JPH10238266A - Excavating tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excavating tool which can perform rotationally hitting excavation by means of a movable block set to the distal end of a device, and which can enhance the rectilinearity during excavation. SOLUTION: An excavating tool incorporates a device 2, a plurality of shaft holes 2f formed in a front end face 2e of the device 2, for rotatably supporting block shafts 4a, and blocks 4 supported to front ends of the block shafts 4a and planted at their front ends with blade members 5. Further, the relative position of each block shaft 4a with respect to the associated block 4, is set so that the part of each block 4 is projected by a predetermined length from the outer peripheral surface of a causing 3 when the block 4 projected from the front end of the casing 3 and is rotated for excavation. Further, a columnar protrusion 11 projected from the front end face of each of the blocks 4 and being coaxial with the device 2 when the side end faces of the blocks 4 are made at their proximal end faces into contact with one another, is provided to the front end of each block 4 at the center of the latter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling tool for drilling a drilling hole by rotary impact drilling, and more particularly to a drilling tool having a movable tip.

[0002]

2. Description of the Related Art An example of the above-mentioned excavating tool is shown in FIGS. FIG. 4 is a partial longitudinal sectional view of the excavating tool 1 at the time of diameter expansion, and FIG.
6 and FIG. 6 are front views of the excavating tool 1 at the time of diameter reduction and diameter expansion, respectively.

In FIG. 4, reference numeral 2 denotes a device. The device 2 includes a shank 2a supported coaxially with the tip of an air hammer (not shown), and a head 2b whose diameter is increased at the tip. It is composed of Device 2
A flow path 2c extends from the shank 2a toward the head 2b. A plurality of communication paths 2d extend radially from the distal end surface of the flow path 2c toward the distal end edge of the device 2, and the distal ends of the communication paths 2d have individual diameters that are enlarged as shown in FIG. The block (to be described later) is open to the front in the excavation rotation direction (the direction of the arrow X in FIG. 5).

[0004] Reference numeral 3 denotes a cylindrical casing, and the device 2 is inserted into the casing 3 so as to be coaxial. Here, the inner diameter of the casing 3 is substantially the same as the outer diameter of the head 2b. As a result, a space H is formed between the outer peripheral surface of the shank 2a and the inner peripheral surface of the casing 3.

On the other hand, a plurality of (three in the figure) shaft holes 2f are provided on the tip end surface 2e of the head 2b so as to be offset from the center of the head 2b and at equal intervals along the circumference of the head 2b. I have. In each of the shaft holes 2f, a block shaft 4a is supported so as to be rotatable and prevented from coming off, and a block 4 of the same shape that forms a fan shape in end view is provided at the tip of each block shaft 4a. The side end surfaces 4b and 4c are opposed to each other, and the arc portion 4d is disposed so as to have substantially the same diameter as the head 2 as a whole. Further, a plurality of tips (blades) 5 made of cemented carbide are implanted on the tip end surface and a part of the outer peripheral surface of the block 4.

Here, the block shaft 4 with respect to the block 4
The relative position of “a” is such that when the block 4 is protruded from the tip of the casing 3 and the excavating tool 1 is rotated in the excavation rotation direction, the block 4 is rotated by the excavation resistance with the ground to be excavated, and the block 4 is rotated. The intersection of one side end surface 4b and the arc portion 4d protrudes from the outer peripheral surface of the casing 3 by a predetermined excavation amount, and at this time, the adjacent side end surfaces 4b and 4c of each block 4 are set to abut each other. Have been.

The side surface of the head 2 is bent radially inward of the communication passage 2d radially outward and forward of the excavation rotation direction, and as a result, the side surface of the head 2 and the casing 3
A gap S communicating with the space H is formed at this portion between the inner peripheral surface and the inner peripheral surface.

On the other hand, reference numeral 6 in FIG. 4 denotes a stopper mounted on the outer peripheral surface of the head 2b. The stopper engages with the reduced diameter portion 3a formed at the distal end of the casing 3 from the base end side to support the casing 3 and press the casing 3 in the distal direction during excavation.

At the time of excavation, first, the block 4 is projected from the tip of the casing 3 in the state shown in FIG.
Next, the rod (not shown) connected to the proximal end side of the air hammer is rotated to move the device 2 and the block 4 to each other as shown in FIG.
While rotating in the direction of the middle arrow X, compressed air is supplied to the air hammer, a hammer piston (not shown) in the air hammer is moved up and down, and this vibration is transmitted to the block 4 via the device 2. Then, as a result, the tip 5 excavates the ground by the rotational force and the impact force applied to the block 4, and the excavation hole is drilled.

Further, as the block 4 is excavated and rotated, the block 4 rotates on its own due to the excavation resistance against the ground. As a result, as shown in FIGS. 4 and 6, one side end face 4b of the block 4 and the arc portion are formed. The intersection with 4d protrudes from the outer peripheral surface of the casing 3 by a predetermined excavation amount, and excavates the hole wall of the excavation hole as the outer peripheral blade A. Moreover, since the outer peripheral blade A protrudes radially outward from the outer peripheral surface of the casing 3, the casing 3 descends into the excavation hole at the same time as excavation due to its own weight and engagement between the reduced diameter portion 3a and the stopper 6, As a result, collapse of the hole wall is prevented.

On the other hand, the earth and sand generated as a result of the excavation are stored in the excavating rotation direction of the individual blocks 4 whose diameters are increased, respectively. In this portion, as shown in FIG. An opening is formed, and a gap S is formed radially outward and forward. Also, with the start of excavation,
Compressed air is supplied to the flow passage 2c, and the compressed air is further injected into the borehole from the communication passage 2d. As a result, the earth and sand generated as a result of the excavation is transferred into the space H through the gap S together with the compressed air injected from the communication passage 2d, rises in the space H, and is discharged from the upper end of the casing 3 to the ground. You.

[0012]

By the way, in the above-mentioned excavating tool 1, the straightness of the tool is low because the tip surface of the block 4 is the same surface, and therefore, as shown by the symbol O in FIG. If an obstacle such as a hard rock exists on the tip side of the peripheral portion of the block 4, the outer peripheral surface of the block 4
4 is displaced to the side avoiding the obstacle O while rubbing on the side surface, and as a result, as shown by an arrow B in FIG. The present invention has been made in view of the above circumstances, and has as its object to improve the straightness of a drilling tool having the above basic structure.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a drilling tool for drilling a drilling hole which is installed at the tip end of a rod coaxially inserted into a cylindrical casing, and which drills a drilling hole through a hammer. A device that is supported by the tip of the rod and receives the impact force and the rotational force of the hammer; and a plurality of devices that are provided on the tip surface of the device at equal intervals along the circumference of the device, offset from the center of the device. And the shaft hole of
A block shaft rotatably supported in each of the shaft holes, a plurality of blocks provided at the distal ends of the block shafts, and a blade body implanted at the distal end surfaces of the blocks; , A pair of left and right side end faces,
It forms a fan shape consisting of an arc portion sandwiched between these side end faces,
When the block is protruded from the tip of the casing, and the device is rotated in the excavation rotation direction, the intersection between one side end surface of the block and the arc portion is a predetermined excavation amount from the outer peripheral surface of the casing. And at the same time, the relative position of the block shaft with respect to the block is set such that the adjacent side end surfaces abut against each other, and a protrusion protruding from the front end surface of the block at the center of the front end of the block. A portion is formed, and the protrusion is formed in a columnar shape coaxial with the device as the side end surfaces of the block come into contact with each other.

Here, it is also possible to form a new protruding portion protruding from the front end surface of the protruding portion at the center of the protruding portion. Further, a ridge of the protruding portion may be chamfered.

On the other hand, the diameter of the columnar projection is:
It is desirable that the distance be within a range of 8 to 35% of a maximum outer diameter of the block when the side end surfaces of the block are brought into contact with each other.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. The present invention is characterized in that, in the excavating tools shown in FIGS. 4 to 6, particularly, the shapes of the devices 2 and the blocks 4 are partially changed. Therefore, members having the same configuration as the excavation tool shown in FIGS. 4 to 6 are denoted by the same reference numerals, and description of the configuration and operation will be omitted.

An example of the excavating tool 10 according to the present invention is shown in FIGS. In the case of this excavating tool 10, the block 4
A protruding portion 11 protruding from the front end surface of the block 4 is formed integrally with the block 4 at the center of the front end. Like the block 4, the protrusions 11 have the same shape as a fan when viewed from the end face, and the front end face 11 a is parallel to the front end face of the block 4.

Along with the formation of the projecting portion 11, a step 11b is formed between the tip end surface of the block 4 and the tip end surface 11a of the projecting portion 11. An inclined surface 11c formed by chamfering a ridge is formed. Further, the tip 5 is planted on the tip end surface 11a and a part of the inclined surface 11c.

In addition, as shown in FIGS. 1 and 3, the projecting portions 11
With the contact between the side end surfaces 4b and 4c, the projecting position is set so as to form a columnar shape coaxial with the device 2. In this case, it is desirable that the diameter of the columnar projecting portion 11 be in the range of 8 to 35% of the maximum outer diameter of the block 4 when the side end surfaces 4b and 4c are brought into contact with each other. This is because when the diameter of the protrusion 11 is out of the above range,
This is because the protrusion 11 becomes too small (or too large), and the pilot effect at the time of excavation by the protrusion 11 decreases.

On the other hand, from the end face of the flow path 2c, the communication path 2
g extends on the axis of the device 2 toward the distal end surface 2 e of the device 2. In addition, the block 4 and the protrusion 11
As shown in FIG. 3, the side end faces 4b, 4
Notches 13 are formed in the central portions of the block 4 and the protruding portion 11 to form the opening 12 communicating with the communication passage 2g with the contact between the members c.

At the time of excavation, the block 4 is projected from the tip of the casing 3 in the state shown in FIG.
Then, the block 4 is rotated in the direction of arrow X in FIG. 2 and the block 4 is vibrated up and down. Then, the tip 5 excavates the ground by the resulting rotational force and impact force, and the excavation hole is drilled.

In addition, the block 4 rotates in accordance with the excavation rotation of the block 4, and as a result, as shown in FIGS. 1 and 3, the end surface of the block 4 protrudes from the outer peripheral surface of the casing 3 by a predetermined amount. Excavate the hole wall of the hole. Furthermore,
The casing 3 descends simultaneously with the excavation and is inserted into the excavation hole, so that collapse of the hole wall is prevented.

On the other hand, the sediment produced as a result of the excavation
Into the space H through the gap S together with the compressed air injected from the front end of the block 4 through the communication passage 2d and the compressed air injected from the front end of the protruding portion 11 through the communication passage 2g and the opening 12 from the flow passage 2c. It is transferred, rises in the space H,
It is discharged from the upper end of the casing 3 to the ground.

Further, in this excavating tool 10, the block 4
A projecting portion 11 projecting from the tip end surface of the block 4 is formed at the center of the tip of the block 4.
Has a cylindrical shape coaxial with the device 2 as the side end surfaces 4b and 4c abut against each other. Therefore, during excavation, the projecting portion 11 exerts a pilot effect, and the straightness of the tool is improved. In particular, as shown by reference numeral O in FIG. 1, when an obstacle exists on the distal end side of the peripheral portion of the block 4, in addition to the pilot effect, the presence of the preceding protrusion 11 hinders the obstacle. The displacement of the block 4 to the side avoiding O is prevented, and as a result, the bending of the borehole is prevented.

Moreover, the front end face of the block 4 and the step 11b
In the corner portion (C in FIG. 1), the ground becomes brittle due to the excavation by the preceding projecting portion 11. Therefore,
Excavation of the ground by the block 4 in the corner portion C is facilitated, and the excavation efficiency is improved.

In order to further improve the straightness of the tool, a further protruding portion 1 is provided at the center of the distal end surface 11a of the protruding portion 11.
As a result, it is also possible to provide a plurality of protrusions 11 whose diameter gradually decreases toward the distal end side over a plurality of steps at the distal end of the block 4.

[0027]

As described above, according to the present invention, a columnar projection coaxial with the device is provided at the center of the front end of the block when the side end surfaces of the block come into contact with each other. The protrusion exerts a pilot effect to improve the straightness of the tool. In particular, in the case where an obstacle exists on the peripheral edge front side of the block, in addition to the pilot effect, the presence of the preceding protrusion hinders the block from shifting to the side avoiding the obstacle, As a result, bending of the excavation hole is prevented.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing an example of a drilling tool according to the present invention when the diameter of the drilling tool is expanded.

FIG. 2 is a front view of the example of the excavating tool according to the present invention when the diameter of the excavating tool is reduced.

FIG. 3 is a front view showing an example of a chip implantation range in the excavation tool according to the present invention when the diameter of the excavation tool is expanded.

FIG. 4 is a partial vertical cross-sectional view showing an example of a conventional drilling tool when the diameter of the drilling tool is expanded.

FIG. 5 is a front view showing an example of a conventional drilling tool when the diameter of the drilling tool is reduced.

FIG. 6 is a front view showing an example of a conventional drilling tool when the diameter of the drilling tool is expanded.

[Explanation of symbols]

 1,10 Excavation tool 2 Device 2e Tip surface of device (head) 2f Shaft hole 3 Casing 4 Block 4a Block shaft 4b, 4c Side end surface of block 4d Arc portion of block 5 Chip (blade) 11 Projection 11a Projection 11a Tip surface 11c Inclined surface X Excavation rotation direction

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhiro Takagi 1528 Nakashinden, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture Gifu Works, Mitsubishi Materials Corporation

Claims (4)

[Claims] 1. A drilling tool that is installed at the tip end of a rod inserted coaxially into a cylindrical casing and drills a drill hole, supported by a tip of the rod via a hammer, A device that receives the impact force and the rotational force of the hammer, a plurality of shaft holes that are provided on the tip end surface of the device and that are offset from the center of the device and that are provided at equal intervals along the periphery of the device; A block shaft rotatably supported on each of the blocks, a plurality of blocks respectively provided at the ends of the block shafts, and a blade body implanted on the end surfaces of these blocks. When the device is rotated in the excavation rotation direction, the block has a fan shape composed of an arc portion sandwiched between these side end surfaces, and the block protrudes from the tip of the casing. The block with respect to the block, such that an intersection of one side end surface and the arc portion of the block projects by a predetermined excavation amount from the outer peripheral surface of the casing, and at that time, the adjacent side end surfaces contact each other. Along with setting the relative position of the shaft, a projecting portion projecting from the tip surface of the block is formed at the center of the tip of the block, and this projecting portion is brought into contact with the side end surfaces of the block, A drilling tool having a cylindrical shape coaxial with the device. 2. The excavating tool according to claim 1, wherein a new protruding portion protruding from the front end surface of the protruding portion is formed at the center of the front end of the protruding portion. 3. The excavating tool according to claim 1, wherein a ridge portion of the projecting portion is chamfered. 4. The method according to claim 1, wherein a diameter of the columnar projecting portion is within a range of 8 to 35% of a maximum outer diameter of the block when the side end surfaces of the block are brought into contact with each other. The excavating tool according to claim 1, 2 or 3, wherein: