JP3532804B2 - Method and apparatus for drawing small-diameter pipes into tunnels with sharp curves - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for simultaneously drawing a plurality of small diameter pipes into a tunnel having a steep curve portion such as an upslope, a downslope, and a meandering to the left and right.

[0002]

2. Description of the Related Art Conventionally, in order to simultaneously draw a plurality of small-diameter pipes into a tunnel buried in the ground, etc.
As shown in 0-061823 and FIG. 13, a plurality of small-diameter pipes 1 in which the other end 1c of another adjacent unit pipe 1a is inserted and connected via a packing 1d into a socket portion 1b of the unit pipe 1a. As shown in FIG. 14, a plurality of small-diameter pipes 1 are provided in parallel, and pipe receiving pedestals 2 for arranging and holding the plural small-diameter pipes 1 in parallel with each other are provided at intervals in the longitudinal direction. A roller 5 is provided on the base 2 so as to run on a rail 4 provided at the bottom of the tunnel 3, and the pipe receiving bases 2 lined up in the longitudinal direction of the small diameter pipe 1 are connected by upper and lower rod-shaped members 6 and positioned at the head. The pipe pedestal 2 is pulled from the front by the pulling wire 7 and drawn into the tunnel 3. Further, through holes are provided on both horizontal sides of each of the above-mentioned pipe pedestals, and both ends of the rod-shaped member are loosely penetrated through these through holes, and nuts are screwed to the ends projecting to the outside thereof, thereby forming a curved portion of the tunnel. When passing through, the rod-shaped member located outside the curved portion expands, the rod-shaped member located inside shrinks, and the other unit pipe 1a within the socket portion 1b of the unit pipe 1a of each small-diameter pipe 1 described above. The other end portion 1c of moves to pass the curved portion.

[0003]

However, as shown in FIG.
In the case of a sharp curve with a smaller radius of curvature, the pulling wire 7 pulling the leading pipe pedestal 2 in a direction greatly different from the center line of the tunnel 3 as shown in FIG. The pipe pedestal 2 is a rail 4 for pulling the pedestal 2.
And the unit pipes 1a of the small diameter pipe 1 are easily disconnected from each other. Such a conventional pulling-in method is intended for a gentle curve having a minimum radius of curvature of the tunnel of 35 m or more, and for a sharp curve portion of 35 m or less,
The posture of the pipe cradle is disjointed, derailing from the rail,
Small pipes may come off. This kind of tunnel
Since the inner diameter is usually narrow at about 1 m, if such an accident occurs especially in a sharp curve, the worker cannot easily enter the accident,
Restoration work is time-consuming and therefore extends the construction period, affecting the entire construction and causing a major problem.

Therefore, according to the present invention, the minimum radius of curvature is 35 m.
Even in the following sharp curves, the pipe trolley does not derail from the rail and the unit pipes that make up the small-diameter pipes are not disconnected from each other, and multiple small-diameter pipes that facilitate smooth work can be tunneled simultaneously. It is an object of the present invention to solve the above problems by providing a pull-in method and a device used in this method.

[0005]

According to a first aspect of the present invention, a plurality of small-diameter pipes, each of which has one end of a small-diameter unit pipe inserted into the other end of another small-diameter unit pipe and connected, are arranged in parallel.
A pipe pedestal to be supported is provided for each unit pipe of the small diameter pipe, and these pipe pedestals are connected to each other by rod-shaped members above and below the center of each pipe so that each pipe pedestal is located at the center line of the tunnel. In the method of pulling the above-mentioned pipe cradle located at the top and running each pipe pedestal on the rail provided at the bottom of the tunnel at the same time to draw a plurality of small diameter pipes into the tunnel, In front of the tunnel
Always fitted along the centerline of the tunnel when fitted inside
A leading carriage capable of traveling on the rail is provided, and the leading carriage and the leading pedestal are connected by a rod-shaped member, and a wire is attached to both ends of the leading trolley and the central horizons of the respective pedestals in the horizontal direction, These wires absorb the difference between the inner and outer arc lengths of the sharp curve , and the two adjacent pipes of the pipe pedestal
Place a rod-shaped member between the pedestals and in the center of the pipe pedestal.
Pipe pedestal fall prevention means consisting of a cliff-like arrangement
Was arranged at appropriate intervals, each unit pipe was fixed by each pipe pedestal, and the leading carriage was towed. A method of pulling a small-diameter pipe into a tunnel having a sharp curve was adopted.

In this case, when passing through a sharp curve, ton
By providing the above-mentioned leading carriage fitted in the channel, even if the towing member pulls the leading carriage from a direction different from the direction of the center line of the tunnel, each receiving pedestal will be along the center line of the tunnel. It is possible to drive and maintain a posture perpendicular to the center line of the tunnel. At the same time, of the wires located at both ends of the center of the leading carriage and each pipe pedestal in the horizontal direction, the wire runs on the outer arc wire and runs at each connection point of the unit pipe of each small diameter pipe. The end of the other unit pipe moves and bends in the socket, each pipe pedestal always maintains a posture perpendicular to the center line of the tunnel, and the small diameter pipe passes along the tunnel alignment. Also up
The small diameter pipe to be transferred on the slope or down slope
Even if it is long, two adjacent pipes in the pipe pedestal
Place a rod-shaped member between the pedestals and in the center of the pipe pedestal.
Pipe pedestal fall prevention means consisting of a cliff-like arrangement
Are arranged at appropriate intervals, so that
Tilt downwards due to the weight of the pipe and pipe pedestal
Prevents slopes and falls and is always perpendicular to the centerline of the tunnel
Can hold the posture. Furthermore, since each unit pipe is supported and fixed by the pipe pedestal, each unit pipe of the small diameter pipe absorbs the internal and external difference corresponding to the curvature in the sharp curve portion evenly and in small amounts. The pipe is designed so that it will not come off at sharp curves.

According to a second aspect of the invention, in the invention of the first aspect, the length of the wire between the adjacent pipe pedestals is a length calculated from the radius of curvature of the sharp curve portion. , As a result, when passing through a sharp curve, of the wires positioned at both ends of the center of the leading carriage and each of the pipe pedestals in the horizontal direction, those located in the outer arc extend to the full and are pulled by this outer wire. Subsequent pedestals will run, but each pedestal can maintain its vertical position relative to the tunnel centerline because the length of the wire is defined according to the curvature of the sharp curve. .

The invention of claim 3 is an apparatus used in the above method, wherein a plurality of small-diameter pipes in which one end of a small-diameter unit pipe is inserted and connected to the other end of another small-diameter unit pipe are connected in parallel. A pipe pedestal to be placed and supported on each unit pipe of the small diameter pipe is provided, and these pipe pedestals are connected to each other with a rod-shaped member at the center thereof so that each pipe pedestal is connected to the center line of the tunnel. In addition, at the lower end of each of these pipe pedestals, there is provided a roller to be mounted on a rail provided at the bottom of the tunnel, and a traction member is provided at the pipe pedestal at the top, and a plurality of small diameters are provided in the tunnel. In the device that pulls in the pipes at the same time, place the tunnel
A leading carriage that can be always run on the rail along the centerline of the tunnel in a state of being fitted in the rail is installed, and this leading carriage is connected to the leading bearing stand and towed to the leading carriage. A member is provided, and wires are attached to both ends of the center of the leading carriage and each of the pipe pedestals in the horizontal direction. These wires absorb the difference between the inner and outer arc lengths of the sharp curve portion, and each unit pipe is attached to each of the pipe pedestals. Of the above pipe holders
Between the two pedestals and the center of the pedestal
Pipe pedestal roll consisting of members arranged in a plow
The fall prevention means are arranged at appropriate intervals .

According to a fourth aspect of the present invention, in the above-mentioned third aspect of the invention, a speed control device such as a brake is provided on the leading carriage, so that even in an upward slope or a downward slope of a tunnel. It is possible to prevent reverse running and runaway. According to a fifth aspect of the present invention, in the invention according to the third or fourth aspect, rollers that are abuttable to the inner wall of the tunnel are respectively provided at the upper and central ends of the leading carriage and the respective tube receivers in the horizontal direction. It is provided by this, the above leading table
The car and each pedestal can be prevented from rising.

The invention according to claim 6 is the invention according to any one of claims 3 to 5, wherein the small-diameter pipe is provided with a bellows at a butt end of adjacent small-diameter unit pipes having a straight tubular shape. It is configured by covering and connecting a pipe or a flexible pipe. As a result, even at a portion having a curved portion with a smaller radius of curvature, it is possible to smoothly bend at the connecting portion of each unit pipe in accordance with the curve of the curved portion.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic structure of the present invention, in which one end of a unit pipe is inserted into the other end of another unit pipe to connect a plurality of small-diameter pipes 1 to each other, and a connecting portion 2 is provided with a connecting portion.
The small-diameter pipes 1 are arranged parallel to each other with a space between them, and the casters 5'which can freely move in the traveling direction are provided at the lower ends of the pipe pedestals 2 and the casters 5 ′ Is placed on the rail 4 of the tunnel 3, and the pipe pedestals 2 are arranged above and below the central portion of the pipe pedestals 2 respectively.
Are connected with. The unit pipe 1a has an outer diameter of about 150 mm and a length of about 2 m for accommodating the power cable.

In addition, a leading carriage 10 of a certain length is provided in front of the leading carriage 2 located at the head of these receiving carriages 2. The leading carriage 10 is provided at the lower ends of the front and rear portions thereof and can freely move in the traveling direction. The casters 11 are placed on the rails 4, and the leading carriage 10 and the leading pipe holder 2 are connected by bar-shaped members 12 above and below the center of the leading carriage 10 and a pulling wire 13 is provided at the front end of the leading carriage 10. The pulling wire 13 is pulled from the front of the tunnel 3, the leading carriage 10 and each of the pipe holders 2 are run along the rails 4, and a large number of small-diameter pipes 1 supported by the pipe holders 2 are introduced into the tunnel 3. Pull in. Further, rollers 14 are provided on the upper and left and right sides of the front and rear parts of the leading carriage 10 in proximity to the inner wall of the tunnel 3. Therefore, the leading carriage 10 can always run along the center line of the tunnel 3 while being fitted in the tunnel 3 as it were. Further, each caster 11 of the leading carriage 10 has a brake so that the traveling speed can be controlled.

Further, as shown in FIG. 2, the central portions of the tube receiving bases 2 in the horizontal direction as well as the leading tube receiving base 2 and the leading carriage 10 are connected so as to connect the adjacent pipe receiving bases 2 to each other.
A wire 8 is stretched between both ends in the horizontal direction of the central part of the. The length of each wire 8 between these adjacent pipe holders 2 and between the leading carriage 10 and the leading pipe holder 2 is calculated from the radius of curvature of the sharp curve portion of the tunnel 3 concerned. Match the length of the outer arc of.

As a result, as shown in FIG. 2, even if the tow wire 13 is towed from a direction different from the center line direction of the tunnel 3 at a sharply curved portion which is bent in the horizontal direction, the tow truck 10 receives the tow wire 13 and leads it. Since the pipe receiving pedestals 2 at the rear of the dolly 10 are connected by the rod-shaped members 6 and 12 (shown in FIG. 1) above and below the center of the pedestals 10, they will always travel along the center line of the tunnel 3. . Further, as shown in FIG. 3, the wire 8 stretched between both ends in the horizontal direction of the central part of each pipe pedestal 2 extends to the outside on the arc, and the wire 8 on the inside slackens and the wire to the outside. Although the pipe pedestal 2 runs by being pulled by 8, the length of the wire 8 is regulated according to the curvature of the sharp curve as described above, so that each pipe pedestal 2 is aligned with the center line of the tunnel 3. On the other hand, keep the vertical position and drive. As the wire 8, a wire having an outer diameter of 6 to 12 mm which is usually commercially available is used.

When the tunnel 3 has an upward slope and there is no conventional leading carriage, and only the tube holder is used to pass the tunnel, as shown in FIG.
As shown in FIG. 5, the pipe pedestal 2 cannot maintain the vertical posture with respect to the center line of the tunnel 3, so that the unit pipe of the small diameter pipe 1 may be disconnected.
5 is provided, the leading carriage 10 travels on the center line of the tunnel 3 and each of the succeeding receiving pedestals can maintain a vertical posture with respect to the center line of the tunnel 3, so that a smooth movement can be achieved. You can pull in. Further, also in the case of a down slope, the same effect as above is obtained.

Further, as shown in FIG. 6, in the connected small-diameter pipes 1, when the small-diameter pipes to be transferred become long on an upslope or a downslope, each pipe pedestal 2 has a small-diameter pipe 1 and a small-diameter pipe 1. Since the pipe pedestal 2 tilts and falls downward due to its own weight and the pipe pedestal 2 cannot hold the vertical line with the center line of the tunnel, the small-diameter pipe 1 may fall off the pipe pedestal 2. Therefore, as shown in FIG. 7, as a member that reinforces the rod-shaped member 6, the rod-shaped member is formed in a plow shape at the center of the pipe receiving base 2 and between two adjacent pipe receiving bases 2. The pipe pedestal tipping prevention means 6 ′ having the arranged configuration is appropriately and preferably arranged at about four pipe pedestals 2.

FIG. 8 shows the details. By providing the fall prevention means 6'in the central portion of the pipe pedestal 2, in order to prevent the pipe pedestal 2 from inclining downward in the slope, each pipe pedestal 2 is always aligned with the center line of the tunnel. On the contrary, it can maintain a vertical posture. This fall prevention means 6 '
Is arranged not only in the rear pipe pedestal 2 but also suitably in every four pipe pedestals 2 when the length of the connected small-diameter pipes 1 becomes long. This is because a force for inclining downwardly of the slope is likely to be applied to the pipe stand 2 in the middle and the middle, and this is prevented.

FIG. 9 is a detailed view of the above-mentioned pipe pedestal 2. The pipe pedestal 2 is composed of a lattice-shaped frame body, the small-diameter pipe 1 is passed through each frame, and the lower end of the leg 2a protruding downward. Is provided with a caster 5 ′ that can travel on a rail 4 provided at the bottom of the tunnel 3, and the inner wall surface of the tunnel 3 is provided at the upper part and the tips of the protruding arms 2 b, 2 c, 2 d protruding left and right, respectively. Is provided with a roller 15 that can freely come into contact with. Further, one end of a rod-shaped member 6 is connected to the upper and lower parts of the center of the pipe pedestal 2, and one end of a wire 8 is stopped at both ends in the horizontal direction of the central part, and the end of the wire 8 is locked. Is locked by a jig capable of adjusting the length of the wire 8 between the adjacent tube pedestals 2. In addition, the rod-shaped member 6 and the leading carriage 10 that connect the respective pipe holders 2 to each other and the first pipe holder 2
Each of the rod-shaped members 12 connecting to and is fixed at both ends so as to be angularly displaceable.

Further, in each of the pipe receiving bases 2, the supported small diameter pipes 1 are fixed. For this fixing, as shown in FIGS. 10 and 11, horizontal projecting pieces 16, 16 are provided on one side of the pipe pedestals 2 located above and below each small-diameter pipe 1, and the upper horizontal projecting piece 16 is loosely inserted. A movable holding piece 18 having a concave curved bottom surface is provided at the lower end of the rod 17, and two nuts 19 and 1 are provided on the upper and lower portions of the rod 17 which sandwich the horizontal projecting piece 16.
9 is screwed on, and these nuts 19 and 19 are moved so that the length of the rod 17 can be adjusted. Further, the holding piece 2 having a concave upper surface is placed on the horizontal projecting piece 16 located below.
0 is provided, and the small-diameter pipe 1 is sandwiched by the movable sandwiching piece 18 and the sandwiching piece 20. Further, since each unit pipe 1a is supported and fixed by the pipe pedestal 2, each unit pipe 1a of the small diameter pipe 1 evenly absorbs the curve even when passing through the above-mentioned sharp curve portion. However, the connection between the unit pipes 1a does not come off at the sharp curve.

In the embodiment described above, the socket portion provided at one end of the unit pipe 1a of the small-diameter pipe 1 is connected to the other end of the adjacent unit pipe 1a through the packing. As shown in FIGS. 12A and 12B, the bellows pipe 21 and the flexible pipe 22 are provided at the butt ends of the adjoining straight tubular unit pipes 1a ′ at the curved portions having a smaller radius of curvature. It is also possible to cover them by connecting them.
Further, the leading vehicle 10 of the present invention is not limited to the configuration of the above-described embodiment, as long as it can travel along the center line of the tunnel 3. Furthermore, the fixing structure of the pipe pedestal 2 and the small-diameter pipe 1 is not limited to the configuration of the above embodiment.

[0021]

According to the inventions of claims 1, 2 and 3, when passing through a sharp curve portion, a state of being fitted in a tunnel,
By providing the above-mentioned leading carriage, even if the towing member pulls the leading carriage from a direction different from the direction of the center line of the tunnel, the leading carriage travels along the center line of the tunnel, so that the trailing carriage connected to this leading carriage is Each pedestal can always maintain a posture perpendicular to the center line of the tunnel. At the same time, of the wires located at both ends of the center of each pipe pedestal, the wires outside the raceway run in a stretched state, and each unit of each small-diameter pipe is connected to another unit within each socket at each connection point of the pipe. By reducing the movement of the other end of the pipe, each pipe pedestal always maintains a posture perpendicular to the center line of the tunnel, and passes through the small diameter pipe along the tunnel alignment. Also, the pedestal
Transfer by providing a fall prevention means in the center of the
Even if the small-diameter pipe is long, it can
It is possible to prevent the platform from tipping down the slope and tipping over.
it can. Therefore, the pedestal should be perpendicular to the tunnel centerline.
Since the posture can be maintained at all times, smooth retraction is possible.
is there. Furthermore, since each unit pipe is supported and fixed by the pipe pedestal, the unit pipe of the small-diameter pipe uniformly absorbs the inner and outer differences corresponding to the curvature in the sharp curve portion in equal and small amounts. Is designed so that it does not come off on sharp curves. Therefore, according to the present invention, even in a tunnel having a sharp curve with a radius of curvature of 35 m or less, the pipe pedestal that supports and travels each small-diameter pipe does not come off the rail in the tunnel, and the small-diameter pipe is used. The unit pipes that make up the unit pipes can be smoothly drawn in without disconnecting each other.

The invention of claim 4 is the same as that of claim 3 above.
In addition to the effect of the invention of the item, the reverse run prevention and the runaway prevention can be achieved even at the uphill or downhill of the tunnel. In addition to the effect of the invention according to claim 1, the invention according to claim 5 can prevent the leading carriage and each pipe receiving stand from rising.
Smoother driving is possible even when passing through the sharp curve on the left, right, top and bottom of the tunnel. Further, in addition to the effects of the inventions of claims 3 to 5 , the invention of claim 6 has, in addition to the effects of the inventions of claims 3 to 5 , each unit pipe corresponding to the curve of the curved part even at a part having a curved part with a smaller radius of curvature. Since the bellows pipe and flexible pipe at the connecting point of are bent, a small-diameter pipe can be smoothly drawn in.

[Brief description of drawings]

FIG. 1 is a side view showing a schematic configuration in a tunnel according to an embodiment of the present invention.

FIG. 2 is a schematic plan view showing a state of a leading carriage and a pipe holder passing through a sharp curve portion of a tunnel according to an embodiment of the present invention.

FIG. 3 is a schematic plan view showing a state of each pipe pedestal and horizontal both-side wires passing through the sharp curve portion of the tunnel according to the embodiment of the present invention.

FIG. 4 is a schematic side view showing a posture state of each of the receiving pedestals at an upslope of the tunnel when there is no leading cart.

FIG. 5 is a schematic side view showing an attitude state of each pipe pedestal at an upslope of a tunnel according to an embodiment of the present invention.

FIG. 6 is a schematic side view showing the posture state of each pipe pedestal at the upslope of the tunnel in the case where there is no fall prevention means in the embodiment of the present invention.

FIG. 7 is a schematic side view showing a posture state of each pipe pedestal at an upslope of a tunnel in the case where a fall prevention unit is provided in an embodiment of the present invention.

FIG. 8 is a detailed view showing the configuration of the fall prevention means of the pipe pedestal shown in FIG. 7 according to the embodiment of the present invention.

FIG. 9 is a front view of a pipe pedestal supporting a plurality of small-diameter unit pipes in a tunnel according to an embodiment of the present invention.

FIG. 10 is a front view showing a structure for fixing the small diameter pipe to the pipe pedestal according to the embodiment of the present invention.

FIG. 11 is a side view showing the structure for fixing the small diameter pipe to the pipe pedestal according to the embodiment of the present invention.

FIG. 12 is a cross-sectional side view showing a mutual connection configuration of unit pipes forming a small diameter pipe in another embodiment of the present invention.

FIG. 13 is a cross-sectional side view showing a connection configuration of unit pipes forming the small diameter pipe of the present invention and the related art.

FIG. 14 is a schematic side view showing a conventional method for drawing a small diameter pipe into a tunnel.

FIG. 15 is a schematic plan view showing a passing state of a sharp curve portion in a conventional method of drawing a small diameter pipe into a tunnel.

[Explanation of symbols]

1 small diameter pipe 1a unit pipe 2 pipe pedestal 3 tunnel 4 rail 5 roller 5'caster 6 rod-shaped member 6'pipe cradle fall prevention means 7 traction member 8 wire 10 leading trolley 11 caster 12 rod-shaped member 13 traction wire 14 leading trolley Roller 15 Tube pedestal roller 21 Unsupported tube 22 Flexible tube

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Oba 4-83-3 Shibaura, Minato-ku, Tokyo Kandenko Kogyo Co., Ltd. (56) References JP 10-332044 (JP, A) JP JP 10-61823 (JP, A) JP-A-10-191540 (JP, A) JP-A-7-293746 (JP, A) JP-A-11-313423 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16L 1/00

Claims (6)

(57) [Claims] 1. A pipe pedestal for arranging and supporting a plurality of small-diameter pipes in which one end of a small-diameter unit pipe is inserted and connected to the other end of another small-diameter unit pipe in parallel. These pipe pedestals are connected to each other by rod-shaped members above and below the center of each pipe pedestal so that each pipe pedestal is located at the center line of the tunnel and the pipe pedestal at the top is pulled. In the method of pulling multiple small diameter pipes into the tunnel at the same time by running each pipe pedestal on the rail provided at the bottom of the tunnel, in front of the leading pipe pedestal, with the pipe fitted in the tunnel, A leading carriage that can always run on the rails along the center line is provided, and this leading carriage is connected to the leading bearing pedestal. Put a wire on the To absorb the difference in inner and outer arc length of the steep curve portion by these wires, among cradle the pipe, adjacent to
Between the two pedestals and in the center of the pedestal
Tube receiver composed of rod-shaped members arranged in a plow
Arrangement of front and rear fall prevention measures at intervals of about four
Then , each unit pipe is fixed on each of the pipe receiving bases, and the leading carriage is towed, and a method for pulling a small diameter pipe into a tunnel having a sharp curve portion. 2. The sharp curve portion according to claim 1, wherein the length of the wire between the adjacent pipe pedestals is a length calculated from the radius of curvature of the sharp curve portion. How to pull a small diameter pipe into a tunnel you have. 3. A pipe pedestal for arranging and supporting a plurality of small-diameter pipes in which one end of the small-diameter unit pipe is inserted and connected to the other end of another small-diameter unit pipe in parallel, Each of these pipe pedestals are connected to each other by rod-shaped members above and below the center of each pipe pedestal so that each pipe pedestal is located at the center line of the tunnel, and at the lower end of each pipe pedestal, In a device that is equipped with a caster to be mounted on a rail provided at the bottom of the tunnel and a traction member is provided on the pipe pedestal located at the beginning, in a device that simultaneously draws a plurality of small-diameter pipes into the tunnel, in front of the leading pipe pedestal ,
A leading carriage that can always run on the rails along the centerline of the tunnel in the state of being fitted in the tunnel is provided, and this leading carriage is connected to the leading receiver, and a traction member is attached to the leading carriage. Provide a wire on both ends of the leading carriage and the center of each pipe pedestal in the horizontal direction, and use these wires to absorb the difference between the inner and outer arc lengths of the sharp curve and fix each unit pipe with each pipe pedestal. Of the above pedestal
Between the two pedestals and in the center of the pedestal
Tube receiver composed of rod-shaped members arranged in a plow
Arrangement of front and rear fall prevention measures at intervals of about four
A device for drawing a small-diameter pipe into a tunnel having a sharp curve, characterized in that 4. The small diameter pipe drawing device for a tunnel having a sharp curve portion according to claim 3, wherein a speed control device is provided on the leading carriage. 5. A roller according to claim 3 or 4, characterized in that rollers are provided at the upper and center ends of the leading carriage and the respective tube supports so as to be able to come into contact with the inner wall of the tunnel. A device for drawing a small diameter pipe into a tunnel having a curved portion. 6. The small-diameter pipe is characterized in that it is constituted by connecting a butt end of adjacent small-diameter unit pipes of a straight tubular shape by covering it with a bellows pipe or a flexible pipe.
Item 7. A small-diameter pipe drawing device into a tunnel having a sharp curve portion according to any one of items 5 to 5 .