JPH0312639B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an excavation head in trenchless pipe burying method.

[Conventional technology]

2. Description of the Related Art Trenchless burying methods have been known for burying relatively small-diameter pipes such as gas pipes and water pipes on roads with heavy traffic or in urban areas. This construction method generally involves laying a pilot pipe from a starting shaft to a destination shaft, and then sequentially burying the main pipe along the pilot pipe while enlarging the hole with a drilling head.

Various types of excavation heads have been known in the past, and the present inventor has previously proposed a new excavation head in Japanese Patent Application Laid-Open No. 11298/1983. This drilling head is connected to the tip of the pilot pipe that has penetrated to the arrival shaft, and is designed to drill to expand the hole while being drawn toward the starting shaft through the pilot pipe. In addition to having bits,
A discharged soil intake port is formed near the bit, and is rotatably connected to a subsequent buried pipe. The soil excavated by the bit is taken into the head through the inlet and sent out to the outside.

Furthermore, when excavating soft ground with this type of excavation head, there is a risk that too much surrounding soil will be taken into the head body, causing the soil wall to collapse. In order to solve these problems, the present inventors proposed a structure for an excavation head that can optimize the intake and discharge of excavated soil, in Japanese Patent Laid-Open No. 118998/1983, in which the excavated soil taken into the head from the excavated soil intake port is By using a screw rod to send out the soil in the direction of the pilot pipe, and controlling the number of revolutions of the screw rod according to the properties of the ground, the soil is compacted inside the head body, which allows it to flow into the head body. proposed a system that would regulate the amount of waste soil taken in.

[Problem that the invention seeks to solve]

However, the drilling head as described above is
During this time, some of the large and small gravel contained in the ground gets stuck in the soil intake port of the head, which hinders the subsequent soil intake, resulting in the inability to excavate and a decrease in efficiency. This creates the problem of

In order to solve this problem, the inventors of the present invention, in the above-mentioned JP-A-59-118998 and JP-A-59-118995, provided a hood-shaped bit holding member on the front side of the head body so as to be able to move forward and backward. In addition to providing soil intake ports on the front surface of the material and the head body, protruding members are provided on the front surface of the head body and on the back surface of the bit holding member so as to face these soil intake ports, to prevent gravel from getting caught in the soil intake port. We have proposed an excavation head with a structure in which, when this occurs, the bit retaining member is moved back toward the head body, thereby pushing each protruding member into the opposing earth removal intake port and pushing out the entrapped gravel, etc.

However, subsequent research has shown that with the above structure, even if you try to move the bit holding member to remove gravel, it is difficult to make sudden movements that could crush the gravel due to earth pressure. An extremely large amount of force is required to move the bit, and since both the bit holding member and the head body have soil intake ports, so to speak, it has a double intake structure, so the dirt and sand between the bit holding member and the front of the head body are The soil flow is not good, making it impossible to properly take in waste soil, etc.
It was found that there were various problems.

In addition, with the structure equipped with the screw rod as described above, depending on the ground, mud may flow into the head body from the soil intake port even during suspension of excavation at night, and then flow out to the pilot pipe side. There are problems that arise.

The present invention has been made in view of the above-mentioned conventional problems, and is an object of the present invention to appropriately solve the problem of clogging caused by gravel, etc., being caught in the soil intake port in an excavation head having a screw rod for discharging soil in the head body. The purpose of the present invention is to provide a structure that can appropriately prevent the incorporation of earth and sand when excavation is halted.

[Means to solve the problem]

Therefore, as shown in FIG. 1, the present invention provides a striking member which has a blade-like portion 8 at the tip thereof behind each of the soil intake ports 7 in the head body 1. 2, each of these striking members 2 is held in the air hammer device 3, and furthermore, the screw rod 15 inserted into the cylindrical portion 4 is movable forward and backward, and the end of the screw rod 5 protrudes into the head body 1. Its basic feature is that it is provided with a valve member 6 that can close the open end of the cylindrical portion 4.

[Effect]

In such an excavation head, the striking member 2 behind each soil intake port 7 is retracted to a position where it does not interfere with the intake of soil in a normal excavation state.
During excavation, if foreign matter such as gravel gets caught in the soil intake port 7, the air hammer device 3 is activated to remove the impact member 2.
is reciprocated in the direction of the soil removal inlet, and the blade-shaped part 8 at the tip
Push out or crush the entangled gravel. On the other hand, when the excavation is stopped at night, etc., the screw rod 5 is moved toward the pilot pipe, and its valve member 6 closes the open end 9 of the cylindrical portion 4, so that the excreted soil in the head body is discharged toward the pilot pipe. be prevented from being

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

2 to 5 show one embodiment of the present invention.

The excavating head is composed of a head body 1 and a tube body 100 rotatably connected to the rear part of the head body 1. Note that a pipe to be buried (hereinafter referred to as a buried pipe) is connected to the pipe body 100 by welding or the like.

The head main body 1 has an earth removal port 7 and an excavation bit 10 on its front surface. That is, a slit-shaped soil intake port 7 is provided in the radial direction of the front surface of the head body to take the soil inside the head body 1, and a slit-shaped soil intake port 7 is provided at a position along the discharge soil intake port 7 and each soil discharge port 7 is provided inside the head body 1. A plurality of excavation bits 10 are provided at positions between the soil intake ports 7.

A cylindrical portion 4 is provided in the center of the head body 1. The cylindrical portion 4 has a connecting portion 11 (femally threaded portion) with a pilot tube at its tip and extends into the head body at its rear end. This cylindrical portion 4 is open at both its distal end, which is a connecting portion 11, and its rear end within the head body 1.

A screw rod 5 for transporting soil is rotatably inserted into the cylindrical portion 4, and its tip protrudes into the space S of the head body 1. The other end of the screw rod 5 extends toward the pilot tube to which the cylindrical portion 4 is connected, and is connected to a power transmission rod (not shown) introduced through the pilot tube. This screw rod 5 can move forward and backward within the cylindrical portion 4. space S
A valve member 6 for closing the open end 9 of the cylindrical portion 4 is attached to the end of the screw rod 5 that protrudes inward. That is, a ring-shaped mounting member 12 having a stopper 121 on one end and a threaded portion 122 on the other end is fitted onto the end of the screw rod 5, and a ring-shaped valve member is fitted onto the mounting member 12. 6 is fitted onto the outside and is tightened and fixed by a nut member 13 attached to the threaded portion 122.

Further, the inner surface of the open end 9 of the cylindrical portion 4 to be closed by the valve member 6 is formed into a tapered shape that increases in diameter toward the inside of the head main body, so that the valve member 6 comes into contact with this tapered surface 91. It's getting old.

A ring-shaped bracket 16 is provided inside the approximately central portion of the head body 1 in the longitudinal direction, and a through hole in the bracket 16 is closed with a plate 40. As a result, a closed space S is formed in the front part of the head body 1.

A striking member 2 for crushing foreign matter is arranged behind each soil discharge intake port 7, and this striking member 2 is held by an air hammer device 3. As shown in FIG. 4, the striking member 2 has a blade-shaped portion 8 at its tip that can be inserted into the soil removal port 7. In addition, in order to allow the blade-shaped portion 8 to properly fit into the soil intake port 7, the soil discharge port 7 is configured to be widened toward the inside of the head main body, as shown in the figure. This makes it possible to effectively crush trapped gravel, etc.

The air hammer device 3 may have a conventionally known mechanism, or may have an appropriate mechanism. In this air hammer device 3, a cylinder 15 containing a piston 14 is connected to the head body 1.
A striking member 2 is held at the tip of a working rod 17 which is fixed to a bracket 16 inside and connected to a piston 14.

A stepped portion 151 is formed on the inner surface of the cylinder 15 at an approximately intermediate position in the longitudinal direction, and this stepped portion 151 allows
The inner diameter of the cylinder is enlarged on the rear side. A columnar portion 25 is provided inside the rear end of the cylinder 15 to protrude along the cylinder axis direction. In addition, the stepped portion 151
Air supply ports 19 are connected to air hoses 18a and 18b at the front and back of the cylinder in the longitudinal direction.
a, 19b are provided through the plate. In addition, the diameter of the cylinder tip is expanded to a predetermined length to vent air.
A gap 20 is formed between the piston 14 and the piston 14 described below. An air vent hole 21 communicating with this gap 20 is formed in the cylinder 15. Furthermore, air vent holes 22 are also formed at locations closer to the rear end than the stepped portion 151 .

On the other hand, the piston 14 is configured such that the front end side thereof has a small diameter and the rear end side has a large diameter through an intermediate step section 141 so as to match the inner diameter of the cylinder formed by the front step section 151. An annular groove 23 is formed on the outer periphery of the large diameter portion 142, and an air passage 24 that opens from the annular groove 23 to the stepped portion 141 is formed at a position in the circumferential direction corresponding to the air vent hole 22.

A fitting hole 26 into which the columnar portion 152 is to fit is provided at the rear end of the piston 14.
An air passage 27 extends toward the tip of the piston and branches in the middle, and each branch passage 271 is an annular groove 2 formed on the outer periphery of the tip region of the small diameter portion 143.
It opens at 8.

A working rod 17 is connected to the piston 14,
This rod 17 is slidably supported by a support portion 29 at its intermediate portion. Note that 30 is a key that prevents the working rod 17 from rotating.

In such an air hammer device 3, the supply of air from the air hoses 18a and 18b is alternately switched, and first, when air is supplied from the air hose 18b to the air passage 24 through the supply port 19b, the air flows into the cylinder. 15 stepped portions 151
The piston 14 is moved toward the rear of the cylinder (rod backward), and the columnar part 25 on the cylinder side is deeply fitted into the fitting hole 26, and the air is connected to the annular groove 28 in which the air passage 271 is opened. It communicates with the supply port 19a. Furthermore, when the stepped portion 141 of the piston 14 reaches the position of the air vent 22, the supplied air is discharged from the air vent 27.
Next, when air is supplied into the air passage 27 from the air hose 18a through the supply port 19a, the air hits the head of the columnar part 25 fitted into the fitting hole 26, causing the piston 14 to move toward the front of the cylinder. (rod moves forward), and the columnar portion 25 is removed from the fitting hole 26. When the annular groove 28 communicates with the gap 20, the supplied air is discharged from the air vent 21. When the piston 14 moves toward the front of the cylinder and then moves toward the stepped portion due to reaction, the annular groove 23 is moved again.
and the air supply port 19b communicate with each other, and air is supplied. And, such air supply port 19a,
By alternately switching the air supply from 19b, the piston 14, the working rod 17 integral therewith, and the striking member 2 reciprocate.

In addition, to explain other configurations, a pipe body 10 is connected to the rear part of the head body 1 by a rotary joint 31.
0 is concatenated. That is, at the rear of the head body 1, there is a shaft body 32 having a hollow part 33 with both ends open.
is provided, and this shaft body 32 is pivotally supported within the tube body 100 by a bearing that constitutes a rotary joint.
The head body and the tube body 100 are rotatably connected to each other. On the other hand, from the direction of the tube body 100, the air supply pipe 34 fixed to the tube body 100 is seen from the shaft body 32.
It is guided into the head body 1 through the hollow portion 33 and is held within the head body 1 by a holding member 35 . This air supply pipe 34 is connected to the shaft body 32
A rotary joint 37 is interposed between the holding member 35 and the bearing member 36, which is pivotally supported in the hollow portion 33 by a bearing member 36.
4, the head body 1 can freely rotate with respect to the tube body 100.

Air hoses 18a and 18b are connected to the air supply pipe 34 via an adapter 38.

Next, how to use the excavation head as described above will be explained.

The drilling head of the present invention is attached to the tip of a pilot pipe penetrating from the starting shaft X to the reaching shaft Y, as shown in FIG. 6, and is drawn toward the starting shaft X while drilling to expand the hole. That is, the excavation head is pulled while only the head body 1 is rotated by the pilot pipe which retreats in the direction of the starting shaft while being rotated by the driving force of the drive device 39, and the excavation head is pulled into the ground by the excavation bit 10 on the front side. Drill the hole. The pipe body 100 carries the buried pipe at its rear and follows the head body 1 in a non-rotating state. The buried pipe led to the excavation head is added on the arrival shaft Y side as the head advances, and the burial is completed when the excavation head reaches the starting shaft X side. In addition, in such a pipe burying process, the rear end of the buried pipe RO may be pressed by a pressing device on the reaching shaft Y side to supplement the propulsive force of the buried pipe RO, and the above-mentioned pressing device may also be used. Instead, excavation is performed so that a gap is created between the buried pipe and the earth wall of the excavation hole, and an anti-friction agent is injected into this gap to reduce the peripheral surface resistance with the earth wall. It can be done.

The soil generated by excavation is guided from the soil intake port 7 to the space S in the head body 1, and further into the cylindrical portion 4.
Through the opening of the screw rod 5, the screw rod 5 rotates in the direction opposite to the direction of rotation of the head body by the rotational driving force of the power transmission rod, and the screw is transferred toward the pilot tube. The soil is sent to the pilot pipe by water for transporting the soil that is ejected from an injection nozzle (not shown) provided near the end of the screw. Note that the power transmission rod rotates in the opposite direction to the rotation direction of the pilot tube, and is simply inserted without being held in the pilot tube, so the power transmission rod rotates in the direction of the inner circumference of the pilot tube. This swirling motion causes a stirring effect on the discharged soil, which prevents heavy soil from settling in the pilot pipe, and allows the transportation water to transport the discharged soil extremely smoothly and reliably.

In the course of such excavation, if foreign matter such as gravel gets stuck in the soil intake port 7 and clogs it, the excavation is temporarily stopped and the air hammer device 3 is activated. As a result, the striking member 2 reciprocates in and out of the soil removal intake port 7, and removes foreign matter such as gravel by pushing it out or crushing it with the peripheral edge of the intake port. Thereafter, the air hammer device 3 is stopped at the position where its rod is most retracted, and excavation is restarted, so that the removed soil can be taken in without being hindered by the striking member 2.

On the other hand, when excavating soft ground with a lot of water, etc., and when the work is stopped at night, etc., the screw rod 5 is moved toward the pilot pipe by pulling the power transmission rod, and the valve member 6 is used to close the cylindrical portion 4. The open end 9 of is closed. This appropriately prevents the mud from flowing into the head body from the soil intake port and flowing out to the pilot pipe side during the suspension of excavation.

In addition, in the process of excavating and discharging soil as described above, the excavation head of the present invention can adjust the amount of soil taken in according to the soil quality of the ground to be excavated. That is, the discharged soil enters the cylindrical body 4 from the space S of the head body, and is transferred from there toward the pilot pipe by the screw rod 5. By controlling the rotation speed of the screw rod 5, the discharged soil in the space is This is to make the soil form a compacted state and to regulate the amount of soil taken into the space S. In general, in the case of soft ground such as sand, there is a tendency for too much waste soil to be taken into the space S, causing soil wall collapse and ground subsidence. This reduces the amount of soil taken into the cylindrical portion 4, which brings the soil in the space S into a compacted state and reduces the amount of soil taken in from the soil intake port 7 of the head body. It becomes like this. On the other hand, when the ground is relatively hard, the number of revolutions of the screw rod 5 can be increased to take in the removed earth in a manner that matches the excavation efficiency. In addition, it is preferable that such rotation speed control is performed based on the detection result by the earth pressure detector in the space S.

〔Effect of the invention〕

According to the present invention as described above, it is possible to appropriately and easily eliminate clogging of foreign objects such as gravel in the soil intake port with a small amount of power, to enable smooth excavation work, and to remove dirt and debris during excavation suspension. This has the effect of appropriately preventing the incorporation of.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram of the present invention. 2 to 5 show one embodiment of the present invention, in which FIG. 2 is a longitudinal sectional view, FIG. 3 is a sectional view taken along the line - in FIG. 2, and FIG. 4 is a sectional view in FIG. 5 is a longitudinal sectional view partially showing the air hammer device. FIG. 6 is an explanatory diagram showing the excavation situation by the excavation head of the present invention. In the figure, 1 is the head body, 2 is a striking member,
3 is an air hammer device, 4 is a cylindrical part, 5 is a screw rod, 6 is a valve member, 7 is an earth removal port, 8 is a blade part, 9 is an open end, 10 is an excavation bit, and 11 is a connection part. show.

Claims (1)

[Claims] 1. The head body has an excavation bit and a soil intake port on the front side, has a connection part with a pilot pipe at the tip, and forms a cylindrical part whose rear end side extends into the head body. In the excavation head, in which a screw rod for transferring the soil in the direction of the pilot pipe is rotatably inserted, a blade-like part that can be inserted into the soil intake at the tip is provided at the back of each soil intake. A striking member held by an air hammer device is disposed to allow the screw rod to move forward and backward in the axial direction, and the open end of the cylindrical portion is closed at the end of the screw rod protruding into the head body. 1. An excavation head for use in trenchless construction, characterized by being provided with a valve member for obtaining the excavation head.