JPH10231677A - Excavation tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the abrasion in the front end of a device caused by clashing with the basic end face of a block in an excavation tool making rotational striking excavation by the movable block installed at the front end of the device. SOLUTION: This excavation tool 10 is equipped with a device 2, a shaft hole 2f provided to the front end face 2e of the device and bearing a block shaft 4a in a rotatable manner and a block 4 provided to the front end of the block shaft 4a so that the outside diameter thereof is the approximately small diameter as the inside diameter of a casing covering the circumference of the excavation tool 10 and planting edge bodies 5 on the front end thereof, a relative position of the block shaft 4a to the block 4 is so set that part of the block 4 is projected from the circumferential surface of the casing 3 by specific quantity when the block 4 is projected from the front end of the casing 3 to make excavating rotation. An abrasion prevention device 11 for preventing the abrasion in the front end face 2e with the excavation is provided at the front end face 2e of the device 2.

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. 5 is a partial vertical cross-sectional view of the excavating tool 1 at the time of expanding the diameter.
7 are front views of the excavating tool 1 at the time of diameter reduction and diameter expansion, respectively.

In FIG. 5, 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 tip is enlarged in diameter. It is composed of Device 2
A flow path 2c extends from the shank 2a toward the head 2b. From the tip of this flow path 2c,
A plurality of communication passages 2d are radially extended toward the leading edge of the device 2, and the leading ends of the communication passages 2d are, as shown in FIG. 6 in the direction of arrow X).

[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 2c 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 when viewed from the bottom 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. 5 denotes a stopper mounted around 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 and drills an excavation hole by the rotational force and the impact force applied to the block 4.

Further, as the block 4 is excavated and rotated, the block 4 rotates due to the excavation resistance with the ground, and as a result, as shown in FIGS. 5 and 7, 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. In addition, since the outer peripheral blade A protrudes radially outward from the outer peripheral surface of the casing 3, the casing 3 descends simultaneously with excavation due to its own weight and engagement of the reduced diameter portion 3a and the stopper 6, and falls into the excavation hole. It is inserted so that 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 excavation rotation direction of the individual blocks 4 whose diameters have been 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 case of the above-mentioned excavating tool, the device 2 receives both the vibration of the hammer piston during the excavation and the impact which the block 4 receives as the excavation occurs. As a result, among the devices 2, especially the head 2
There has been a problem that the distal end face 2e of the b is worn due to collision with the base end face of the block 4. Further, the wear of the tip end surface 2e was particularly remarkable on the contact surface with the block 4 on the rear side in the excavation rotation direction from the outer peripheral blade A. The present invention has been made in view of the above circumstances, and has as its object to prevent abrasion of the tip end surface 2e in a drilling tool having the above-described 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; a shaft hole provided at a position offset from the center of the device on the front end surface of the device; And a block provided at the tip of the block shaft so that its outer diameter is substantially the same as the inner diameter of the casing, and a blade body implanted on the tip surface of the block. With the block protruding from the tip of the casing, when the device is rotated in the excavation rotation direction, a part of the block protrudes by a predetermined excavation amount from the outer peripheral surface of the casing. Sea urchin, together with the relative position of the block axis relative to the block is set, the front end surface of the device, and its being provided is abrasion preventing means for preventing the wear of the tip surface due to excavation.

[0014] More preferably, the shaft holes are provided at a plurality of locations on the tip end surface of the device so as to be offset from the center of the device and at equal intervals along the periphery of the device. At the tip of each of the inserted block shafts, the fan-shaped blocks are provided so that their side end faces face each other, and their arc portions are formed to have substantially the same diameter as the inner diameter of the casing as a whole. Projecting from the tip of the casing, and when the device is rotated in the excavation rotation direction, the intersection between one side end surface of the block and the arc portion projects by a predetermined excavation amount from the outer peripheral surface of the casing. The relative position of the block axis with respect to the block is set so that the adjacent side end surfaces abut each other at this time.

On the other hand, as the abrasion preventing means, for example, a chip implanted and fixed on the distal end surface of the device is used. In this case, the tip is located on the back side in the excavation rotation direction from the block protruding from the outer peripheral surface of the casing,
It is desirable to be planted on the contact surface with the block.

Alternatively, the abrasion preventing means may be a cylindrical body inserted and fixed so as to be coaxial with the shaft hole, and a distal end portion thereof may be a flange portion which is flush with a distal end surface of the device.

It is preferable to use shrink fit or press fitting for fixing the abrasion preventing means to the device, and it is preferable to use a cemented carbide as a material of the abrasion preventing means.

[0018]

Embodiments of the present invention will be specifically described below with reference to the drawings. In addition, the present invention is characterized in that in the excavating tool shown in FIGS. 5 to 7 described above, in particular, the tip end face 2e of the device 2 is provided with a wear preventing means for preventing the tip end face 2e from being worn due to excavation. Therefore, the same reference numerals are given to other configurations and operations, and description thereof will be omitted.

One example of a drilling tool according to the present invention is shown in FIGS. In the case of this excavating tool, a plurality of cemented carbide tips (abrasion preventing means) 11 having a columnar shape are implanted on the tip end surface 2 e of the device 2. This chip 11
It is implanted and fixed in the opening formed in the front end face 2e by shrinkage fitting or press fitting, and the front end face is flush with the front end face 2e.

As shown by a symbol R in FIG. 3, the area of the tip 11 to be implanted on the tip surface 2e is the portion where the tip surface 2e is most severely worn by excavation, that is, the outer peripheral edge A of the tip surface 2e. Block 4 on the rear side in the excavation rotation direction
And the contact surface.

In this excavating tool 10, since the tip surface 2e is protected by the tip 11, the tip surface 2e is protected during excavation.
Does not wear the tip end surface 2e even if it collides with the base end surface of the block 4. In particular, since the tip 11 is implanted on the contact surface with the block 4 on the rear side in the excavation rotation direction from the outer peripheral blade A in the tip surface 2e, the abrasion of the tip surface 2e in this portion is particularly effective. Is prevented.

FIG. 4 shows another example of the excavating tool 10 according to the present invention.
Shown in In the case of this excavation tool 10, a cylindrical body (abrasion prevention means) 12 made of cemented carbide having a cylindrical shape and a flange portion 12a formed at one end is formed in the shaft hole 2f. It is coaxial with the hole 2f, and is inserted so that one end surface of the flange portion 12a is flush with the distal end surface 2e. This cylindrical body 12 is fitted with a shaft hole 2f by shrink fitting or press fitting.
The block shaft 4a is rotatably supported in the shaft hole 2f via the tubular body 12.

Also in this excavating tool 10, the tip surface 2e
Is protected by the one end face of the flange portion 12a, so that even if the tip end face 2e collides with the base end face of the block 4 during excavation, the tip end face 2e is not worn. Further, as shown in FIG. 4, it is also possible to prevent the tip surface 2e from being worn by using the cylindrical body 12 and the tip 11 together.

In the above example, when fixing the chip 11 and the cylindrical body 12 to the head 2b, instead of using brazing or screwing, shrink fit or press fitting is used because the head 2b is thermally deformed when brazing. This is because screws may loosen due to vibration during excavation.

[0025]

As described above, according to the present invention, the tip end face of the device is provided with the wear preventing means, so that the tip end face of the device is protected by the wear prevention means. Wear of the distal end surface due to collision between the distal end surface and the proximal end surface of the block 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 of an example of the excavation tool according to the present invention when the diameter of the excavation tool is increased.

FIG. 5 is a partial vertical cross-sectional view of an example of a conventional drilling tool when the diameter of the drilling tool is expanded.

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

FIG. 7 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 Tip (blade body) 11 Tip (anti-abrasion means) 12 Cylindrical body (meaning prevention means) 12a Flange part X Excavation rotation direction R Chip implantation area

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

Claims (7)

[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 shaft hole provided at a position offset from the center of the device on a distal end surface of the device, and a block shaft rotatably supported in the shaft hole, A block provided at the distal end of the block shaft such that the outer diameter thereof is substantially the same as the inner diameter of the casing, and a blade body implanted on a distal end surface of the block; When the device is rotated in the excavation rotation direction, a part of the block protrudes from the outer peripheral surface of the casing by a predetermined excavation amount so as to project from the outer peripheral surface of the casing. Drilling tool with relative position is set for the block axis, the end surface of the device, wherein the abrasion prevention means is provided for preventing the wear of the tip surface due to excavation that. 2. The excavating tool according to claim 1, wherein the attrition preventing means is a tip implanted and fixed on a tip surface of the device. 3. The chip mounting area according to claim 2, wherein the chip is implanted in a contact surface with the block on the rear side in the excavation rotation direction from the block protruding from the outer peripheral surface of the casing. Drilling tools. 4. The wear preventing means is a cylindrical body inserted and fixed so as to be coaxial with the shaft hole, and a distal end portion thereof is a flange portion coplanar with a distal end surface of the device. The excavating tool according to claim 1, 2 or 3, wherein: 5. The excavating tool according to claim 2, wherein the attrition preventing means is fixed to the device by a method selected from shrinkage fitting and press fitting. 6. The excavating tool according to claim 2, wherein said wear preventing means is made of a cemented carbide. 7. The device according to claim 7, wherein the shaft hole is provided on a tip surface of the device.
Offset from the center of the device, and provided at a plurality of locations so as to be at equal intervals along the circumference of the device, at the tip of the block shaft inserted into each of the shaft holes, the fan-shaped block, each side When the end faces are opposed to each other, and the arc portion is provided so as to have substantially the same diameter as the inner diameter of the casing as a whole, the block is projected from the tip of the casing, and when the device is rotated in the excavation rotation direction, The block shaft with respect to the block so that an intersection between one side end surface of the block and the arc portion protrudes from the outer peripheral surface of the casing by a predetermined excavation amount, and at this time, the adjacent side end surfaces abut each other. The excavating tool according to any one of claims 1 to 6, wherein a relative position is set.