JPH05141171A - Drilling tool - Google Patents

Abstract

PURPOSE:To make the diametral contraction of a block achievable without entailing any problem. CONSTITUTION:Three blocks 11a are installed on the bottom of a device 2 free of rotation, and the blocks 11a are rotated by drilling resistance at the time of drilling a relative position of a block shaft 3a in relation to the blocks 11a, and thereby one side end 12a of the blocks 11a and a crossed part of a circular part are projected out as far as a portion of the specified drilled value from an outer circumferential surface of the device 2. At that time, both side ends 12a, 12b of the these blocks 11a come into contact with both side ends of these adjacent blocks 11a. In a drilling tool set up like this, in the device 2, is provided, a nozzle hole 18 being opened in a bottom central part of the device 2 and spraying a fluid is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excavating tool used when excavating the ground or earth and sand in various types of anchor construction, various drilling well construction, various foundation pile hole construction, etc. The present invention relates to an excavating tool.

[0002]

2. Description of the Related Art Conventionally, as one of the excavating tools for excavating the ground, earth and sand, there has been provided an excavating tool as described in JP-A-63-11789. As shown in FIGS. 6 and 7, this drilling 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 in a point symmetry with respect to the center of the device 2. Shaft holes 2a and 2b are formed in two, and each shaft hole 2
The block shafts 3a and 3b are rotatably mounted around the shafts a and 2b so as to be rotatable and prevented from slipping off.
Blocks 5a, 5b each having a substantially semi-circular shape having a diameter substantially equal to that of the device 2 and having a large number of bits 4 ... It is provided facing each other.

In such an excavating tool, when the device 2 is rotated in the excavating direction X by the hammer cylinder 1, the blocks 5a and 5b rotate about the block shafts 3a and 3b while receiving excavating resistance, and the block 5a is rotated. , 5b
One end of each of the straight end surfaces 6a, 6b of the device 2 protrudes from the outer peripheral surface of the device 2 by a predetermined amount, and some of the straight end surfaces 6a, 6b abut each other to stop the rotation of the blocks 5a, 5b. Then, the blocks 5a and 5b receive the rotational force of the device 2, excavate the ground by the bit 4 ... And further advance the ground by the impact force of the hammer, thereby excavating the ground. ..

However, in the above excavating tool, as shown in FIG.
As shown in FIG. 1, one end portion of the blocks 5a and 5b protruding outward from the outer peripheral surface of the device 2 (hereinafter, referred to as outer peripheral blade A)
The outer peripheral blade A is present only at two locations 180 degrees outside the device 2, which is superior to the above-mentioned eccentric drilling type, but can be drilled in a well-balanced manner. However, there is a problem that hole bending may occur when excavating a heterogeneous layer.

Therefore, the present applicants first applied for a drilling tool capable of solving the above problems (Japanese Patent Application No. 2-2).
No. 00354). As shown in FIGS. 8 and 9, this drilling tool has three shaft holes 2a, 2 on the bottom surface of the device 2 which receives the impact force of the hammer and the rotational force of the hammer cylinder.
b and 2c are displaced from the center of the device 2 and equiangularly arranged in the circumferential direction, and the block shafts 3a, 3b and 3c are rotatably fitted into the shaft holes 2a, 2b and 2c, respectively, and the block shaft 2a , 2b, 2c, the blocks 11a, 11 each having a substantially fan shape at the tips thereof and the bits 4 being planted on the tip surfaces thereof.
b and 11c are provided so that the left and right side end faces 12a and 12b are opposed to each other and the arc portions 12c of these blocks form a substantially circle as a whole, and when the device 2 rotates in the excavation direction, the excavation hole is formed. The blocks 11a, 11b, 11c rotate on their own due to excavation resistance with the bottom, and the intersection of one side end face 12a and the arc part 12c of the block protrudes from the outer peripheral surface of the device 2 by a predetermined excavation amount, and at that time. The block shaft 3 for the blocks 11a, 11b, 11c so that the both end surfaces 12b, 12a of each block contact the side end surfaces 12a, 12b of the adjacent blocks.
The relative positions of a, 3b, and 3c are set.

In the excavating tool having the above construction, the hammer cylinder 1 and the device 2 as well as the blocks 11a,
When 11b and 11c rotate in the excavation direction, the block 1
1a, 11b and 11c are block shafts 12 due to excavation resistance
Rotating around a, 12b, 12c, blocks 11a,
An intersecting portion between one side end surface 12a of each of 11b and 11c and the arc portion 12c projects from the outer peripheral surface of the device 2, and this portion functions as the outer peripheral blade A. In addition, the block 11
When a, 11b, and 11c rotate, side end surfaces 12a and 12b of each block are adjacent to each other.
2a, which act as stoppers for each other and restrict further rotation of each block. In this state, the blocks 11a, 11b, 11c receive the rotational force of the device 2 to excavate the ground by the outer peripheral blade A and the like.

Therefore, when excavating with the above-mentioned excavating tool, since three blocks are provided, the number of the outer peripheral blades A generated for one block is naturally three, and these outer peripheral blades A are arranged in the circumferential direction. Since they are arranged at equal intervals, well-balanced excavation can be performed, and even if the ground is inhomogeneous, bending of holes is less likely to occur.

[0008]

By the way, in the excavating tool having the above-mentioned structure, the three blocks 11 are used for excavation.
In order to move a, 11b, and 11c to the outside in the radial direction of the device 2 to expand the diameter, blocks 11a, 11b, and 11
The respective side end surfaces 12a and 12b of c are configured so as not to be in close contact with each other on the side of the central portion of the bottom surface of the device 2, so that the blocks 11a, 11b and 11c can be moved radially outward of the device 2. Therefore, in the above drilling tool, as shown in FIG. 8, when the diameter is reduced, the blocks 11a, 1a on the bottom center side of the device 2 are
There is a space S between 1b and 11c, and this space becomes smaller as the diameter increases and disappears when the diameter is completely expanded. When the blocks 11a, 11b, and 11c decrease in diameter after the end of excavation, the space S appears again. Further, the space S becomes larger as the diameter is reduced.

Thus, the blocks 11a, 11b, 1
Since the space S appears at the time of the diameter reduction of 1c, when the cutting waste enters the space S, the cutting waste is caught between the side end faces 12a and 12b of the blocks sliding with each other to prevent the diameter reduction. There was a problem that the drilling tool could not be pulled out from the drill hole. The present invention has been made to solve the above problems, and an object thereof is to provide an excavating tool that can reduce the diameter of a block without problems.

[0010]

In order to achieve the above object, a drilling tool according to claim 1 of the present invention has at least three or more devices on the bottom surface of a device which receives the impact force of a hammer and the rotational force of a hammer cylinder. Shaft holes are provided offset from the center of the device and equiangularly in the circumferential direction, and a block shaft is rotatably fitted in the shaft holes. The blocks in which the bits are planted are provided so that the left and right side end faces face each other and the arc portions of the blocks form a substantially circular shape as a whole, and when the device rotates in the excavation direction, the bottom of the excavation hole The block rotates due to excavation resistance with and the intersection of one side end face of the block and the arc portion protrudes from the outer peripheral surface of the device by a predetermined excavation amount, and at that time, both end faces of each block are In a drilling tool in which the relative position of the block axis with respect to the block is set so as to abut the side end surface of the matching block, an ejection hole for ejecting a fluid is formed in the device by opening at the center of the bottom surface of the device. It was done.

The excavating tool according to a second aspect is the excavating tool according to the first aspect, wherein at least one of the side end surfaces of the block that abut each other has one end portion in the longitudinal direction of the other end surface. A notch groove extending toward the end is formed.

[0012]

In the excavating tool of claim 1, when the hammer cylinder rotates in the excavating direction, the device also rotates integrally. Further, as the hammer piston descends, the device and the block attached to the tip of the device advance. When the device rotates in the direction of excavation, excavation resistance causes each block to rotate about the block axis,
The intersection of one side end surface of the block and the circular arc portion protrudes from the outer peripheral surface of the device by a predetermined amount of excavation, that is, increases in diameter, and this portion serves as an outer peripheral blade to excavate a hole. Further, when the blocks rotate, the side end faces of the blocks abut against the side end faces of the adjacent blocks, respectively, which serve as stoppers to restrict further rotation of the blocks.

When the device is rotated in the opposite direction to reduce the diameter of the block, a space appears between the blocks at the central portion of the bottom surface of the device, and the space becomes larger as the diameter decreases. Since the compressed air is blown out from the ejection hole opened in the central portion of the front surface of the, the cutting wastes that try to enter the space are removed by the compressed air. Therefore, since the excavated dust does not enter the space and is not caught between the side end faces of the blocks that slide with each other, the diameter of the block can be reduced reliably and smoothly.

Further, in the excavating tool of claim 2, when the opening of the ejection hole is closed by a block during excavation, the compressed air flowing from the exhaust hole into the ejection hole passes through the notch groove and the bottom surface of the device. Since the shavings are blown out to the outer peripheral portion to remove the shavings, the shavings can be removed more effectively.

[0015]

1 to 4 show an embodiment of a drilling tool according to the present invention, in which the reference numeral 2 designates a device. The bottom surface of this device 2 has shaft holes 2a, 2b, 2c.
Are formed so as to be displaced from the center of the device 2 and to be equiangularly placed (120 ° apart) in the circumferential direction of the device.

Block shafts 3a, 3b, 3c are rotatably fitted in the shaft holes 2a, 2b, 2c in such a manner as to be rotatable. The block shafts 3a, 3b, 3c are prevented from coming off by locking pins. That is, on the outer peripheral surface of the device 2, three lateral holes 7 are formed which cross a part of the shaft holes 2a, 2b, 2c and reach the vicinity of the central portion of the device 2.
a, 7b, 7c are formed at equal intervals in the circumferential direction. Locking pins 10 are inserted into the lateral holes 7a, 7b, 7c, respectively, and these locking pins 10 are engaged with recesses 10a formed on the outer peripheral portions of the block shafts 3a, 3b, 3c. There is.

Reference numerals 11a, 11b and 11c denote blocks provided at the tips of the block shafts 3a, 3b and 3c so as to be orthogonal to the block shafts. The block 1
1a, 11b and 11c may be formed integrally with the block shafts 3a, 3b and 3c, or they may be formed separately and connected by bolts or the like.

Each of these blocks 11a, 11b, 11c
Are of the same shape formed in a substantially fan shape in bottom view, and the radius of the fan shape is set to be substantially the same as the radius of the device 2. The blocks 11a, 11b, 11c are left and right side end faces 1
The arcuate portions 12c of the blocks are arranged such that the arcuate portions 12c of the blocks 2a, 12b face each other and form a substantially circular shape as a whole. The blocks 11a, 11b, 11c are left and right side end faces 1
The lengths of 2a and 12b are different from each other, and the angle between both end faces 12a and 12b is 120 degrees.

The tip surfaces of the blocks 11a, 11b, 11c are located on the side of the block axes 3a, 3b, 3c and are planes 111a, 11 orthogonal to the block axes 3a, 3b, 3c.
1b, 111c and these planes 111a, 111b, 1
First inclined surfaces 13a, 13b, 13 inclined downward from the arc-shaped ridgeline of 11c toward the outer peripheral side of the device 2.
c, and second inclined surfaces 14a, 14b, 14c which are inclined downward from the arc-shaped ridgelines outside the first inclined surfaces 13a, 13b, 13c toward the outer peripheral side of the device 2, Moreover, the first inclined surfaces 13a, 13b,
A step 112 is provided between 13c and the second inclined surfaces 14a, 14b, 14c. In this way, the step 1
By providing 12, the first inclined surfaces 13a, 13a
Since it is possible to secure the wall thickness between the b, 13c and the bit 4 planted on the second inclined surfaces 14a, 14b, 14c, it is possible to plant a large number of the bit 4 and excavation efficiency. Can be improved.

Further, when the device 2 rotates in the excavating direction, the end of the side end face 12a of the block protruding from the outer peripheral surface of the device 2 is gradually extended toward the front in the rotational direction at the end of the side end face 12a of the block. Inclined surfaces 15a, 15b, 15c that are inclined toward the side are formed. Tip surfaces 13a, 13b, 13c, surfaces 14a, 14 of the block
b, 14c, the surfaces 15a, 15b, 15c and the inclined surface are provided with a plurality of bits 4 ...

When the device 2 is rotated here, the outer peripheral side of the tip surfaces of the blocks 11a, 11b, 11c rotates at a higher speed than the central side, so that the bit 4 ... A larger rotational reaction force acts from. Then, the resultant force F of this rotational reaction force and the reaction force of the impact force orthogonal to this reaction force acts as inclined toward the outer peripheral side bit. On the other hand, bit 4 is for blocks 11a, 11b, 1
The strength of breakage is strong against a force perpendicular to the tip surface of 1c, but the weaker the strength of the force, the weaker the strength is, and the damage or dropout easily occurs.

Therefore, in the above drilling tool, the block 1
Inclined surfaces 15a, 15 on the outer peripheral side of 1a, 11b, 11c
b, 15c are formed on the inclined surfaces 15a, 15b, 15
Since the bits 4 are planted vertically in c, the resultant force F is
As shown in FIG. 4, since it acts almost at right angles to the bits 4 on the outer peripheral side, it is possible to prevent the bits 4 ... from being damaged or dropped.

The relative positions of the block shafts 3a, 3b, 3c with respect to the blocks 11a, 11b, 11c are such that when the device 2 rotates in the excavation direction, the blocks 11a, 11b, 11c rotate by the excavation resistance with the bottom of the excavation hole. do it,
The intersection of one side end surface 12a of the block and the circular arc portion 12c protrudes from the outer peripheral surface of the device 2 by a predetermined amount of excavation, and at that time, the side end surface 12b, 1 of each block.
2a is set so as to contact the side end surfaces 12a and 12b of the adjacent blocks.

Further, the blocks 11a, 11b, 11
The outer circumference of each c is formed by an arc having a different radius. That is, the outer circumferences of the blocks 11a, 11b, 11c are, as shown in FIG. 6, two arcs S1,
It is composed of S2 and a curve S3 that smoothly connects these arcs S1 and S2. The arcs S1 and S2 are arcs centered on the same point, and the radius of the arc S1 is set larger than the radius of the arc S2. Further, the arc S1 is the device 2
Is located on the side projecting from the outer peripheral surface of the device 2 when rotated in the excavating direction, and the arc S2 is located on the side not projecting.

A large number of bits 4 are planted on the tip surfaces of the blocks 11a, 11b and 11c, but the radius of the outer circumference of the protruding side of the blocks 11a, 11b and 11c is the non-protruding side. Since it is larger than the radius of the outer circumference, a large number of bits can be implanted in the protruding side portion. Therefore, when the device 2 rotates in the excavation direction, even if the work of the protruding portions of the blocks 11a, 11b, 11c is large, a large number of bits 4 are implanted in this portion, so that they do not protrude. It is possible to prevent the bit 4 planted in the protruding portion from being worn before the bit 4 planted in the portion is worn, so that the life of the excavating tool can be improved. ..

An exhaust hole 17 extending in the axial direction is formed at the center of the device 2. The exhaust hole 17 is opened in the base end surface of the device 2, and the compressed air discharged when the hammer piston falls is introduced from this opening. Further, the device 2 is formed with an ejection hole 18 extending from the upper end portion of the exhaust hole 17 and opening to the center of the bottom surface of the device 2.
A part of the compressed air that has flowed into the exhaust hole 17 is ejected.

In the device 2, lateral holes 19 which communicate with the tip of the exhaust hole 17 and extend outward in the radial direction are formed at 120 ° positions below the shaft holes 2a, 2b, 2c. .. The lateral holes 19 are communicated with three blow holes 20 ... Which extend to the bottom surface side of the device 2 in the axial direction and open on the bottom surface of the device 2. These blow holes 20 ...
Each of the openings is provided in a recess 21 formed in the exposed portion of the bottom surface of the device 2 in a state where the blocks 11a, 11b, and 11c are expanded in diameter, and the compressed air flowing into the exhaust hole 17 through these openings is opened. It is designed to eject a part of the. The outer end of the recess 21 is the device 2
Is connected to an excavation waste discharge groove 23 which is provided on the outer periphery of and is formed between the excavation pipe 9 and the outside.

The cutting waste discharge groove 23 is formed integrally with the outer circumference of the device 2 and has an arc shape between the centering projections 22a for keeping the device 2 itself concentric with the outer circumference of the drill pipe 9. Which are formed on the cutting waste discharge groove 23 and the projection 22.
a is alternately arranged in the circumferential direction between the device 2 and the drill pipe 9. The width dimension of the cutting waste discharge groove 23 is equal to or less than a certain size so that the cutting waste entering the drilling pipe 9 through the cutting waste discharge groove 23 is not inadvertently clogged in the drilling pipe 9. It is set within a certain range so that it can only pass through.

Also, the blocks 11a, 11b, 11
Of the side end surfaces 12a, 12b of the c that are in contact with each other, the side end surface 12 on which the inclined surfaces 15a, 15b, 15c are not formed
A cutout groove 25 extending from one end in the longitudinal direction of the side end surface 12b to the other end is formed in b. As shown in FIG. 5, the cutout groove 25 is formed by cutting out the surface side of each block 11a, 11b, 11c in contact with the device 2 into a substantially rectangular cross section including the side end surface 12b. When the diameters of 11a, 11b, and 11c are reduced, the compressed air ejected from the ejection holes 18 flows in and ejects the compressed air toward the outside of the device 2.

Next, the operation of the excavating tool having the above structure will be described. When the hammer cylinder 1 receives a driving force and is rotated in the direction of arrow X, the device 2, the block shaft and the block also rotate in the same direction integrally therewith. Further, when a hammer piston arranged in the hammer cylinder 1 is driven to apply a downward impact force to the device 2, the blocks 11a, 1
Bits 4 excavate debris due to the rotational force of 1b and 11c thrusting into the ground.

When the blocks 11a, 11b and 11c rotate in the excavating direction together with the hammer cylinder 1 and the device 2, the blocks 11a, 11b and 11c rotate about the block shafts 12a, 12b and 12c due to excavation resistance, and the blocks 11a, 11b and 11c rotate. One end surface 1 of 11b and 11c
An intersecting portion of 2a and the arc portion 12c projects from the outer peripheral surface of the device 2, and this portion functions as the outer peripheral blade A. Further, when the blocks 11a, 11b, 11c rotate about their own axes, the side end faces 12a, 12b of the blocks abut against the side end faces 12b, 12a of the adjacent blocks, which serve as stoppers to each other, and Regulate rotation. In this state, the blocks 11a, 11b, 11c
Receives the rotational force of the device 2 and excavates the ground by the outer peripheral blade A and the like.

Here, since three blocks are provided, the number of outer peripheral blades A generated for one block is naturally three, and the outer peripheral blades A are arranged at equal intervals in the circumferential direction. .. Therefore, well-balanced excavation can be performed, and hole bending is unlikely to occur even in the case of heterogeneous ground.

Further, at the time of excavation, each block 11
a, 11b, 11c are the left and right side end faces 1 as described above.
Side end faces 12b and 12a of blocks where 2a and 12b are adjacent to each other
The block shafts 3a, 3b, 3c, which are respectively in contact with the block and are fixed to the block, are fitted and supported in the shaft holes 2a, 2b, 2c.
a, 11b, 11c will be supported at three points. Therefore, the individual blocks 11a, 11b, 11c are firmly fixed, and rattling is unlikely to occur during excavation, and good excavation can be performed.

Furthermore, during excavation, when an excavation reaction force C parallel to one side end surface 12a is applied to one block 11a from the inner peripheral surface of the excavation hole as shown in FIG. Block shaft 3a integrated with the block
Side end surfaces 12b, 12 that are in contact with each other
It also acts on the other block 11b via a. Thus, even when a force parallel to one side end surface 12a of the block is applied, the force is applied to the block shaft 3a and the other block 12a.
and the load applied to one block shaft 3a is reduced accordingly. After all, one block shaft 3a (3
The load applied to b, 3c) can be reduced and the diameter of the block shaft can be reduced.

When the piston in the hammer cylinder 1 drops, the compressed air pushed out by the hammer piston flows into the exhaust hole 17, blows out through the lateral hole 19 and the blow hole 20 to the bottom surface of the device 2, and is excavated. The cutting debris is removed toward the outside of the device 2. Then, the removed cutting waste is discharged upward through the cutting waste discharge groove 23 along the flow of the compressed air through the inside of the drill pipe 9. On the other hand, the compressed air flowing from the exhaust hole 17 into the ejection hole 18 is blocked by the openings 11a, 11b and 11c when the blocks 11a, 11b and 11c are expanded in diameter, that is, at the time of excavation. The cutting waste is removed together with the compressed air blown out from the blow hole 20 through the notch groove 25 to the outer periphery of the bottom surface of the device 2.

As described above, during excavation,
As shown in FIG. 4, the resultant force F of the rotational reaction force and the reaction force of the impact force orthogonal to this rotational reaction force is the inclined surfaces 15a, 15b,
The bit 4 implanted in 15c acts most inclined with respect to the vertical axis, but these bit 4 have inclined surfaces 15a, 1
Since they are planted almost vertically in 5b and 15c, the resultant force F acts almost at right angles to the bit 4, and therefore the bit 4 can be prevented from being damaged or falling off.

After the excavation is completed, the hammer cylinder is rotated in the direction opposite to the above-mentioned excavation direction.
1a, 11b, 11c rotate in the direction opposite to that at the time of excavation,
As shown in FIG. 2, the circular arc portion 12c located at the outermost periphery of the block is equal to the bottom surface of the device 2 or arranged inside thereof. By doing so, the excavation pipe 9 can be slid, so that the excavation tool can be pulled out by pulling the hammer cylinder 1 upward.

Further, in the above excavating tool, the block 11
When the diameters of a, 11b, and 11c start to decrease, a space S appears between the blocks 11a, 11b, and 11c in the central portion of the bottom surface of the device 2, and the space S increases as the diameter decreases. Since the compressed air is blown out from the ejection hole 18 that opens in the central portion of the front surface, the cutting dust that is about to enter the space S is removed by the compressed air. Therefore, since the excavated waste does not enter the space S and bite between the side end surfaces 12a and 12b of the blocks that slide with each other, the blocks 11a, 11b and 11c can be reliably and smoothly reduced in diameter. ..

Further, between the device 2 and the drill pipe 9 on the outside thereof, the cutting waste discharge groove 23 and the centering projection 22a integrally provided on the outer periphery of the device 2 are alternately arranged in the circumferential direction. Since they are arranged, the required number of discharge passages for guiding the cutting waste to the inside of the drilling pipe 9 can be arranged on the outer periphery of the device 2, so that the discharging efficiency of the cutting waste is improved.

Further, when arranging the device-centering protrusion 22a and the cutting waste discharge groove 23 in a shifted manner in the length direction of the device 2, for example, the device-centering protrusion is provided on the base end side of the device. As compared with a case where a ring-shaped groove for discharging excavation debris is provided at the tip of the device 2, rattling of the device 2 is reduced during excavation, and it is possible to prevent the excavation debris from being caught between the device 2 and the excavation pipe 9.

In addition, the length of the device 2 can be shortened as compared with the case where the centering protrusion 22a of the device 2 and the cutting waste discharge groove 23 are arranged so as to be displaced in the length direction of the device 2 as described above. The entire device can be made compact.

In the above embodiment, the blocks 11a,
Although the case where three blocks 11b and 11c are provided has been described as an example, the present invention is not limited to this and the present invention is also applicable to a block having four or more blocks. Further, in the above embodiment, the blocks 11a, 11b, 11c are
The left and right end surfaces 12a, 12b of the same are formed flat, but the present invention is not limited to this, and the same end surfaces 12a, 12b are not limited to this.
May be formed in an arc shape that engages with each other.

[0043]

As described above, according to the drilling tool of claim 1 of the present invention, since the device has the ejection hole for opening the central portion of the bottom surface of the device and ejecting the fluid,
When the block is reduced in diameter, even if a space appears between the blocks in the central portion of the bottom surface of the device, the compressed debris blown out from the ejection hole removes the cutting debris trying to enter the space. Therefore, since the excavated dust does not enter the space and is not caught between the side end faces of the blocks that slide with each other, the diameter of the block can be reduced reliably and smoothly.

According to the excavating tool of the second aspect, at least one of the side end surfaces of the block that abut each other extends from one end portion in the longitudinal direction of the side end surface toward the other end portion. Since the notch groove is formed, when the opening of the ejection hole is blocked by a block during excavation, the compressed air flowing into the ejection hole from the exhaust hole blows out through the notch groove to the outer periphery of the bottom surface of the device. Since excavation debris is removed, excavation debris can be removed more effectively.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing a device in which a block is mounted in a drilling tool of the present invention.

FIG. 2 is a bottom view of the drilling tool of the present invention when not being drilled.

FIG. 3 is a bottom view of the excavating tool of the present invention during excavation.

FIG. 4 is a cross-sectional view of a main part of the excavating tool of the present invention during excavation.

FIG. 5 is a cross-sectional view showing a cutout groove of the drilling tool of the present invention.

FIG. 6 is a bottom view of a conventional drilling tool when not being drilled.

FIG. 7 is a bottom view of the conventional excavating tool during excavation.

FIG. 8 is a bottom view of a conventional drilling tool when not being drilled.

FIG. 9 is a bottom view of the conventional excavating tool during excavation.

[Explanation of symbols]

 1 Hammer Cylinder 2 Device 2a, 2b, 2c Shaft Hole 3a, 3b, 3c Block Shaft 4 Bit 10 Locking Pin 11a, 11b, 11c Block 12a, 12b Side End Surface of Block 12c Arc Part 13a, 13b, 13c 1st Block Inclined surface 14a, 14b, 14c 2nd inclined surface 15a, 15b, 15c inclined surface 17 exhaust hole 18 jet hole 19 lateral hole 20 blow hole 23 excavation waste discharge groove 25 notch groove 112 step A outer peripheral edge X excavation direction

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuaki Tsujimoto 1528, Nakanisha, Yokoi, Kobe, Anpachi-gun, Gifu Pref., Mitsubishi Materials Corporation Gifu Factory

Claims (2)

[Claims] 1. At least three or more shaft holes are provided on the bottom surface of a device that receives the impact force of a hammer and the rotational force of a hammer cylinder, and are displaced from the center of the device and equiangularly in the circumferential direction. A block shaft is rotatably fitted in a hole, and a block having a substantially fan shape and a bit planted on the tip surface is attached to the tip of the block shaft. When the device is rotated in the excavation direction, the block rotates on the basis of excavation resistance with the bottom of the excavation hole and the intersection of one side end surface of the block and the arc portion when the device is rotated in the excavation direction. Is projected from the outer peripheral surface of the device by a predetermined amount of excavation, and at that time, both end surfaces of each block contact the side end surfaces of the adjacent blocks so that the phase of the block shaft with respect to the block A drilling tool having a pair of positions, wherein the device is provided with a jet hole that opens at a central portion of a bottom surface of the device to jet a fluid. 2. A cutout groove extending from one end portion in the longitudinal direction of the side end surface toward the other end portion is formed in at least one of the side end surfaces of the block that abut each other. The drilling tool according to claim 1.