JP2002061482A - Excavation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excavation device of a structure capable of reliably holding the state of the enlarged diameter of enlarging/contracting bits. SOLUTION: A fixed-diameter preceding bit 7 which precedes the enlarging/ contracting bit 6 and enlarging/contracting bit 6 enlarged and contracted in the radial direction by rotating about the axis which intersects the axis of excavation is provided with a bit assembly 3 pivoted at a main shaft 5, used for impact-type excavation to exert a striking force and excavate by an impact- type excavator and a down-the-hole hammer, and provided with both a rear shaft 8 of which the movement is interlocked with movements in the direction and reverse direction of excavation and a sandwiching mechanism provided at a section opposite to the rear shaft 8 and the enlarging/contracting bits 6 to enlarge and contract the enlarging/contracting bits 6 by sandwiching and releasing the enlarging/contracting bits 6 by the movements of the rear shaft 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excavator used for a boring method using an impact excavator or a down-the-hole hammer.

[0002]

2. Description of the Related Art In a drilling apparatus used in the above-mentioned boring method, an expansion / contraction bit is provided at the tip of a drill rod, and the diameter of the expansion / contraction bit is increased. Is being done.

[0003] As a drilling device provided with such an expansion / contraction bit, Super Mex Bit (trade name: manufactured by Mitsubishi Materials Corporation) is known. Such a technique is disclosed in Japanese Patent Application Laid-Open Nos. 62-133284 and 2-1.
No. 6286.

[0004] The Super-Mex bit switches the expansion and contraction of the expansion and contraction bit by rotating the drill rod in the forward and reverse directions. In Japanese Patent Application Laid-Open No. 62-133284, a substantially diamond-shaped blade is pivotally supported at the tip of a drill rod. When the drill reaches the bottom of the prepared hole, the blade is rotated to perform drilling. The pilot hole is enlarged. This Japanese Patent Laid-Open No. 2-1
In Japanese Patent No. 6286, the diameter of the expansion / contraction bit is increased by rotating the drill rod in the forward direction, and the diameter is reduced in synchronization with the lifting of the drill rod.

[0005]

However, in any of the above-mentioned prior arts, it is difficult to reliably expand the diameter of the expansion / contraction bit, and there is a problem that the diameter of the expansion / contraction bit is reduced during excavation. In addition, there is a problem that excavated waste such as earth and sand enters the inside of the expansion / contraction bit, and when the diameter of the reduced diameter bit is reduced, the excavated waste is compacted and the diameter cannot be reduced. In addition to the above, in the above-mentioned Super Mex bit, since the diameter of the expansion / contraction bit is reduced by the reverse rotation of the drill rod, there is a problem that the screw of the drill rod is loosened and falls into the drilled hole.

The present invention has been made in view of such a conventional problem, and it is possible to reliably maintain the expanded state of the expansion and contraction bit, thereby enabling excavation to be performed smoothly. It is an object to provide a drilling rig. It is another object of the present invention to provide an excavator capable of smoothly switching an expansion bit from a diameter-expanded state to a diameter-reduced state.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, an invention according to a first aspect of the present invention is directed to an enlargement / reduction bit which expands and contracts in a radial direction by rotating about an axis crossing an excavation axis. A device used for impact-type excavation, in which a leading bit having a fixed diameter is provided with a bit assembly supported by a main shaft, and an impact-type excavator excavates by applying a striking force with a down-the-hole hammer while entraining a casing outside the bit assembly. A rear shaft that moves in conjunction with the movement in the excavation direction and in the opposite direction, and is provided at a position opposite to the rear shaft and the expansion / contraction bit, and performs the clamping and release of the expansion / contraction bit by the movement of the rear shaft. A pinching mechanism that expands and contracts the expansion / contraction bit so that when moved in the excavation direction, the expansion / contraction bit is Increased diameter, scaled bit when moving in the direction of excavation and reverse direction, characterized in that diameter smaller than the inner diameter of the casing.

In the present invention, when the rear shaft moves in the excavation direction, the clamping mechanism clamps the expansion / contraction bit to expand the diameter of the expansion / contraction bit. As described above, in the structure in which the diameter is increased by the mechanical clamping force, the expanded state can be firmly maintained. Also, when the rear shaft moves in the opposite direction, the pinching mechanism releases the pinching of the expansion / contraction bit, thereby reducing the diameter of the expansion / contraction bit. Therefore, the enlargement / reduction of the enlargement / reduction bit can be switched by moving the rear shaft, and the enlargement / reduction can be performed smoothly.

Further, the present invention can be used for a wire line method without using a drill rod. In that case, the expansion and contraction of the expansion and contraction bit can be performed smoothly when the wire is wound and suspended.

According to a second aspect of the present invention, in the first aspect of the present invention, the leading bit has a flow path communicating with the inside of the enlarged / reduced bit in the expanded state, and the enlarged / reduced bit from this flow path is provided. And a valve mechanism that can be opened and closed to prevent the flow to the air.

According to the present invention, since the valve mechanism is closed to prevent intrusion of the cutting waste into the expansion / contraction bit, the cutting waste is not compacted when the diameter is reduced. For this reason,
The diameter of the expansion / contraction bit can be reduced smoothly.

According to a third aspect of the present invention, in the first aspect of the present invention, the casing and the expansion / contraction bit are provided with a torque transmission mechanism for mutually transmitting torque. .

As described above, by providing the torque transmitting mechanism between the expansion / contraction bit and the casing, torque can be transmitted through the casing. Therefore, when torque transmission is performed from the drill rod, torque transmission can be performed from both the drill rod and the casing. Thus, the present invention can be applied to excavators having different torque transmission paths. Further, when the casing is used as a medium for transmitting torque, the drill rod does not need to have strength, so that an inexpensive material such as a resin tube can be used, and the weight can be reduced.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the casing is capable of accommodating therein an enlarged / reduced bit having a reduced diameter. It is characterized in that cutting bits prevent entry of cuttings.

According to the present invention, the intrusion of cuttings into the storage space in the casing is prevented, so that the diameter of the expansion and contraction bit in the storage space can be reduced smoothly.

According to a fifth aspect of the present invention, the rear shaft and the expansion and contraction bit, the expansion and contraction bit and the main shaft, and the opposing end surfaces of the main shaft and the preceding bit are in contact with each other, and the striking force is applied. Is transmitted.

In such a structure in which the opposing end surfaces of the members come into contact with each other to transmit the striking force, the striking force does not act on the shaft portion on which the members are pivotally supported. can do.

[0018]

FIG. 1 is a cross-sectional view of an embodiment of the present invention in an enlarged diameter state, and FIG. 2 is a cross-sectional view of a reduced diameter state. The drilling device 1 of this embodiment includes a drill rod 2, a bit assembly 3, and a casing 4.

The drill rod 2 has a hollow cylindrical shape.
Hanging from an excavator on the ground, and screwed in accordance with the excavation depth, they are sequentially connected in the longitudinal direction. A bit assembly 3 is attached to the tip of the drill rod 2.

As shown in FIG. 3, the bit assembly 3 includes a main shaft 5, an expansion / contraction bit 6, a leading bit 7, and a rear shaft 8. Then, the main shaft 5 is connected to the tip of the drill rod 2, the expansion / contraction bit 6 is attached along the longitudinal direction of the main shaft 5, and the leading bit 7 is connected to the tip of the main shaft 5.

As shown in FIG. 4, the main shaft 5 has a long hole 10 for mounting the rear shaft 8, a mounting hole 11 for mounting to the drill rod 2, and a spring mounting hole 12 for an auxiliary spring 13 to be described later. Are sequentially formed in the longitudinal direction. The leading end is a mounting section 14 to which the preceding bit 7 is mounted. As shown in FIG. 4B, a fluid flow path 15 penetrates the main shaft 5 in the longitudinal direction.

As shown in FIGS. 3 and 5, the enlargement / reduction bit 6 is constituted by a pair of bit pieces 6a. The pair of bit pieces 6a is an end (rear end) on the drill rod 2 side.
The tip 36 is embedded in the end (front end) of the leading bit 7 side.

The pair of bit pieces 6a are assembled by inserting the pivot shaft 17 composed of a spring pin into the main shaft 5 and the pair of bit pieces 6a in a state where the assembling flange portions 6c provided in the intermediate portion are overlapped. Can be The pivot shaft 17 intersects with the drill rod 2 at right angles to the drill axis. In the assembled state of the pair of bit pieces 6a,
The bit 6a rotates radially in a certain range around the pivot shaft 17. By this rotation, the expansion / contraction bit 6 expands / contracts in the radial direction. When the diameter of the expansion / contraction bit 6 is increased, FIG.
As shown in FIG. 5, the bit 6 is enlarged larger than the outer diameter of the casing 4, and when the enlarged / reduced bit 6 is reduced in diameter, the casing 4
Smaller than the inner diameter of Due to this diameter reduction, the expansion / contraction bit 6 can be stored in the casing 4 as shown in FIG. Such expansion and contraction is performed by holding the holding projection 6b between the holding pieces 8a of the rear shaft 8 as described later.

A hollow portion 6d is formed on a surface of the pair of bit pieces 6a facing the chip 36, and the above-described auxiliary spring 13 is housed in the hollow portion 6d. When the diameter of the expansion / contraction bit 6 is increased, the hollow portions 6d are separated from each other, so that the gap 19 communicating with the flow path 15 is formed in the expansion / contraction bit 6. In addition,
The auxiliary spring 13 urges the pair of bit sides 6a away from each other, and assists the rotation of the expansion / contraction bit 6 in the radially expanding direction.

The leading bit 7 has a fixed diameter.
As shown in FIG. 7, the tip 20 is embedded in the tip portion. The leading bit 7 is attached to the mounting portion 14 at the tip of the main shaft 5 via the connecting pin 21, so that a drilling hole is drilled prior to the expansion / contraction bit 6. In this way, by providing the leading bit 7, the leading bit 7 performs the main excavation, and the expanding / contracting bit 6 mainly performs the diameter expansion of the excavation hole. Therefore, the burden on the expanding / contracting bit 6 can be reduced. It has become. The leading bit 7 includes
A channel 18 communicating with the channel 15 of the main shaft 5 is formed.

The rear shaft 8 is attached to the tip of the drill rod 2 by screwing. A holding piece 8a for holding the holding projection 6b of the expansion / contraction bit 6 protrudes from the tip of the rear shaft 8. Also, the rear shaft 8
Is mounted with a sliding pin 23 orthogonal to the drilling axis of the drill rod 2, and the sliding pin 23 is slidably inserted into the elongated hole 10 of the main shaft 5. Further, an L-shaped fluid flow path 24 that is continuous in the axial direction and the radial direction is formed inside the rear shaft 8.

A check ball 25 as a valve mechanism is housed in the flow path 18 of the preceding bit 7. The check ball 25 is housed in the flow path 18 so as to be located between the flow path 15 of the main shaft 5 and the connection pin 21 and is movable between them. Further, the diameter of the check ball 25 is larger than the inner diameter of the flow path 15 of the main shaft 5, whereby the flow path 1
5 can be blocked.

As shown in FIG. 8, the casing 4 is formed of a hollow tube, and a plurality of casings 4 are connected in the longitudinal direction by screwing. As shown in FIGS. 1 and 2, the drill rod 2 and the bit assembly 3 are accommodated inside the casing 4. The front end portion of the casing 4 has a torque transmission groove 26 cut out in a rectangular shape in the longitudinal direction.
Are formed. The torque transmission groove 26 fits on the outer surface of the expansion / contraction bit 6, and acts to transmit the rotational torque of the casing 4 to the expansion / contraction bit 6 by this engagement. In addition, in the storage space of the casing 4 in which the bit assembly 3 is stored, the above-described check ball 25 and the expansion / contraction bit 6 prevent intrusion of cuttings (FIG. 1).
And FIG. 2). For this reason, the excavated waste is not compacted in the storage space, and the expansion and contraction bit 6 can be smoothly expanded and contracted.

In such an embodiment, the striking force at the time of digging is changed from the drill rod 2 to the rear shaft 8 → the expansion / contraction bit 6.
The power is transmitted in the order of → the main shaft 5 → the leading bit 7. In this case, the opposite end faces of the rear shaft 5 and the expansion / contraction bit 6 (the end faces of the holding piece 8a and the holding protrusion 6b), the expansion / contraction bit 6
The opposing end face of the main shaft 5 (the end face indicated by reference numeral 27 in FIG. 3) and the opposing end face of the main shaft 5 and the leading bit 7 (the end face indicated by reference numeral 28 in FIG. 3) come into contact with each other. Transmits the impact force. In such a striking force transmission structure, the rear shaft 8,
Since no striking force acts on the shaft support portions of the expansion / contraction bit 6 and the leading bit 7, fatigue breakage of the shaft portion can be prevented.

In the above embodiment, when the drill rod 2 moves in the drilling direction, the rear shaft 8 moves integrally with the drill rod 2 in the same direction. During this movement, the sliding pin 23 is
Slide. Therefore, the rear shaft 8 moves relatively to the main shaft 5. By this movement, the holding piece 8a at the tip portion holds the holding projection 6b of the expansion / contraction bit 6. Thereby, the diameter of the expansion / contraction bit 6 expands in the radial direction.
Excavation is performed to a predetermined depth while entraining the casing 4 with the diameter of the expansion bit 6 expanded.

At the time of this excavation, the drilling fluid supplied to the drill rod 2 is supplied from the fluid passage 24 of the rear shaft 8 to the tip of the preceding bit 7 and is ejected. Excavation waste such as earth and sand generated by excavation is
The check ball 25 abuts on the flow path 15 of the main shaft 5 due to the pressure of the digging dust, thereby closing the flow path 15. For this reason, the cutting waste does not enter the void 19 formed in the enlarged / reduced bit 6 in the enlarged state. Therefore, when the diameter of the reduced diameter bit 6 is reduced, the cutting waste is not compacted, and the diameter of the enlarged / reduced bit can be reduced smoothly. In addition, since such a check ball 25 moves by the pressure of digging waste, it can be formed of a lightweight material such as resin.

On the other hand, when the drill rod 2 moves in the direction opposite to the drilling direction, the rear shaft 8 moves integrally in the same direction. Also at this time, the sliding pin 23 slides in the long hole 10 of the main shaft 5, and the rear shaft 8 moves relatively to the main shaft 5 in the opposite direction. With this movement, the holding piece 8a is separated from the holding protrusion 6b of the expansion / contraction bit 6, so that the holding is released. At this time, the entire bit assembly 3 including the expansion / contraction bit 6 moves in the direction opposite to the excavation direction, and the entire bit assembly 3 is housed in the casing 4 while the diameter of the expansion / contraction bit 6 is reduced. Therefore, the drill rod 2 and the bit assembly 3 can be recovered while the casing 4 remains in the drill hole.

In this embodiment, the rear shaft 8 moves in conjunction with the movement of the drill rod 2 in the drilling direction, the holding piece 8a holds the holding projection 6b, and the expansion bit 6 is mechanically moved. Since the diameter is expanded with a suitable holding force, the expanded state can be reliably maintained. Further, since the diameter of the expansion / contraction bit 6 can be reduced without excavating waste, the diameter can be reliably reduced. Thereby, excavation can be performed smoothly.

Further, since the torque transmission groove 26 formed in the casing 4 can be fitted to the outer surface of the expansion / contraction bit 6 to transmit the torque, the torque can be transmitted from both the drill rod 2 and the casing 4. Thus, the present invention can be applied to excavators having different torque transmission paths. In addition, when the casing 4 is used as a medium for transmitting torque, the drill rod 2 does not need to have strength. Therefore, a low-strength material such as a resin pipe can be used for the drill rod 2. Therefore, it is possible to reduce the cost and weight, and further simplify the excavation work.

The present invention can be variously modified without being limited to the above embodiments. For example, the present invention can also be applied to a wire line method in which the bit assembly 3 is hung by a wire and excavated while being hit. Further, the valve mechanism for securing the diameter of the expansion / contraction bit 6 may be a structure of a check ball 25 such as a spring-biased valve body, and the torque transmission groove 26 of the casing 4 may be omitted.

[0036]

According to the first aspect of the present invention, since the diameter is increased by a mechanical clamping force, the expanded state can be firmly maintained. Also, when moving in the excavation direction,
Since the diameter of the expansion / contraction bit is increased, the expanded state of the expansion / contraction bit can be reliably maintained, and the diameter of the expansion / contraction bit is reduced when the bit is moved in the opposite direction, so that excavation can be performed smoothly.

According to the second aspect of the present invention, since the valve mechanism prevents the cutting waste from entering the expansion / contraction bit, the cutting waste is not compacted when the diameter is reduced, and the diameter of the expansion / contraction bit can be smoothly reduced. It can be carried out.

According to the third aspect of the present invention, torque can be transmitted through the casing. Therefore, when the casing is used as a medium for transmitting torque, the drill rod does not require strength, and is made of an inexpensive material such as a resin pipe. Can be used, and the weight can be reduced.

According to the fourth aspect of the present invention, it is possible to smoothly reduce the diameter of the expansion / contraction bit without excavating debris entering the storage space of the casing.

According to the fifth aspect of the present invention, since a striking force does not act on the shaft portion on which each member is pivotally supported, it is possible to prevent fatigue damage of the shaft portion.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an expanded state according to an embodiment of the present invention.

FIG. 2 is a sectional view of a reduced diameter state in one embodiment of the present invention.

3A and 3B show a bit assembly, wherein FIG. 3A is a cross-sectional view in an expanded state, and FIG. 3B is a cross-sectional view from the side.

FIG. 4 shows a main shaft, (a) is a front view,
(B) is a longitudinal sectional view.

5A and 5B show bit pieces of the scaled bit, FIG. 5A is a front view, and FIG. 5B is a side view.

6A and 6B show a preceding bit, wherein FIG. 6A is a front view and FIG. 6B is a longitudinal sectional view.

FIG. 7 shows a rear shaft, (a) is a longitudinal sectional view,
(B) is a sectional view from the side.

FIG. 8 shows a casing, (a) is a longitudinal sectional view, (b)
Is a sectional view from the side.

FIG. 9 is an end view taken along line LL in FIG. 1;

FIG. 10 is a sectional view taken along line MM in FIG. 1;

FIG. 11A is a bottom view showing a state where the diameter of the expansion bit is enlarged, and FIG. 11B is a bottom view showing the state where the diameter is reduced.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drilling apparatus 2 Drill rod 3 Bit assembly 4 Casing 5 Main shaft 6 Expansion / contraction bit 7 Leading bit 8 Rear shaft 15 Main shaft flow path 19 Void 25 Check ball 26 Torque transmission groove

Claims (5)

[Claims] An expansion / contraction bit that expands / contracts in the radial direction by rotating about an axis that intersects a digging axis, and a bit assembly in which a leading bit of a fixed diameter preceding the expansion / contraction bit is supported by the main shaft. An impact type excavator, a device used for impact type excavation for excavating by applying a striking force by a down-the-hole hammer while entraining a casing outside the bit assembly, wherein the excavator moves in association with the excavation direction and movement in the opposite direction. A rear shaft, and a clamping mechanism provided at a position opposite to the rear shaft and the expansion / contraction bit, for clamping / releasing the expansion / contraction bit by moving the rear shaft, thereby enlarging / reducing the expansion / contraction bit. When the bit expands larger than the outer diameter of the casing and moves in the direction opposite to the Drilling apparatus, characterized in that the diameter smaller than the inner diameter of the ring. 2. The valve according to claim 1, wherein the leading bit has a flow passage communicating with the inside of the enlarged / reduced bit in the expanded state, and an openable / closable valve mechanism for preventing a flow from the flow passage to the enlarged / reduced bit is provided. The excavator according to claim 1, wherein 3. The excavator according to claim 1, wherein the casing and the expansion / contraction bit are provided with a torque transmission mechanism that mutually engages to transmit torque. 4. The casing is characterized in that an enlarged / reduced bit having a reduced diameter can be stored therein, and in this storage space, the intrusion of cuttings is prevented by the valve mechanism and the enlarged / reduced bit. The excavator according to claim 2, wherein 5. The excavation according to claim 1, wherein the rear shaft and the expansion and contraction bit, the expansion and contraction bit and the main shaft, and the main shaft and the preceding bit and the opposite end surfaces of the preceding bit are in contact with each other to transmit a striking force. apparatus.