JPS629436Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an improvement of the excavation head in the horizontal long-distance excavation method.

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 passing 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, and the inventor of the present invention previously proposed a new excavation head in Japanese Patent Application No. 56-106290 (Japanese Unexamined Patent Publication No. 58-11298). It was done. This equipment consists of a hole-expanding bit and a pipe body connected to the rear part of the bit via a swivel joint, and also has a soil intake inlet near the hole-expanding bit, and the soil excavated by the bit is transferred to the intake port. The pipe is taken into the head and sent out in the direction of the buried pipe connected to the rear part.

However, upon further study, it was discovered that such a drilling head also has one drawback. That is, especially in the case of soft ground, if the excavation head rotates too slowly, too much surrounding soil may be taken in, causing ground subsidence, or if the excavation head rotates too quickly, there is no room to take in the removed soil. On the other hand, there is a problem where the soil surface rises and falls. For this reason, it is necessary to control the rotational speed of the excavation head according to the soil quality, soil pressure, etc., but this significantly reduces work efficiency.

The present invention was devised to improve these conventional disadvantages, and aims to provide an excavation head that can appropriately control the amount of soil taken in and perform efficient excavation. be.

For this reason, the present invention provides a connecting member having a connection part with the pilot tube at its tip in the radial center of the hole-expanding bit, which is hollow inside, and makes the connecting part protrude from the front surface of the hole-expanding bit. At the same time, the rear end side portion is located in the hollow part of the hole expansion bit, and an injection channel is formed inside the connection member from the connection part to an intermediate position in the longitudinal direction, and from the terminal end of the injection channel to the connection member. A rod slide hole communicating with the injection channel is formed toward the rear end, into which a rod having a large diameter portion at one end is slidably inserted. A spring is inserted into the rod portion, each end of which engages with the large diameter portion and the engaging portion inside the rear end of the connecting member, and the other end of the rod protruding from the rear end of the connecting member has an expanded An arm extending in the front direction of the hole bit is fixed, and a discarded soil intake amount adjusting valve is provided at the tip of the arm so as to be located inside the discarded soil intake port, and the connecting member has an expanded hole. A water injection hole is provided that communicates the inside of the bit with the water injection channel, and the water injection channel has a space between its terminal end and the opening position of the water injection hole.
A spacer having a through hole is disposed, and a valve to close the through hole is provided at a position on the rear end side of the connecting member of the spacer, and a spring that presses the valve from the rear end side of the connecting member to the through hole forming part. Its basic feature is that

An embodiment of the present invention will be described below with reference to the accompanying drawings. First, in FIG. It is composed of a tube body 3 and these are connected via a swivel joint mechanism 4.

This swivel joint mechanism 4 includes a boss 5 whose one end is fixed in the hole expansion bit 2, radial ball bearings 7 and 8 that are provided in the housing 6 of the tube body 3 and pivotally supports the boss 5, and a taper roll. The hole expanding bit 2 is rotatable with respect to the housing 6 about the boss 5.

Further, in FIG. 1, reference numeral 11 denotes a soil discharge pipe, and this discharge pipe 11 is inserted through the center of the hole in the boss 5 from the inside of the hole expansion bit 2 via the bush 12, and is inserted through the pipe body 3 into the soil to be buried. Extends in the direction of the tube. The hole enlarged bit side and the pipe body side of the discharge pipe 11 are each bent downward, and a connecting pipe 13 is provided on the pipe body side, and a jet pump (not shown) is connected to the connecting pipe 13.

The front surface of the hole expanding bit 2 is marked with figures 2 and 3.
As shown in the figure, multiple bits are provided.
In addition, a discharged soil intake port 15 is formed near this bit.

A connecting member 16 is provided at the center in the radial direction of the hole expanding bit 2. The connecting member 16 has a concave portion 17 formed at its tip to connect to the pilot tube. A thread is formed on the inner surface of the recess 17 to engage with a thread on the outer peripheral surface of the pilot tube.

The connecting member 16 has a connecting portion formed by the recess 17 protruding from the front surface of the hole expanding bit, and a rear end portion thereof is located within the hollow portion of the hole expanding bit 2. Further, an injection channel 18 is formed inside the connecting member 16 from the recess 17 side to an intermediate position in the longitudinal direction, and communicates with the injection channel 18 from the terminal end of the injection channel 18 to the rear end of the connecting member 16. A rod slide hole 36 is formed.

In addition, the rod insertion hole 1 is provided at the rear end of the connecting member body.
A spring retaining screw 19 having a diameter of 91 is screwed into the spring retaining screw 19, and its inner end surface is connected to the spring engaging portion 3 described below.
7.

In the rod slide hole 36, a large diameter portion 2 is provided at one end.
A rod 20 having a diameter 2 is slidably inserted through one end side of the rod 20, and a spring 21 is fitted to the rod portion inside the rod slide hole 36. One end of the spring 21 abuts against the back surface of the large diameter portion 22 of the rod, and the other end abuts against the engagement portion 37.

At the other end of the rod protruding from the rear end of the connecting member,
An arm 23 extending inside the hole expanding bit 2 in the front direction thereof is fixed by a stop bolt 25, and a discharged soil intake amount adjustment valve is installed at the tip of the arm 23 so as to be located inside the discharged soil intake port 15. 24 are provided.

The connection member 16 includes the inside of the hole expansion bit and the injection channel 1.
A water injection hole 33 that communicates with 8 is provided.

A spacer 26 having a through hole 27 is fitted into the water injection channel 18 between its terminal end and the opening position of the water injection hole 33, and the spacer 26 has a through hole 27 through a recess 28 at a position on the rear end side of the connection member of the spacer main body. A valve 29 to be closed is slidably fitted. This valve 29 is pressed toward the through hole 27 from the rear end side of the connecting member by a spring 31 in a spring housing cylinder 30 provided at the rear.

In addition, in the drawing, 32 is a water injection hole for sending water sent through the pilot pipe to the front of the hole expansion bit, 34 is a through hole formed in the flange part of the spring storage cylinder, and 35 is formed in the valve 29. It is a through hole.

Next, an example of how the above-described device is used will be described. First, in this device, as shown in Fig. 4, vertical shafts 40, 41 are made on the starting side and the reaching side, respectively, and a pilot pipe 42 is buried from the starting shaft 40 to the reaching shaft 41. Next, in the reaching shaft 41, the tip of the pilot pipe 42 is screwed into the tip recess 17 of the drilling head 1 described above, and the drilling head 1 is connected to the pilot pipe 42.

Thereafter, as shown in FIG. 5, the pilot pipe 42 is
is rotated and pulled toward the starting shaft 40 side. As a result, only the hole expanding bit 2 is rotated by the swivel joint mechanism 4, and the hole is expanded in the horizontal direction.
At the same time, a predetermined length of buried pipe 44 is successively added to the rear end of the pipe body 3.

In the present invention, the excavated soil as described above enters the hole expansion bit 2 from the soil intake port 15, but at this time, the valve 24 located inside the intake port 15 is closed due to the earth pressure. Accordingly, the amount of soil taken in is automatically controlled by shifting from side to side in the diagram. That is, for example, when the burial site is in soft ground and the earth pressure applied to the front surface of the hole expansion bit 2 is small, the elastic force of the spring 21 causes the valve 24 to open slightly or close, and the hole expansion bit 2 When the rotation becomes faster and the earth pressure becomes larger, the earth pressure pushes the valve 24 inward against the elastic force of the spring 21, and the discharged soil intake port 15 opens wide. It becomes possible to take in a large amount of waste soil. When this valve 24 is pushed, the rod 2
0 moves to the right as it faces toward FIG.
Resilience will be generated. Therefore, in order to change the contraction strength of the valve 24, the spring 21 can be replaced.

In the present invention, the waste soil thus taken into the hole expansion bit 2 is mixed with water injected from the water injection channel 18 and the water injection hole 33 through the pilot pipe 42 to form a slurry, which is connected to the connecting pipe 13. The soil is discharged to the rear of the pipe 3 to be buried through a discharge pipe 11 using a jet pump.

In addition, the soil to be excavated usually contains gravel, and during excavation, this gravel may get caught on the seat surface of the valve 24, resulting in a situation where the valve is unable to control the amount of soil taken in. However, in the excavation head of the present invention, in such a case, the valve 24 is forcibly opened by water pressure, and the gravel etc. can be removed. That is,
As mentioned above, during excavation, water flows into the injection channel 18 through the pilot pipe 42, but the valve 2
4, when the water pressure is made higher than normal, the valve 29 accommodated in the spacer 26 is pushed against the elastic force of the spring 31, opening the through hole 27, and water flows through the through hole. 27, 35 and 3
4 and flows into the recess 45 at the tip of the rod, and this pressure pushes the rod 20 and opens the valve 24, thereby removing trapped gravel and the like.

According to the present invention described above, the amount of soil taken in is automatically controlled according to the soil pressure by the soil intake amount adjustment valve provided inside the soil intake port, and therefore the amount of soil taken into the excavation head is controlled automatically according to the soil pressure. Appropriate and efficient excavation can be performed by preventing too much or too little soil being taken in, and without causing ground subsidence or heaving of the soil surface. In addition, even if gravel or other debris gets caught on the seat surface of the valve for adjusting the amount of soil taken in, and this interferes with controlling the amount of soil taken in, the valve can be operated by adjusting the water supply pressure from the pilot pipe. By doing
The gravel and the like can be easily removed, and the valve can stably control the removal and intake of soil.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is a view taken along arrow A-A in Fig. 1, Fig. 3 is a diagram showing how the waste soil intake amount adjustment valve is installed, and Figs. 4 and 5 are schematic diagrams for explaining the working situation according to the present invention. . In the figure, 1 is the drilling head, 2 is the hole expansion bit, and 14
is a bit, 15 is a drain intake port, 16 is a connecting member, 18 is an injection channel, 20 is a rod, 21 is a spring, 22 is a large diameter part, 23 is an arm, 24 is a valve, 26 is a spacer, and 27 is a through hole. , 29 is a valve, 31 is a spring, 33 is a water injection hole, 36 is a rod slide hole, and 37 is an engaging portion.

Claims (1)

[Scope of utility model claims] A connection member having a connection part at its tip for connecting with a pilot tube is provided at the radial center of a hollow reaming bit, the connection part is protruded to the front surface of the reaming bit, and the rear end part is positioned within the hollow part of the reaming bit. A water injection passage is formed inside the connection member from the connection part to a longitudinal intermediate position, and a rod slide hole communicating with the water injection passage is formed from the end of the water injection passage to the rear end of the connection member. A rod having a large diameter part at one end is slidably inserted into the rod slide hole via its one end side, and the rod part in the rod slide hole has each end engaged with the large diameter part and an engagement part on the inside of the rear end of the connection member. a spring for pressing the valve against the hole forming portion from the rear end of the connecting member; a spring for pressing the valve against the hole forming portion from the rear end of the connecting member; a spring for pressing the valve against the hole forming portion from the rear end of the connecting member; a spring for pressing the valve against the hole forming portion from the rear end of the connecting member; a spring for pressing the valve against the hole forming portion from the rear end of the connecting member;