JP2001150224A - Cutting device for existing pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting device for a buried pipe comprising a structure allowing to prevent an increase of man-hours of a work by easily and surely performing drawing and removing of an internal cutter when a cutting work is finished in the existing pipe. SOLUTION: This cutting device for the existing pipe comprises a structure to cut a part of the existing pipe by a cutter so as to draw and remove the existing pipe buried in the ground. The cutter 3 is provided with a rotary driving shaft 6 inserted from one end of the existing pipe, a cutter edge 9 driven by the rotary driving shaft 6 capable of freely expanding and contracting a diameter, and a driving source 4 to drive the rotary driving shaft 6. The cutter edge 9 is composed of a swinging member to be freely swung to a direction allowing a cutting edge to contact/separate to/from an inner surface of the existing pipe, and the cutting edge is swung toward the inner surface of the existing pipe 1 since a swinging end on an opposite side to the cutting edge is pressed and moved by a diameter contracting and expanding driving member 8 moving together with the rotary driving shaft 6 in the axial direction. The rotary driving shaft 6 is provided with a returning part 20, in addition to the diameter contracting and expanding driving member 8, allowing to contract the diameter of the cutter edge 9 by pressing and moving the swinging end on the opposite side to the cutting edge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting device for an existing pipe, and more particularly, to a cutting edge returning mechanism of a cutting device used for removing an existing pipe without cutting.

[0002]

2. Description of the Related Art Existing pipelines are sometimes removed for reasons such as aging of existing pipelines or demolition of houses. One method of removing an existing pipe is to grab one end of the existing pipe, pull the end on the gripped side to advance the pipe, and pull out the existing pipe from the ground.

In the above-mentioned method, a shaft for excavating an existing pipe such as an aged pipe is excavated, and a drawing device is arranged in the shaft and a cutter for cutting the drawn existing pipe is provided. The existing pipe, which is disposed and whose end is grasped by the pulling device, is repeatedly removed from the existing pipe in the ground by repeating the process of cutting the portion exposed in the shaft when the cutter is pulled out with a predetermined stroke. Has become. The cavity after the existing pipe is removed is filled with, for example, sand or a fluidized backfill material to prevent the ground from sinking, or is renewed by providing a new pipe.

[0004]

However, when the existing pipe is removed by the above-mentioned method, there are the following problems. When pulling out the existing pipe, a large frictional resistance is generated between the existing pipe and the earth and sand due to the soil pressure, so that a traction driving force exceeding this frictional resistance is required. If the traction drive force is increased for the purpose of overcoming the frictional resistance acting on the existing pipe, the existing pipe may come off at the joint position if the existing pipe is connected by a joint. is there. Conventionally, since it is not detected that the pipe has come off at the position of the joint, the existing pipe that has come off remains in the ground, and there is a possibility that the existing pipe cannot be removed over its entire length. is there. Therefore, in the case of removing an existing pipe buried under a road, the ground may be cut to expose the existing pipe. However, when performing excavation work, it is desirable to increase work efficiency because traffic is interrupted or additional work such as backfilling work is required during the work. Therefore, in order to increase the efficiency of the excavation work, the labor and equipment required for the excavation work tend to be large, which causes a problem that the operation cost increases. Moreover, when removing existing pipes such as aging pipes left in private areas, it is difficult to perform the excavation itself because of the construction of houses.

[0005] On the other hand, it is conceivable to use an inner cutter provided with a rotary blade that can be inserted into an existing pipe, instead of performing cutting. According to such a configuration, since the cutting operation is performed from the inner surface of the existing pipe, the various adverse effects described above can be solved. However, in order to cut an existing pipe with the rotary blade, the cutting edge of the rotary blade is appropriately applied to the inner surface of the existing pipe, and cutting is performed by changing the cutting depth from that state. By the way, when the existing pipe is cut by the thickness of the existing pipe and the cutting is completed, the inner cutter is removed from the existing pipe, but if the cutting edge of the cutter blade has not returned to the original state, the inner cutter will be removed. It may not be possible to pull it out of the tube. In particular, if the cutting edge is stuck on the inner surface of the pipe, the condition cannot be resolved, and new work such as incising the existing pipe where the inner cutter is located using another tool is necessary. Sometimes, it is necessary to cut or cut to remove the cutter blade. However, since the work using the inner surface cutter is a non-cutting work, performing work such as cutting an existing pipe or performing new cutting causes an increase in cost due to an increase in the number of work steps.

SUMMARY OF THE INVENTION In view of the above problems in the apparatus used for cutting when removing an existing pipe, the object of the present invention is to easily and reliably pull out and remove the inner surface cutter when the cutting operation is completed in the existing pipe. An object of the present invention is to provide an existing pipe cutting device having a configuration capable of preventing an increase in the number of work steps.

[0007]

In order to achieve this object, according to the present invention, a part of an existing pipe is cut by a cutter in order to pull out and remove the existing pipe buried underground. In the existing pipe cutting device having a structure, the cutter includes a rotary drive shaft inserted from one end of the existing pipe, a cutter blade that can be expanded and reduced in diameter by being rotationally driven by the rotary drive shaft, A drive source for driving a rotary drive shaft, the cutter blade is constituted by a swing member capable of swinging in a direction in which the cutting edge comes into contact with and separates from the existing pipe inner surface, and a swing end opposite to the cutting edge is provided. The cutting edge is swung toward the inner surface of the existing pipe by being pushed and moved by a diameter-enlarging and reducing-diameter driving member that moves in the axial direction together with the rotary drive shaft, and the rotary drive shaft includes And reduced diameter drive member Separately, it is characterized in that a return part which can reduce the diameter of the cutter blade by moving down the opposite swinging end of the cutting edge is provided.

According to a second aspect of the present invention, the return portion is opposite to the diameter-enlargement and diameter-reduction drive member across a swinging end opposite to a cutting edge of the cutter blade in an axial direction of the rotary drive shaft. And pushes the oscillating end of the cutter blade in opposition to the oscillating end of the cutter blade opposite to the cutting edge in conjunction with the expanding portion of the diametrically increasing and decreasing drive member moving away from the cutter blade. It is characterized in that it is moved to separate the cutting edge of the cutter blade from the inner surface of the existing pipe.

[0009]

According to the first and second aspects of the present invention, apart from the diameter-enlarging and diameter-reducing driving member, which is a member for swinging the cutter blade in the direction of moving toward and away from the inner surface of the existing pipe, the side opposite to the blade edge of the cutter blade. Since the return member that separates the blade edge of the cutter blade from the existing pipe inner surface by pushing and moving the rocking end in opposition to the rocking end of The cutting edge of the cutter blade cut in contact with the inner surface of the pipe can be forcibly returned to the reduced diameter position. Thus, even if the cutting edge is caught on the inner surface of the pipe, the diameter is forcibly reduced, so that the cutter blade can be easily pulled out of the pipe without interference between the cutter blade and the inner surface of the pipe.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a schematic diagram showing a state of a removing operation using an existing pipe cutting device according to an embodiment of the present invention. In the drawing, when the existing pipe 1 is removed, a cutting device 2 corresponding to the cutting device is connected to the existing pipe 1. And the cutting operation is performed at the cutting position. In the case of the present embodiment, the cutting device 2 used for the cutting operation is provided with an electric motor 4 located outside the end of the existing pipe 1 and serving as a rotational drive source of a cutter 3 described later, and an output shaft of the electric motor 4. A reduction gearbox 5 serving as an axis;
A flexible shaft 6 is connected to the output side of the reduction gear box 5 and corresponds to a shaft that rotationally drives a cutter blade 9 described later. The cutter 3 is connected to the tip of the flexible shaft 6.

As shown in FIG. 2, the flexible shaft 6 is composed of a plurality of wires arranged in layers, and a wire group located in the inner layer is formed as a core wire group 6A. The wire group located in the outer layer of the core wire group 6A is configured as an outer cylinder wire group 6B. One end of the core wire group 6 </ b> A of the wire group is connected to a diameter-enlarging and diameter-reducing drive member 8 of the cutter 3 described later, and the other end is connected to the output shaft of the reduction gear box 5. Outer cylinder wire group 6B
Is connected at one end to the output shaft of the reduction gearbox 5 and at the other end to a cutter blade support member 7 of the cutter 3 described later. The core wire group 6A constituting the flexible shaft 6 has a smaller diameter than the outer cylinder wire group 6B, and is inserted into the outer cylinder wire group 6B to be rotatable. For this reason. The peripheral speed is set to be smaller than that of the outer cylinder wire group 6B.
The difference in the peripheral speed is set based on the relationship between the rotation speed of the cutter blade 9 described later and the cutting speed into the existing pipe 1, that is, the so-called feed speed of the cutter blade 9. Also,
In each wire group, the wires connected to the output shaft of the reduction gear box 5, the rotation support member 7 described later, and the diameter-enlargement and diameter-reduction drive member 8, respectively, are rotated in the winding direction so as to be rotated. Is set. This allows
When the core wire group 6A and the outer cylinder wire group 6B rotate, they are tightened, so that there is no looseness in the extending direction of the wire group, and loss of torque transmission is reduced.

The construction of the cutter 3 is shown in FIG. FIG. 3 shows a cutter blade 9 provided on the cutter 3.
The upper and lower sides of the center line indicate the time of diameter reduction, and the lower side of the center line indicates the time of diameter expansion. In FIG. 3A, the cutter 3 includes a rotation support member 7 for the cutter blade 9 and a drive member 8 for increasing and reducing the diameter of the cutter blade 9. A screw rod 10 is inserted through the center of the rotation support member 7, and the screw rod 10 can rotate by screwing halfway in the axial direction to a nut portion 7 </ b> A fixed in the rotation support member 9. . The screw rod 10 is supported by a nut 7A so that it can move in the axial direction when rotated. As shown in FIG. 3B, one end of the rotation support member 7 is provided with an opening 7B at which a cutter blade 9 described later can be protruded and retracted at an even position along the circumferential direction. The base of the cutter blade 9 is pivotally supported between the portions 7B.

As shown in FIG. 3B, the cutter blades 9 are arranged at three divided positions in the circumferential direction of the threaded rod 10, and a support shaft 9A provided at the base is pivotally supported by the rotation support member 7. The swinging end can be swung.
As shown in FIG. 3B, cutting blades are formed, each having a predetermined angle as a cutting edge and, as shown in FIG. .

In FIG. 3A, the diameter-enlarging and diameter-decreasing driving member 8 has a tapered cone-shaped outer peripheral surface at one axial end located on the guide portion 7B side of the rotation supporting member 7.
A is fixed. The enlarged diameter portion 8A is opposed to the inside of the swing end of the cutter blade 9, and when the large diameter portion is opposed to the swing end of the cutter blade 10, the cutter blade 9 is pushed in the radial direction and moved in the radially enlarged direction. Can be. As shown in FIG. 3A, a pin 11 is inserted through the other end in the axial direction of the diameter-enlargement and reduction-diameter driving member 8, and this pin 11 is connected to the center wire portion 6 </ b> A of the flexible shaft 6. It is inserted and integrated into a hole 12A formed in the connected rotating body 12. Thus, the screw rod 10 can rotate independently even when the rotation support member 7 cannot rotate.

On the other hand, in the axial direction of the threaded rod 10, the cutter blade 9 is placed in the reduced-diameter state at a position opposite to the enlarged-diameter portion 8 A of the drive member 8 with the diameter increased and reduced with the support shaft 9 A of the cutter blade 9 interposed therebetween. The return member 20 for returning to the above is integrated. The return member 20 is formed of a piece member having a tapered cone portion 20A opposed to a pressing piece portion 9B formed at a swinging end opposite to the cutting edge with respect to the support shaft 9A of the cutter blade 9. The tapered cone portion 20A is formed with a gradient surface whose diameter increases as the threaded rod 10 moves in a direction in which the diameter expanding portion 8A of the diameter expanding and reducing drive member 8 moves away from the inner surface of the cutter blade 9. For this reason, when the screw rod 10 moves in the direction in which the enlarged diameter portion 8A moves away from the inner surface of the cutter blade 9, the pressing piece 9B of the cutter blade 9 is pushed and moved by the tapered cone portion 20A, and the cutting edge of the cutter blade 9 is cut. The cutter blade 9 swings in a direction away from the inner surface of the existing pipe 1.

Since the present embodiment has the above configuration,
When the flexible shaft 6 is inserted toward the cutting position and the cutter 3 is positioned, the electric motor 4 is started and the cutting of the existing pipe 1 can be started. When the electric motor 4 is not operating, the diameter of the cutter blade 9 is reduced by the urging of the elastic body, but when the electric motor 4 is started, the diameter of the cutter blade 9 is expanded via the flexible shaft 6. That is, of the flexible shaft 6,
Since the core wire group 6A connected to the rotating body 12 and integrated with the screw rod 10 has a higher peripheral speed than the outer cylinder wire group 6B connected to the rotation support member 7, the screw rod 10 can be quickly moved. Rotating to enlarge and reduce the diameter of the drive member 8
A is opposed to the swinging end of the cutter blade 9. This allows
The cutter blade 9 swingably supported by the rotation supporting member 7 cuts the existing pipe 1 by the rotation of the cutter blade 9 and the expanding operation by the pressing operation of the expanding portion 8A.

When the cutting operation of the existing pipe 1 is completed, the electric motor 4 is restarted in the opposite direction to the conventional one, and
Moves in the opposite direction. When the screw rod 10 moves as described above, the enlarged diameter portion 8A of the enlarging / reducing drive member 8 moves away from the inner surface of the cutter blade 9, and the return member 20 is replaced by the pressing piece portion of the cutter blade 9. 9B, the pressing piece 9B is pressed and moved. As a result, the cutter blade 9 swings in a direction in which the blade edge is separated from the inner surface of the existing pipe 1. Therefore, even if the blade edge is stuck on the peripheral wall of the existing pipe 1, the blade edge is forcibly applied. The cutter blade 9 can be returned to the reduced diameter state by being separated from the peripheral wall.

When the cutter blade 9 returns to the reduced diameter state, the cutter 3 can be pulled out from the existing pipe 1.
The cutter 3 can be easily collected and the operation can be shifted to the operation of drawing out the existing pipe 1.

[0019]

According to the first and second aspects of the present invention,
Separately from the diameter-enlargement and diameter-reduction drive members that swing the cutter blade toward and away from the inner surface of the existing pipe, the swing end is opposed to the swing end opposite to the blade edge of the cutter blade. A return member that pushes and moves the blade edge of the cutter blade away from the inner surface of the existing pipe is provided so as to be interlocked with the rotary drive shaft. It can be forcibly returned to the reduced diameter position. Thus, even if the cutting edge is caught on the inner surface of the pipe, the diameter is forcibly reduced, so that the cutter blade can be easily pulled out of the pipe without interference between the cutter blade and the inner surface of the pipe. As a result, since the cutting device does not remain in the pipe after cutting, it is possible to eliminate work such as cutting and cutting for taking out the pipe and prevent an increase in working time.

[Brief description of the drawings]

FIG. 1 is a schematic view for explaining a removal operation state using an existing pipe cutting device according to an embodiment of the present invention.

FIGS. 2A and 2B are diagrams for explaining a configuration of a shaft held by the cutting device according to the embodiment of the present invention, wherein FIG. 2A shows a core wire group and FIG.

FIG. 3 is a view for explaining a main configuration of a cutting device according to an embodiment of the present invention, wherein FIG.
(B) is an arrow view in the direction indicated by reference numeral (B) in (A).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Existing pipe 2 Cutting device 3 Cutter 4 Electric motor which serves as a rotation drive source 5 Reduction gear box 6 Flexible shaft corresponding to a rotation drive shaft 6A Middle core wire group 6B Outer cylinder wire group 7 Rotation support member 7B Guide part 8 Expansion Diameter and diameter reduction drive member 8A Large diameter part 9 Cutter blade 10 Screw rod 20 Return member 21 Tapered cone part

Claims (2)

[Claims] 1. An existing pipe cutting device having a structure in which a part of an existing pipe is cut by a cutter in order to pull out and remove the existing pipe buried in the ground, wherein the cutter is configured to cut the existing pipe. A rotary drive shaft inserted from one end, a cutter blade that can be enlarged and reduced in diameter driven by the rotary drive shaft, and a drive source that drives the rotary drive shaft; It is constituted by a swinging member capable of swinging in a direction in which the cutting edge comes into contact with and separating from the inner surface of the pipe, and a swinging end opposite to the cutting edge is pushed by a diameter-enlarging and reducing-diameter driving member that moves in the axial direction together with the rotary drive shaft. It is configured to swing the blade edge toward the inner surface of the existing pipe by being moved, and the rotary drive shaft has a swing end opposite to the blade edge separately from the diameter-enlargement and diameter-reduction drive members. Push and move the cutter Cutting device of the existing pipe, characterized in that the return part is provided which can reduce the diameter of the. 2. The return section is disposed on the opposite side of the diameter-enlarging and diameter-reducing drive member across a swinging end opposite to a cutting edge of the cutter blade in an axial direction of the rotary drive shaft. As the enlarged diameter portion of the diameter-enlargement and diameter-reduction drive member moves away from the cutter blade, it opposes the swing end of the cutter blade opposite to the blade edge and pushes the swing end thereof, thereby moving the blade edge of the cutter blade. 2. The apparatus for cutting an existing pipe according to claim 1, wherein the apparatus is separated from an inner surface of the existing pipe.