JP2882069B2 - Drilling tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
In connection with drilling tools used for excavating the ground and soil in various drilling wells or various types of foundation pile hole construction, etc., it relates to a drilling tool that can plant a large number of bits made of carbide tips, etc. is there.

[0002]

2. Description of the Related Art Conventionally, as one of excavating tools for excavating ground, earth and sand, the one described in Japanese Patent Application Laid-Open No. 63-11789 is known.

[0005] As shown in FIGS. 5 to 7, the excavating tool is provided on the bottom surface of the device 2 which receives the impact force of a hammer (not shown) and the rotational force of the hammer cylinder 1, with respect to the center of the device 2. Block axes 3a, 3
b is rotatable around the axis and fitted to the block shafts 3a and 3b in a substantially semicircular shape having a diameter substantially equal to the diameter of the device 2 at the distal end of each of the block shafts 3a and 3b. Blocks 5a, 5b on which bits 4 are implanted are provided with their straight end faces 6a, 6b facing each other, and the position of the block shafts 3a, 3b is adjusted when the device 2 rotates in the excavation direction. One end of each of the blocks 5a, 5b projects from the outer peripheral surface of the device 2 by a predetermined excavation amount, and at this time, the straight end surfaces 6a, 6
b are eccentric from the center of the device 2 so as to abut each other.

In the above-mentioned excavating tool, when the device 2 is rotated in the excavating direction by the hammer cylinder 1, the blocks 5a and 5b rotate around the block shafts 3a and 3b while receiving the excavating resistance, and the blocks 5a and 5b are rotated. 5a, 5b
The end portions of the straight end surfaces 6a, 6b protrude from the outer peripheral surface of the device 2 by a predetermined amount, and a part of the straight end surfaces 6a, 6b abut against each other to stop the rotation of the blocks 5a, 5b. In this state, the blocks 5a and 5b receive the rotational force of the device 2, excavate underground by the bits 4, and further advance underground by the impact force of the hammer.

[0005] At this time, the excavated soil and the like are blown out of compressed air discharged when the hammer piston falls in the hammer cylinder 1 from the air holes 8 a and 8 b provided on the bottom surface of the device 2. It is separated from the tip and then moves into the excavation pipe 9 via the discharge groove 9a provided in the device 2, from which it is discharged further upward.

[0006]

As shown in FIG. 7, the excavating tool has one end (hereinafter referred to as an outer peripheral edge A) projecting outward from the outer peripheral surface of the device 2 of the blocks 5a and 5b. ), It is preferable to implant a large number of bits 4 at the position of the outer peripheral edge A of the block 5 in order to enhance the excavating ability. Since the interval (wall thickness) between the implanted bits is reduced, there is a limitation in increasing the number of bits 4 at the position of the outer peripheral blade A in the excavating tool having the conventional structure. The present invention has been made in view of such a background, and an object of the present invention is to provide a drilling tool that can increase the number of bits to be implanted in a block and can enhance the excavating ability. To provide.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a block axis is provided on a bottom surface of a device which receives an impact force of a hammer and a rotational force of a hammer cylinder, respectively, symmetrically with respect to the center of the device. Each block is fitted in a freely semi-circular shape having a diameter substantially equal to the diameter of the device, and a bit is implanted on the distal end surface of each block at the distal end of each block shaft. The end faces are provided to face each other, and the position of the block shaft, when the device is rotated in the excavation direction, both ends of each of the two blocks both project by a predetermined excavation amount from the outer peripheral surface of the device, and In a drilling tool that is eccentric from the center of the device so that the straight end faces of both blocks come into contact with each other when the block is expanded in diameter, the tip end face of the block is positioned on the block shaft side. A plane perpendicular to the block axis, a first inclined surface inclined downwardly from the arc-shaped ridge line of the plane toward the outer peripheral side of the device, and an arc-shaped outer surface of the first inclined surface. And a second inclined surface which is inclined downward from the ridge line toward the outer peripheral side of the device, and a step is provided between the first inclined surface and the second inclined surface. .

[0008]

According to the excavating tool of the present invention, a first inclined surface inclined downward from the arc-shaped ridge line of the plane at the tip of the block toward the outer peripheral side of the device, and an outer surface of the first inclined surface. Is provided between the arc-shaped ridge line and the second inclined surface which is inclined downward toward the outer peripheral side of the device. A sufficient thickness can be secured.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

[0010] The drilling tool shown in the figure also basically has a device 10 receiving the impact force of the hammer and the rotational force of the hammer cylinder, like the drilling tool shown in Figs. Each of the block shafts 20 is rotatably fitted around the axis symmetrically with respect to the center with respect to the point, and has a substantially semicircular shape having a diameter substantially equal to the diameter of the device 10 at the distal end of each block shaft 20. Blocks 22 having bits 21 implanted on the surface are provided with their respective straight end faces 22a facing each other, and the position of the block shaft 20 is adjusted when the device 10 rotates in the excavation direction.
The two end portions of the device 10 project from the outer peripheral surface of the device 10 by a predetermined excavation amount, and the straight end surfaces 22a of the two blocks 22 come into contact with each other when the block 22 is expanded. It has a basic configuration decentered from the center.

However, in the present invention, the block 22
A flat surface 22b positioned on the block axis 20 side and orthogonal to the block axis 20;
A first inclined surface 22c inclined downward from the arc-shaped ridge line 2b toward the outer peripheral side of the device 10;
Of the device 10 from the arc-shaped ridgeline outside the inclined surface 22c of
The second inclined surface 22 which is inclined downward toward the outer peripheral side of the
d, and the greatest feature is that a step 22f is provided between the first inclined surface 22c and the second inclined surface 22d.

Hereinafter, the main members of these excavating tools will be described more specifically. First, the device 10
A notch 10b communicating with an air hole 10a for blowing out compressed air is provided between the bottom surface and the outer peripheral surface,
On the outer peripheral surface of the device 10, there is formed a discharge groove 10c communicating with the notch portion 10b and discharging the excavated chips upward.

An insertion hole 11 for inserting the block shaft 20 is provided on the bottom surface of the device 10, and the insertion hole 11 is shifted from the center of the device 10 and is point-symmetric with respect to the center of the device 10. It is formed to become. The insertion hole 11 has the block shaft 2
0 is fitted so as to be rotatable and prevented from falling off.
This is performed by a locking pin 15 or the like inserted from the outer periphery of the block 0 toward the block shaft 20.

Next, the structure of the block shaft 20 and the block 22 will be described. The block shaft 20 and the block 22 are provided orthogonal to each other, and even if the block shaft 20 and the block 22 are formed integrally. Alternatively, they may be formed separately and connected by bolts or the like.

More specifically, each of the blocks 22 has the same shape formed in a substantially fan shape (semicircular shape in the embodiment) when viewed from the bottom, and the radius of the fan shape is substantially equal to the radius of the device 10. Is set. And these blocks 22
Are arranged such that the straight end faces 22a face each other and that the arc portions (outer peripheral portions) 22g of the blocks form a substantially circular shape as a whole.

On the tip end surface of the block 22, apart from the first and second inclined surfaces 22c and 22d,
When the device 10 rotates in the excavation direction, the straight end surface 22 of the block 22 protruding from the outer peripheral surface of the device 10
A third inclined surface 22e is formed at an end of the first inclined surface 22a so as to be inclined downward as it goes forward in the rotation direction, and the third inclined surface 22e is formed on the third inclined surface 22e.
Bit 21 is implanted substantially perpendicular to 2e.

The angle of inclination of each of the inclined surfaces 22c, 22d and 22e formed on the front end surface of the block 22 with respect to the vertical axis is set to 45 ° in this embodiment, but the angle of inclination is not limited to this. Instead, it is appropriately set according to the shape and size of the block 22, the rotational speed of the device 10, and the like.

On the other hand, as the bit 21 implanted on the flat surface 22a and the first to third inclined surfaces 22c, 22d, 22e of the block 22, for example, a bit made of a carbide chip or the like is applied. The axes XX and YY of the bits 21 implanted on the first and second inclined surfaces 22c and 22d are configured to be parallel to each other as shown in FIG.

In the embodiment, as shown in FIG. 3, the bit 21 located on the third inclined surface 22e has its vertex R
However, at a position where one end of each of the two blocks 22 is protruded from the outer peripheral surface of the device by a predetermined excavation amount, an outer side of an extension line ZW extending along the curvature of the outer surface of the block. It is provided so as to be located.

In the embodiment, between the flat surface 22b and the straight end surface 22a of the two blocks 22, the two blocks 22 are provided.
When one end of each of the two protrudes from the outer peripheral surface of the device 10 by a predetermined excavation amount, a concave portion 25a which is arranged to face each other and forms a concentric concave portion 25 with the device 10 at the center of the block 22 is formed. Each is formed. In the embodiment, the concave portion 25a is formed of a circular bottom and a tapered surface inclined upward from the bottom, but the shape is not limited to the embodiment.

In the figure, reference numeral 30 denotes a drill pipe.

Next, the operation of the above-structured excavating tool will be described.

In the above-described excavation tool, when the device 10 is rotated in the excavation direction, the block 22 rotates around the block shaft 20 due to the excavation resistance, and the block 22 rotates.
One end of the second straight end surface 22a protrudes from the outer peripheral surface of the device 10, and this portion functions as the outer peripheral blade A (see FIG. 3).

When the block 22 rotates,
The straight end faces 22a of each block abut against each other, which serve as stoppers to restrict further rotation of each block. In this state, the block 22 receives the rotational force of the device 10 and excavates underground by the outer peripheral blade A or the like.

At this time, when the hammer piston falls, compressed air is blown out from the air hole 10a to remove excavated swarf.

Since a notch 10b communicating with the discharge groove 10c is formed at the tip of the air hole 10a, a part of the compressed air flows directly as shown by the arrow in FIG. Excavated swarf can be efficiently removed.

At the time of excavation, individual blocks 22
Are formed with concave portions 25a, and the concave portions 25 are formed at the center positions of the blocks 22 when the diameter of the blocks 22 is expanded, so that the blocks 22 are hardly inserted into the rock at the time of drilling, so that rattling during excavation is less likely to occur. In addition to good excavation, the component force Fa of the propulsive force generated in the concave portion 25 acts in the radial direction as shown in FIG.
Therefore, neck breakage can be effectively prevented, and the tool life can be prolonged.

In the embodiment, the apex of the bit 21 implanted on the third inclined surface 22e of the block 22 is set such that one end of each of the two blocks 22 has a predetermined excavation amount from the outer peripheral surface of the device. In the position protruded by
Since the block was located outside the extension line WZ extending along the curvature of the outer surface of the block, the block 2 was excavated during excavation.
In the case where an impact force is applied to 2, a force can be applied in a radially outward direction of the device 10, and there is an advantage that a force acting on the outer peripheral blade A can be borne.

Further, in the embodiment, in the perforated state,
The position of each of the two blocks 22 facing the leading side in the rotational direction is a third inclined surface 22e inclined downward, and the bit 21 is planted substantially perpendicularly to the third inclined surface 22e. Therefore, the bit 21 can withstand the force in the rotating direction, and the proof strength of the bit 21 is improved, and the bit 21 is prevented from being damaged or dropped.

Further, in the embodiment, a first inclined surface 22c which inclines downward from the arc-shaped ridge line of the flat surface 22b at the tip of the block toward the outer peripheral side of the device 10, and a first inclined surface 22c of the first inclined surface 22c. A second inclined surface 2 which is inclined downward from the outer arc-shaped ridge line toward the outer peripheral side of the device.
Since the step 22f is provided between the bit 21 and the second bit 2d, the thickness between the bits 21 implanted on the inclined surfaces 22c and 22d can be secured, so that the number of bits 21 can be increased. This makes it possible to improve the excavation efficiency.

[0031]

As described above, according to the present invention, the first inclined surface inclined downward from the arc-shaped ridge line of the plane at the tip of the block toward the outer peripheral side of the device, and the first inclined surface Since a step is provided between the arc-shaped ridge line outside the surface and a second inclined surface inclined downward toward the outer peripheral side of the device, the thickness between bits implanted on these inclined surfaces is provided. It is possible to secure a sufficient thickness, to implant a large number of bits, and to achieve an excellent effect of improving the excavating ability of an excavating tool.

[Brief description of the drawings]

FIG. 1 is a side view in which a part of a drilling tool is cut away.

FIG. 2 is a plan view showing a state where a block of the excavating tool is reduced in diameter.

FIG. 3 is a plan view showing a state where a block of the excavating tool is expanded in diameter.

FIG. 4 is a perspective view of a device and a block.

FIG. 5 is a sectional view showing a conventional excavating tool.

FIG. 6 is a plan view showing a state where a block of a conventional excavating tool is reduced in diameter.

FIG. 7 is a plan view showing a state where a block of a conventional excavating tool is expanded in diameter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Device 11 Insertion hole 20 Block axis 21 Bit 22 Block 22a Straight end surface 22b Flat surface 22c First inclined surface 22d Second inclined surface 22e Third inclined surface 25 Recess

Claims (1)

(57) [Claims] 1. A block which is rotatably fitted around a block axis in a point-symmetric manner with respect to the center of the device on a bottom surface of a device which receives an impact force of a hammer and a rotational force of a hammer cylinder. At the tip of the block, a block having a substantially semicircular shape having substantially the same diameter as the diameter of the device and having a bit implanted on the tip end face is provided with the straight end faces facing each other, and the position of the block shaft is When the device is rotated in the excavation direction, one end of each of the blocks protrudes from the outer peripheral surface of the device by a predetermined excavation amount, and when the block is expanded, the two blocks have a straight shape. In a drilling tool having end faces eccentric from the center of the device so that the end faces abut each other, the tip end face of the block is located on the block axis side and orthogonal to the block axis; A first inclined surface inclined downward from the arc-shaped ridge line toward the outer peripheral side of the device, and an inclined surface inclined downward from the arc-shaped ridge line outside the first inclined surface toward the outer peripheral side of the device. An excavating tool comprising: a second inclined surface having a step, and a step provided between the first inclined surface and the second inclined surface.