JP3075092B2 - 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 earth and sand, rocks and the like in civil engineering works such as anchor work, various drilling works and foundation pile works, and more particularly, to a block for excavating earth and sand during excavation. The present invention relates to a technique for improving a drilling tool so as not to make it impossible to excavate earth and sand due to a diameter reduction.

[0002]

2. Description of the Related Art As an example of the above-mentioned excavating tool, Japanese Patent Application No. Hei.
No. 7199. This excavating tool was invented for the purpose of improving the durability of the excavating device described in Japanese Patent Application Laid-Open No. 63-11789, and as shown in FIGS. ,
The device 10 includes a device 10 to be inserted into a drilling pipe 30, and a pair of blocks 20 attached to a bottom surface 10 a of the device 10.

As shown in FIG. 5, the device 10 comprises:
A small diameter portion 10A having a spline groove 12 on the outer peripheral surface, and a pair of insertion holes 1 for inserting the shaft portion 21 of the block 20.
1 is provided with a large-diameter portion 10B, the rotational force of a not-shown hammer cylinder is transmitted via the spline groove 12, and the impact force of the not-shown hammer in the axial direction is also transmitted to the excavation pipe 30. The upper surface 13a of the engaging flange 13 is added. Also, the device 10 has a bottom surface 10a.
A pair of insertion holes 11 are formed symmetrically and in parallel with respect to the axis.

[0005] As shown in FIGS. 5 to 8, the block 20 includes a shaft portion 21 fitted into the insertion hole 11 of the device 10, and the device 10 integrally provided at the tip of the shaft portion 21. A body portion 22 having a semicircular cross-section having a cylindrical outer peripheral surface 22b having substantially the same radius as the outer peripheral surface of the main body portion 22; And a number of bits 23 formed. (In FIGS. 6 and 7, the bit 23 is not shown.) The shaft 20 of the block 20 is inserted into the insertion hole 11 of the device 10 with the flat end faces 22a facing each other. It is rotatably fitted, and is prevented from slipping off in a state of being slidable in the axial direction by a predetermined dimension by an engagement pin 17.

When the device 10 is rotated by a hammer cylinder in an excavation direction indicated by an arrow X in FIG. 5, the main body portion 22 of the block 20 receives the excavation resistance against soil and the like and rotates around the shaft portion 21 as a rotation axis. However, as shown in FIG. 6, a part of the flat end surface 22a abuts on each other to stop the rotation, and one end of the flat end surface 22a is radially outward by a predetermined amount from the outer peripheral surface 10b of the device 10. The projected diameter is increased. The portion of the main body portion 22 protruding from the outer peripheral surface 10b of the device 10 is the outer peripheral blade A
It excavates earth and sand and plays the role of excavating the wall surface of the hole. Further, the impact force of the hammer and the rotational force of the hammer cylinder applied to the device 10 are transmitted to the block 20, so that the block 20 crushes and excavates the earth and the like by a large number of bits 23 planted on the tip surface thereof. , Go underground. At this time, the excavated earth and sand is supplied through the air holes 15a, 15b, and 15c provided in the device 10 as shown in FIG. 5, and is blown out from the exhaust port 15d. The air is moved in the discharge groove 14 on the flow of the compressed air discharged to the outside, and is further discharged upward through the inside of the excavation pipe 30.

When the hammer cylinder is rotated in the direction opposite to the direction of excavation after the excavation is completed, each block 20 rotates in the direction opposite to the direction of excavation due to frictional force with earth and sand, as shown in FIG. The arc-shaped outer peripheral portion 22b of the main body portion 22 is in a reduced diameter state in which the outer peripheral portion 22b is located on the inner side in the radial direction from the outer peripheral surface 10b of the device 10. Thereby, the excavating tool 90 can be pulled upward from the inside of the excavating pipe 30.

[0007]

In the above-mentioned excavating tool, the shaft portion 21 of the block 20 is rotatably fitted into the insertion hole 11 of the device 10, and the main body portion 22 of the block 20 is Flat bottom 10
a is slidable. Thus, block 2
Reference numeral 2 denotes a state in which the diameter is increased or reduced depending on the rotation direction of the device 10 and the excavation resistance with earth and sand. Therefore, for example, when excavating a clay layer or hard rock zone, the change in excavation resistance and the vibration due to the impact force applied by the hammer cylinder act synergistically,
In some cases, the block 20 is in a reduced diameter state during excavation, so that it becomes impossible to excavate earth and sand.

Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide an excavating tool in which a block is not reduced in diameter during excavation. .

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to provide a device for receiving the impact force of a hammer and the rotational force of a hammer cylinder according to the present invention, and a symmetrical shape with respect to the center of the bottom surface of the device on the front side in the excavation direction. A pair of blocks each having a shaft portion rotatably fitted in a pair of perforated insertion holes, and a substantially semicircular body fixed to the shaft portion, wherein the pair of blocks are The flat end faces of the main body portion are made to face each other when the shaft portion is fitted into the insertion hole of the device, and the shaft portion is formed by digging resistance with earth and sand with the rotation of the device. The device is rotated as an axis, and when the device rotates in the excavation direction, a part of the main body portion projects radially outward from the outer peripheral surface of the device. The flat end faces of the body part are in an expanded state in which they abut against each other, and when the device rotates in the anti-digging direction, the body part is in a reduced diameter state located radially inward of the outer peripheral surface of the device. As described above, in the excavating tool in which the main body portion is eccentrically attached to the shaft portion, the shaft portion of the block is slidably fitted in the insertion hole of the device in the axial direction so as to prevent the block from coming off, The present invention can be attained by a drilling tool, wherein a locking portion is provided on a bottom surface of the device so as to engage with the block in the expanded state and prevent the block from rotating in the direction of the reduced diameter. .

[0010]

In the excavating tool of the present invention, the block in which the earth is excavated in the expanded state is pressed by the excavated earth and sand and is brought into close contact with the bottom surface of the device.
Then, since the block is engaged with the locking portion provided on the bottom surface and is prevented from rotating in the direction of reducing the diameter,
Even when vibration due to a change in excavation resistance or an impact applied by a hammer is applied, the diameter is not reduced. When the device is lifted up after the excavation is completed, the pressure of the excavated earth and sand is not applied to the block, and the shaft of the block is pulled out from the insertion hole of the device by its own weight and vibration by a hammer. Displaces axially away from the bottom surface of the device. Thereby, the engagement between the block and the locking portion provided on the bottom surface of the device is released, so that the block can be reduced in diameter by rotating the device in the anti-digging direction, thereby easily. The device can be pulled out of the soil.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a first embodiment of a drilling tool according to the present invention; Here, FIG. 1 is a perspective view showing the state of the device of the excavating tool of the present embodiment with the bottom surface facing upward, FIG. 2 is a front view for explaining the relative relationship between the block and the device in the enlarged diameter state, and FIG. FIG. 4 is a front view for explaining the relative relationship between the block and the device in the reduced diameter state, and FIG.
FIG. 4 is a longitudinal sectional view taken along the line IV-IV shown in FIG. 3. 1 to 4, the illustration of a large number of bits implanted in the block is omitted to make the drawings simple and easy to understand. In addition, the same reference numerals are used for the same parts as those of the conventional excavation tool.

Since the excavating tool of this embodiment has the same structure as the above-mentioned conventional excavating tool except that a locking portion is provided on the bottom surface of the device, only the characteristic portions will be described below. Will be described in detail. That is, as shown in FIG. 1, engagement projections 41.4 as locking portions are provided on the bottom surface 10a of the device 10 of the excavation tool 100 of the present embodiment.
2, 43 and 44 are protruded. These engaging projections 4
1, 42, 43, and 44 are in an expanded state shown by a two-dot chain line in FIG. 1 and their flat end faces 22a are in contact with each other and are brought into close contact with the bottom face 10a of the device 10 by the pressure of the excavated earth and sand. Flat end surfaces 22a and outer peripheral cylindrical surfaces 2 of the pair of blocks 20R and 20L in the set state.
2b. That is,
The side surfaces 41a and 42a of the engagement protrusions 41 and 42 are shown in FIG.
The side surface 42b of the engagement protrusion 42 is provided on the flat end surface 22a of the block 20R on the right side, and the engagement protrusion 43 is provided on the outer peripheral cylindrical surface 22b of the block 20L on the left side shown in FIG. The side surfaces 43a and 44a of the 44 are in close contact with the outer peripheral cylindrical surface 22b of the block 20R on the right side in the figure, and the side surface 43b of the engaging projection 43 is in close contact with the flat end surface 22a of the block 20L on the left side in the figure. Have been.

As a result, as shown in FIG. 2, the flat end faces 22a come into contact with each other in an expanded state, and a pair of blocks adhered to the bottom face 10a of the device 10 by the pressure of the excavated earth and sand. 20R ・ 20L
However, the blocks 20R and 20L are rotated by the excavation resistance or the vibration caused by the impact applied by the hammer, and rotate in the direction indicated by the arrow in FIG. Flat end face 22a
And the outer peripheral cylindrical surface 22b respectively
The pair of blocks 20R and 20L cannot be reduced in diameter because they are locked by the side surfaces of 42, 43 and 44. Therefore, during excavation work, the pair of blocks 20R
-It is possible to prevent the diameter of the 20L from being reduced so that the earth and sand cannot be excavated.

On the other hand, when the operator lifts the device 10 when the excavation operation is completed, the pressure of the earth and sand to be excavated does not act on the pair of blocks 20R and 20L. Are no longer biased toward the bottom surface 10a of the device 10. In addition to this, as shown in FIG.
Since the 0 shaft portion 21 is fixed so as to be displaceable in the axial direction in the insertion hole 11 of the device 10 by the locking pin 17, the pair of blocks 20 </ b> R and 20 </ b> L each have its own shaft portion 21 due to its own weight. The device 10 can be displaced so as to get out of the insertion hole 11 of the device 10 and can be separated from the bottom surface 10 a of the device 10. When the pair of blocks 20R and 20L is separated from the bottom surface 10a of the device 10, the pair of blocks 20R and 20L and the device 1
0, the engagement projections 41.4 projecting from the bottom surface 10a.
The engagement with 2.43.44 is released.

Therefore, when the device 10 is rotated in the anti-digging direction while the device 10 is pulled up,
The pair of blocks 20R and 20L, which have been disengaged from the engagement protrusions 41, 42, 43 and 44, rotate around the shaft portion 21 as an axis, and as shown in FIGS. 20L is the engagement protrusion 41, 42, 43
-The diameter is reduced by riding on 44.

On the other hand, when the hammer cylinder and the hammer are operated by inserting the excavating tool 100 of the present embodiment in the reduced diameter state into the excavating pipe 30, the compressed air discharged when the hammer falls falls on the device 10. The block 20R is provided through the provided air holes 15a, 15b, and 15c.
It blows out between 20L and the bottom surface 10a of the device 10.
As a result, soil and the like that have entered between the blocks 20R and 20L and the bottom surface 10a of the device 10 are removed, so that the blocks 20R and 20L are in an expanded state and are prevented from being in close contact with the bottom surface 10a of the device 10. There is no. Therefore, the block 20R ・ 2 in the expanded state
0L surely contacts the bottom surface 10a of the device 10 and securely engages with the engaging projections 41, 42, 43, 44.

In this embodiment, the device 10
Of the bottom surface 10a, the block 20R in an expanded state
The engagement protrusion 41
Since the 42, 43, and 44 are provided, it is possible to maximize the contact area between the blocks 20R and 20L in the expanded state and the bottom surface 10a of the device 10, and thus the blocks 20R and 20L and the device 10 can be used during excavation. The contact surface pressure of the device 10 can be reduced, and the durability of the blocks 20R and 20L and the device 10 can be improved. However, there is no need to be limited to this. For example, a concave portion is formed in the surface of the blocks 20R and 20L that is in close contact with the bottom surface 10a of the device 10, and the blocks 20R and 20L are in an expanded state on the bottom surface 10a of the device 10. Sometimes, an engagement projection may be provided at a position where the engagement projection engages with the recess.

[0018]

According to the drilling tool of the present invention, the shaft portion of the block is slidably fitted in the insertion hole of the device in the axial direction so as to prevent the block from coming off, and is fixed to the bottom surface of the device.
A locking portion is provided to engage the expanded block and prevent the block from rotating in the reduced-diameter direction. It is possible to prevent the block from being reduced in diameter during excavation even when vibration is applied due to the impact of a hammer or a hammer. Therefore, the excavating tool of the present invention does not run idle during excavation, and can excavate earth and sand efficiently.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a bottom surface portion of a device of a drilling tool according to the present invention.

FIG. 2 is a front view illustrating a state in which a block of the excavating tool shown in FIG. 1 is expanded in diameter.

FIG. 3 is a front view illustrating a state in which a block of the excavating tool shown in FIG. 1 is reduced in diameter.

4 is a sectional view taken along the line IV-IV shown in FIG.

FIG. 5 is an overall vertical sectional view of a conventional excavation tool.

6 is a front view illustrating a state where a block of the excavating tool shown in FIG. 5 is expanded in diameter.

7 is a front view illustrating a state where the diameter of the block of the excavating tool shown in FIG. 5 is reduced.

FIG. 8 is a perspective view for explaining the operation of the excavating tool shown in FIG.

[Explanation of symbols]

 Reference Signs List 10 device 10A small diameter portion 10B large diameter portion 11 insertion hole 12 spline groove 13 flange 14 discharge groove 15a air hole 15b air hole 15c air hole 15d exhaust port 17 locking pin 20 block 20R block 20L block 21 shaft portion 22 body portion 22a flat End face 22b Outer cylindrical surface 23 Bit 30 Drilling pipe 41 Engagement projection 42 Engagement projection 43 Engagement projection 44 Engagement projection 90 Conventional excavation tool 100 Excavation tool according to the present invention

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuyoshi Yoshida 1528 Nakashinda, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture Mitsubishi Materials Corporation Gifu Works (56) References JP-A-5-71288 (JP, A) JP-A-5-65787 (JP, A) JP-A-4-169692 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E21B 10/32

Claims (1)

(57) [Claims] 1. A device receiving an impact force of a hammer and a rotational force of a hammer cylinder, and a pair of insertion holes formed symmetrically with respect to the center of a bottom surface of the device on the front side in the excavation direction. A pair of blocks each having a shaft portion fitted into the shaft portion and a substantially semicircular main body portion fixed to the shaft portion, wherein the pair of blocks have the shaft portions fitted into insertion holes of the device, respectively. Sometimes, the flat end faces of the main body portion are made to face each other, and the device is rotated around its axis portion as an axis due to digging resistance with earth and sand along with the rotation of the device, and the device is moved in the digging direction. When rotating, the flat end faces of the main body part abut each other with a part of the main body part protruding radially outward from the outer peripheral surface of the device. The main body portion is biased to the shaft portion so that when the device is rotated in the anti-digging direction, the main body portion is in a reduced diameter position located radially inward of the outer peripheral surface of the device. An excavating tool that is attached with a center, wherein a shaft portion of the block is slidably fitted in an insertion hole of the device in an axial direction so as to prevent the block from coming off, and the block, which is in a state of expanded diameter, is formed on a bottom surface of the device. An excavating tool is provided with a locking portion that engages with the block to prevent the block from rotating in the direction of the reduced diameter.