a guide groove provided on the wall surface of the chute, and the protrusion is slidably engaged with the guide groove. Wherein, the guide groove includes: a first sub-groove inclined downward from the upper end of the second guide toward the axis direction, and a second sub-groove communicating with the lower end of the second guide of the first sub-groove; the extending direction of the second sub-groove forms a preset angle with the extending direction of the first sub-groove, the upper end of the second guide is closed, and the lower end of the second guide extends to the bottom end of the drill pipe.

2. The under-reaming bit according to claim 1, characterized in that, The extending direction of the second sub-groove is substantially parallel to the axis direction of the drill pipe.

3. The under-reaming bit according to claim 1, characterized in that, The pushing member includes: A connecting portion, the connecting portion is connected to the drill pipe and can move along the axial groove to protrude from or retract into the axial groove; A base, arranged below the connecting portion and fixedly connected to the connecting portion.

4. The under-reaming bit according to claim 3, characterized in that, The connecting portion is provided with a long strip-shaped through hole with both ends closed, and the extending direction of the through hole is substantially parallel to the axis of the drill pipe; the under-reamed bit further includes a connecting member passing through the through hole and the axial groove to slidably connect the connecting portion and the drill pipe.

5. The under-reaming bit according to claim 3, wherein, The base is a cone with the cone top located below, and the bottom of the cone is fixed to the connecting portion; the base is coaxially arranged with the drill pipe.

6. The under-reaming bit according to claim 3, wherein The blade includes: A cutting edge, located on the outer edge of the blade, on the side away from the axis of the drill pipe; A back of the blade, located on the side of the blade close to the axis of the drill pipe; An upper sliding surface, connecting the upper end of the cutting edge and the upper end of the back of the blade, and the upper sliding surface abuts against the chute; A lower sliding surface, connecting the lower end of the cutting edge and the lower end of the back of the blade, and the lower sliding surface abuts against the connecting portion.

7. The under-reaming bit according to claim 6, characterized in that, The connecting portion is provided with an inclined surface abutting against the lower sliding surface of the blade, and the inclined surface is away from the axis of the drill pipe from top to bottom.

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