JP2002115479A - Drilling method and cutter used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To build a casing pipe 2, provided at the tip of a casing top 3 inside a bore hole H, while forming the bore hole H, and further by forming, effectively a bore hole h with a larger drilling diameter in succession from its tip. SOLUTION: The casing pipe 2 is built, while forming the bore hole H by a drilling tool 1; then a cutter 11 is attached to this drilling tool 1 and inserted to the casing pipe 2; and the inner diameter portion 3A of the casing top 3 is cut and removed by the cutter 11. The cutter 11 is equipped with a cylindrical cutter main body 12, having an outer diameter to be inserted to the inside of the casing pipe 2 and an inner diameter, to which a drum peripheral portion 4A of the tool body 4 of the drilling tool 1 can be fitted and inserted are equipped, a cutting blade 13A is provided at the tip portion of the cutter main body 12, and also an attaching portion 12B, which makes the cutter body 12 detachable with respect to the drum portion 4A of the drilling tool 1 is provided at the body 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excavation method in which a casing pipe is erected in a hole while forming a hole with an excavation tool, and the casing built in the hole in the excavation method. The present invention relates to a cutter suitable for forming a hole from a pipe.

[0002]

2. Description of the Related Art As an excavation tool used in an excavation method in which a casing pipe is erected in a hole while forming the hole, for example, the one shown in FIGS. 7 and 8 is known. The excavating tool 1 is rotated in a rotation direction T around an axis O via a rod (not shown) in a substantially cylindrical casing top 3 attached to the end of a casing pipe 2 by welding or the like. At the same time, the tool main body 4 that receives a striking force toward the tip end in the direction of the axis O by the hammer interposed between the rod and the rod is inserted so that the tip end projects. Also, the casing top 3 has an inner diameter portion 3A whose casing pipe 2
On the rear end side of the body periphery 4A of the tool body 4 of the excavating tool 1, the diameter is larger than the inside diameter 3A of the reduced casing top 3. And a step 4B having an outer diameter smaller than the inner diameter of the casing pipe 2 is formed.
Abuts on the rear end face of the inner diameter portion 3A of the casing top 3 so that the excavating tool 1 is relatively rotatable around the axis O of the casing top 3 and is engageable toward the tip side in the axis O direction. ing.

[0003] Here, the excavating tool 1 is a so-called diameter-expanding bit in which a plurality of excavating bits 5 are attached to the tip of the tool body 4 so as to be rotatable around an axis X eccentric from the axis O. The excavating bits 5 projecting from the tip of the casing top 3 at the time of excavation are rotated around the axis X by the rotation of the tool body 4, and the outer diameter thereof is larger than the outer diameter of the casing pipe 2. Are slightly enlarged, the side surfaces of the excavating bits 5 adjacent to each other are brought into contact with each other and positioned. Also,
When the tool body 4 rotates in the direction opposite to the rotation direction T during excavation, each excavation bit 5 also rotates in the opposite direction about the axis X, and its outer diameter is larger than the diameter of the inner diameter portion 3A of the casing top 3. It has been made smaller.

On the other hand, from the tip end surface of the tool body 4, the axis X
Are formed along the line 4C.
By inserting a cylindrical shaft portion 5A formed on the rear end side of the excavation bit 5 into C, the excavation bit 5 is rotatable around the axis X. An annular groove 5B having a semicircular cross section is formed in the shaft portion 5A, and a direction contacting the hole 4C from the outer peripheral surface of the body peripheral portion 4A of the tool body 4 in a cross section orthogonal to the axis O. To the hole 4C
A mounting hole 4D is formed in the inner periphery of the shaft portion 5A.
Is inserted into the hole 4C so that the mounting hole 4D and the annular groove 5B of the shaft portion 5A coincide with each other in the direction of the axis O.
The drilling bit 5 is locked in the direction of the axis O while being allowed to rotate around the axis X, and is attached to the tool main body 4 by fitting the mounting pin 6 into the annular groove 5B. . Further, the body peripheral portion 4A of the tool body 4 has
When drilling, the dust generated by the drill bits 5
A plurality of cutting grooves 4E... For discharging from the inner circumference of the casing top 3 to the rear end through the inside of the casing pipe 2 are arranged at equal intervals in the circumferential direction and in the direction of the axis O in the body circumferential portion 4A.
Is formed over the entire length. Note that reference numeral 4F in FIG.
Is a shank for attaching the tool body 4 of the excavating tool 1 to the hammer.

However, in the excavation method using such an excavating tool 1, a rotary impact force is applied to the tool body 4 during excavation, so that the ground is excavated with the excavating bits 5 expanded. The casing pipe 2 is built into the excavated hole by the engagement between the step portion 4B and the casing top 3. After the ground is excavated to a predetermined depth and the casing pipe 2 is buried in this way, by turning the tool body 4 in the opposite direction to the excavation, the excavation bits 5 are also turned around the axis X. Since the outer diameter of the tool body 4 inserted into the casing top 3 is smaller than the inner diameter portion 3A of the casing top 3, the diameter of the tool body 4 is reduced. Can be pulled out of the casing pipe 2. Therefore, according to the excavation method, for example, when excavating the ground made of a soft stratum, the excavation can be performed while the drilling is prevented from being collapsed by the casing pipe 2, so that reliable and efficient excavation is performed. Can be performed.

[0006]

By the way, after drilling a hole to a certain extent in this way and assembling the casing pipe 2, drilling is further performed from the tip of the casing pipe 2. In this case, the drilling hole formed continuously from the tip of the casing pipe 2 often requires the largest possible excavation diameter. However, in such a case, the tool main body 4 is pulled out while leaving the casing pipe 2 on the ground as described above, and then a general drilling tool such as a down-the-hole bit is inserted into the casing pipe 2 and the tip thereof is inserted. The casing pipe 2 is made to protrude, and a drilling hole is formed continuously from the casing pipe 2 by the excavation tool. The outer diameter of the drilling tool, such as the down-the-hole bit, which continues to form a drilling hole, while the casing top 3 of 3A is still attached, must be smaller than the inner diameter of the inner diameter portion 3A of the casing top 3. Absent. For this reason, conventionally, there was naturally a limit in securing a large excavation diameter for the continuously formed hole.

The present invention has been made in view of such circumstances, and a casing pipe having a casing top provided at a tip end is formed in a hole while forming the hole as described above. In the case of continuously forming a hole from the tip, a large excavation diameter can be secured by the continuously formed hole, and an efficient excavation method is provided. It is intended to provide a cutter.

[0008]

In order to solve the above-mentioned problems and achieve such an object, the excavation method of the present invention comprises:
A casing top having an inside diameter smaller than the inside diameter of the casing pipe is provided at the tip of the casing pipe, and a drilling tool is inserted into the casing pipe so as to project from the tip of the casing top, and a tip is attached to the inside diameter of the casing top. The casing pipe is erected in the hole while forming a hole with the drilling tool, and then the cutter is attached to the drilling tool and inserted into the casing pipe. Thus, the inside diameter of the casing top is cut and removed. Therefore, the inner diameter portion of the casing top is cut and removed by the cutter inserted into the casing pipe in this manner, and thereafter, an excavation tool having an outer diameter equal to the inner diameter of the casing top is inserted into the casing pipe, and the casing top is removed. By projecting from the tip, it is possible to continuously form a drilling hole with a larger drilling diameter, and this cutter is attached to the drilling tool used to form the previous drilling hole and cuts the inner diameter of the casing top Therefore, there is no need to separately prepare a tool for driving the cutter to cut the inner diameter portion, which is efficient.

[0009] The cutter of the present invention is a cutter used in such an excavation method, wherein the outer diameter of the excavation tool is inserted into the casing pipe and the outer diameter of the excavation tool inserted into the inner diameter of the casing top. A cylindrical cutter body having an inner diameter to which a trunk peripheral portion can be inserted; a cutting blade for cutting an inner diameter portion of the casing top provided at a tip end of the cutter body; The outer periphery of the body is provided with a mounting portion that can be attached and detached. Therefore, the body of the excavation tool is inserted into the inner periphery of the cylindrical cutter body, and then the cutter body is excavated by the mounting portion. By attaching to the tool and inserting it into the casing pipe, rotating the excavating tool together with the cutter body and giving feed to the tip side, the cutting blade provided at the tip of this cutter body It can be removed by cutting the inner diameter portion of the over single top. Further, by forming a ridge on the inner periphery of the cutter body that can be inserted into a cutting groove formed on the body periphery of the drilling tool, the ridge is formed in the direction of rotation of the cutting tool. , The mounting rigidity of the cutter body in the rotation direction can be improved, and more efficient cutting can be performed.

[0010]

1 and 2 show an embodiment of a cutter according to the present invention.
The cutter body 12 can be attached to the tool body 4 of the excavating tool 1 shown in FIGS. 7 and 8 and can be inserted into the casing pipe 2 so as to cut the inner diameter portion 3A of the casing top 3. It was done. That is, the cutter 11 of the present embodiment has the cutter body 1
2 is an inner diameter of the tool body 4 of the excavating tool 1, into which the substantially cylindrical outer peripheral portion 4 </ b> A can be inserted, and the casing pipe 2.
The cutter body 12 is formed in a substantially cylindrical shape having an outer diameter that can be inserted therein, and a step portion 12A is formed on the distal end side of the inner peripheral portion of the cutter body 12 so as to reduce the diameter by one step. The tool body 4 is inserted into the cutter body 12 from the rear end side with the trunk portion 4A of the tool body 4 inserted into the cutter body 12 so that the stepped portion 4B of the tool body 4 comes into contact with the rear end face of the cutter body 12. Is made to contact the step 12A.

Further, the body peripheral portion 4A is inserted into the cutter body 12 in this way, and the tip surface of the tool body 4 and the step portion 4B are connected to the step portion 1 of the cutter body 12.
When the mounting holes 4D are opened in the outer peripheral surface of the body peripheral portion 4A in a state where they are brought into contact with the rear end surface, the mounting holes 4D are coaxial with the mounting holes 4D. The same number of mounting holes 12B are formed as the mounting portions in the present embodiment. Further, in the state where the tool main body 4 is inserted into the cutter main body 12 and brought into contact with the inner periphery of the cutter main body 12, the body peripheral portion 4 of the tool main body 4
A protruding ridge 12C can be inserted into each of the cutting groove 4E formed on the outer periphery of A, and these protruding ridges 12C are coaxially arranged with the mounting holes 4D, 12B. Thus, it is possible to abut against the wall surface of the cutting groove 4F on the rotation direction T side. A number of cutting blade tips 13 made of a hard material such as cemented carbide are implanted at equal intervals in the circumferential direction on the tip end face of the cutter body 12, and the tip end has a diameter equal to the diameter of the tip end face. The cutting edge 13A protrudes from the front end face so as to form an isosceles triangular mountain shape when viewed in the radial direction.

Next, an embodiment of the excavation method of the present invention using such a cutter 11 will be described with reference to FIGS. In the present embodiment, the drilling tool 1 having the drill bit 5 attached to the tip of the tool body 4 first forms the drill hole H in the ground G as described above. After the casing pipe 2 to which is joined is erected, the drilling bits 5 are once reduced in diameter, the drilling tool 1 is pulled out from the casing pipe 2, and the mounting pins 6 are pulled out from the mounting holes 4D to drill the drilling bits 5. Is removed from the tool body 4 and the cutter 11 is replaced with the cutter 11 as shown in FIGS.
Attach.

That is, in a state where the mounting pins 6 are pulled out and the excavation bits 5 are removed,
Since the mounting holes 4D remain open at the outer periphery of the cutter body A, the cutter body 1
2 is inserted into the inner peripheral portion of the cutter body 2, and the front end surface of the tool body 4, the step portion 4B, the wall surfaces of the cutting grooves 4E, and the step portion 12A of the cutter body 12, the rear end surface, and the projection. Article 1
2C... Are respectively brought into contact with each other, and the cutter body 12 is locked by fitting the mounting pins 14 slightly longer than the mounting pins 6 into the coaxial mounting holes 12B. And attach it to the drilling tool 1. Therefore, even if the tip surface of the tool main body 4 faces downward in this state, the cutter main body 12 does not come off. Note that the outer peripheral end of the mounting pin 14 thus fitted does not protrude beyond the outer peripheral surface of the cutter body 12.

Next, the cutter body 12 having the cutter body 12 attached to the tool body 4 is inserted into the casing pipe 2 again, and is advanced in the direction of the axis O while being rotated by the rod to give an appropriate feed. As shown in FIG. 5, the cutting blade 13 at the tip of the cutter body 12
A bites into the inner diameter portion 3A of the casing top 3 from the rear end side and cuts the inner diameter portion 3A, whereby the inner diameter portion 3A is removed while chips are being generated. When reaching the tip of the casing top 3, the inner diameter of the casing top 3 is formed to be substantially equal to the outer diameter of the cutter body 12, that is, the inner diameter of the casing pipe 12. Therefore, after that, the excavating tool 1 together with the cutter 11 is pulled out again from the casing pipe 2 and another excavating tool 15 such as a down-the-hole bit is inserted into the casing pipe 2 as shown in FIG. By protruding from the top 3 and restarting the excavation, a hole h can be formed following the hole H.

Therefore, according to such an excavation method, the inner diameter portion 3A of the casing top 3 is cut and removed, so that the excavation tool 15 that forms the hole h following the hole H can be removed from the outer diameter 3A. Can be of the maximum size that can be inserted into the casing pipe 2, so that the drilling diameter of the hole h can be increased to substantially the same size as the inner diameter of the casing pipe 2. A large excavation diameter can be secured. In the excavation method having the above-described configuration, the cutter 11 for cutting the inner diameter portion 3A of the casing top 3 is attached to the excavation tool 1 used for forming the drilled hole H. It is more efficient and economical than preparing a separate cylindrical cutter having an outer diameter that can be inserted into the casing pipe 2 just for cutting the inner diameter portion 3A of the top 3. Further, the tool body 4 in which the cutting of the casing top 3 has been completed can be used as the excavating tool 1 for forming a hole by removing the cutter body 12 and attaching the excavating bits 5. In addition, in the present embodiment, the excavating tool 1 advances while rotating around the axis O via the rod to form the hole H. On the other hand, the cutter 11 also advances and rotates while rotating. Blade 1
Since cutting is performed by 3A, the same excavating tool 1 as used for excavation is used, even if the hammering force is not applied.
Cutting can also be performed by the above operation, which is more efficient.

On the other hand, in the cutter 11 having the above-mentioned structure used in such an excavation method, the cutter body 1 is provided.
2 is a cylinder having an outer diameter that can be inserted into the casing pipe 2 and an inner diameter that can be inserted into the body peripheral portion 4A of the tool body 4 of the excavating tool 1 that is inserted into the inner diameter portion 3A of the casing top 3. Are provided at the tip thereof, and the mounting holes 12B as mounting portions are provided.
Are detachably attached to the tool main body 4 by the mounting pins 14 inserted into the..., The cutter main body 4 is rotated and advanced integrally by rotating the tool main body 4 and moving forward as described above. The inner diameter 3A
Can be cut. In the present embodiment,
By inserting the body peripheral portion 4A of the tool body 4 into the cylindrical cutter body 12, the cutter body 12
Of the cutter body 1
2 can be exactly aligned with the axis O, so that there is no uncut portion in the inner diameter portion 3A or conversely, the casing top 3 is unnecessarily cut off excessively. The excavating tool 15 forming h can be reliably and smoothly projected from the tip of the casing top 3. Moreover, in the present embodiment, the mounting pin 1
Are inserted into mounting holes 4D for locking the excavating bits 5 in the tool body 4 of the excavating tool 1, and the cutter body 1
2 is detachably attached, it is not necessary to newly form an attached portion corresponding to the attachment portion for detachably attaching the cutter body 12 to the tool body 4 side, which is more efficient. is there.

Further, in the cutter 11 of the present embodiment,
The cylindrical portion 4A of the tool body 4 is formed in a cylindrical shape in this manner.
Is inserted into the inner peripheral portion of the cutter body 12 into which the tool is inserted.
2C... Are formed, and the mounting holes 4D.
When the cutter main body 12 is mounted on the tool main body 4 with the mounting pins 14 being coaxial with the tool main body 4, these ridges 12C can be brought into contact with the wall surface of the cutting groove 4E facing the rotation direction T side. Have been. For this reason, according to the present embodiment, it is possible to reliably transmit the rotational torque from the tool main body 4 to the cutter main body 12 by performing contact with the ridges 12C... And the cutting powder grooves 4E. And the load acting on the cutter body 12 in the rotation direction T rear side during cutting can be received.
The mounting rigidity of the mounting pin 14 can be improved.
Can be prevented from being broken due to excessive load acting on. Moreover, in this embodiment,
In the above-described mounting state, the step 12A on the distal end side of the inner peripheral portion of the cutter main body 12 and the rear end face can contact the distal end face of the tool main body 4 and the step 4B.
To reliably transmit the thrust force toward the front end of the cutter body 12 in the direction of the axis O, and to receive a load acting on the cutter main body 12 toward the rear end of the cutter in the direction of the axis O to perform more stable cutting. Can be.

In this embodiment, the tip of the cutting blade tip 13 implanted in the cutter main body 12 forms an isosceles triangular mountain shape when viewed in the radial direction.
A negative axial rake angle is given to 3A. For example, the tip portion of the cutting edge tip 13 is formed into a right triangular mountain shape as viewed in the radial direction, and the axial rake angle of the cutting edge 13A is set to 0 °, or A side surface (rake face) extending from the cutting edge 13A so as to face the rotation direction T side is inclined toward the rotation direction T side toward the tip end side so as to give the cutting edge 13A a positive axial rake angle. Is also good. The radial width of the cutting blade tip 13, that is, the width of the cutting blade 13A is the same as that of the above embodiment, and the cutter body 1
The outer diameter of the cutting tip 2 may be made slightly smaller than the inner diameter of the casing pipe 2 so that the outer peripheral portion of the cutting tip 13 projects from the outer peripheral surface of the cutter body 12.

[0019]

As described above, according to the excavation method of the present invention, the cutter is attached to the excavation tool used for forming the drilled hole, and the inner diameter of the casing top is cut and removed. A large excavation diameter can be ensured in the drilling formed following the drilling, and the drilling can be performed using the drilling tool used for the previous drilling, which is efficient. Further, according to the cutter of the present invention used in such an excavation method, by inserting the torso of the excavation tool into the cutter body and detachably attaching the torso by the attachment portion, the excavation tool is rotated while being advanced. By doing so, it is possible to cut the inner peripheral portion of the casing top, and furthermore, if an inner peripheral portion of the cutter body is provided with a protruding portion that can be inserted into a cutting groove on the outer periphery of the excavating tool, It is possible to transmit the rotational torque to the cutter body reliably and perform stable cutting.

[Brief description of the drawings]

FIG. 1 is a front view showing a cutter 11 according to an embodiment of the present invention.

FIG. 2 is a side view of the cutter 11 shown in FIG.

FIG. 3 is a front view when the cutter 11 shown in FIGS. 1 and 2 is attached to the excavating tool 1;

FIG. 4 is a side view when the cutter 11 shown in FIGS. 1 and 2 is attached to the excavating tool 1;

FIG. 5 is a diagram illustrating an embodiment of the excavation method of the present invention.

FIG. 6 is a diagram illustrating an embodiment of the excavation method of the present invention.

FIG. 7 is a front view of the excavating tool 1 according to the present invention.

8 is a side view of the excavating tool 1 shown in FIG.

[Explanation of symbols]

 1,15 Excavation tool 2 Casing pipe 3 Casing top 3A Inner diameter part of casing top 3 4 Tool body 4A Trunk part 4B, 12A Stepped part 4D, 12B Mounting hole (mounting part) 4E Cutting groove 5 Drilling bit 6, 14 Mounting Pin 11 Cutter 12 Cutter body 12C Ridge 13A Cutting edge O Rotation axis of drilling tool 1 T Rotation direction of drilling tool 1

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Kunihiko Tanaka, Inventor F-term (reference) 2D029 DC01 1-8-30 Tenmabashi, Kita-ku, Osaka-shi, Osaka

Claims (3)

[Claims] 1. A casing top having an inner diameter smaller than the inner diameter of the casing pipe is provided at a tip of the casing pipe, and a drilling tool is inserted into the casing pipe so as to project from the tip of the casing top, and the casing top is provided. The casing pipe is erected inside the drilling tool while forming a drilling with the drilling tool, and then a cutter is attached to the drilling tool to insert the casing pipe into the casing pipe. An excavation method comprising inserting and cutting off the inner diameter of the casing top with the cutter. 2. A cutter used in the excavation method according to claim 1, wherein an outer diameter capable of being inserted into the casing pipe and a body peripheral portion of the excavating tool inserted into an inner diameter portion of the casing top. A cylindrical cutter body having an inner diameter capable of being fitted therein, a cutting blade for cutting an inner diameter portion of the casing top is provided at a tip end portion of the cutter body, and the cutter body is attached to a periphery of the excavating tool. A cutter provided with a detachable mounting portion at the portion. 3. The cutter according to claim 2, wherein a ridge portion is formed on an inner periphery of the cutter body so as to be insertable into a cutting groove formed on a body periphery of the excavating tool. cutter.