JP6022974B2 - How to remove existing pipes - Google Patents

Description

  This invention is drawn into the inner circumference of an existing pipe buried in the ground and inserted into a specific part of a newly laid pipe by inserting a branch joint into the specified part. The present invention relates to a method for removing an existing tube that removes a portion covering a portion. Specifically, even in the case of a new pipe laid on the inner peripheral part of the existing pipe after the diameter expansion, which is cut at one cutting portion along the axial direction and expanded in a substantially U-shaped shape. The present invention relates to a method for removing an existing pipe that can remove a part of the existing pipe that covers a range of a specific part.

  Many conduits such as a gas conduit for sending fuel gas and a water pipe for flowing clean water are buried in the ground. Conventionally, pipes such as steel pipes and ductile cast iron pipes are generally used as gas conduits. When such a pipe is aged, when a large external force such as an earthquake is applied to the pipe, the pipe may be greatly damaged. Therefore, replacement of an old pipe with a new pipe made of a flexible material such as a polyethylene pipe has been promoted. When excavating the entire section where the existing pipes are buried when replacing the existing pipes, the construction is large and the construction period is long, and the impact on the surrounding traffic conditions increases. A non-open-cut pipe replacement method is used in which the pipe is replaced without excavation.

  In the non-open-cut pipe replacement method, an existing pipe is cut at two or more locations along its axial direction and divided into three or more divided pieces, and then the new pipe is divided into a plurality of divided pieces. There is a first construction method in which the existing pipe is drawn inside and laid. In addition, the existing pipe is cut at one cutting portion along the axial direction, and the existing pipe after cutting is expanded into a substantially U-shaped shape, and then the new pipe is replaced with the existing pipe after the expansion. There is a second construction method in which it is drawn into the inner periphery and laid. When it is necessary to branch a branch pipe (supply pipe, etc.) from a specific part of the new pipe that is the main pipe after laying the new pipe by the non-open pipe replacement method, the branch joint interrupts the specific part of the new pipe Placed and connected.

  When such a branch joint is connected to a specific part of a new pipe laid on the inner periphery of the existing pipe, it is necessary to remove a part of the existing pipe over a range covering the specific part. A part of the existing pipe is cut and removed using the cutting device disclosed in No. 1. FIG. 15 is an explanatory view showing the entire cutting device disclosed in Patent Document 1. FIG. 16 is a view for explaining the cast iron pipe holding member of the cutting apparatus shown in FIG. 15, and FIG. 17 is a view for explaining the cast iron pipe cutting member of the cutting apparatus shown in FIG.

  In Patent Document 1, when a synthetic resin pipe 211 (corresponding to a newly installed pipe) is laid, a cast iron pipe 201 (corresponding to an existing pipe) is divided into four equal parts in the circumferential direction and four parts cut along the axial direction. It is a piece, and the cross-sectional shape of the cast iron pipe 201 (four divided pieces) after cutting is a substantially annular shape including a cut portion. The synthetic resin pipe 211 having a diameter smaller than that of the cast iron pipe 201 is drawn into the cast iron pipe 201 after cutting and laid. In the cutting device of Patent Document 1, as shown in FIGS. 15 and 16, in the split holders 103, 103 in the cast iron pipe holding members 101, 101, the semicircular arc-shaped recesses 103 a, 103 a are respectively cast iron pipes. Are fixedly attached to the four divided pieces by four fastening bolts 108b through the recesses 103a and 103a. In this state, in the split holders 109 and 109 in the cast iron pipe cutting member 102, each of the semicircular arc-shaped recesses 109a and 109a surrounds and holds the outer periphery of the cast iron pipe 201, and the recesses 109a and 109a have 4 The two rotary blades 111 of the cast iron pipe cutting mechanism 114 are moved along the outer periphery of the cast iron pipe 201 within a range of a rotation angle of 90 degrees. Since the cast iron pipe 201 is cut in advance along the axial direction into four divided pieces, in Patent Document 1, the four pieces are divided at a specific portion where a branch joint is to be connected to the synthetic resin pipe 211. Among them, in order to remove a part of the cast iron pipe 201 in a specific range that covers the specific part, the rotary blade 111 cuts the four divided pieces in a circle on both sides in the axial direction of a part of the cast iron pipe 201. Thereby, a part of the cast iron pipe 201 can be removed from the four divided pieces.

Japanese Patent Laid-Open No. 2000-198816

However, Patent Document 1 has the following problems. The technology of Patent Document 1 is based on the premise of the first method of non-open-cut pipe replacement, and cannot be used at the site where a new pipe is laid by the second method, and a branch joint is connected to the new pipe. In the specific part to be tried, a part of the existing pipe covering the range of the specific part cannot be removed. The reason is
(1) In the second construction method, in order to draw the new pipe into the inner periphery of the existing pipe, the existing pipe is cut along one axis along the axial direction, and the existing pipe after cutting is substantially U-shaped. Unlike the first construction method, the cross-sectional shape of the existing pipe after cutting is not a substantially annular shape including the cut portion. Therefore, in Patent Document 1, the semicircular recesses 103a and 103a of the split holders 103 and 103 in the cast iron pipe holding members 101 and 101 and the semicircles of the split holders 109 and 109 in the cast iron pipe cutting member 102 are disclosed. The arc-shaped recesses 109a and 109a cannot surround and hold the outer periphery of the existing pipe whose diameter has been expanded into a substantially U-shape. Therefore, it is impossible to remove a part of the existing pipe by cutting the existing pipe whose diameter is enlarged to a substantially U shape by the rotary blade 111 of the cast iron pipe cutting mechanism 114 using the cutting device of Patent Document 1.
(2) In addition, in the second construction method, the existing pipe is cut only at one location along the axial direction, and the cutting device disclosed in Patent Document 1 simply cuts the existing pipe and cuts the existing pipe. No cutting is performed along the axial direction. For this reason, it is not possible to remove a part of the existing pipe by simply cutting the both sides in the axial direction of the part of the existing pipe covering the specific part of the new pipe.

  The present invention was made to solve the above problems, and when connecting a joint to a specific part of a new pipe that is drawn into the existing pipe and laid, the shape of the existing pipe that covers the new pipe is obtained. However, an object of the present invention is to provide a method of removing an existing pipe that can easily remove a part of the existing pipe that covers the range of the specific portion.

In order to solve the above problems, the existing pipe removing method of the present invention has the following configuration.
(1) Of the existing pipes laid on the inner periphery of the existing pipes buried in the ground, cover the planned connection parts of the existing pipes against the planned connection parts that are to be connected by interrupting the joints. In the method of removing the existing pipe that removes the connection surrounding portion, the first cutting blade is moved in the circumferential direction of the existing pipe, and the existing pipe is moved in the circumferential direction relative to the position corresponding to the connection planned section. Is provided with a circumferential cutting step in which the existing pipe is divided on both sides in the axial direction across the planned connection surrounding portion, and in the circumferential cutting step, the outer periphery of the existing pipe is shaped into the shape of the existing pipe. Correspondingly wrapping the existing pipe with a guide member that can be covered, and moving the first cutting blade around the existing pipe with the first cutting device held by the existing pipe via the guide member, connection For the position corresponding to the planned part, the existing pipe is the axis along the axial direction. In a state where at least two places are cut at the cutting part, the pipe is divided into a plurality in the circumferential direction of the existing pipe, and the planned connection surrounding part is in a state where the shaft side cutting part and the peripheral side cutting part are crossed and cut. It is removed afterwards.
(2) In the method for removing an existing pipe described in (1), the existing pipe is cut in at least one of the two axial cut portions and then expanded in diameter when the new pipe is installed. Further, it is characterized in that it is deformed into a shape having a wide spacing portion between the cut end portions on both sides which are cut at the shaft side cutting portion and separated from each other.
(3) In the method for removing an existing pipe described in (1) or (2), the guide member is a flexible plate-like member that can be deformed along the shape of the existing pipe. .
(4) In the method for removing an existing pipe described in any one of (1) to (3), the first cutting device is disposed around the guide body and the device main body portion on which the first cutting blade is disposed. A long holding member that hangs around and holds the apparatus main body on the existing pipe, and in the circumferential cutting step, the holding member moves relative to the guide member along the circumferential direction of the existing pipe. Thus, the apparatus main body moves along the circumferential direction of the existing pipe, and the first cutting blade cuts the circumferential cutting part.
(5) In the method for removing an existing pipe described in (4), the holding member is a chain.

(6) In the method for removing an existing pipe described in any one of (1) to (5), the first cutting blade is a disk-shaped blade that rotates about the first rotation axis, and has a cylindrical shape. A first depth-of-cut limiting member formed with an outer peripheral surface, and the axis of the first outer peripheral surface of the first depth-of-cut-limited member and the first rotation axis of the first cutting blade are coaxial. The first diameter difference that is the difference between the first cutting blade radius that is arranged and the radius of the first cutting blade and the first limiting member radius that is the radius of the first cutting depth limiting member is the existing pipe. The thickness equal to the thickness in the radial direction or the first diameter difference is set to be larger than the thickness within an allowable error range.
In the configuration (6), the “allowable error range” means that the first outer peripheral surface of the first cut depth limiting member is attached to the guide member that wraps the existing pipe with respect to the existing pipe covering the new pipe. When the peripheral cutting part is being cut with the first cutting blade in a state of contact or in a state where the first outer peripheral surface of the first cutting depth limiting member is in contact with the outer peripheral surface of the existing pipe, Even if the cutting edge of a 1st cutting blade exceeds the internal peripheral surface of an existing pipe, it says the tolerance | permissible_range which can be settled to the extent which reaches | attains the outer peripheral surface of the new pipe in the existing pipe, and does not contact. In particular, the existing pipe after laying the new pipe, for example, when the diameter of the existing pipe is expanded to a substantially U-shape, or the replacement of the existing pipe by the non-open-cut pipe replacement method, There are cases where the axis center of the planned connection surrounding portion is warped, and the planned connection surrounding portion is not linear but bent. Even in such a case, in the circumferential direction of the existing pipe, the inner peripheral surface of the existing pipe and the outer peripheral surface of the new pipe are close to each other, and the gap between both surfaces is the smallest. The allowable range in which the cutting edge can be accommodated to such an extent that it does not contact the outer peripheral surface of the new pipe.

(7) In the method for removing an existing pipe described in any one of (1) to (6), a second cutting device having a second cutting blade for cutting the shaft-side cutting portion is used. The cutting blade is a disk-shaped blade that rotates about the second rotation axis, has a second cutting depth limiting member formed with a cylindrical second outer peripheral surface, and has a second cutting depth limiting member. The axial center of 2 outer peripheral surfaces and the 2nd rotating shaft of a 2nd cutting blade are arrange | positioned coaxially, the 2nd cutting blade radius which is a radius of a 2nd cutting blade, and 2nd cutting depth restriction | limiting The second diameter difference, which is the difference from the second limiting member radius, which is the radius of the member, is equal to the thickness in the radial direction of the existing pipe, or the second diameter difference is within the allowable error range from the wall thickness. It is characterized in that it is set to a large value.
In the configuration (7), the “allowable error range” means that the second outer peripheral surface of the second cut depth limiting member is in contact with the outer peripheral surface of the existing pipe covering the new pipe. When the side cutting part is cut with the second cutting blade, even if the cutting edge of the second cutting blade exceeds the inner peripheral surface of the existing pipe, it reaches the outer peripheral surface of the new pipe inside the existing pipe and makes contact This is the allowable range that can be accommodated to the extent that In particular, the existing pipe after laying the new pipe, for example, when the diameter of the existing pipe is expanded to a substantially U-shape, or the replacement of the existing pipe by the non-open-cut pipe replacement method, There are cases where the axis center of the planned connection surrounding portion is warped, and the planned connection surrounding portion is not linear but bent. Even in such a case, in the circumferential direction of the existing tube, the inner peripheral surface of the existing tube and the outer peripheral surface of the new tube are close to each other, and the gap between both surfaces is the smallest. The allowable range in which the cutting edge can be accommodated to such an extent that it does not contact the outer peripheral surface of the new pipe.

The operation and effect of the method for removing an existing pipe of the present invention having the above configuration will be described.
(1) Of the existing pipes laid on the inner periphery of the existing pipes buried in the ground, cover the planned connection parts of the existing pipes against the planned connection parts that are to be connected by interrupting the joints. In the method of removing the existing pipe that removes the connection surrounding portion, the first cutting blade is moved in the circumferential direction of the existing pipe, and the existing pipe is moved in the circumferential direction relative to the position corresponding to the connection planned section. Is provided with a circumferential cutting step in which the existing pipe is divided on both sides in the axial direction across the planned connection surrounding portion, and in the circumferential cutting step, the outer periphery of the existing pipe is shaped into the shape of the existing pipe. Correspondingly wrapping the existing pipe with a guide member that can be covered, and moving the first cutting blade around the existing pipe with the first cutting device held by the existing pipe via the guide member, connection For the position corresponding to the planned part, the existing pipe is the axis along the axial direction. In a state where at least two places are cut at the cutting part, the pipe is divided into a plurality in the circumferential direction of the existing pipe, and the planned connection surrounding part is in a state where the shaft side cutting part and the peripheral side cutting part are crossed and cut. After that, when the new pipe is drawn and laid on the inner circumference of the existing pipe that was previously buried by the non-open-cut pipe replacement method, the shape of this existing pipe is newly established. In some cases, the shape of the first cutting blade of the first cutting device may be changed in the circumferential cutting step regardless of the shape of the existing pipe after the new pipe is laid. Can move around the existing pipe and cut the peripheral cutting part.

  That is, two or more existing pipes are previously provided along the axial direction in the existing pipe in which the new pipe is laid on the inner periphery by the non-open-cut pipe replacement method, as in Patent Document 1 cited in the related art. Are cut into three or more divided pieces, and the interval between adjacent divided pieces is relatively narrow, and the shape of the existing pipe after cutting is the same as the shape before cutting. It has n’t changed much. In the cutting device of Patent Document 1, even if the existing pipe is divided into four pieces, the periphery of the four divided pieces is held, and the cutting blade passes between the adjacent divided pieces. The whole four pieces can be cut. However, in the existing pipe in which the new pipe is laid on the inner periphery by the non-open-cut pipe replacement method, the existing pipe is cut at one cutting portion along the axial direction, for example, and the existing pipe after cutting is installed. In some cases, after the pipe is expanded to a substantially U shape, the newly installed pipe is drawn into the inner peripheral portion of the existing pipe after the diameter expansion. In such a case, the existing pipe is separated into two parts by expanding the diameter, with the cut part cut by the cutting part interposed therebetween, and the distance between the divided parts separated from each other becomes large, and the new pipe is laid. The shape of the existing existing pipe changes greatly from that before laying. The cutting device of Patent Document 1 cannot be used unless the cross-sectional shape of the existing pipe after cutting is a substantially annular shape including a cutting portion, and the existing pipe whose diameter is expanded into a substantially U-shape is cut into a ring. I can't do it.

  On the other hand, the existing pipe removing method of the present invention wraps the outer circumference of the existing pipe with a guide member, for example, at a position adjacent to the moving path of the first cutting blade. As a result, as exemplified above, when the new pipe is replaced, such as an existing pipe whose diameter has been expanded to a substantially U-shaped shape, it is cut at the cutting portion along the axial direction, and this diameter is increased by sandwiching the cutting portion. Even with existing pipes in which the distance between the separated parts is increased and the shape of the existing pipe after the installation of the new pipe has changed significantly from that before the installation, the first cutting device can surround the existing pipe through this guide member. Can be held movably along and installed. Therefore, since the 1st cutting device can be installed so that movement around the existing pipe is possible irrespective of the shape of an existing pipe, the peripheral side cutting part of an existing pipe can be cut with the 1st cutting blade. Of course, as in Patent Document 1, an existing tube having a substantially annular shape that has been divided into three or more pieces that have been cut in advance along two or more cutting portions along the axial direction. The 1 cutting device can be moved around the existing pipe, and the peripheral cutting part of the existing pipe can be cut by the first cutting blade.

  By the way, when the existing pipe is cut by one cutting part along the axial direction and the existing pipe after cutting is expanded in a substantially U shape, as exemplified above, the circumferential cutting step In this case, even if the existing pipe is divided on both sides in the axial direction sandwiching the planned connection surrounding portion, the connection planned surrounding portion crosses the new installation pipe by only one spaced apart portion divided into two parts by expanding the diameter. It cannot be removed. The removal method of the existing pipe of the present invention includes such a separation portion, and there are at least two cutting portions cut by the shaft-side cutting portion, so that the existing pipe is removed from the position corresponding to the planned connection portion. The connection surrounding part of the pipe can be divided into a plurality of parts in the circumferential direction. In addition, if the cutting portion including the above-described separation portion and cut by the shaft-side cutting portion and the cutting portion obtained by dividing the existing pipe on both sides in the axial direction sandwiching the connection surrounding portion are crossed, The planned connection surrounding portion can be easily removed from the position corresponding to the planned connection portion of the new pipe among the existing pipes without crossing the new pipe.

  Therefore, according to the method for removing an existing pipe of the present invention, even when a joint is connected to a connection planned portion (specific part) of the new pipe drawn into the existing pipe and laid, the existing pipe covering the new pipe Regardless of the shape, there is an excellent effect that it is possible to easily remove a part of the existing pipe covering the range of the specific part (scheduled connection surrounding part).

  Of course, even when a new pipe having a diameter smaller than the diameter of the existing pipe remains in the shape of the existing pipe buried in the ground, it is drawn into the inner periphery of the existing pipe and laid. According to the existing pipe removing method, the connection surrounding portion can be easily removed.

(2) In the method for removing an existing pipe described in (1), the existing pipe is cut in at least one of the two axial cut portions and then expanded in diameter when the new pipe is installed. The shaft of the existing pipe having an enlarged diameter is characterized in that it is deformed into a shape having a wide spacing portion between the cut end portions on both sides which are cut at the shaft side cutting portion and separated from each other. Even when the existing pipe is deformed into a shape having a wide spacing portion, such as a U-shaped shape, a horseshoe shape, etc., as a cross-sectional shape in the direction, the guide member is entirely around the outer circumference of the existing pipe. As a result, the movement path of the first cutting blade of the first cutting device can be ensured without interruption around the entire circumference of the guide member covered on the existing pipe. Thereby, the 1st cutting device can move the perimeter of an existing pipe, and can cut the peripheral side cutting part of an existing pipe with the 1st cutting blade irrespective of the shape of an existing pipe. .

(3) In the method for removing an existing pipe described in (1) or (2), the guide member is a flexible plate-like member that can be deformed along the shape of the existing pipe. Therefore, when laying a new pipe, the existing pipe has a cross-section in the axial direction, such as a U-shaped shape, a horseshoe shape, etc. Even when the guide member is greatly deformed, the guide member can cover the outer periphery of the existing pipe corresponding to the outer peripheral shape of the deformed existing pipe. Thereby, regardless of the shape of the existing pipe, the moving path of the first cutting blade of the first cutting device can be ensured without interruption around the entire circumference of the guide member covered by the existing pipe. Moreover, in an actual site, foreign matter such as earth and sand or rust may adhere to the outer peripheral surface of the existing pipe. In this case, regardless of the shape of the existing pipe, the guide member is covered on the outer peripheral surface of the existing pipe, and the first cutting device can move along the outer peripheral surface of the guide member. , Can move smoothly around the existing pipe.

(4) In the method for removing an existing pipe described in any one of (1) to (3), the first cutting device is disposed around the guide body and the device main body portion on which the first cutting blade is disposed. A long holding member that hangs around and holds the apparatus main body on the existing pipe, and in the circumferential cutting step, the holding member moves relative to the guide member along the circumferential direction of the existing pipe. Thus, the apparatus main body moves along the circumferential direction of the existing pipe, and the first cutting blade cuts the circumferential side cutting section. Therefore, the holding member covers the new pipe. Since the guide member can be hung around regardless of the shape, the apparatus main body can move freely along the guide member enclosing the existing pipe by moving the holding member. Therefore, if the holding member can be hung around the existing pipe through the guide member, the circumferential cutting step is performed with a greater degree of freedom for cutting the existing pipe regardless of the deformation state of the existing pipe. can do.

(5) The method for removing an existing pipe described in (4) is characterized in that the holding member is a chain, so that the chain is wound around the existing pipe via the guide member. The main body of one cutting device can be held so as to be freely movable around the existing pipe. Further, for example, when a sprocket that can mesh with the chain is pivotally supported by the main body of the first cutting device, the chain is engaged with the sprocket, If the apparatus main body moves in the existing pipe circumferential direction when the peripheral cutting part is cut by the first cutting blade, the sprocket rotates while meshing with the chain. At this time, although the chain moves relative to the guide member, the change in tension accompanying the movement is relatively small, and the device main body is maintained in a stable position with little wobble relative to the existing pipe. Thus, the circumferential direction of the existing pipe can be moved. For this reason, the first cutting blade can cut the existing pipe smoothly without excessively acting on the first cutting blade during the cutting of the peripheral cutting portion.

(6) In the method for removing an existing pipe described in any one of (1) to (5), the first cutting blade is a disk-shaped blade that rotates about the first rotation axis, and has a cylindrical shape. A first depth-of-cut limiting member formed with an outer peripheral surface, and the axis of the first outer peripheral surface of the first depth-of-cut-limited member and the first rotation axis of the first cutting blade are coaxial. The first diameter difference that is the difference between the first cutting blade radius that is arranged and the radius of the first cutting blade and the first limiting member radius that is the radius of the first cutting depth limiting member is the existing pipe. The first cutting blade of the first cutting device is characterized in that the size equal to the thickness in the radial direction or the first diameter difference is set to be larger than the thickness within an allowable error range. However, when the peripheral cutting portion is cut and cut toward the inner peripheral portion of the existing pipe, the cutting edge of the first cutting blade comes into contact with the new pipe before the cutting edge comes into contact with the new pipe. The first outer peripheral surface of the cutting depth limiting member is an outer peripheral surface and abutting the existing pipe. Thereby, the first cutting depth limiting member can prevent the cutting edge of the first cutting blade from being positioned deeper than the contact state with the outer peripheral surface of the existing pipe on the inner peripheral side of the existing pipe. It is possible to suppress the new pipe from being damaged or broken by the first cutting blade.

(7) In the method for removing an existing pipe described in any one of (1) to (6), a second cutting device having a second cutting blade for cutting the shaft-side cutting portion is used. The cutting blade is a disk-shaped blade that rotates about the second rotation axis, has a second cutting depth limiting member formed with a cylindrical second outer peripheral surface, and has a second cutting depth limiting member. The axial center of 2 outer peripheral surfaces and the 2nd rotating shaft of a 2nd cutting blade are arrange | positioned coaxially, the 2nd cutting blade radius which is a radius of a 2nd cutting blade, and 2nd cutting depth restriction | limiting The second diameter difference, which is the difference from the second limiting member radius, which is the radius of the member, is equal to the thickness in the radial direction of the existing pipe, or the second diameter difference is within the allowable error range from the wall thickness. The second cutting blade of the second cutting device cuts the shaft-side cutting portion toward the inner peripheral side of the existing pipe. When you are cutting Nde cutting edge of the second cutting blade, prior to contact with the new pipes, the second outer peripheral surface of the second cutting depth limiting member is an outer peripheral surface and abutting the existing pipe. Thus, the second cutting depth limiting member can prevent the cutting edge of the second cutting blade from being positioned deeper than the contact state with the outer peripheral surface of the existing pipe on the inner peripheral side of the existing pipe. It is possible to suppress the new pipe from being damaged or broken by the second cutting blade.

It is a figure explaining the removal method of the existing pipe | tube concerning embodiment and modification, and is a side view which shows the state before removing the connection surrounding part from the existing pipe | tube embed | buried in the ground. It is a figure explaining the removal method of the existing pipe | tube which concerns on embodiment and a deformation | transformation form, and is a figure which shows the state after removing the connection connection surrounding part from the existing pipe | tube embed | buried in the ground. It is a figure explaining the axial direction cutting process among the removal methods of the existing pipe | tube which concerns on embodiment and modification, and is a side view of the existing pipe | tube shown in FIG. It is explanatory drawing of the axial direction cutting process shown in the cross section from the AA arrow in FIG. It is a figure explaining the circumferential direction cutting process among the removal methods of the existing pipe | tube which concerns on embodiment, and is a side view of the existing pipe | tube shown in FIG. It is explanatory drawing which shows the state which attached the 1st cutting device which concerns on embodiment to the existing pipe, and is the figure seen from the left side in FIG. 1. It is explanatory drawing of the circumferential direction cutting process shown by the cross section from a BB arrow and CC arrow in FIG. 1, and it is the figure seen from the right side in FIG. It is a side view showing roughly the 1st cutting device used with the removal method of the existing pipe concerning an embodiment. It is a side view of the 1st cutting device seen from the opposite side to Drawing 8. It is a top view which shows the chain comprised by the 1st cutting device which concerns on embodiment. It is a front view of the chain shown in FIG. It is a figure explaining the composition of the 1st cutting device concerning a modification. It is a top view which shows the chain connected with the compression spring among the 1st cutting devices which concern on a deformation | transformation form. It is a front view of the chain shown in FIG. It is explanatory drawing which shows the whole cutting device disclosed by patent document 1. FIG. It is a figure explaining the cast iron pipe holding member of the cutting device shown in FIG. It is a figure explaining the cast iron pipe cutting member of the cutting device shown in FIG.

  Hereinafter, an embodiment and a modification of a method for removing an existing pipe according to the present invention will be described in detail based on the drawings. In the present embodiment and the modified embodiment, the new pipe is one of the non-open-cut pipe replacement methods, and the existing pipe is cut at one cutting portion along the axial direction, and the inner peripheral portion of the existing pipe after cutting is cut. Is expanded into a substantially U-shaped shape and then drawn into the inner peripheral portion of the expanded existing pipe.

(Embodiment)
Drawing 1 is a figure explaining the removal method of the existing pipe concerning an embodiment, and is a side view showing the state before removing the connection surrounding part from the existing pipe buried in the ground. In FIG. 1, the left-right direction in the drawing is the axial direction AX of the existing pipe, and the axial direction A also conforms to the direction shown in FIG.

  The existing pipe 1 is a metal pipe such as a steel pipe or a ductile cast iron pipe. By replacing the new pipe 11, the existing pipe 1 is deformed from an annular shape into a substantially U-shaped shape (see FIGS. 4, 6, and 7) in the cross section viewed from the axial direction AX. However, the existing pipe 1 remains buried in the ground. On the other hand, the new pipe 11 is a resin pipe such as a polyethylene pipe. As shown in FIG. 1, the new pipe 11 is laid through the inner peripheral portion 5 of the existing pipe 1 previously buried in the ground by the above-described non-open-cut pipe replacement method, and is used as a conduit instead of the existing pipe 1. It is functioning.

  When the new pipe 11 is laid as a main pipe in this way, there is a case where a supply pipe or the like that is a branch pipe may be branched and connected to the new pipe 11 via a branch joint. In this case, since the periphery of the new pipe 11 is covered with the existing pipe 1, the connection planned portion 12 to be connected by interrupting the branch joint in the new pipe 11 is connected to the existing pipe before connecting the branch joint. Of the pipe 1, it is necessary to remove the planned connection surrounding part 2 that covers the planned connection part 12 of the new pipe 11. The second cutting device 70 is used in addition to the first cutting device 30 described below to remove the planned connection surrounding portion 2.

  First, the 1st cutting device 30 is demonstrated using FIG. 5 thru | or FIG. FIG. 5 is a view for explaining a circumferential cutting step in the existing pipe removing method according to the embodiment, and is a side view of the existing pipe shown in FIG. 1. FIG. 6 is an explanatory diagram showing a state in which the first cutting device according to the embodiment is attached to an existing pipe, and is a view seen from the left side in FIG. 5. FIG. 7 is an explanatory diagram of the circumferential cutting step shown in cross section from the BB arrow and the CC arrow in FIG. 1, and is a view from the right side in FIG. Drawing 8 is a side view showing roughly the 1st cutting device used with the removal method of the existing pipe concerning an embodiment. FIG. 9 is a side view of the first cutting device viewed from the side opposite to FIG. FIG. 10 is a plan view showing a chain configured in the first cutting device according to the embodiment. FIG. 11 is a front view of the chain shown in FIG.

  In the 1st cutting device 30, the 1st cutting blade 32 is comprised so that a movement along circumferential direction CR (refer FIG. 6 etc.) of the existing pipe 1 is possible. The first cutting device 30 includes an apparatus main body 31 and a long chain 41 that hangs around a guide member 20 described later and holds the apparatus main body 31 on the existing pipe 1 (corresponding to the holding member of the present invention). ). The apparatus main body 31 includes a first cutting blade 32 and a first cutting depth limiting plate 60 (corresponding to the first cutting depth limiting member of the present invention) formed on a rigid structure formed in a substantially rectangular parallelepiped shape by a metal frame. It is the main-body part of the 1st cutting device 30 which comprised the main functions of the 1st cutting device 30, such as. The apparatus main body 31 includes a sprocket 50 that can mesh with the chain 41 and a chain support roller 52 that supports the chain 41 meshed with the sprocket 50, and handles 39 are attached to the left and right sides.

  Further, the sprocket shaft 51 is disposed in the apparatus main body 31 in a structure (not shown) that can be rotated along with the movement of the apparatus main body 31 along the circumferential direction CR of the existing pipe 1. Two sprockets 50 are supported on the sprocket shaft 51 in a two-row parallel arrangement, and rotate together with the rotation of the sprocket shaft 51. Further, chain support roller shafts 53 are fixed to the apparatus main body 31 on both sides of the sprocket shaft 51, respectively. A chain support roller 52 is supported on each chain support roller shaft 53 in a free state with respect to the chain support roller shaft 53.

  When the first cutting device 30 is attached to and held on the existing pipe 1, two sets of chains 41 are hung around each sprocket 50 and supported by two chain support rollers 52 as shown in FIGS. 5 and 6. In the state, it is wound around the existing pipe 1. Each chain 41 has a long shape having chain end portions at both ends, and is wound around the outer circumference of the existing pipe 1 and applies a predetermined tension corresponding to the length of the outer circumference of the existing pipe 1. The length can be. As shown in FIGS. 10 and 11, the chain 41 is configured such that the rolling surface 43 a of the roller 43 that is pivotally supported by the pin 42 is disposed inside the inner plate 44 and the outer plate 45 with respect to the radial direction Pr of the pin 42. Chain. In both sets of the chain 41, the chain connecting portion 41C pivotally supported by the pin 42 of the chain end portion on one end side can be freely attached to and detached from the pin 42 of the chain end portion on the other end side. The connection between the one end and the other end wound around the tube 1 and the release thereof are performed by attaching and detaching with the chain connecting portion 41C.

  A tension adjustment mechanism 36 is provided on the right side (the side shown in FIG. 9) of the apparatus main body 31. The tension adjusting mechanism 36 has a structure that can be adjusted by changing the tension of the two sets of chains 41 by rotating the tension adjusting knob 36A.

  Specifically, in this tension adjustment mechanism 36, when an operation of rotating the tension adjustment knob 36A in one direction (for example, clockwise direction), the two sets of chains 41 are loosened. Thus, even if the apparatus main body 31 is placed around the guide member 20 that covers the outer periphery of the existing pipe 1 and the chain 41 is fixed around the guide member 20, the operator can The apparatus main body 31 can be moved along the circumferential direction CR of the existing pipe 1 by grasping 39. On the other hand, when the operation of rotating the tension adjustment knob 36A in the other direction (also in the counterclockwise direction) is performed, a larger tension is applied to the two sets of chains 41. As a result, the apparatus main body 31 is in a state of being firmly and stably supported around the guide member 20 covering the outer periphery of the existing pipe 1, and as will be described later, The circumferential cutting part 4 can be cut along the circumferential direction CR by the first cutting blade 32 disposed on the movement path of the first cutting blade 32.

  The first cutting blade 32 is a blade capable of cutting a relatively hard pipe such as a steel pipe or a ductile cast iron pipe, for example. The first cutting shaft 32 is driven by a driving force generated by circulating high-pressure hydraulic oil with a hydraulic driving source (not shown). It is a disc-shaped cutting blade that rotates around 33. The radius of the first cutting blade 32 is the first cutting blade radius Cr1. The first cut depth limiting plate 60 (corresponding to the first cut depth limiting member of the present invention) is formed in a disk shape having a cylindrical first outer peripheral surface 61a. The axial center 63 of the first outer peripheral surface 61a and the first rotating shaft 33 of the first cutting blade 32 are coaxially arranged, and the first cutting blade 32 and the first cutting depth limiting plate 60 are integrally formed. It has become. The radius of the first outer peripheral surface 61a of the first cut depth limiting plate 60 is the first limiting plate radius Dr1 (Cr1> Dr1).

  A first diameter difference Fr1 (0 ≦ Fr1) that is a difference between the first cutting blade radius Cr1 that is the radius of the first cutting blade 32 and the first limiting plate radius Dr1 that is the radius of the first cutting depth limiting plate 60. However, the thickness t of the existing pipe 1 in the radial direction RD and the present embodiment have the same size as shown in FIGS. 7 and 8 to be referred to. In consideration of the state of the existing pipe 1 embedded in the actual site (deformation, rust adhesion, etc.), the first diameter difference Fr1 is set larger than the wall thickness t within the “allowable error range”. It is preferable.

  The “allowable error range” here is a state in which the first outer peripheral surface 61a of the first cut depth limiting plate 60 is in contact with the outer peripheral surface 6a of the existing pipe 1 covering the new pipe 11. Even when the cutting edge of the first cutting blade 32 exceeds the inner peripheral surface of the inner peripheral portion 5 of the existing tube 1 when the peripheral cutting portion 4 is cut by the first cutting blade 32, The allowable range which can be settled to the extent which reaches | attains the outer peripheral surface of the newly installed pipe | tube 11 in the surrounding part 5, and does not contact. In particular, the existing pipe 1 after laying the new pipe is replaced with a new pipe by the non-open-cut pipe replacement method in addition to the case where the diameter of the existing pipe 1 is expanded to a substantially U-shape as in this embodiment. In construction, there is a case where the axis center is warped in the connection planned surrounding portion of the existing pipe, and the connection planned surrounding portion is not linear but bent. Even in such a case, in the circumferential direction of the existing pipe, the inner peripheral surface of the existing pipe and the outer peripheral surface of the new pipe are close to each other, and the gap between both surfaces is the smallest. The allowable range in which the cutting edge can be accommodated to such an extent that it does not contact the outer peripheral surface of the new pipe.

  A cut depth adjusting mechanism 35 is provided on the left side (the side shown in FIG. 8) of the apparatus main body 31. The cutting depth adjusting mechanism 35 changes the position of the first rotating shaft 33 of the first cutting blade 32 up and down in the height direction (vertical direction in FIG. 8) by rotating the cutting depth adjusting knob 35A. Adjust.

  Specifically, in the incision depth adjusting mechanism 35, when an operation of rotating the incision depth adjusting knob 35A in one direction (for example, clockwise direction), the first rotation shaft 33 moves downward, The first cutting blade 32 is lowered integrally with the first cutting depth limiting plate 60. Thereby, when cutting the existing pipe 1, the cutting edge of the first cutting blade 32 can begin to cut the existing pipe 1, and the cutting depth of the cutting edge of the first cutting blade 32 can be made deeper. On the other hand, when an operation of rotating the cutting depth adjustment knob 35A in the other direction (also counterclockwise) is performed, the first rotation shaft 33 moves upward, and the first cutting blade 32 is moved to the first direction. It rises integrally with the cut depth limiting plate 60. Thereby, the cutting depth of the cutting edge of the first cutting blade 32 can be made shallower, and the cutting edge of the first cutting blade 32 can be retracted from the existing pipe 1.

  As shown in FIGS. 8 and 9, the apparatus main body 31 has roller shafts 34 </ b> X below the left and right sides (the side shown in FIG. 8 and the side shown in FIG. 9). At both ends of each roller shaft 34X (on the left and right sides in FIGS. 8 and 9), there are two apparatus main body rollers 34, 34 that are pivotally supported by the roller shaft 34X. Although not shown, the apparatus main body 31 includes a driving force transmission mechanism (such as a hydraulic hose) for rotating the first cutting blade 32 by hydraulic drive, and cooling for cooling the first cutting blade 32 by water cooling. A mechanism (such as a cooling hose) is provided.

  The guide member 20 is used together with the first cutting device 30 when cutting the peripheral cutting portion of the existing pipe in the circumferential cutting step of the existing pipe removing method according to the present embodiment. The guide member 20 is a flexible plate-like member that can be deformed along the shape of the existing pipe 1. Specifically, in this embodiment, the guide member 20 corresponds to the shape of the existing pipe 1 on the outer peripheral surface 6a of the existing pipe 1 adjacent to the movement path (circumferential cutting portion 4) of the first cutting blade 32. An aluminum plate that can cover the existing pipe 1 and has a thickness of 1 mm. As shown in FIGS. 5 to 7, the guide member 20 has a size that can be wound sufficiently to cover and cover the outer periphery of the existing pipe 1, and two sets of chains 41 included in the first cutting device 30 are provided. It is formed in a size that can be disposed on the surface of the wound guide member 20 without directly contacting the outer peripheral surface 6a of the existing pipe 1.

  Next, the second cutting device 70 will be briefly described with reference to FIGS. FIG. 3 is a diagram illustrating an axial cutting step in the existing pipe removing method according to the embodiment, and is a side view of the existing pipe shown in FIG. 1. FIG. 4 is an explanatory diagram of an axial cutting process shown by a cross section taken along the line AA in FIG.

  The 2nd cutting device 70 has the 2nd cutting blade 72 for cut | disconnecting the axial side cutting part 3 of the connection surrounding part 2 among the existing pipes 1, and is grinder etc. which are marketed in this embodiment. It is a tool. The second cutting blade 72 is a blade capable of cutting a relatively hard pipe such as a steel pipe or a ductile cast iron pipe, for example, and is a disc-shaped cutting blade that is electrically rotated about the second rotation shaft 73. The radius of the second cutting blade 72 is the second cutting blade radius Cr2. The second cut depth limiting plate 80 (corresponding to the second cut depth limiting member of the present invention) is formed in a disk shape having a cylindrical second outer peripheral surface 81a. The axial center 83 of the second outer peripheral surface 81a and the second rotating shaft 73 of the second cutting blade 72 are arranged coaxially, and the second cutting blade 72 and the second cutting depth limiting plate 80 are integrally formed. It has become. The radius of the second outer peripheral surface 81a of the second cut depth limiting plate 80 is a second limiting plate radius Dr2 (Cr2> Dr2).

  A second diameter difference Fr2 (0 ≦ Fr2) that is a difference between the second cutting blade radius Cr2 that is the radius of the second cutting blade 72 and the second limiting plate radius Dr2 that is the radius of the second cutting depth limiting plate 80. However, the thickness t of the existing pipe 1 in the radial direction RD and the present embodiment have the same size as shown in FIGS. 3 and 4 to be referred to. In consideration of the state of the existing pipe 1 embedded in the actual site (deformation, rust adhesion state, etc.), the second diameter difference Fr2 is set larger than the wall thickness t within the “allowable error range”. It is preferable.

  The “allowable error range” here is a state in which the second outer peripheral surface 81a of the second cut depth limiting plate 80 is in contact with the outer peripheral surface 6a of the existing pipe 1 covering the new pipe 11. Even when the cutting edge of the second cutting blade 72 exceeds the inner peripheral surface of the inner peripheral portion 5 of the existing tube 1 when the shaft-side cutting portion 3 is cut by the second cutting blade 72, the inside of the existing tube 1 The allowable range which can be settled to the extent which reaches | attains the outer peripheral surface of the newly installed pipe | tube 11 in the surrounding part 5, and does not contact. In particular, the existing pipe 1 after laying the new pipe is replaced with a new pipe by the non-open-cut pipe replacement method in addition to the case where the diameter of the existing pipe 1 is expanded to a substantially U-shape as in this embodiment. In construction, there is a case where the axis center is warped in the connection planned surrounding portion of the existing pipe, and the connection planned surrounding portion is not linear but bent. Even in such a case, in the circumferential direction of the existing tube, the inner peripheral surface of the existing tube and the outer peripheral surface of the new tube are close to each other, and the gap between both surfaces is the smallest. The allowable range in which the cutting edge can be accommodated to such an extent that it does not contact the outer peripheral surface of the new pipe.

  Next, a method for removing the existing pipe according to the present embodiment will be described with reference to FIGS. Drawing 2 is a figure explaining the removal method of the existing pipe concerning an embodiment, and is a figure showing the state after removing the connection schedule surrounding part from the existing pipe buried in the ground.

  As shown in FIG. 1, the new pipe 11 is laid through the inner peripheral part 5 of the existing pipe 1 previously buried in the ground by a non-open-cut pipe replacement method. It is functioning. At the time of construction of the new pipe 11, the existing pipe 1 is cut at one cutting portion along the axial direction AX in this embodiment, and the existing pipe 1 after cutting is substantially omitted as shown in FIGS. The diameter of the U-shaped portion is increased, and the interval between the divided portions separated from each other due to the increased diameter is increased with the spacing portion 3A interposed therebetween. After the construction of the new pipe 11, when connecting the supply pipe or the like that is a branch pipe with the new pipe 11 that is the main pipe, as shown in FIG. 1, the branch that is connected to the supply pipe or the like among the new pipe 11 In the connection planned portion 12 to be connected by interrupting the joint, the planned connection surrounding portion 2 covering the connection planned portion 12 is removed from the existing pipe 1.

  In this embodiment, an axial cutting step is first performed to remove the connection planned surrounding portion 2 of the existing pipe 1. In the axial cutting step, as shown in FIGS. 1, 3 and 4, the existing pipe 1 is cut at the axial side cutting part 3 along the axial direction AX with respect to the position corresponding to the connection surrounding part 2. The planned connection surrounding portion 2 is divided into a plurality of portions in the circumferential direction of the existing pipe 1. The existing pipe 1 is cut at one cutting portion along the axial direction AX as the shaft-side cutting portion 3 at the time of construction of the new pipe 11, and has a separation portion 3A and is expanded in a substantially U-shape. Therefore, in such an existing pipe 1, in this embodiment, in order to divide the connection surrounding part 2 into approximately two equal parts, another shaft side cutting part 3 is located at a position almost opposite to the spacing part 3 </ b> A. Set.

  As shown in FIG. 1, the distance of the connection surrounding part 2 with respect to the axial direction AX is a range between the surrounding part end Qb and the surrounding part end Qc, and specifically, is a distance of about 300 to 500 mm. To completely divide the substantially U-shaped connection planned surrounding portion 2 into two, in the newly set shaft-side cutting portion 3, as shown in FIG. 2, a cutting start position Q1 for starting cutting and cutting are performed. The cutting end position Q2 to be finished is arranged on both sides of the surrounding portion ends Qb and Qc. Specifically, the cutting start position Q1 is set at a position separated from the surrounding part end Qb by a few centimeters on the side opposite to the surrounding part end Qc, and the cutting end position Q2 is based on the surrounding part end Qc. In addition, it is set at a position separated by several centimeters on the side opposite to the surrounding portion end Qb. The second cutting device 70 is used for cutting the shaft side cutting unit 3.

  In the second cutting device 70, the second cutting blade 72 and the second cutting depth limiting plate 80 to be used are the second diameters of the second cutting blade radius Cr2 and the second limiting plate radius Dr2 in this embodiment. The difference Fr <b> 2 is selected so as to be equal to the wall thickness t of the existing pipe 1, and is integrally fixed to the second rotating shaft 73. In the cutting of the shaft-side cutting part 3, the operator rotates the second cutting blade 72 while supporting the second cutting device 70 by hand, and the inner peripheral surface side (radial direction RD diameter) of the inner peripheral part 5 of the existing pipe 1. Cut inside. The cutting start of the second cutting blade 72 is performed so that it can be completely cut to the inner peripheral surface on the inner peripheral portion 5 side of the existing pipe 1 having a thickness t between the cutting start position Q1 and the surrounding portion end Qb. It is performed at a position near the start position Q1, and at this position, the cutting edge of the second cutting blade 72 is brought into contact with the outer peripheral surface 6a of the existing tube 1 and directed toward the inner peripheral surface side (radial direction RD diameter inner side) of the existing tube 1. And cut. As the operator cuts the second cutting blade 72, the second outer peripheral surface 81 a of the second cutting depth limiting plate 80 comes into contact with the outer peripheral surface 6 a of the existing pipe 1. Thereby, the cutting edge of the second cutting blade 72 does not advance to the inner peripheral surface side of the existing pipe 1 beyond the depth at the time of contact.

  The second cutting device 70 is in a state where the second outer peripheral surface 81a of the second cutting depth limiting plate 80 and the outer peripheral surface 6a of the existing pipe 1 are in contact with each other along the shaft-side cutting portion 3 by the operator. Alternatively, the vehicle is manually driven to the cutting end position Q2 before the contact. The cutting of the shaft side cutting part 3 is performed when the inner peripheral surface on the inner peripheral part 5 side of the existing pipe 1 is completely cut at least between the surrounding part end Qb and the surrounding part end Qc. ,finish. Thus, in addition to the separation portion 3A, the second cutting blade 72 of the second cutting device 70 cuts the shaft-side cutting portion 3 from the cutting start position Q1 to the cutting end position Q2, and the connection-side surrounding portion 2 By completely cutting between the surrounding part end Qb and the surrounding part end Qc in the cutting part 3, the connection surrounding part 2 is divided into two in the circumferential direction CR.

  Next, the circumferential cutting step of the existing pipe removing method according to the present embodiment will be described with reference to FIGS. 1 and 5 to 7. In the circumferential cutting step, the axial direction AX that cuts the existing pipe 1 at the circumferential cutting section 4 along the circumferential direction CR and sandwiches the planned surrounding enclosure section 2 at a position corresponding to the planned connection section 12 of the new pipe 11. This is a step of dividing the existing pipe 1 on both sides, and is performed after the axial cutting step in this embodiment. The first cutting device 30 and the guide member 20 are used for cutting the circumferential cutting portion 4.

  Before cutting, in the cutting depth adjusting mechanism 35 of the apparatus main body 31, the cutting depth adjusting knob 35A is rotated in the other direction, the first rotating shaft 33 is disposed upward, and the cutting edge of the first cutting blade 32 is moved. Then, it is retracted to a position away from the existing pipe 1. Further, in the tension adjustment mechanism 36 of the apparatus main body 31, the tension adjustment knob 36 </ b> A is rotated in one direction to loosen the tension of the chain 41.

  In the circumferential cutting step, the outer peripheral surface 6a of the existing pipe 1 adjacent to the circumferential cutting portion 4 is arranged in FIGS. 5 to 7 so that the first cutting blade 32 of the apparatus main body 31 can be disposed on the circumferential cutting portion 4. As shown in FIG. 3, the existing pipe 1 is wrapped with a guide member 20 that can cover the existing pipe 1 corresponding to the shape of the existing pipe 1 whose diameter is increased to a substantially U-shape. After the guide member 20 is covered over the entire outer peripheral surface 6 a of the existing pipe 1, the apparatus main body 31 of the first cutting device 30 is placed on the outer peripheral surface of the guide member 20. The apparatus main body 31 is hung around the guide member 20 that wraps the outer peripheral surface 6a of the existing pipe 1 by the two sets of chains 41, and the two ends of the two sets of the chain 41 that are wound are respectively connected by the chain connecting portions 41C. The first cutting device 30 is held on the existing pipe 1 by being connected in a ring shape.

  Specifically, referring to FIG. 6, the two sets of chains 41 hung around the sprocket 50 are hung on two chain support rollers 52 as shown in FIG. Is hung around the outer periphery of the guide member 20 covering the outer peripheral surface 6a. In the two sets of chains 41, the chain connection portion 41 </ b> C pivotally supported by the pin 42 of the chain end portion on one end side of the chain 41 in the free state is engaged with the pin 42 of the chain end portion on the other end side. As a result, the two chains 41 connected in series are wound around the guide member 20. Two sets of chains 41 are wound around the existing pipe 1 through the guide member 20 in a state where the two chains 41 are hung around the sprockets 50 and supported by the two chain support rollers 52.

  Next, the tension adjustment knob 36A of the tension adjustment mechanism 36 is rotated in the other direction so that the four apparatus main body rollers 34 included in the apparatus main body 31 are stably placed on the outer peripheral surface of the guide member 20. Apply tension to the chain 41. The tension of the chain 41 is applied along the circumferential direction CR of the existing pipe 1 while the apparatus main body roller 34 rolls against the guide member 20 wound around the outer peripheral surface 6 a of the existing pipe 1. Even if it rotates, it is set to such a size that the apparatus main body 31 can be held without being separated from the guide member 20.

  Next, the apparatus main body 31 is moved to the vicinity of the cutting start position P1 that is the starting point of cutting. Specifically, with reference to FIG. 7, the operator grasps one of the handles 39 (left side in FIG. 7) while applying the above-described tension to the chain 41, and the apparatus main body roller While rolling 34 on the guide member 20, the apparatus main body 31 is pulled and moved to the vicinity of the cutting start position P <b> 1 along the circumferential direction CR of the existing pipe 1. That is, the apparatus main body portion is located near the cutting start position P1 as the position of the apparatus main body portion 31 where the first cutting blade 32 can reliably start cutting the existing pipe 1 at the cutting start position P1 at which the circumferential cutting portion 4 starts to cut. 31 is moved.

  Next, when the apparatus main body 31 is moved to the vicinity of the cutting start position P1, the first cutting blade 32 is rotated. Next, in the cutting depth adjusting mechanism 35 of the apparatus main body 31, the cutting depth adjusting knob 35 </ b> A is rotated in one direction and the first rotating shaft 33 is moved downward, whereby the cutting edge of the first cutting blade 32 is moved. The outer peripheral surface 6a of the existing pipe 1 at the cutting start position P1 of the peripheral cutting part 4 is brought into contact with the inner peripheral surface 5 of the inner peripheral part 5 of the existing pipe 1 (in the radial direction RD diameter inner side). As the operator operates the cutting depth adjustment knob 35A to cut the first cutting blade 32, the first outer peripheral surface 61a of the first cutting depth limiting plate 60 is fixed to the outer peripheral surface 6a of the existing pipe 1. It abuts on the guide member 20 covering the. Thereby, the cutting edge of the first cutting blade 32 does not advance to the inner peripheral surface side of the existing pipe 1 beyond the depth at the time of contact.

  In the circumferential cutting step, the first cutting blade 32 is moved around the existing pipe 1 while the first cutting device 30 is held on the existing pipe 1 via the guide member 20. That is, while the sprocket 50 rotates, the chain 41 supported by the two chain support rollers 52 and wound around the sprocket 50 moves relative to the guide member 20 along the circumferential direction CR of the existing pipe 1. As a result, the apparatus main body 31 moves along the circumferential direction CR of the existing pipe 1, and the first cutting blade 32 cuts the circumferential-side cutting part 4.

  More specifically, the operator can operate the apparatus main body in a state where the first outer peripheral surface 61a of the first cut depth limiting plate 60 and the outer peripheral surface 6a of the existing pipe 1 are in contact with each other or in a state before contact. While grasping the handle 39 of 31 and rolling the apparatus main body roller 34 on the guide member 20, the apparatus main body 31 is manually pulled to the vicinity of the cutting end position P2 along the circumferential direction CR of the existing pipe 1. Move. At this time, even if the separation portion 3A exists in the existing pipe 1, the guide body 20 wraps around the existing pipe 1, so that the apparatus main body 31 moves over the guide member 20 over the entire circumference of the existing pipe 1. It can move smoothly. Therefore, the first cutting blade 32 can cut the existing tube 1 at the peripheral cutting portion 4 while the apparatus main body 31 moves to the vicinity of the cutting end position P2 along the circumferential direction CR of the existing tube 1. . The cutting of the peripheral cutting part 4 is performed when the inner peripheral surface on the inner peripheral part 5 side of the existing pipe 1 is completely cut between the cutting start position P1 and the cutting end position P2. finish. As shown in FIG. 1, the circumferential side cutting portion 4 is cut at two locations on both sides of the connection surrounding portion 2 with respect to the axial direction AX of the existing pipe 1.

  In the method for removing the existing pipe according to the present embodiment, the existing pipe 1 is a shaft-side cutting part 3 along the axial direction AX with respect to the position corresponding to the connection planned part 12 of the new pipe 11 and includes the separation part 3A. It is divided into two in the circumferential direction CR of the existing pipe 1 in a state where it is cut at two places, and the connection-scheduled surrounding portion 2 is cut into a state where the shaft-side cutting portion 3 and the circumferential-side cutting portion 4 intersect each other. It will be removed after becoming.

  Specifically, in the section where the new pipe 11 is laid on the inner peripheral portion 5 of the existing pipe 1, the separating portion 3 </ b> A exists over the entire section. Further, in the axial cutting step, in the cutting of the shaft-side cutting portion 3, the cutting start position Q1 is a position separated from the surrounding portion end Qb by a few centimeters on the side opposite to the surrounding portion end Qc. The end position Q2 is a position spaced about several centimeters on the side opposite to the surrounding portion end Qb with the surrounding portion end Qc as a base point. For this reason, in the planned connection surrounding portion 2 to be removed, the space between the surrounding portion end Qb and the surrounding portion end Qc at both ends is surely cut. On the other hand, in the circumferential cutting step, the circumferential side cutting portion 4 of the existing pipe 1 intersects the shaft side cutting portion 3 at the surrounding portion end Qb and the surrounding portion end Qc, and the cutting surface of the shaft side cutting portion 3 and the circumference thereof It is cut in a state where the cut surface of the side cut portion 4 intersects. Therefore, a portion of the existing pipe 1 that corresponds to the connection planned portion 12 of the new pipe 11 is circumferentially separated from the axial direction AX by the separation portion 3A and the cutting of the shaft-side cutting portion 3 by the axial cutting step. While existing in a state of being divided into two CRs, the existing pipe 1 was divided on both sides in the axial direction AX across the connection surrounding portion 2 by cutting the two peripheral side cutting parts 4 in the circumferential cutting step. It is in a state. Thus, the part corresponding to the connection planned part 12 of the new pipe 11 is divided into two in the circumferential direction CR from the existing pipe 1, and the connection planned surrounding part 2 is removed from the existing pipe 1 as shown in FIG. Can do.

The operation and effect of the existing pipe removing method according to this embodiment having the above-described configuration will be described.
In the removal method of the existing pipe of this embodiment, the branch joint is interrupted and connected among the new pipes 11 laid by the non-open-cut pipe replacement method on the inner peripheral portion 5 of the existing pipe 1 buried in the ground. In the existing pipe removing method for removing the planned connection surrounding part 2 covering the planned connection part 12 from the existing pipe 1 with respect to the planned connection part 12 to be attempted, the first cutting blade 32 is arranged in the circumferential direction CR of the existing pipe 1. A shaft that cuts the existing pipe 1 at the peripheral cutting section 4 along the circumferential direction CR and sandwiches the planned connection surrounding section 2 at a position corresponding to the planned connection section 12 by the first cutting device 30 that can move along the axis. A circumferential cutting step of dividing the existing pipe 1 on both sides in the direction AX, and in the circumferential cutting step, the guide that can cover the existing pipe 1 with the outer peripheral surface 6a of the existing pipe 1 corresponding to the shape of the existing pipe 1 Wrapping with the member 20, the first cutting device 30 and the guide member 20 Then, with the existing pipe 1 being held, the first cutting blade 32 is moved around the existing pipe 1, and the existing pipe 1 extends along the axial direction AX with respect to the position corresponding to the planned connection portion 12. A plurality (in this embodiment, in the circumferential direction CR of the existing pipe 1 is cut in at least two places (in this embodiment, one place in the axial cutting step in addition to the separation portion 3A) at the shaft-side cutting portion 3. 2) and the planned connection surrounding portion 2 is removed after the shaft-side cutting portion 3 and the circumferential-side cutting portion 4 intersect and are cut off. When the pipe 11 is drawn and laid in the inner peripheral portion 5 of the existing pipe 1 previously embedded by the non-open-cut pipe replacement method, the shape of the existing pipe 1 is greatly changed from the shape before the new pipe 11 is laid. Even in such a case, the existing pipe after the new pipe 11 is laid Regardless of the shape, in the circumferential direction cutting step, it can be the first cutting blade 32 of the first cutting device 30 moves around the existing pipe 1, cutting the peripheral side cutting section 4.

  That is, two or more existing pipes are previously provided along the axial direction in the existing pipe in which the new pipe is laid on the inner periphery by the non-open-cut pipe replacement method, as in Patent Document 1 cited in the related art. Are cut into three or more divided pieces, and the interval between adjacent divided pieces is relatively narrow, and the shape of the existing pipe after cutting is the same as the shape before cutting. It has n’t changed much. In the cutting device of Patent Document 1, even if the existing pipe is divided into four pieces, the periphery of the four divided pieces is held, and the cutting blade passes between the adjacent divided pieces. The whole four pieces can be cut. However, among the existing pipes in which the new pipe is laid on the inner periphery by the non-open-cut pipe replacement method, the existing pipe 1 has one cutting portion (in the axial direction AX, as in this embodiment). After the existing pipe 1 after cutting is expanded to a substantially U-shaped shape, the new pipe 11 is drawn into the inner peripheral portion 5 of the existing pipe 1 after the diameter expansion. There are some cases. In such a case, the existing pipe 1 is divided into two parts by the diameter expansion with the cutting part (the separation part 3A) cut by the cutting part interposed therebetween, and as shown in FIG. The interval between the separated parts that are separated from each other increases, and the shape of the existing pipe 1 after the new pipe 11 is laid is greatly changed from that before the laying. The cutting device of Patent Document 1 cannot be used unless the cross-sectional shape of the existing pipe after cutting is a substantially annular shape including a cutting portion, and the existing pipe whose diameter is expanded into a substantially U-shape is cut into a ring. I can't do it.

  On the other hand, the method for removing the existing pipe of the present embodiment is similar to the present embodiment in that the outer peripheral surface 6a of the existing pipe 1 is located at a position adjacent to the movement path (circumferential cutting portion 4) of the first cutting blade 32. Is wrapped with a guide member. As a result, as exemplified above, when the new pipe 11 is replaced, such as the existing pipe 1 whose diameter has been expanded to a substantially U-shape, the cut part along the axial direction AX is cut. Even in the existing pipe 1 in which the distance between the divided parts spaced apart from each other due to the diameter expansion is increased and the shape of the existing pipe 1 after the new pipe 11 is laid is greatly changed from that before laying, the first cutting device 30 Can be held movably along the circumference of the existing pipe 1 via the guide member 20 and can be installed. Therefore, since the 1st cutting device 30 can be installed so that movement around the existing pipe 1 is possible irrespective of the shape of the existing pipe 1, the 1st cutting blade 32 cut | disconnects the surrounding side cutting part 4 of the existing pipe 1. FIG. be able to. Of course, as in Patent Document 1, an existing tube having a substantially annular shape that has been divided into three or more pieces that have been cut in advance along two or more cutting portions along the axial direction. The 1 cutting device 30 can be moved around the existing pipe, and the peripheral cutting part of the existing pipe can be cut by the first cutting blade 32.

  By the way, as exemplified above, when the existing pipe 1 is cut at one cutting portion along the axial direction AX, and the existing pipe 1 after cutting is expanded in a substantially U shape, In the direction cutting step, even if the existing pipe 1 is divided on both sides in the axial direction AX sandwiching the connection surrounding portion 2, if only one separation portion 3 </ b> A that is divided and separated by expanding the diameter is provided, the connection connection surrounding is performed. Part 2 cannot be removed across the new pipe 11. The existing pipe removing method of the present embodiment includes such a separation portion 3A, and there are at least two cutting portions cut by the shaft-side cutting portion 3, so that the position corresponding to the planned connection portion 12 is present. On the other hand, the planned connection surrounding portion 2 in the existing pipe 1 can be divided into a plurality (two in this embodiment) in the circumferential direction CR. On top of that, the cut portion including the above-described separation portion 3A and cut by the shaft side cut portion 3 and the cut portion obtained by dividing the existing pipe 1 on both sides in the axial direction AX sandwiching the connection surrounding portion 2 are intersected. If it will be in the state, the connection schedule surrounding part 2 can be easily removed from the position corresponding to the connection plan part 2 of the new installation pipe 11 among the existing pipes 1 without crossing the new installation pipe 11.

  Therefore, according to the removal method of the existing pipe of this embodiment, the connection schedule of the new pipe 11 that is drawn and laid in the existing pipe 1 that is expanded in a substantially U-shape by the non-open-cut pipe replacement method. Even when a branch joint is connected to the portion 12 (specific part), a part of the existing pipe 1 that covers the range of the specific part (enclosed to be connected) regardless of the shape of the existing pipe 1 that covers the new pipe 11 The part 2) has an excellent effect that it can be easily removed.

  Of course, even if a new pipe with a diameter smaller than the diameter of the existing pipe remains in the shape of the existing pipe buried in the ground, it is drawn into the inner periphery of this existing pipe and installed. The planned connection surrounding portion can be easily removed by the method of removing the existing pipe in the form.

  Moreover, in the removal method of the existing pipe | tube of this embodiment, when the existing pipe | tube 1 was cut | disconnected by the one axial side cutting part 3 of at least two places at the time of laying of the new pipe | tube 11, it was expanded in diameter. The diameter is increased because the shape is changed to a shape having a wide spacing portion 3A between the cut end portions P1, P2 on both sides which are cut by the shaft side cutting portion 3 and separated from each other. As a cross-sectional shape of the existing pipe 1 in the axial direction AX, for example, even when the existing pipe 1 is deformed into a shape having a wide separating portion 3A, such as a U-shape or a horseshoe shape, the guide The guide member in which the movement path (circumferential cutting portion 4) of the first cutting blade 32 of the first cutting device 30 is covered with the existing pipe 1 by covering the entire circumference of the existing pipe 1 with the member 20. It can be ensured without interruption around the entire circumference of the outer periphery of 20. Thereby, the 1st cutting device 30 can move the perimeter of the existing pipe 1, and irrespective of the shape of the existing pipe 1, the surrounding side cutting part 4 of the existing pipe 1 is made into the 1st cutting blade 32. Can be cut with.

  Further, in the method for removing an existing pipe according to the present embodiment, the guide member 20 is a 1 mm thick aluminum plate material having flexibility that can be deformed along the shape of the existing pipe 1. When the new pipe 11 is laid, the existing pipe 1 has a cross-section in the axial direction AX, for example, a U-shaped shape, a horseshoe, or the like, by expanding the inner circumference of the existing pipe 1 from the annular shape before the new pipe 11 is laid. Even when the guide member 20 is greatly deformed into a shape such as a mold shape, the guide member 20 can cover the outer periphery of the existing tube 1 in accordance with the deformed outer periphery of the existing tube 1. Accordingly, the movement path of the first cutting blade 32 of the first cutting device 30 can be ensured without interruption around the entire circumference of the guide member 20 covered on the existing pipe 1 regardless of the shape of the existing pipe 1. Moreover, in an actual site, foreign matter such as earth and sand or rust may adhere to the outer peripheral surface 6a of the existing pipe 1 that is buried. In this case, regardless of the shape of the existing pipe 1, the guide member 20 is covered by the outer peripheral surface 6 a of the existing pipe 1, and the apparatus main body 31 of the first cutting device 30 is on the outer peripheral surface of the guide member 20. Since it can move along, the apparatus main body 31 can move smoothly around the existing pipe 1.

  Moreover, in the removal method of the existing pipe | tube of this embodiment, the 1st cutting device 30 hung around the apparatus main body part 31 with which the 1st cutting blade 32 was arrange | positioned, and the guide member 20, and the apparatus main body part 31 is made. A long chain 41 held by the existing pipe 1, and in the circumferential cutting step, the chain 41 moves relative to the guide member 20 along the circumferential direction CR of the existing pipe 1, thereby Since the main body part 31 moves along the circumferential direction CR of the existing pipe 1 and the first cutting blade 32 cuts the circumferential side cutting part 4, the chain 41 covers the new pipe 11. The guide body 20 can be wrapped around the guide member 20 regardless of the shape of the existing pipe 1, so that the apparatus main body 31 is wrapped around the outer peripheral surface 6 a of the existing pipe 1 by moving the chain 41. 20 can be moved freely along. Therefore, if the chain 41 can be hung around the existing pipe 1 via the guide member 20, the circumferential cutting step has a greater degree of freedom in cutting the existing pipe regardless of the deformation state of the existing pipe 1. Can be implemented.

  In addition, the existing pipe removing method of the present embodiment is characterized in that the holding member is the chain 41. Therefore, by the chain 41 wound around the existing pipe 1 through the guide member 20, The device main body 31 of the first cutting device 30 can be held so as to be freely movable around the existing pipe 1. Further, as in the present embodiment, when the sprocket 50 that can mesh with the chain 41 is pivotally supported by the device main body 31 of the first cutting device 30, the chain 41 is connected to the sprocket 50. When the peripheral cutting part 4 is cut by the first cutting blade 32, the apparatus main body 31 is connected to the existing pipe 1 if the guide member 20 is wrapped around the existing pipe 1. , The sprocket 50 rotates while meshing with the chain 41. At this time, although the chain 41 moves relative to the guide member 20, the change in tension accompanying the movement is relatively small, and the apparatus main body 31 is attached to the existing pipe 1 in a stable position with little wobble. The circumferential direction CR of the existing pipe 1 can be moved while maintaining this state. For this reason, the first cutting blade 32 can smoothly cut the existing pipe 1 without excessively acting on the first cutting blade 32 when the peripheral cutting portion 4 is cut.

  Moreover, in the removal method of the existing pipe | tube of this embodiment, the 1st cutting blade 32 is a disk shaped blade rotated centering on the 1st rotating shaft 33, and the 1st cylindrical outer peripheral surface 61a was formed. An incision depth limiting plate 60 is provided, and the axis 63 of the first outer peripheral surface 61a of the first incision depth limiting plate 60 and the first rotation shaft 33 of the first cutting blade 32 are arranged coaxially. The first diameter difference Fr1, which is the difference between the first cutting blade radius Cr1 that is the radius of the first cutting blade 32 and the first limiting plate radius Dr1 that is the radius of the first cutting depth limiting plate 60, Since the feature is that the size equal to the wall thickness t in the radial direction RD of the existing pipe 1 or the first diameter difference Fr1 is set larger than the wall thickness t within an allowable error range. The first cutting blade 32 of the cutting device 30 cuts and cuts the peripheral cutting part 4 toward the inner peripheral part 5 side of the existing pipe 1. The Rutoki, the cutting edge of the first cutting blade 32, prior to contact with the new tube 11, the first outer peripheral surface 61a of the first cut depth limiting plate 60 comes into contact with the outer peripheral surface 6a of the existing pipe 1. Thereby, the 1st cutting depth restriction | limiting board 60 is located in the inner peripheral part 5 side of the existing pipe 1 further deeper than the contact state with the outer peripheral surface 6a of the existing pipe 1 in the cutting edge of the 1st cutting blade 32. Therefore, it is possible to prevent the new pipe 11 from being damaged or broken by the first cutting blade 32.

  Moreover, in the removal method of the existing pipe | tube of this embodiment, the 2nd cutting device 70 which has the 2nd cutting blade 72 for cut | disconnecting the axial side cutting part 3 is used, and the 2nd cutting blade 72 is the 2nd rotating shaft 73. A second blade outer peripheral surface 81a of the second cut depth limiting plate 80, which has a second cut depth limiting plate 80 formed with a cylindrical second outer peripheral surface 81a. Of the second cutting blade 72 and the second rotating shaft 73 of the second cutting blade 72 are arranged coaxially, the second cutting blade radius Cr2 which is the radius of the second cutting blade 72, and the second cutting depth. The second diameter difference Fr2 that is the difference from the second restriction plate radius Dr2 that is the radius of the thickness restriction plate 80 is equal to the thickness t in the radial direction RD of the existing pipe 1 or the second diameter difference Fr2. Is set to be larger than the wall thickness t within an allowable error range. Before the cutting edge of the second cutting blade 72 comes into contact with the new tube 11 when the two cutting blades 72 cut the shaft-side cutting portion 3 toward the inner peripheral portion 5 of the existing tube 1 and cut it. In addition, the second outer peripheral surface 81 a of the second cut depth limiting plate 80 contacts the outer peripheral surface 6 a of the existing pipe 1. Thereby, the second cutting depth limiting plate 80 is located on the inner peripheral part 5 side of the existing pipe 1 deeper than the second cutting blade 72 is in contact with the outer peripheral surface 6a of the existing pipe 1. It is possible to prevent the new pipe 11 from being damaged or broken by the second cutting blade 72.

(Deformation)
Hereinafter, a method for removing the existing pipe according to the present modification will be described with reference to FIGS.
In the embodiment, two sets of chains 41 are wound around two sprockets 50 and wound around the existing pipe 1 while being supported by the two chain support rollers 52 to hold the first cutting device 30.
On the other hand, in the modified embodiment, tension is applied to the chain 141 connected to the compression spring 150 by the elastic force of the compression spring 150, and the chain 141 is wound around the existing pipe 1 to hold the first cutting device 130. ing.
That is, the modified embodiment is different from the embodiment in that the chain 141 for holding the first cutting device 130 on the existing pipe 1 is different from the embodiment, but the other portions are the same as in the first embodiment.
Therefore, the description will focus on the parts different from the first embodiment, and the description of the others will be simplified or omitted.

(Deformation)
FIG. 12 is a diagram illustrating the configuration of the first cutting device according to a modified embodiment. FIG. 13: is a top view which shows the roller chain connected with the compression spring among the 1st cutting devices which concern on a deformation | transformation form. FIG. 14 is a front view of the roller chain shown in FIG.

  In the 1st cutting device 130, the 1st cutting blade 32 is comprised so that a movement along the circumferential direction CR (refer FIG. 12) of the existing pipe 1 is possible. The first cutting device 130 adjusts the tension of the device main body 131, a long chain 141 that is hung around the guide member 20 and holds the device main body 131 on the existing pipe 1. A compression spring 150 that can be expanded and contracted. The apparatus main body 131 has the main functions of the first cutting device 130 such as the first cutting blade 32 and the first cutting depth limiting plate 60 in a rigid structure formed in a substantially rectangular parallelepiped shape by a metal frame. It is a main body portion of the first cutting device 130 and has handles 39 on both the left and right sides.

  As shown in FIG. 12, the guide member 20 has a size that can be wound sufficiently to cover and cover the outer periphery of the existing pipe 1, and includes two sets of chains 141 (or compression springs 150) provided in the first cutting device 130. ) Is not in direct contact with the outer peripheral surface 6a of the existing pipe 1, but is formed in a size that can be disposed on the surface of the wound guide member 20.

  As shown in FIGS. 13 and 14, the chain 141 has the rolling surface 143 a of the roller 143 supported by the pin 142 arranged outside the inner plate 144 and the outer plate 145 with respect to the radial direction Pr of the pin 142. Chain. The chain 141 has an elongated shape with both ends, and is a chain end with a roller 143 disposed at one end (the left side in FIGS. 12 to 14), but the other end on the opposite side. A chain end 141E connected to the compression spring 150 is attached to the portion (the right side in FIGS. 12 to 14), and the other end of the chain 141 and one end of the compression spring 150 are connected to the end of the chain. 141E are connected in series. The chain 141 is wound around the existing pipe 1 via the guide member 20, and when a certain amount of tension is applied corresponding to the length around the existing pipe 1, the rolling surface 143a of the roller 143 is provided. Is moved relative to the guide member 20 while being grounded on the outer peripheral surface of the guide member 20 so as to be rotatable.

  The compression spring 150 is configured so that two springs can be moored and detached in a series arrangement. The other end of the compression spring 150 is locked and fixed to a spring locking portion 138 of the apparatus main body 131 as shown in FIG. The chain 141 continuously connected to the compression spring 150 is hung around the outer periphery of the existing pipe 1 covered with the guide member 20 with the other end of the compression spring 150 fixed to the spring locking portion 138 at all times. As shown in FIG. 12, one end of the chain 141 in a state is hung around a chain anchoring portion 137 of the apparatus main body 131.

  The apparatus main body 131 is provided with a tension adjustment mechanism. The tension adjustment mechanism adjusts the position of the spring locking portion 138 by changing the position in the height direction (vertical direction in FIG. 12) up and down by rotating the tension adjustment knob 36A. In this tension adjustment mechanism, when an operation of rotating the tension adjustment knob 36A in one direction (for example, clockwise direction) is performed, the position of the spring locking portion 138 moves downward, and the compression spring 150 has its natural length. The chain 141 closes and shrinks, and the chain 141 is slackened. Thus, even if the apparatus main body 131 is fixed around the guide member 20 that covers the outer periphery of the existing pipe 1 by hanging one end of the chain 141 around the chain mooring portion 137, the operator can The apparatus main body 31 can be moved along the circumferential direction CR of the existing pipe 1 by grasping 39. On the other hand, when the tension adjustment knob 36A is rotated in the other direction (same counterclockwise direction), the position of the spring locking portion 138 moves upward, and the compression spring 150 is moved before the operation. The chain 141 grows depending on the state, and a large tension is applied to the chain 141. Accordingly, the apparatus main body 131 is in a state of being firmly and stably supported around the guide member 20 that covers the outer periphery of the existing tube 1, and the first cutting blade that becomes the peripheral cutting portion 4 of the existing tube 1. The first cutting blade 32 disposed on the 32 movement paths can cut the circumferential cutting portion 4 along the circumferential direction CR.

The operation and effect of the existing pipe removing method according to this modification having the above-described configuration will be described.
As with the existing pipe removal method of the present embodiment, the existing pipe removal method of the present modified embodiment also has a new construction laid on the inner peripheral portion 5 of the existing pipe 1 embedded in the ground by the non-cutting pipe replacement method. In the existing pipe removal method of removing the planned connection surrounding portion 2 that covers the planned connection portion 12 of the existing pipe 1 from the planned connection portion 12 to be connected by interrupting the branch joint in the pipe 11, With the first cutting device 130 in which the cutting blade 32 is movable along the circumferential direction CR of the existing pipe 1, the existing pipe 1 is moved by the circumferential cutting section 4 along the circumferential direction CR with respect to the position corresponding to the connection planned portion 12. It is provided with a circumferential cutting step that cuts and divides the existing pipe 1 on both sides in the axial direction AX sandwiching the planned surrounding portion 2, and in the circumferential cutting step, the outer peripheral surface 6 a of the existing pipe 1 is formed into the shape of the existing pipe 1. Correspondingly, the existing pipe 1 is wrapped with a guide member 20 that can be covered. With the first cutting device 130 held by the existing pipe 1 via the guide member 20, the first cutting blade 32 is moved around the existing pipe 1, with respect to the position corresponding to the connection scheduled portion 12. In the state where the existing pipe 1 is cut at least two places (in the present modification, one place in the axial cutting step in addition to the separation section 3A) at the axial-side cutting section 3 along the axial direction AX. After being divided into a plurality (two in this modification) in the circumferential direction CR and the planned connection surrounding portion 2 is in a state where the shaft-side cutting portion 3 and the circumferential-side cutting portion 4 intersect and are cut, When the new pipe 11 is drawn and laid into the inner peripheral portion 5 of the existing pipe 1 previously embedded by the non-open-cut pipe replacement method, the shape of the existing pipe 1 is removed. May change significantly from the shape before laying the new pipe 11, Even in such a case, the first cutting blade 32 of the first cutting device 130 moves around the existing pipe 1 in the circumferential cutting step regardless of the shape of the existing pipe 1 after the new pipe 11 is laid, and the peripheral side cutting is performed. The part 4 can be cut.

  Therefore, according to the removal method of the existing pipe of this embodiment, the connection schedule of the new pipe 11 that is drawn and laid in the existing pipe 1 that is expanded in a substantially U-shape by the non-open-cut pipe replacement method. Even when a branch joint is connected to the portion 12 (specific part), a part of the existing pipe 1 that covers the range of the specific part (enclosed to be connected) regardless of the shape of the existing pipe 1 that covers the new pipe 11 The part 2) has an excellent effect that it can be easily removed.

  Further, the existing pipe removing method of the present embodiment includes the compression spring 150 that can be expanded and contracted to adjust the tension of the chain 141, and the chain 141 that is connected to the compression spring 150 by the apparatus main body 131 in the circumferential cutting step. Therefore, when the first cutting blade 32 cuts the circumferential side cutting portion 4, the apparatus main body portion 131 is attached to the existing pipe 1. When making a round, the guide member 20 is in contact with the guide member 20 and is supported firmly and stably without wobbling, and the trajectory of the first cutting blade 32 at the time of cutting is above the peripheral cutting portion 4 to be cut. Therefore, the peripheral side cutting part 4 is cut at a more accurate position.

  Further, in the method for removing the existing pipe of the present embodiment, the holding member has the rolling surface 143 a of the roller 143 supported by the pin 142 outside the inner plate 144 and the outer plate 145 with respect to the radial direction Pr of the pin 142. Therefore, when the first cutting blade 32 cuts the circumferential cutting portion 4 while moving around the existing pipe 1, the roller 143 is connected to the rolling surface 143 a of the chain 141. The chain 141 rolls in contact with the guide member 20, and the chain 141 moves around the guide member 20 wrapping the outer peripheral surface 6 a of the existing pipe 1. Thereby, the apparatus main body part 131 can move easily. Therefore, since the apparatus main body 131 can move smoothly, the time from the start of cutting to the end of cutting can be shortened by cutting the peripheral cutting part 4 by the first cutting blade 32, and the peripheral cutting part 4 can be efficiently used. Can be cut.

  In addition, as described in the paragraph [0067] to paragraph [0073], the operation and effect of the existing pipe removal method according to this modified embodiment is the same as in the embodiment. Since the operation and effect of the removal method are exactly the same, the detailed description here is omitted.

  In the above, the present invention has been described with reference to the embodiments and modifications. However, the present invention is not limited to the above embodiments and modifications, and can be appropriately modified and applied without departing from the scope of the present invention. .

(1) For example, in the embodiment and the modified embodiment, in order to remove the planned connection surrounding portion 2 from the existing pipe 1, the axial cutting step is first performed to cut the axial side cutting portion 3, and then the circumferential cutting is performed. The process was performed and the circumference side cutting part 4 was cut | disconnected. However, the order of cutting the shaft side cutting part and the cutting of the circumferential side cutting part is not limited, and among the existing pipes, the existing pipes are connected to the connection planned part to be connected by interrupting the joint. It is only necessary that the planned connection surrounding portion covering the planned connection portion can be removed by cutting the peripheral cutting portion in the circumferential cutting step of the existing pipe removing method of the present invention.

(2) In the embodiment and the modified embodiment, the guide member 20 is made of an aluminum plate. However, the holding member can move relatively along the guide member wrapped around the outer periphery of the existing pipe, and If the cutting device can make a round around the existing pipe covered with the guide member and the first cutting blade can move along the circumference of the existing pipe and cut the existing pipe, the type of the holding member, The material, shape, etc. can be changed as appropriate.

(3) Moreover, in the modification, the apparatus main body 131 of the first cutting device 130 is in a stable state on the guide member 20 wound around the outer peripheral surface 6a of the existing pipe 1 in the circumferential direction CR of the existing pipe 1. For example, the first cutting device 130 contacts the guide member 20 with a rubber or the like that prevents the existing pipe 1 from swinging in the axial direction AX, so that the guide member 20 has a frictional resistance in the axial direction AX. The apparatus main body 131 may be configured with a slightly larger shake prevention means.

DESCRIPTION OF SYMBOLS 1 Existing pipe 2 Connection plan surrounding part 3 Axis side cutting part 4 Circumference side cutting part, Movement path 5 (of 1st cutting blade) Inner peripheral part 6a Outer peripheral surface A (of existing pipe) Axial direction C (of existing pipe) Circumferential direction R (of the existing pipe) Radial direction t (of the existing pipe) Thickness (of the existing pipe) Thickness 11 New pipe 12 Planned connection portion 20 Guide members 30, 130 First cutting devices 31, 131 Device main body portion 32 First cutting blade Cr1 (first cutting blade) first cutting blade radius 33 first rotating shaft 41, 141 chain (holding member)
60 First cut depth limiting plate (first cut depth limiting member)
61a First outer peripheral surface 63 Axis axis Dr1 (of the first outer peripheral surface) First limiting plate radius Fr1 (first cutting depth limiting plate) First diameter difference 70 Second cutting device 72 Second cutting blade Cr2 (second Second cutting blade radius 73 (second cutting blade) second rotation shaft 80 second cutting depth limiting plate (second cutting depth limiting member)
81a Second outer peripheral surface 83 (second outer peripheral surface) axis Dr2 (second cutting depth limiting plate) second limiting plate radius Fr2 second diameter difference

Claims (6)

Of the existing pipes laid in the inner periphery of the existing pipes buried in the ground, the connection that covers the planned connection parts of the existing pipes to the planned connection parts that are to be connected by interrupting the joints In the removal method of the existing pipe that removes the planned surrounding part,
With the first cutting device in which the first cutting blade is movable along the circumferential direction of the existing pipe, the existing pipe is cut at the circumferential cutting section along the circumferential direction with respect to the position corresponding to the planned connection portion. A circumferential cutting step of dividing the existing pipe on both sides in the axial direction across the connection-scheduled surrounding portion,
In the circumferential cutting step, an outer periphery of the existing pipe is wrapped with a guide member that can cover the existing pipe corresponding to the shape of the existing pipe, and the first cutting device is interposed via the guide member. Moving the first cutting blade around the existing pipe while being held in the existing pipe;
The guide member is a flexible plate-like member that can be deformed along the shape of the existing pipe, and is provided around the entire circumference of the existing pipe at a position that avoids the peripheral cutting portion. That
The first cutting device in a state in which the first cutting blade is disposed in the circumferential cutting portion moves along the entire surface of the existing pipe while rolling along the surface of the guide member. ,
The existing pipe is divided into a plurality in the circumferential direction of the existing pipe in a state where the existing pipe is cut at at least two positions along the axial direction along the axial direction with respect to the position corresponding to the planned connection portion, and the connection The planned surrounding portion is removed after the shaft-side cutting portion and the circumferential-side cutting portion intersect and are cut.
A method for removing an existing pipe characterized by the above. In the removal method of the existing pipe described in Claim 1,
When the new pipe is laid, the existing pipe is cut at one of the at least two locations by the shaft-side cutting portion and then expanded in diameter, so that the existing pipe is cut at the shaft-side cutting portion and separated from each other. It has been deformed into a shape having a wide space between the cut ends on both sides,
A method for removing an existing pipe characterized by the above. In the removal method of the existing pipe | tube as described in Claim 1 or Claim 2 ,
The first cutting device includes a device main body portion on which the first cutting blade is disposed, a long holding member that hangs around the guide member and holds the device main body portion on the existing pipe, Have
In the circumferential cutting step, the holding member moves relative to the guide member along the circumferential direction of the existing pipe, so that the apparatus main body moves along the circumferential direction of the existing pipe. The first cutting blade cutting the circumferential cutting portion,
A method for removing an existing pipe characterized by the above. In the removal method of the existing pipe described in Claim 3 ,
The holding member is a chain;
A method for removing an existing pipe characterized by the above. In the removal method of the existing pipe | tube as described in any one of Claim 1 thru | or 4 ,
The first cutting blade is a disk-shaped blade that rotates about a first rotation axis, and has a first cutting depth limiting member formed with a cylindrical first outer peripheral surface,
The axial center of the first outer peripheral surface of the first cutting depth limiting member and the first rotating shaft of the first cutting blade are arranged coaxially;
A first diameter difference that is a difference between a first cutting blade radius that is a radius of the first cutting blade and a first limiting member radius that is a radius of the first cutting depth limiting member is a radial direction of the existing pipe. The thickness equal to the thickness of the first, or the first diameter difference is set to be larger than the thickness within the allowable error range,
A method for removing an existing pipe characterized by the above. In the removal method of the existing pipe | tube as described in any one of Claims 1 thru | or 5 ,
A second cutting device having a second cutting blade for cutting the shaft-side cutting portion is used;
The second cutting blade is a disk-shaped blade that rotates around a second rotation axis, and has a second cutting depth limiting member formed with a cylindrical second outer peripheral surface,
The axial center of the second outer peripheral surface of the second cutting depth limiting member and the second rotating shaft of the second cutting blade are arranged coaxially;
A second diameter difference that is a difference between a second cutting blade radius that is a radius of the second cutting blade and a second limiting member radius that is a radius of the second cutting depth limiting member is a radial direction of the existing pipe. A thickness equal to the thickness of the second thickness difference, or the second diameter difference is set to be larger than the thickness within a tolerance.
A method for removing an existing pipe characterized by the above.

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