JPH06193384A - Air bag for bearing soft duct - Google Patents

Abstract

PURPOSE:To transmit a large driving force of the casing of an auger screw positively over a soft duct. CONSTITUTION:Reinforcing layers 40, 42 formed from a sheet member, in which codes are arranged in parallel and formed in a reed screen shape and the reed screen-shaped codes-are covered with a rubber, are installed to an air bag 22 for bearing a soft duct. The direction of the codes of the reinforcing layer 40 and the direction of the codes of the reinforcing layer 42 are inclined at 10 deg. in the axial direction of a casing 12 respectively, and the codes of the reinforcing layer 40 and the codes of the reinforcing layer 42 are crossed mutually. Consequently, an air chamber 25 can be filled with high pressure air, and the air bag 22 for bearing the soft duct can bear the soft duct 17 powerfully from the inside. Accordingly, the air bag 22 for bearing the soft duct is not slid to the soft duct 17 even when the casing is propelled by a large force, and the soft duct 17 obtains large driving force and is propelled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft duct which is attached to a trench machine to support the soft duct from the inner peripheral surface when the soft duct is propelled when the soft duct is propulsively buried in a tunnel excavated by the trench machine. The present invention relates to a duct supporting air bag.

[0002]

2. Description of the Related Art A dug tunnel is formed by excavating the ground with a boring machine such as an auger screw, and a soft duct formed of synthetic resin or the like in the boring tunnel as the boring machine progresses. A method of burying a soft duct in an unsealed tunnel by pushing the button simultaneously with the pushing of the trenching machine is disclosed in Japanese Utility Model Publication Nos. 1-180591 and 2-26696.

An air bag is provided on the outer circumference of a steel pipe which is a casing of an auger screw which is a digging machine.
A fluid is press-fitted into the air bag to support the soft duct externally fitted to the steel pipe by expanding the soft duct from the inner side to propel the soft duct.

[0004]

By the way, since friction resistance acts between the outer peripheral surface of the soft duct and the unsealed tunnel, the contact surface of the air duct with the soft duct is opposite to the propelling direction. A large load acts in the direction. As a result, the contact surface between the air bag and the soft duct slips or the air bag deforms, and the propulsion amount of the soft duct becomes smaller than the propulsion amount of the propulsion device. Since the axial force of the propulsion unit is directly applied to the rear end surface of the soft duct by contacting with the base portion and damages the rear end surface, the propulsive force of the soft duct cannot be increased as much as necessary.

In consideration of the above facts, the present invention provides an air bag for supporting a soft duct, which strongly supports the soft duct from the inside thereof and can surely give a large propulsion force of the casing of the auger screw to the soft duct. The purpose is to do.

[0006]

As a result of extensive studies by the inventors, in order to support a soft duct with a large supporting force and suppress deformation during propulsion, a cord layer is provided inside a soft duct supporting air bag. It has been found that it is effective to provide, and that the code angle of the code layer has an optimum value.

According to the present invention, the air bag is expanded by expanding a cylindrical air bag having an annular air chamber which is provided on the outer circumference of an auger screw casing for transmitting the thrust force of the original pushing jack to the tip blade mouth. A soft duct supporting air bag used in a method of propelling and embedding the soft duct by supporting the soft duct loosely fitted into the soft duct, wherein the soft duct supporting air bag is 0 ° to the propelling direction. It is characterized by having a cord layer composed of cords inclined at 45 °.

[0008]

When air is supplied to the soft duct supporting air bag of the present invention, the air chamber expands and the outer peripheral surface is pressed against the inner peripheral surface of the soft duct to be in close contact therewith, and the soft duct is attached to the casing of the auger screw. It is supported via a supporting air bag. When thrust is applied to the casing by the push jack, the soft duct is supported by the soft duct supporting air bag and propelled in the tunnel excavated by the tip blade.

Since the soft duct supporting air bag of the present invention is provided with the cord layer, it is possible to fill high-pressure air, and the cord direction of the cord layer is 0 ° with respect to the propelling direction. Since it is inclined at ˜45 °, expansion of the air chamber in the radial direction is allowed, and deformation of the outer shape in the propulsion direction can be suppressed. Therefore, the soft duct supporting air bag can strongly support the soft duct from the inside, and can reliably apply the large propulsive force of the casing to the soft duct.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

FIG. 2 shows a boring machine 10 to which the present invention is applied.
Is shown. As shown in FIG. 2, the boring machine 10 is provided with a cylindrical casing 12, and a plurality of casings 12 are connected according to the length of the tunnel to be excavated. A cutter 14 for excavating underground is provided in the casing 12 on the tip side in the excavation direction (arrow A side)
Is attached. Inside the casing 12, there is provided a screw 16 that conveys the excavated soil excavated by the cutter 14 to a shaft (not shown) opposite to the cutter 14.

A soft duct 17 for supporting the inner surface of the excavated tunnel is arranged outside the casing 12. In this embodiment, the soft duct 17 has an inner diameter D1 of φ600 mm (see FIG. 1).

The casing 12 of this embodiment has a double structure having an outer pipe 12A and an inner pipe 12B arranged inside the outer pipe 12A.
The above-mentioned screw 16 is disposed inside B.
In the present embodiment, the outer diameter D2 of the outer pipe 12A is φ
It is 532 mm (see FIG. 1). Also, the inner pipe 12B
Are fixed to the outer pipe 12A via a spacer (not shown).

A tubular air bag 22 is attached in close contact with the outer circumference of an outer pipe 12A of a predetermined casing 12 among a plurality of joined casings 12.

As shown in FIG. 2, the air bag 22 is
A ring-shaped first inner surface rubber 24 is provided at the center. First
The inner surface rubber 24 has a rectangular shape whose cross section along the axis is long in the axial direction, and a release sheet 26 is continuously embedded along the circumferential direction at the center portion in the thickness direction. This release sheet 2
6 is made of a material to which rubber is not adhered, and in this embodiment, a reinforced polyethylene sheet is used. Both end portions in the width direction of the release sheet 26 have the first inner surface rubber 2
4 is located on the inner side in the width direction than both ends in the width direction. As shown in FIG. 3, the release sheet 26 is for forming an air chamber 25 in the first inner surface rubber 24. When air is supplied between the release sheet 26 and the first inner surface rubber 24, The release sheet 26 and the first inner surface rubber 24 are separated from each other, and the volume of the air chamber 25 in the first inner surface rubber 24 is increased. In addition, in the present embodiment, the thickness of the first inner surface rubber 24 is about 2 mm.

As shown in FIG. 1, this first inner rubber 24
Is entirely covered with the second inner rubber 28.
The second inner surface rubber 28 is vulcanized and adhered to the first inner surface rubber 24, but only the widthwise both ends of the first inner surface rubber 24 are provided with a sheet-shaped peeling member 30 having a U-shaped cross section. And is not adhered to the second inner rubber 28. The release member 30 is also made of a material to which rubber is not adhered, like the release sheet 26. In this embodiment, a reinforced polyethylene sheet is used like the release sheet 26. In this embodiment, the thickness of the second inner surface rubber 28 is about 2 mm.

A reinforcing ring 31 is disposed on the tip end side of the second inner surface rubber 28 in the excavating direction so as to be in contact with the side wall portion 28B.
The reinforcing ring 31 has a rectangular cross section and is vulcanized and adhered to the side wall portion 28B of the second inner rubber 28. The reinforcing ring 31 of this embodiment is made of steel, and has an outer diameter of 574 mm, a wall thickness of 12 mm, and a width of 40 mm in this embodiment.

The second inner surface rubber 28 and the reinforcing ring 3
A third inner rubber 32 is vulcanized and adhered to the outer peripheral surface of 1. In this embodiment, the thickness of the third inner rubber 32 is about 2 mm.

Reinforcing layers 40 and 42 are vulcanized and adhered to the outer peripheral surface of the third inner rubber 32. These reinforcement layers 4
0 and 42 are formed by a sheet member in which cords of rayon, nylon, steel, Kevlar, etc. are arranged in parallel to form a blind, which is covered with rubber, and one end of the sheet member and the other end thereof are formed. Are overlapped, and the overlapping dimension, that is, the overlap dimension is 100 mm in this embodiment.
It is said that.

The cords of the reinforcing layers 40 and 42 have a longitudinal direction of 0 ° to 4 with respect to the propelling direction (axial direction) of the casing 12.
It is preferable to incline in the range of 5 °, and 0 ° to 10 °
It is more preferable to incline in the range. In the present embodiment, the longitudinal direction of the cord of the reinforcing layer 40 and the longitudinal direction of the cord of the reinforcing layer 42 are respectively inclined by 10 ° with respect to the axial direction of the casing 12, and the cord of the reinforcing layer 40 and the reinforcing layer are The cords of 42 are inclined in opposite directions, and the cords intersect each other.

An outer peripheral rubber 4 is provided on the outer periphery of the reinforcing layers 40 and 42.
4 is vulcanized and adhered. The thickness of the outer peripheral rubber 44 is
In this embodiment, it is about 2 mm.

A plurality of female threads 46 are formed on the reinforcing ring 31 along the circumferential direction at predetermined intervals. On the other hand, the casing 12 has a round hole 48 at a position facing the female screw 46.
Are formed. A bolt 49 penetrates the round hole 48 from the inner peripheral side of the casing 12 toward the outer side, and the bolt 49 further includes the outer peripheral rubber 44, the reinforcing layers 40, 4 and 4.
The second inner surface rubber 32 and the second inner surface rubber 28 are penetrated and screwed into the female screw 46 of the reinforcing ring 31.

A cap 50 for supplying air is attached to the air bag 22. This base 50 is
It is formed in a cylindrical shape and has a flange portion 50A formed at one end. The mouthpiece 50 has a flange portion 50 </ b> A embedded in the first inner surface rubber 24 and an axial end portion in contact with the release sheet 26. Further, the base 50 penetrates the second inner surface rubber 28, the third inner surface rubber 32, the reinforcing layers 40 and 42, and the outer peripheral rubber 44 on the side opposite to the flange 50 </ b> A, and the end portion of the third inner surface rubber 32. It is flush with the outer surface.

A pipe taper screw (female screw) 52 is formed on the inner periphery of the base 50, and one male screw of a pipe joint 54 penetrating the casing 12 from the inner peripheral side is screwed on the pipe taper screw 52. I am fit. Pipe fitting 54
A hose 56, to which air is supplied by an air compressor (not shown), is connected to the other side.

The air bag 22 of this embodiment has an axial dimension L of 890 mm and a thickness T of 28 mm.

Next, the operation of this embodiment will be described. The moat machine 10 is first installed in a stand (not shown). After installing the trench machine 10 in the standing shaft, the soft duct 17 is arranged outside the casing 12.

Thereafter, a compressor (not shown) is operated to supply compressed air to the air chamber 25 of the air bag 22. When the compressed air is supplied to the air chamber 25, as shown in FIG. 3, the inner peripheral surface of the first inner surface rubber 24, that is, the inner wall surface of the air chamber 25 is separated from the release sheet 26, and the first inner surface rubber 240 is A portion of the release sheet 26 located on the outer side in the axial direction expands convexly toward the soft duct 17 side, and the
2 The outer peripheral surface is in close contact with the inner peripheral surface of the soft duct 17, and the soft duct 17 is supported by the casing 12.

Next, the cutter 14 is rotated by a drive device (not shown) and the rear end of the casing 12 is pressed by a source push jack (not shown) to propel the excavator 10 into the ground. At this time, the rear end of the soft duct 17 is not brought into contact with the original push jack. The soft duct 17 is supported by the casing 12 by an air bag 22, and receives only the propulsive force of the casing 12 to propel it in the excavated tunnel.

Each time the casing 12 is finished propelling, the next casing 12 and the soft duct 17 are connected to sequentially propel the trench machine 10 into the ground. At this time, the air bag 22
May be attached to all the casings 12, or may be attached for each predetermined number as shown in FIG.

As shown in FIG. 2, when the air bags 22 are attached for every predetermined number of casings 12, the propulsive force FP applied to the soft duct 17 is the air bag 22.
The part that is in contact with is the largest, and the propulsive force decreases due to the frictional force with the inner surface of the tunnel as it goes in the propulsive direction. For this reason, the mounting interval of the air bag 22 is set so that the propulsive force FP of the soft duct 17 does not become zero.

The air bag 22 has reinforcement layers 40, 4
2 is provided and the cord direction is set to the optimum value, high-pressure air can be filled to strongly support the soft duct 17. That is, since the cord direction is inclined 10 ° with respect to the propelling direction, radial expansion of the air chamber 25 is allowed and high internal pressure can be endured, and the outer shape of the air bag 22 at the time of propulsion is propelled. Deformation in the direction is suppressed.

Therefore, even if the soft duct 17 receives the large propulsive force FO of the casing 12, the air bag 2
2 and the soft duct 17 do not slide relative to each other in the axial direction. Therefore, unlike the conventional case, the problem of pushing the soft duct 17 with the original push jack does not occur, and the soft duct 17 at the rear end is neither deformed nor damaged.

Further, when the air bag 22 is propelled, it is pulled in the direction opposite to the propelling direction of the casing 12 due to the frictional force with the soft duct 17, but the tear resistance is enhanced by the reinforcing layers 40 and 42. It does not puncture easily like a conventional air bag that does not have a reinforcing layer.

The excavated soil excavated by the cutter 14 is conveyed inside the inner pipe 12B by the screw 16 and discharged to the standing side.

After propelling to a predetermined position, the compressed air in the air chamber 25 is released to the outside air through the hose to reduce the outer diameter of the air bag 22. After that, the soft duct 17 is set in the excavated tunnel by retracting the air bag 22 together with the casing 12 to the standing side.

[Test Example] In order to investigate the effect of the present invention,
The relationship between the cord angle of the reinforcing layers 40 and 42 and the propulsive force (thrust force) of the soft duct, and the relationship between the cord angle and the deformation amount of the airbag during propulsion were examined.

In the test, the soft duct 17 is supported by two air bags 22 filled with an internal pressure of 7.0 kg / cm ² .
A thrust force was applied to the casing 12 with the original push jack, and the thrust force acting on the soft duct 17 was measured with a load meter.

Table 1 below shows thrust forces when the axial displacement between the casing 12 and the soft duct 17 due to the deformation of the air bag 22 becomes 10 mm. Table 2 below shows the thrust force at the start of sliding.

Practically, it is preferable that the thrust force of the soft duct 17 is 20 tons or more.

[0040]

[Table 1]

[0041]

[Table 2]

From the test results shown in Tables 1 and 2, it is practically preferable that the cord angles of the reinforcing layers 40 and 42 be 45 ° or less in terms of deformation and propulsion force of the air bag 22. it is obvious.

[0043]

Since the air duct for supporting the soft duct of the present invention has the above-mentioned structure, it strongly supports the soft duct from the inside thereof and surely imparts a large propulsive force of the casing of the auger screw to the soft duct. It has an excellent effect that

[Brief description of drawings]

FIG. 1 is a sectional view of an airbag according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an excavator using an air bag according to an embodiment of the present invention.

FIG. 3 is a sectional view of the airbag showing an inflated state.

[Explanation of symbols]

12 Casing 14 Cutter (Tip Blade Tip) 16 Screw (Auger Screw) 17 Soft Duct 22 Air Bag (Soft Duct Support Air Bag) 40 Reinforcement Layer 42 Reinforcement Layer

Claims (1)

[Claims] 1. An inflatable tubular air bag provided on the outer circumference of a casing of an auger screw for transmitting a thrust force of the original pushing jack to a tip blade end and having an annular air chamber capable of expanding / contracting therein, thereby allowing play in the air bag. A soft duct supporting air bag for use in a method of propelling and embedding the soft duct by supporting the fitted soft duct from the inside, wherein the soft duct supporting air bag is 0 ° to 45 ° with respect to a propelling direction. An air bag for supporting a soft duct, characterized in that it has a cord layer composed of cords that incline to each other.