JP2701200B2 - Impact-type small-diameter propulsion method for gravel and its device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention pushes an outer pipe and a small-diameter laid pipe into the ground by a main pushing device provided in a shaft, and at the same time, a ground pile by an air hammer provided at the tip of the outer pipe. The present invention relates to a small-diameter propulsion method and an apparatus for excavating by impact.

[0002]

2. Description of the Related Art Conventionally, a cutting method and a striking method are generally used as a small-diameter propulsion method of 800 mm or less in a gravel ground. Among them, the hitting method generally crushes gravel by the impact force of an air hammer, and thus has advantages such as higher crushing ability of gravel and faster excavation speed than the cutting method. When a pipeline is laid in the ground of gravel ground by a hitting machine, the exhaust air of the air hammer is discharged to the ground in front. The earth and sand crushed by the bit of the hammer is conveyed to the rear of the hammer by an appropriate means through an earth discharging groove provided on the outer periphery of the bit device in front of the bit head.

[0003]

However, in the hitting type small-diameter propulsion method using an air hammer, the air is blown to the ground in front of the face as described above. As a result, the surrounding ground may be damaged, making it impossible to excavate or control the direction. Further, there is no smooth method for transporting the crushed earth and sand with a hammer bit backward, and there is a possibility that the earth and sand adhere to the inner wall of the earth discharging route and become clogged during the transportation. In order to pass these earth and sand through the laying pipe,
There is a possibility that the inner circumference of the laying pipe may be damaged.

Accordingly, the present invention provides a small-diameter thrust method using an air hammer, which does not destroy the ground and which can smoothly transport crushed earth and sand to a shaft, and an apparatus used in this method. To solve the above problems.

[0005]

According to a first aspect of the present invention, an outer pipe and a laid pipe following the outer pipe are pushed into the ground by a main pushing device provided in a shaft, and at the same time, air provided at a tip of the outer pipe is provided. In the propulsion method of hitting and excavating the ground with a hammer, the exhaust air discharged forward from the side of the bit head of the hammer device is U-turned, and along the discharging groove provided on the outer periphery of the bit device in front of the bit head. A small-diameter propulsion method corresponding to gravel was adopted, in which the earth and sand crushed by the bit head and entered into the earth removal groove were conveyed to the rear of the hammer device by the exhaust air.

According to a second aspect of the present invention, the outer pipe and the laying pipe following the outer pipe are pushed into the ground by a main pushing device provided in the shaft, and at the same time, the ground is hit by an air hammer provided at the tip of the outer pipe. In the propulsion method for excavation, the exhaust air discharged forward from the side of the bit head of the hammer device is U-turned and guided rearward along a discharging groove provided on the outer periphery of the bit device in front of the bit head. The earth and sand crushed by the head and entering the earth discharging groove is conveyed to the rear of the hammer device by the exhaust air, and the earth and sand are crushed by the outer periphery of the crusher portion and the outer tube inner periphery that rotate integrally with the hammer device at the relevant place. A small-diameter propulsion method for gravels was adopted, in which the ground was crushed and water was supplied to the soil and conveyed backward by an auger screw provided in the laying pipe.

According to a third aspect of the present invention, the outer pipe and the laying pipe following the outer pipe are pushed into the ground by a main pushing device provided in the shaft, and at the same time, the ground is hit by an air hammer provided at the tip of the outer pipe. In the propulsion device for excavation, the exhaust air is discharged from a front surface of an exhaust hole of exhaust air discharged forward from a side of a bit head of the hammer device to one side of a discharging groove provided on an outer periphery of a bit device in front of the bit head. A hitting type small-diameter propulsion device compatible with gravel was provided with a guide hood for making a U-turn of air and a spiral stirring bar from one end to the other end of the outer periphery of the hammer device.

According to a fourth aspect of the present invention, the outer tube and the laying tube following the outer tube are pushed into the ground by a main pushing device provided in the shaft, and at the same time, the ground is hit by an air hammer provided at the tip of the outer tube. In the propulsion device for excavation, the exhaust air is discharged from a front surface of an exhaust hole of exhaust air discharged forward from a side of a bit head of the hammer device to one side of a discharging groove provided on an outer periphery of a bit device in front of the bit head. A guide hood for making a U-turn of air is provided, a crusher portion having an outer peripheral convex portion that rotates integrally with the hammer device is provided behind the hammer device, and a tubular casing is provided behind the crusher portion, and a casing is provided therein. An auger screw for transporting sediment is provided, and a sediment intake port connected to the inside of the casing is provided at the rear of the crusher. Re proximate the mouth provided with the injection port of the water, and the gravel-compatible blow type small caliber propulsion device.

[0009]

According to the first aspect of the present invention, the exhaust air discharged from the side of the bit head of the air hammer to the front is made U-turn by a guide hood provided at an exhaust port to be provided around the bit device in front of the bit head. Most of the water is discharged backward along the draining groove, and most of the water reaches the rear of the hammer device through a gap between the outer periphery of the hammer device and the inner periphery of the outer pipe. However, some of the exhaust air flows backward from behind the hammer device and is blown to the ground in front through the gap between the outer circumference of the bit device and the inner circumference of the outer tube. The trapped earth and sand enter into the draining groove on the outer periphery of the bit device. The earth and sand that has entered the earth removal groove is conveyed to the rear of the hammer device by the exhaust air that makes a U-turn from the exhaust port.

[0010] According to the second aspect of the present invention, the first aspect is provided.
In addition to the operation of the item, the earth and sand transferred to the rear of the hammer device is ground on the outer periphery of the rotating crusher portion and the inner periphery of the outer tube, and is finely sized to pass through the rear equipment.
And water is added to improve the fluidity. Then, the air is sent to the auger screw with the force of the exhaust air, and then sent to the rear of the laying pipe by the auger screw.

[0011] According to the third aspect of the present invention, the first aspect is provided.
In addition to the effect of the item, when the earth and sand on the exhaust air passes through the gap between the outer periphery of the hammer device and the inner periphery of the outer pipe and reaches the rear of the hammer device, it is guided by a stirring bar provided on the outer periphery of the hammer device. Is transferred spirally around the outer periphery of the hammer device. Also, since the hammer device is rotating during excavation, the earth and sand is agitated by these agitating rods.

[0012] According to the fourth aspect of the present invention, the above-mentioned second aspect is provided.
In addition to the effects of the item, the sprayed water is used to wash away the earth and sand adhering to the inner wall of the earth removal route and improve the fluidity of the earth and sand,
These earth and sand are introduced into the intake by the force of the exhaust air, and are transported from the intake to the auger screw portion in the casing. From here, it is transported backward in the casing by an auger screw.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, a device used in the method of the present invention will be described. A cylindrical hammer device 2 is provided in a distal end portion of an outer tube 1, and a bit device 3 is provided at a front end of the hammer device 2. A bit head 4 is provided at the tip of the bit device 3, and the bit head 4 projects outward from the front end of the outer tube 1. At the rear end of the hammer device 2, there is provided a sediment taking-up body 6 having a substantially circular cross section having a crusher portion 5 having an outer peripheral convex portion having a reduced gap with the inner periphery of the outer tube 1 at a front end portion. An auger screw shaft 7 is provided after the take-in body 6.

The sediment intake body 6 having the crusher portion 5 is rotatably supported by a bearing portion 8 provided on the inner periphery of the outer tube 1. And this sediment uptake body 6
The inner peripheral portion of the outer tube 1 is closed by the bearing 8. The auger screw shaft 7 is covered by a cylindrical casing 9 having one end supported at the rear end of the bearing portion 8. The casing 9 is covered with a laying pipe 10 connected to the rear end of the outer pipe 1 with a gap on the outer periphery. The hammer device 2 supporting the bit head 4 and the bit device 3, the sediment intake body 6 having the crusher portion 5, and the auger screw shaft 7 are connected with their central axes aligned on the same line, and the rear end of the auger screw shaft 7 is connected. As shown in FIG. 3, the main pushing device 27 provided in the shaft
These are integrally rotated by being supported by the drive rotation shaft 32. As shown in FIG. 3, the rear ends of the laying pipe 10 and the casing 9 are supported by a main shaft 30 fixed to a rotary driving body of the main pushing device 27, and are rotatable.

The bit head 4 is divided into two bit pieces 4a as shown in FIG. 8 and FIG. 13. When the bit head 4 is rotated rightward, the two bit pieces 4a become larger than the outer diameter of the outer tube 1. When rotated in the opposite direction, it contracts,
As shown in FIG. 9, it becomes smaller than the inner diameter of the outer tube 1. Further, exhaust air outlets 1 are provided on both sides of the outer periphery of the bit device 3.
1 are provided, each of which is located between two bit pieces 4 as shown in FIGS. Further, as shown in FIGS. 1 and 12, earth discharging grooves 12 are provided diagonally from the outer peripheral front end to the rear end of the bit device 3 at each of the 11 exhaust ports. And each of the exhaust ports 11
A guide hood 13 for making the exhaust air of the exhaust port 11 U-turn backward is provided on one side of the earth discharging groove 12. A spiral stirring bar 14 is provided on both sides of the outer periphery of the hammer device 2 from its front end to its rear end. Further, one side of the front end of the outer tube 1 is provided with a thick portion 1a.

As shown in FIGS. 5 and 6, an air hole 15 for sending compressed air to the hammer device 2 is provided on the center axis of the front part of the sediment intake body 6, and the front end thereof is provided at the front end. The rear end of the hammer device 2 is fitted. Also, two sediment intake ports 16 are provided on both sides of the outer periphery of the sediment intake body 6 behind the crusher unit 5, and the sediment insertion holes 17 are respectively formed from these respective sediment intake ports 16 in parallel with the central axis of the sediment intake body 6. The earth and sand insertion holes 17
Has an opening 17a at the end face of the step 6a in the middle in the longitudinal direction of the sediment intake body 6. In addition, the sediment uptake body 6
7 on both sides of the position avoiding the earth and sand insertion holes 17 described above.
As shown in the figure, air intake holes 18 penetrating from the outer periphery to the air holes 15 are provided. An annular groove 19 is provided on the inner periphery of the bearing 8 facing each of the air intake holes 18, and a guide hole 20 is provided from an appropriate portion of the annular groove 19 to the outer periphery of the bearing 8. This guide hole 20
Is provided between the outer periphery of the bearing portion 8 and the inner periphery of the outer tube 1.

The stepped portion 6a of the earth and sand taking body 6
From the rear, a small-diameter portion 6b is formed. The small-diameter portion 6b has a tapered shape whose outer diameter gradually increases, and has a cylindrical middle-diameter portion 6c after the small-diameter portion 6b. At the center axis position of the small diameter portion 6b and the middle diameter portion 6c, there is a hollow portion 21 from the rear end surface to just before the air hole 15, and the front end portion of the hollow portion 21 is a small diameter hollow portion via a step portion 21a. 21b. Water pipes 22 are respectively drawn out from the front end of the small-diameter hollow portion 21b through the respective earth and sand insertion holes 17, and the injection ports 23 are provided at the tip of each of the water pipes 22 at 16 soil intake ports. . The rear end of the sediment intake body 6 and the front end of the auger screw shaft 7 are connected via an annular connecting member 24 as shown in FIG. Therefore, the hollow portion 21 of the sediment intake body 6
And the hollow portion 7a of the auger screw portion 7 are connected. A front end of the casing 9 is supported by a connection pipe 25 connected to a rear end of the bearing 8. An annular gap 26 is formed between the inner periphery of the connection pipe 25 and the outer periphery of the small diameter portion 6b and the middle diameter portion 6c of the sediment intake body 6.
The front end of the annular gap 26 communicates with the openings 17 a of the earth and sand insertion holes 17. Although not shown, the crusher 5 has a large number of ridges on the outer periphery of the protrusion.

As shown in FIGS. 3 and 4, the laying pipe 10, the casing 9 and the rear end of the auger screw shaft 7 are connected to a main pushing device 27 provided in a shaft (not shown) via a chucking portion 28. Have been. That is, the laying pipe 10 inserts the connection pipe 29 connected to the rear end thereof into the inner periphery of the tubular main shaft 30 and locks the annular stopper metal fitting 31 locked to the front end of the main shaft 30 to the connection pipe 29. ing. The main shaft 30 has a rear flange portion 30 a connected to a rotary driving body of the main pushing device 27. The casing 9 has its rear end inserted into the small-diameter inner peripheral portion 30b of the main shaft 30 and locked. The rear end of the auger screw shaft 7 is connected to a drive rotary shaft 32 protruding from the main pushing device 27.

A substantially annular cover body 33 provided on the outer periphery of the main shaft 30 rotatably supports the main shaft 30.
Each of the frame bodies 3 having one end fixed to both sides thereof
4 and the other end of each frame 34 is connected to the main shaft 3
The flange 30a extends outward from the outer periphery and is fixed to the main pushing device 27. A compressed air supply port 35 is provided on one side of the cover body 33. Compressed air entering from the compressed air supply port 35 is supplied to the inner circumference of the installation pipe 10 through a hole 30c of the main shaft 30 connected thereto. And between the outer periphery of the casing 9. The inner circumference of the casing 9 and the outer circumference of the auger screw shaft 7 communicate with an inner circumferential gap 36 of the main shaft 30, and communicate with an expanded portion 38 of the cover body 33 through an opening 37 formed in the outer circumference of the main shaft 30. Have been. The bulging portion 38 of the cover body 33 has an appropriate earth and sand discharge port 39, and the bulging portion 38 has an opening 40 for inspection and auger connection.

The method of the present invention will be described using these devices. First, compressed air to be sent to the hammer device 2 is injected from the compressed air supply port 35 in the shaft, sent forward by an annular gap between the inner periphery of the installation pipe 10 and the outer periphery of the casing 9, and rearward of the bearing 8. Outer guide hole 20
Then, it passes through the annular groove 19 following this, reaches the air hole 15 from the air intake hole 18 of the sediment intake body 6, and enters the hammer device 2 provided at the front end of the air hole 15. Water enters the hollow portion 21 of the sediment intake body 6 through the inside of the drive rotary shaft 32 of the shaft vertical pushing device 27 and the hollow portion 7a of the auger screw shaft 7 that follows, and enters the small-diameter hollow portion 21.
b through each water supply pipe 22, and is injected from each injection port 23 at the tip thereof.

The operation of the hammer device 2 causes the bit device 3 to repeatedly protrude from the front end of the hammer device 2. As a result, the bit head 4 continuously hits the ground. And these impacts crush the ground gravel. At that time, the hammer device 2, the earth and sand intake body 6 and the auger screw shaft 7 are integrally rotated by the drive rotation shaft 32 of the main pushing device 27, and the bit device 3 and the bit head 4 are rotated.
Will also be hit while rotating. Exhaust air is exhausted from each exhaust port 11 of the bit device 3, and the exhaust air makes a U-turn backward by the guide hood 13, enters the earth discharging groove 12, and further, the outer circumference of the hammer device 2 and the inner circumference of the outer pipe 1. Is guided by each stirring bar 14 and reaches the rear of the hammer device 2 while rotating spirally. Behind the hammer device 2, a crusher portion 5 having an outer periphery having a narrower gap with the inner periphery of the outer tube 1 is provided. It passes through the outer periphery of the crusher part 5 and enters the earth and sand insertion hole 17 from the earth and sand intake ports 16 on both sides of the earth and sand intake body 6.

The returned exhaust air flows backward on the outer periphery of the hammer device 2 and blows from the gap between the outer periphery of the bit device 3 and the inner periphery of the outer tube 1 to the ground in front. However, these exhaust air turns back upon hitting the gravel or the like of the ground, and enters the above-mentioned discharging groove 12 from the side of the bit head 4. At this time, these exhaust airs enter the above-mentioned discharge groove 12 by entraining the above-mentioned crushed earth and sand. So it merges with the above exhaust air,
The outer periphery of the hammer device 2 is guided by the stirring rods 14 and spirally rotates to reach the crusher unit 5. Thus, the rotation of the crusher unit 5 causes the earth and sand to be rubbed between the outer periphery of the crusher unit 5 and the inner periphery of the outer pipe 1 to form fine earth and sand. It enters the insertion hole 17.

At this time, water is injected from the injection ports 23 at the 16 locations of each earth and sand intake port, and the water mixes with the earth and sand. Then, it contains moderate water and passes through each earth and sand insertion hole 17 to form an annular gap 26.
to go into. Then, it enters between the inner periphery of the casing 9 and the outer periphery of the auger screw shaft 7, and is discharged to the rear of the pipe by the auger screw. Then, it enters the inner circumferential gap portion 36 of the main shaft 30 of the chuck portion 28 and enters the bulging portion 38 of the cover body 33 from the opening portion 37. Then, the swelling portion 38 is discharged from the earth and sand discharge port 39 to the ground via a pipe or the like.

In this manner, the excavation is promoted in the gravel ground. When the laying pipe is connected after the completion of the one-span excavation, the water in the hollow portion 7a of the auger screw shaft 7 and the hollow portion 21 of the sediment intake body 6 is removed. The target 41 provided on the step portion 21a of the hollow portion 21 of the sediment intake body 6 is measured from the main pushing device 27 side in the shaft, and when the tip is displaced from the target direction, which direction Just check if it ’s tilted,
Chucking section 2 via the rotary drive of main pusher 27
8, the laying pipe 10, the outer pipe 1 and the casing 9 are rotated to increase the thickness 1a of the outer pipe 1 in an inclined direction.
Take it again and push it again to correct the direction.

Instead of the above-described embodiment, in the small-diameter propulsion method, the exhaust air discharged forward from the side of the bit head of the hammer device is U-turned and provided on the outer periphery of the bit device in front of the bit head. Guided backward along the draining trench, crushed by the bit head,
With the exhaust air discharged forward, the earth and sand that has entered the above-mentioned dumping groove is conveyed to the rear of the hammer device by the exhaust air. The earth and sand conveyed to
A method of crushing the outer periphery of the crusher portion and the inner periphery of the outer tube, which rotate integrally with the hammer device at the relevant portion, further spraying and supplying water to the earth and sand, and conveying the water backward by an auger screw provided in the laying tube may be adopted.

In the above device, the hammer device may further include: a front surface of an exhaust hole for exhaust air discharged forward from a side of a bit head of the hammer device; It is also possible to provide a guide hood for making a U-turn of the exhaust air, and to provide a spiral stirring bar from one end to the other end of the hammer device. A guide for U-turning the exhaust air from the front surface of the exhaust hole of the exhaust air discharged forward from the side of the bit head of the hammer device to one side of a discharging groove provided on the outer periphery of the bit device in front of the bit head. An auger screw that provides a hood, provides a crusher portion having an outer peripheral protrusion that rotates integrally with the hammer device behind the hammer device, provides a tubular casing behind the crusher portion, and conveys earth and sand therein. The thruster may be provided with a sediment intake port connected to the inside of the casing at the rear of the crusher section, and a water injection port provided near the sediment intake port.

[0027]

According to the first aspect of the present invention, the exhaust air of the air hammer is U-turned on the side of the bit device,
It is sprayed to the rear of the hammer device through the dumping ditches,
Since only a part of the exhaust air turned back from the back of the hammer device is blown onto the ground and the power of this rebounding air is used to put the earth and sand pulverized by the hammer into the dumping groove, extra exhaust air is applied to the ground. Do not spray and do not destroy the ground. Therefore, in order to blow air to the ground in front of the face as before, the surrounding ground is damaged by air blow etc. due to loosening of the ground or escape of the matrix,
There is no danger of inability to dig or control direction. In addition, since the above-described exhaust air having made a U-turn conveys the earth and sand entering the earth discharging groove to the rear of the hammer device, this is an extremely efficient method.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the earth and sand transferred to the rear of the hammer device is ground on the outer circumference of the rotating crusher portion and the inner circumference of the outer pipe, and is finely ground. The particle size. Since water is added to the mixture to improve the fluidity, the earth and sand can be smoothly transported to the auger screw by the power of the exhaust air. And there it is sent to the back of the laying pipe by the auger screw. Therefore, the discharge of earth and sand is extremely easy.

According to the third aspect of the present invention, in addition to the effect of the first aspect, the earth and sand on the exhaust air passes through the gap between the outer periphery of the hammer device and the inner periphery of the outer pipe and is located rearward of the hammer device. Since the stirring bar is spirally provided on the outer periphery of the hammer device, the outer periphery of the hammer device is guided and guided by the stirring bar, and is transported. Therefore, the earth and sand can be transported more strongly by the spiral flow of the exhaust air.

According to a fourth aspect of the present invention, in addition to the effect of the second aspect, water is added to wash out the sediment adhered to the earth discharging route, improve the fluidity of the sediment, and remove the sediment from the exhaust air. Is transferred to the auger screw point in the casing by the force of this, and from there, it is transported backward by the auger screw that entered the casing, so that the earth and sand is transported in the casing, and the earth and sand do not flow directly on the inner circumference of the laid pipe. The laying pipe is not damaged.

[Brief description of the drawings]

FIG. 1 is a sectional side view showing a front portion of an apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional side view showing the middle part of the device according to the embodiment of the present invention, which is continued from FIG. 1;

FIG. 3 is a partially sectional side view showing a rear portion of the apparatus according to the embodiment of the present invention.

FIG. 4 is a plan view showing a rear portion of the apparatus according to the embodiment of the present invention.

FIG. 5 is an enlarged sectional side view of a sediment intake body of the apparatus according to the embodiment of the present invention.

FIG. 6 is an enlarged sectional view of a crusher portion and a sediment intake body portion in the middle of the apparatus according to the embodiment of the present invention.

7 is an enlarged cross-sectional view of a crusher portion and a sediment intake body portion at the center of the device according to the embodiment of the present invention, and is a cross-sectional view of the device of FIG. 6 rotated by 90 degrees about a central axis.

FIG. 8 is a front view of the device according to the embodiment of the present invention in a state where a bit head is expanded.

FIG. 9 is a front view of the device according to the embodiment of the present invention in a state where the bit head is contracted.

FIG. 10 is a longitudinal sectional view of a hammer device at a front portion of the device according to the embodiment of the present invention.

FIG. 11 is a vertical cross-sectional view of a location of a sediment intake body at the center of the device according to the embodiment of the present invention.

FIG. 12 is an enlarged side view of the bit head and the bit device according to the embodiment of the present invention.

FIG. 13 is an enlarged front view of the bit head and the bit device according to the embodiment of the present invention.

[Description of Signs] 1 outer pipe 2 hammer device 3 bit device 4 bit head 5 crusher part 6 sediment intake body 7 auger screw shaft 8 bearing part 9 casing 10 laying pipe 11 exhaust port 12 discharge groove 13 guide hood 14 stirring rod 16 Sediment intake 17 Sediment insertion hole 21 Hollow part 22 Water supply pipe 23 Injection port 27 Main pushing device 28 Chucking part 30 Main shaft 32 Drive shaft

Continuation of the front page (56) References JP-A-7-173995 (JP, A) JP 4-80197 (JP, B2) JP-B 3-26279 (JP, B2) JP-T 5-500696 (JP) , A)

Claims (4)

(57) [Claims] 1. A propulsion method in which an outer pipe and a laying pipe following the outer pipe are pushed into the ground by a main pushing device provided in a shaft, and at the same time, a ground is hit and excavated by an air hammer provided at a tip of the outer pipe. Exhaust air discharged forward from the side of the bit head of the hammer device is U-turned, guided rearward along a discharging groove provided on the outer periphery of the bit device in front of the bit head, and crushed by the bit head. A small-diameter, small-diameter propulsion method for gravel, characterized in that the earth and sand that has entered the earth removal groove is transported to the rear of the hammer device by the exhaust air. 2. A propulsion method in which an outer pipe and a laying pipe following the outer pipe are pushed into the ground by a main pushing device provided in a shaft, and at the same time, a ground is hit and excavated by an air hammer provided at a tip of the outer pipe. Exhaust air discharged forward from the side of the bit head of the hammer device is U-turned, guided rearward along a discharging groove provided on the outer periphery of the bit device in front of the bit head, and crushed by the bit head. The earth and sand that has entered the earth removal groove is transported to the rear of the hammer device by the above-mentioned exhaust air, and the earth and sand are crushed by the outer periphery of the crusher portion and the outer tube that rotate integrally with the above-mentioned hammer device at the relevant location, and further, into the earth and sand. A striking, small-diameter, small-diameter propulsion method, characterized in that water is supplied and transported backward by an auger screw provided in a laying pipe. 3. A propulsion device for pushing an outer pipe and a laid pipe following the outer pipe into the ground by a main pushing device provided in a shaft, and simultaneously hitting and excavating the ground by an air hammer provided at a tip of the outer pipe, A guide for U-turning the exhaust air from the front surface of the exhaust hole of the exhaust air discharged forward from the side of the bit head of the hammer device to one side of a discharging groove provided on the outer periphery of the bit device in front of the bit head. A small-diameter, small-diameter thrust-type propulsion device, comprising a hood and a spiral stirring bar extending from one end to the other end of the hammer device. 4. A propulsion device for pushing an outer pipe and a laid pipe following the outer pipe into the ground by a main pushing device provided in a shaft, and at the same time, striking and excavating the ground by an air hammer provided at a tip of the outer pipe, A guide for U-turning the exhaust air from the front surface of the exhaust hole of the exhaust air discharged forward from the side of the bit head of the hammer device to one side of a discharging groove provided on the outer periphery of the bit device in front of the bit head. An auger screw that provides a hood, provides a crusher portion having an outer peripheral protrusion that rotates integrally with the hammer device behind the hammer device, provides a tubular casing behind the crusher portion, and conveys earth and sand therein. The crusher section is provided with a sediment intake port connected to the inside of the casing at the rear of the crusher section. Characterized by having an opening,
Impact-type small-diameter propulsion device for gravel.