JP3067482B2 - Drilling tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling tool used for excavation of ground and earth and sand used in civil engineering works such as anchor work, various drilling works, foundation pile work, and in particular, a bit is planted. The present invention relates to a drilling tool having improved durability of a block.

[0002]

2. Description of the Related Art As a conventional example of the above-mentioned excavating tool, there is Japanese Patent Application No. 3-7199. This drilling tool is disclosed in
This invention was invented for the purpose of improving the durability of the excavating tool described in Japanese Patent Publication No. 11789, and the configuration thereof is schematically shown in FIGS. 6 to 8.

[0003] Reference numeral 10 denotes a device that receives the impact force of a hammer and the rotational force of a hammer cylinder. This device 1
At positions symmetrical with respect to the center of 0, insertion holes 14 into which a pair of block shafts 12 are rotatably inserted are provided as shown in FIG. The block shaft 12
Is provided with a substantially semicircular block 16 having substantially the same diameter as the device 10. This block 1
A large number of bits 18 formed of a wear-resistant material such as a cemented carbide are implanted on the tip end surface of 6. The blocks 16 are arranged such that their straight end faces 16a along the respective radial directions face each other. When the device 10 rotates in one direction, the block 16 projects from the outer periphery of the device 10 by a predetermined excavation amount. The rotation in the opposite direction brings the arc portion 16b into a reduced diameter state in which the arc portion 16b contracts inside the outline of the device 10.

In the above-mentioned excavating tool, the mechanical strength of the device 10 or the block shaft 12 is reduced by setting the interval between the insertion holes 14 into which the block shafts 12 are inserted or the inside diameter of the insertion holes 14 within a predetermined range. Care has been taken to ensure this.

[0005] A first inclined surface 16c is formed on the outer peripheral portion of the block 16 so as to incline toward the base end in the axial direction of the device 10 toward the outside, and is different from the first inclined surface 16c. Second inclined surface 16 inclined at an angle
d is formed, and a bit 18 is implanted in this portion at a higher density than the flat portion 16e near the center.
Reference numeral 20 denotes an exhaust port for discharging exhaust gas from the hammer cylinder downward and laterally to prevent intrusion of earth and sand into the lower surface of the device 10 and the like, and reference numeral 22 denotes a block shaft 14.
Is a pin that locks the concave portion 14a of FIG.

[0006]

In the above-mentioned excavating tool, the tip of the bit 18 is hemispherical, so that even when a hard rock is to be excavated, the bit 18 is unlikely to be broken by an impact at the time of excavation. Therefore, a long service life can be obtained, but when excavating soft rock, the impact applied to the bit 18 during excavation is relatively small, and the bit 18 is required to have a very high impact resistance. Absent. Therefore, for soft rock excavation,
Rather, there was a demand for another type of tool with a high drilling speed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a drilling tool which can be used mainly for digging soft rock and can achieve a high digging speed.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a block shaft is rotatably fitted on a bottom surface of a device which receives an impact force of a hammer and a rotational force of a hammer cylinder. , the block axis of this the tip is provided with a block on the front end face bit is implanted, the positions of said block shaft, one end of said block when said device is rotated in the direction of excavation is a device protrudes from the outer peripheral surface by a predetermined excavation amount, as the diameter increases, the excavation tool comprising eccentrically from the center of the device, the blanking
In a state where the lock has been expanded, the outer peripheral side of the device
Than the second bit tip the tip of the first bit, which is planted on the inner side than this is close to the circumferential direction of the device
It is characterized by having a small radius of curvature when viewed from the direction . According to a second aspect of the present invention, in the first aspect, a surface inclined with respect to the block axis is provided on an outer peripheral portion of a bottom surface of the device, and the first bit is implanted on this surface. Features. According to a third aspect of the present invention, in the first or second aspect, the tip of the second bit is formed in a hemispherical shape. According to a fourth aspect of the present invention, in any one of the first to third aspects, a tip of the first bit is formed in a chisel shape. According to a fifth aspect of the present invention, in the third aspect, the tip of the first bit is formed in a conical shape having the same diameter as a hemisphere formed by the tip of the second bit.

[0009]

According to the above-mentioned structure, the circumferential direction of the device at the time of diameter expansion is obtained.
As the bit near the outer circumference is seen from the inside, it becomes a sharp shape from the inside, so the impact force of the hammer and the rotation force of the hammer cylinder
Thus, it is possible to perform efficiently drilling effectively bite the bit into the rock soft.

[0010]

1 and 2 show a first embodiment of the present invention. In this embodiment, a chisel-shaped cutting blade 24 is provided at the tip of a bit 22 provided on the first inclined surface 16c and the second inclined surface 16d on the outer peripheral portion of the block 16. The tips of the bits 18 inside these bits 22 are formed in a hemispherical tip as in the conventional example.

As shown in FIG. 2, the bit 22 comprises a cylindrical portion 26 embedded in the block 16 and a chisel-shaped cutting blade 24 provided on the upper portion thereof .
As shown in FIG.
Thus, the edge of the cutting edge 24 at the tip of the device 10
It is attached so as to extend along the circumferential direction . It said chisel-like cutting edge 24 of which is given a slight rounded in consideration of chipping resistance, therefore, the tip of the bit 22 is de
The radius of curvature is set to be smaller than the tip of the bit 18 on the inner peripheral side when viewed from the circumferential direction of the vise 10 .

Therefore, in the first embodiment,
The radius of curvature of the bit 22 in the outer peripheral portion is in the circumferential direction of the device 10.
Since less than bits 18 of the inner peripheral portion as viewed from, the
Bit 22 Do bite into the rock by the impact force of the hammer
The device 10 is rotated by the rotational force from the hammer cylinder.
Has a low resistance to rotation, which makes it particularly effective on soft rock masses, which can be easily broken and therefore high excavation speeds can be obtained. Also, small resistance in the bit 22 of the outer peripheral portion of the most significant impact on the bending moment occurring on the tip of the block shaft 1 2, because rock can be divided efficiently, only a small force necessary for drilling, block axis bending moment becomes smaller occurs 1 second tip. Thus the insertion hole 14 of the device 1 0 from the leading end of the block shaft 1 2 is bent by the bending moment to be less damaged. Also, the inner spherical bit 18 having a large radius of curvature first collides with the bedrock, and after the impact is alleviated to a certain extent, the outer bit 22 having a small radius of curvature (sharply shaped) is impacted. , The outer bits 22 are protected.

FIG. 3 shows bits applied to the second embodiment of the present invention. The tip of the bit 26 has a conical shape, and by having such a shape, the radius of curvature of the tip becomes smaller than that of the bit 18 at the inner peripheral portion. Speed can be increased.

FIG. 4 shows bits applied to a third embodiment of the present invention. The tip of the bit 28 has a conical shape with a two-step apex angle, and with such a shape, the radius of curvature at the tip is smaller than that of the bit 18 at the inner periphery. Further, by adopting such a two-stage conical shape, the tip portion is set to an optimum angle in consideration of excavation efficiency and life, and the base portion is set to the bit 28.
Optimum dimensions can be obtained in consideration of the amount of protrusion and the prevention of breakage.

FIG. 5 shows bits applied to a fourth embodiment of the present invention. The bit 30 has a bullet shape, and by having such a shape, the radius of curvature of the tip portion is
It is smaller than the bit 18 on the inner circumference.

Note that the specific shape of the bit is not limited to the above embodiments, and as long as a bit having a smaller radius of curvature at the tip than the bit on the inner peripheral side as viewed from the peripheral direction of the device is used, Works effectively to increase the excavation speed.

[0017]

As is apparent from the above description, the present invention
Is the tip of the blocks shaft fitted to the bottom surface of the device which receives the impact force and the rotational force of the hammer cylinder of the hammer,
In a drilling tool provided with a block in which a bit is implanted on a distal end surface, the distal end of a first bit located on the outer peripheral side of the device is implanted inside the excavating tool in a state where the diameter of the block is expanded. Of the device from the end of the second bit
Because it has a small radius of curvature when viewed from the circumferential direction ,
The bit on the outer peripheral side is the resistance when rotating while biting the rock
Is small, which ensures that the
Easily divide it greatly effects crush the rock than the bit inner periphery of can be Itsui, therefore, when the striking force can be obtained a good drilling rate effectively allowed to act on the rock DOO
In addition, the bending moment generated on the block axis is small.
The block shaft and device insertion holes are damaged.
Can be prevented .

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of a drilling tool according to the present invention.

FIG. 2 is a perspective view of a bit of the excavating tool of FIG. 1;

FIG. 3 is a perspective view of a bit according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a bit according to a third embodiment of the present invention.

FIG. 5 is a perspective view of a bit according to a fourth embodiment of the present invention.

FIG. 6 is a perspective view of a conventional drilling tool.

FIG. 7 is a bottom view of a prior art excavation tool.

FIG. 8 is a longitudinal sectional view of a conventional drilling tool.

[Explanation of symbols]

10 Device 12 Block axis 14
Insertion hole 16 block 18 bit 22
Bit 26 bit 28 bit 30
bit

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Fujimori 1528 Nakashinda, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture Mitsubishi Materials Corporation Gifu Works (56) References JP-A-3-250189 (JP, A) JP 5-22684 (JP, U) JP 3 122189 (JP, U) (58) Fields studied (Int. Cl. ⁷ , DB name) E21B 10/36 E21B 10/32 E21B 10 / 56 E21B 10/58

Claims (5)

(57) [Claims] 1. A shock force and block axis on the bottom surface of the device which receives the rotational force of the hammer cylinder of the hammer is rotatably fitted around the axis, the distal end of the block axis of this bit is embedded in the distal end surface blocks the provided position of the block axis, such that the device is one end of the block when it is rotated in the direction of excavation is enlarged protrudes by a predetermined excavation amount from the outer peripheral surface of the device, the device In the excavating tool eccentric from the center of the device , in a state where the diameter of the block is expanded , the tip of the first bit located on the outer peripheral side of the device is the tip of the second bit implanted inside the device. From the tip, the device
Drilling tool, characterized in that viewed from the circumferential direction there is a small radius of curvature. 2. The device according to claim 1, wherein a surface inclined with respect to the block axis is provided on an outer peripheral portion of a bottom surface of the device, and the first bit is implanted on this surface.
Drilling tools. 3. The excavating tool according to claim 1, wherein the tip of the second bit is formed in a hemispherical shape. 4. The excavating tool according to claim 1, wherein a tip portion of the first bit is formed in a chisel shape. 5. The excavating tool according to claim 3, wherein the tip of the first bit is formed in a conical shape having the same diameter as a hemisphere formed by the tip of the second bit.