Pipe cutting tools

Abstract

To provide a pipe cutting tool which can make a cutting width of an inner peripheral surface of an existing pipe constant.SOLUTION: A pipe cutting tool includes: a cutting part which rotates around an anteroposterior direction with the anteroposterior direction being along a pipe axis direction to cut an inner peripheral surface of an existing pipe; and a front side part disposed at the front side as seen in the anteroposterior direction relative to the cutting part. The cutting part includes: a blade edge part which is disposed at a preceding side end part as seen in the rotation direction of the cutting part and extends in the anteroposterior direction; and a blade end outer peripheral surface formed from the blade edge part along the succeeding side as seen in the rotation direction. The front side part includes a front side outer peripheral surface formed along the rotation direction. The front side outer peripheral surface is configured to contact with the inner peripheral surface of the existing pipe.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention is a pipe cutting tool for cutting the inner diameter of an existing pipe. [Background technology]

[0002] Patent Document 1 discloses a diameter expansion device equipped with cutting blades that expands the diameter of an existing pipe (buried plastic pipe) with a circular cross section. The diameter expansion device has an outer periphery that serves as a diameter expansion surface that expands the inner diameter of the existing pipe, and multiple cutting blades are arranged radially on the front side of the diameter expansion device, with the tip of a new pipe (replacement plastic pipe) fixed to the rear side of the diameter expansion device.

[0003] In the configuration described in Patent Document 1, a cutting blade is used to form an expansion notch on the inner surface of the existing pipe along the pipe axis direction, the inner diameter of the existing pipe is expanded by the expansion surface of the expansion device, and the new pipe following the expansion device is inserted into the existing pipe by widening the expansion notch and guiding the existing pipe. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-184996 Summary of the Invention [Problem to be solved by the invention]

[0005] In addition to the above-mentioned cutting, another possible method for processing the existing pipe from the inner diameter side is to move a device capable of cutting the existing pipe from the inner diameter side in the pipe axial direction and cut the wall thickness of the existing pipe from the inner diameter side over a predetermined length along the pipe axial direction. However, when cutting the wall thickness of the existing pipe from the inner diameter side over a predetermined length, it is extremely difficult to make the cutting depth (cutting width) constant.

[0006] Therefore, the present invention provides a pipe cutting tool that can make the cutting width of the inner peripheral surface of an existing pipe constant. [Means for solving the problem]

[0007] The present invention is a pipe cutting tool comprising: a cutting section that cuts the inner surface of an existing pipe by rotating around the fore-and-aft direction, with the fore-and-aft direction aligned with the pipe axis direction; and a front section that is arranged forward of the cutting section in the fore-and-aft direction, wherein the cutting section is arranged at the leading end of the cutting section in the rotation direction and comprises a blade end extending in the fore-and-aft direction and a blade end outer surface formed from the blade end along the trailing side in the rotation direction, and the front section has a front outer surface formed along the rotation direction, and the front outer surface is configured to abut against the inner surface of the existing pipe.

[0008] According to the above configuration, when the cutting section is rotated and advanced within the existing piping, the front outer peripheral surface of the front part abuts against the inner peripheral surface of the existing piping at the front side of the cutting section, thereby maintaining the blade end of the cutting section at a predetermined cutting position relative to the inner peripheral surface of the existing piping, and stabilizing rotation at the cutting position with the outer peripheral surface of the blade end.

[0009] In the pipe cutting tool of the present invention, the front outer peripheral surface may be located further backward in the rotational direction than the cutting edge and forward in the front-to-rear direction than the cutting edge outer peripheral surface.

[0010] According to this configuration, the front outer peripheral surface maintains the cutting position of the blade end relative to the inner peripheral surface of the existing pipe, but does not interfere with cutting by the blade end, allowing for stable cutting.

[0011] In addition, in the pipe cutting tool of the present invention, a trailing separation portion may be provided at a position trailing the cutting portion in the rotational direction, the trailing separation portion being positioned at a distance from the inner surface of the existing pipe.

[0012] According to the above configuration, the trailing separation section is positioned at a trailing position in the rotational direction of the cutting section, spaced apart from the inner surface of the existing piping, thereby reducing the contact area between the piping cutting tool and the inner surface of the existing piping, making it easier to move the piping cutting tool inside the existing piping, for example.

[0013] In addition, in the pipe cutting tool of the present invention, a leading separation portion may be provided at a position on the leading side of the cutting portion in the rotational direction, the leading separation portion being positioned at a distance from the inner surface of the existing pipe.

[0014] According to this configuration, chips generated by cutting the inner peripheral surface with the cutting edge can be efficiently removed by the preceding separation portion. [Effects of the Invention]

[0015] As described above, according to the present invention, the blade end of the cutting portion rotates stably while maintaining the cutting position within the existing pipe using the blade end outer surface and the front outer surface, thereby making it possible to maintain a constant cutting width on the inner surface of the existing pipe. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram showing an example of the arrangement of pipes in a building that are the target of a pipe renewal method using a pipe cutting tool according to one embodiment of the present invention. [Figure 2] FIG. 2 is a detailed view of the adhesion removal device according to the embodiment. [Figure 3] FIG. 3 shows the adhesion remover according to the embodiment, where (a) is a right side view of the adhesion remover, and (b) is a front view of the adhesion remover. [Figure 4] Figure 4 shows the adhesion removal process according to the same embodiment, where (a) shows a cross-sectional view of an existing pipe with adhesions adhering to the inner surface of the pipe, (b) shows the process of inserting an adhesion removal device into the pipe, and (c) shows the state at the completion of the adhesion removal process. [Figure 5]Figure 5 shows a pipe cutting tool according to the same embodiment, where (a) is a left side view of the pipe cutting tool, (b) is a front view of the pipe cutting tool, (c) is an enlarged view of the cutting portion and the front side, and (d) is a plan view of the pipe cutting tool. [Figure 6] Figure 6 shows the pipe cutting process according to the same embodiment, where (a) is a cross-sectional view showing the state in which the rope body has been inserted from the outlet to the inlet, (b) is a cross-sectional view showing the state in which the pipe cutting tool has been inserted into the existing pipe, and (c) is a cross-sectional view showing the state in which the pipe cutting tool has been inserted to the outlet. [Figure 7] Figure 7 shows the pipe insertion process according to the same embodiment, where (a) is a cross-sectional view showing the state in which the rope body is inserted from the outlet to the inlet and a new pipe is attached to the joint member at the end of the rope body, and (b) is a cross-sectional view showing the state in which the new pipe is inserted into the existing pipe. [Figure 8] FIG. 2 is a diagram illustrating a transportation device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] A pipe renewal method using a pipe cutting tool 21 according to one embodiment of the present invention will be described below with reference to Figures 1 to 8. For ease of explanation, the side of the existing pipe 1 in the axial direction where the adhesion removal device 12 and the pipe cutting device 20 are inserted will be referred to as the inlet 4, and the opposite side will be referred to as the outlet 5. First, an overview of the existing pipe 1 used in a building (for example, a house or a factory) will be described.

[0018] As shown in FIG. 1, an existing indoor pipe 1 is generally covered by a floor surface 3 at least halfway along its pipe axis. The pipe axis direction is along the axial direction of the existing pipe 1. In addition, an inlet 4 to an outlet 5 along the pipe axis direction are exposed from the floor surface 3, and the inlet 4, which is one end of the existing pipe 1, is connected to a water heater via a header member 6, for example, and the outlet 5, which is the other end of the existing pipe 1, is connected to a faucet 7 in the bathroom, for example. Note that the inlet 4 and the outlet 5 are not limited to being connected as described above, and for example, the inlet 4 may be attached to the water heater via a joint member.

[0019] The existing pipe 1 is formed by inserting a flexible pipe (e.g., a water supply pipe or a hot water supply pipe) made of a polyethylene pipe, a cross-linked polyethylene pipe, a three-layer aluminum pipe, or the like into a protective material 9 made of a tubular insulating material, for example, a foamed resin. Therefore, in the radial direction of the existing pipe 1, the inner diameter of the protective material 9 is larger than the outer diameter of the pipe. Also, as shown in FIG. 1, the existing pipe 1 of this embodiment is flexible and can be bent. Furthermore, the existing pipe 1 is fixed at a predetermined interval in the pipe axis direction to a slab 3a or the like arranged below the floor surface 3 (not shown). Note that, hereinafter, the pipe of the existing pipe 1 that has already been inserted into the protective material 9 will be referred to as the "old pipe 10."

[0020] In the pipe renewal method of this embodiment, the wall thickness of the existing pipe 1 is cut from the inner diameter side, and then a new pipe (hereinafter referred to as "new pipe 11") is installed inside the protective material 9 (specifically, inside the old pipe 10 whose wall thickness has been cut from the inside) along the pipe axis direction.

[0021] The new pipe 11 is inserted into the existing pipe 1 along the pipe axis direction. Like the old pipe 10, the new pipe 11 is made of a polyethylene pipe, a cross-linked polyethylene pipe, a three-layer aluminum pipe, or the like, and is a flexible pipe that can be bent. In addition, the new pipe 11 in this embodiment has an outer diameter larger than the inner diameter of the old pipe 10.

[0022] The pipe renewal method using the pipe cutting tool 21 of this embodiment will be specifically described as follows: (1) Preparation process for pipe replacement, (2) an adhesion removal step of removing adhesion X adhered to the inner peripheral surface of the old pipe 10; (3) a pipe cutting process of enlarging the inner diameter of the old pipe 10 by cutting the inner peripheral surface of the old pipe 10; (4) an insertion step of inserting the new pipe 11 into the old pipe 10 whose inner diameter has been enlarged using a pipe insertion tool 25; In this renewal method, the protective material 9, the old pipe 10, and the new pipe 11 have a circular cross section.

[0023] The above-mentioned (1) renewal preparation process will now be described. The renewal preparation process includes a removal process for freeing one end and the other end of the existing pipe 1 in the pipe axis direction, and a pipe interior inspection process for inspecting the inside of the existing pipe 1.

[0024] In the removal process, as shown by the two-dot chain line in Figure 1, for each existing pipe 1, the area of ​​the existing pipe 1 that is exposed to the floor surface 3 is made a free end. The removal process is carried out by removing one end of the existing pipe 1 from the header member 6 to make it an inlet 4, and removing the other end of the existing pipe 1 from the faucet 7 to make it an outlet 5, leaving a single protective material 9 and old pipe 10 that include straight and curved areas (for example, curved portion 8 in Figure 1), thereby making the inlet 4 and outlet 5 free ends. The removal process may also include a step of orienting the free end in a convenient (easily workable) direction.

[0025] In this removal process, the middle portion of the existing pipe 1 remains firmly fixed to the slab 3a as described above, so that the existing pipe 1 (protective material 9 and old pipe 10) including the straight and curved regions remains.

[0026] The pipe interior inspection process is a process of checking the condition inside the existing pipe 1 between the inlet 4 and the outlet 5 of the existing pipe 1. In this pipe interior inspection process, a pipe interior inspection device (not shown) capable of inspecting the inside of the old pipe 10 is inserted from one end of the existing pipe 1 into the old pipe 10, and the pipe interior inspection device is advanced toward the other end of the existing pipe 1 to inspect the inside of the existing pipe 1. Here, if the pipe interior inspection device is inserted into the old pipe 10 and it is confirmed that deposit X (e.g., limescale or dirt) is attached to the inner surface of the old pipe 10 as shown in FIG. 4(a), the process proceeds to the attachment removal process (2). Note that in the pipe interior inspection process, even while the pipe interior inspection device is being advanced toward the other end, if deposit X attached inside the existing pipe 1 is discovered, the pipe interior inspection device may be pulled out from one end of the existing pipe 1 and the process may proceed to the attachment removal process (2). Alternatively, the inside-pipe inspection device may be inserted into the old pipe 10 to inspect the entire area of ​​the old pipe 10 in the pipe axis direction, and then the adhesion removal step (2) may be carried out.

[0027] The adhesion removal step (2) is a step of removing adhesion X from the inner peripheral surface of the old pipe 10. In order to remove adhesion X from the inner peripheral surface of the old pipe 10, an adhesion removal device 12 is used, which is equipped with an adhesion remover 13 that removes adhesion X by rotating around the pipe axis direction.

[0028] The adhesion removal device 12 is for removing adhesion X from the inner surface of the old pipe 10. In addition to the adhesion removal tool 13, the adhesion removal device 12 includes a drive unit 14 that is disposed outside the protective material 9 and the old pipe 10 and generates a rotational force, and a connecting unit 15 that can transmit the rotational force generated by the drive unit 14 to the adhesion removal tool 13. As shown in FIG. 2, in the adhesion removal device 12, the drive unit 14, the connecting unit 15, and the adhesion removal tool 13 are arranged in this order from the rear side (left side in FIG. 2) in the front-to-rear direction L. Here, the "front-to-rear direction L" refers to the direction in which the adhesion removal device 12 and the pipe cutting device 20 are inserted into the existing pipe 1, and the adhesion removal device 12 is inserted into the existing pipe 1 sequentially from the front side to the rear side. The adhesion removal device 12 of this embodiment includes a transport unit 17 that transports the adhesion removal tool 13 and the connecting unit 15 from the inlet 4 side to the outlet 5 side.

[0029] The driving unit 14 is used to rotate the adhesion remover 13. As shown in Fig. 2, a general rotary power tool is used as the driving unit 14. The driving unit 14 is configured so that the tip thereof can be connected to the connecting unit 15.

[0030] As shown in Fig. 2, the coupling part 15 of this embodiment includes a handle 16 attached to the tip of the drive part 14, and a connection part 18 that connects the handle 16 to the adhesion remover 13. The handle 16 is formed so that it can be detachably coupled to the shape of the tip of the drive part 14. The handle 16 is formed with a length in the tube axial direction that can withstand being gripped by the drive part 14 so that it is aligned with the tube axial direction. The handle 16 is also configured so that it can transmit the rotational force of the drive part 14 to the connection part 18.

[0031] The connecting portion 18 is a portion that connects the handle 16 and the adhesion remover 13. The rear end of the connecting portion 18 is connected to the front end of the handle 16, and the front end is connected to the adhesion remover 13, thereby connecting the handle 16 and the adhesion remover 13. The connecting portion 18 can also transmit the rotational force of the drive unit 14, which is transmitted via the handle 16, to the adhesion remover 13. Specifically, the connecting portion 18 of this embodiment includes a rod-shaped shaft 19 that extends along the pipe axis direction, and an attachment portion (not shown) that is disposed at the front end of the shaft 19. The shaft 19 of this embodiment is configured to be flexible so as to fit along the curved portion of the old pipe 10 shown in FIG. 1 . Meanwhile, the attachment portion is connected to the adhesion remover 13. In this embodiment, the attachment portion is configured as a male thread (not shown), and this male thread is threaded into a female thread formed at the rear end of the adhesion remover, thereby connecting the attachment portion to the adhesion remover 13. The connection portion 18 of this embodiment is configured by connecting a plurality of shafts 19 via joint portions 191 that are arranged at both ends of the shafts 19 in the axial direction.

[0032] The connecting part 18 is configured so as to be insertable into the old pipe 10. Therefore, the outer diameter of the connecting part 18 is set to be smaller than the inner diameter of the old pipe 10. Moreover, the connecting part 18 of this embodiment is set to a length in the axial direction that extends from the inlet 4 to the outlet 5 of the existing pipe 1. Therefore, in the adhesion removal device 12, the adhesion remover 13 can be inserted from the inlet 4 to the outlet 5 of the existing pipe 1.

[0033] The adhesion remover 13 is a tool that removes adhesion X that has adhered to the inner surface of the old pipe 10. This adhesion remover 13 receives a rotational force transmitted from a drive unit 14 and rotates around the pipe axis of the existing pipe 1. As shown in Figures 3(a) and 5(a), in explaining the adhesion remover 13 and a pipe cutting tool 21 (described later), the direction in which the adhesion remover 13 and the pipe cutting tool 21 rotate will be referred to as the rotation direction R.

[0034] The adhesion remover 13 is configured to be insertable into the old pipe 10. Therefore, the radial length of the adhesion remover 13 is set to be equal to or less than the inner diameter φA of the old pipe 10. Here, as shown in Fig. 3(a) , of the first radial direction A and the second radial direction B that are perpendicular to each other, the length of the adhesion remover 13 in the first radial direction A is approximately the same as the inner diameter φA of the old pipe 10, and the length in the second radial direction B is shorter than the inner diameter φA of the old pipe 10.

[0035] The adhesion remover 13 includes a removal body 13a extending in the front-to-rear direction L and a removal portion 132 formed on the removal body 13a. The removal body 13a is a columnar or cylindrical body with a central axis in the front-to-rear direction L, and its radial size is smaller than the inner diameter φA of the old pipe. In the rotational direction R, the removal body 13a includes a leading removal portion 13b that is located on the leading side of the removal portion 132 in the rotational direction R, and a trailing removal portion 13c that is located on the trailing side of the removal portion 132 in the rotational direction R, as will be described later.

[0036] The removal leading portion 13b extends toward the leading side in the rotation direction R of the removal portion 132. The removal leading portion 13b of this embodiment has a removal front and rear portion 133 from which a removal leading surface 134 (described later) rises, and a removal rotation portion 138 extending in the rotation direction R. The removal front and rear portion 133 is a surface that expands in the front and rear direction L and the radial direction. This removal front and rear portion 133 is configured as an inclined surface that is inclined with respect to the front and rear direction L. The removal front and rear portion 133 of this embodiment is a tapered surface that extends radially inward as it progresses toward the front side in the front and rear direction L. The removal rotation portion 138 is a curved surface that curves from the removal front and rear portion 133 side toward a leading side surface portion 137a (described later). This removal rotation portion 138 extends in the front and rear direction L between the removal front and rear portion 133 and the leading side surface portion 137a (described later). The removal rotation portion 138 of this embodiment is configured to expand in the front and rear direction L as it progresses toward the leading side in the rotation direction R.

[0037] The removal trailing portion 13c extends in the front-rear direction L to support the removal portion 132 from the trailing side in the rotational direction R. The removal trailing portion 13c includes a removal support portion 139 that supports a removal creeping surface 135a (described later) from the trailing side in the rotational direction R, and a tapered portion 136 that supports a removal continuing surface 135c (described later) from the trailing side in the rotational direction R. The removal support portion 139 is configured as a curved surface that curves in the rotational direction R. Furthermore, the removal support portion 139 is configured as a surface that is flush with the removal creeping surface 135a in the rotational direction R. The removal support portion 139 of this embodiment extends in the rotational direction R between the removal creeping surface 135a and the trailing side surface portion 137b. The tapered portion 136 is located forward of the removal support portion 139 in the front-rear direction L. The removal support portion 139 of this embodiment extends in the rotational direction R between the removal portion 132 and a trailing side surface portion 137b (described later).

[0038] The removal main body 13a of this embodiment includes a leading side surface 137a that is arranged on the leading side of the removal leading portion 13b in the rotational direction R, and a trailing side surface 137b that is arranged on the trailing side of the removal trailing portion 13c in the rotational direction R. The leading side surface 137a and the trailing side surface 137b are configured as flush surfaces that extend in the front-rear direction and the first radial direction A.

[0039] The removal main body 13a has a rear removal side portion 131 on the rear side in the front-to-rear direction L. The rear removal side portion 131 is a surface that expands in the radial direction. This rear removal side portion 131 defines the rear end of the adhesion remover 13. The rear removal side portion 131 has an attachment portion 130 for connecting the adhesion remover 13 to the connecting portion 15. As shown in FIG. 3(b), the attachment portion 130 in this embodiment is configured as a female thread into which a male thread serving as an attachment portion can be threaded. Therefore, in this embodiment, the adhesion remover 13 is connected to the connecting portion 15 by threading the female thread serving as the attachment portion 130 into the male thread.

[0040] The removal part 132 removes the adhesion X. The removal part 132 removes the adhesion X by cutting by rotating around the front-rear direction L. The removal part 132 includes a removal leading surface 134 which is an end face on the leading side in the rotation direction R, a removal outer peripheral surface 135 formed on the trailing side in the rotation direction R from the radially outer end edge of the removal leading surface 134, and a removal cutting edge 132a formed on the ridges of the removal leading surface 134 and the removal outer peripheral surface 135.

[0041] The removal destination surface 134 is a surface that intersects the removal front and rear portion 133 and extends radially outward. This removal destination surface 134 stands perpendicularly from the removal front and rear portion 133 and extends parallel to the front and rear direction L. This removal destination surface 134 extends radially between the removal cutting edge portion 132a and the removal front and rear portion 133. Specifically, as shown in FIG. 3(b), the removal destination surface 134 is a surface that is located among the removal outer peripheral surface 135, a removal creeping surface 135a that extends along the front and rear direction L, a removal leading edge surface 135c that extends radially, a removal continuing surface 135c that is continuous with the removal creeping surface 135a and the removal leading edge surface 135c, and the removal front and rear portion 133.

[0042] The removal outer peripheral surface 135 is the radial outer surface of the removal portion 132 and is configured as a surface extending in the rotation direction R. This removal outer peripheral surface 135 includes a removal creeping surface 135a along the rotation direction R, a removal tip surface 135b that defines the tip of the removal portion 132, and a removal continuing surface 135c that is continuous with the removal creeping surface 135a and the removal tip surface 135b.

[0043] The removal creeping surface 135a is a curved surface that curves in the rotational direction R. This removal creeping surface 135a extends from the radial outer edge of the removal preceding surface 134 to the trailing side in the rotational direction R. Therefore, the removal creeping surface 135a in this embodiment extends in the circumferential direction between the removal preceding surface 134 and the removal support portion 139. Moreover, the removal creeping surface 135a in this embodiment extends along the front-rear direction L.

[0044] The removal continuous surface 135c extends from the preceding removal surface 134 to the trailing side in the rotational direction R and is curved in the rotational direction R. The removal continuous surface 135c is disposed forward of the removal creeping surface 135a in the front-rear direction L. The removal continuous surface 135c of this embodiment is configured as an inclined surface that slopes radially inward as it progresses forward from the removal creeping surface 135a in the front-rear direction L.

[0045] The removal tip surface 135c extends from the continuous removal surface 135c toward the front and rear removal portion 133. The removal tip surface 135c of this embodiment extends inward along the radial direction. Note that the removal tip surface 135c of this embodiment is located forward of the front and rear removal portion 133.

[0046] The removal cutting edge 132a is formed on a ridge where the removal target surface 134 and the removal outer peripheral surface 135 are continuous. That is, the removal cutting edge 132a is a cutting edge formed on the leading edge of the removal outer peripheral surface 135 in the rotation direction R, and on the radially outer edge of the removal target surface 134. Therefore, the removal cutting edge 132a is disposed at the leading end of the rotation direction R. Specifically, the removal cutting edge 132a of this embodiment includes front and rear removal cutting edges 132b formed on the leading edge of the removal creeping surface 135a in the rotation direction R and formed on the radially outer edge of the removal target surface 134, and an inclined removal cutting edge 132c formed on the leading edge of the removal continuous surface 135c in the rotation direction R and formed on the radially outer edge of the removal target surface 134. The front-rear removal cutting edge portion 132b is formed in a straight line parallel to the front-rear direction L by setting the distance from the central axis in the front-rear direction L to be the same throughout the entire area in the front-rear direction L. On the other hand, the inclined removal cutting edge portion 132c is formed in an inclined line that inclines so that the distance from the central axis in the front-rear direction L decreases as it advances forward in the front-rear direction L.

[0047] The adhesion remover 13 has an adhesion leading separation portion that is arranged relative to the adhesion X adhering to the inner peripheral surface of the old pipe 10, on the leading side in the rotation direction R of the removal portion 132. This adhesion leading separation portion is formed between the removal leading surface 134 and the removal front and rear portion 133 in the rotation direction R. Therefore, the adhesion leading separation portion is arranged on the leading side in the rotation direction R of the removal leading surface 134. In other words, the adhesion leading separation portion is a space portion that extends in the front and rear direction L.

[0048] The adhesion remover 13 has an adhesion trailing separation portion that is disposed at a distance from the inner circumferential surface of the old pipe 10 on the trailing side of the removal portion 132 in the rotational direction R. This adhesion trailing separation portion is a space that is formed between the removal support portion 139 and the leading side surface portion 137a in the rotational direction R and penetrates in the front-rear direction L.

[0049] As shown in Fig. 8, the sending and receiving section 17 includes a sending section 170 arranged on the inlet 4 side and a welcoming section 174 arranged on the outlet 5 side. The sending section 170 includes a sending device 171 that can send out the connecting section (specifically, the shaft) from the rear end side toward the front end side, and a sending connection section 173 that is arranged between the sending device 171 and the inlet 4 of the existing piping 1. Note that, as shown in Fig. 8, the sending device 171 of this embodiment is arranged so as to send out the connecting section 15 in the pipe axis direction relative to the opening of the inlet 4 of the existing piping 1.

[0050] The feeder 171 is a tool capable of moving the elongated body along its axial direction. The feeder 171 of this embodiment is circular and includes a pair of feeder bodies 172 arranged to sandwich the connecting portion 15 from the sides, and the feeder bodies 172 are configured to rotate in opposite directions about an axis in the vertical direction. With this configuration, the feeder 171 can move the connecting portion 15 sandwiched between the pair of feeder bodies 172 along the axial direction of the connecting portion 15 by rotating the pair of feeder bodies 172. Note that the feeder 171 of this embodiment can operate to move the connecting portion 15 in a direction to insert it from the inlet 4 side of the existing piping 1, or can operate to move the connecting portion 15 so as to pull it out from the inlet 4 of the existing piping 1.

[0051] Feed connection portion 173 connects feed machine 171 and inlet 4 of existing piping 1. In this embodiment, feed connection portion 173 includes straight secondary pipe 173a connected to feed main body 172, branching jig 173b, and secondary pipe attachment jig 173c. Secondary pipe 173a is a pipe through which adhesion remover 13, connecting portion 15, and pipe cutting tool 21 (described later) can be inserted. Therefore, the inner diameter of secondary pipe 173a is larger than the outer diameters of adhesion remover 13, connecting portion 15, cord body 23, and pipe cutting tool 21. The inner diameter of secondary pipe 173a is also larger than the inner diameter of existing piping 1.

[0052] Branching jig 173b is disposed between secondary pipe 173a and secondary pipe attachment jig 173c. Branching jig 173b can be connected in the pipe axis direction and in a direction perpendicular to the pipe axis direction. Branching jig 173b in this embodiment is connected to dust collection and recovery unit 173e (described later) via branch pipe 173d in a direction perpendicular to the pipe axis direction.

[0053] The secondary pipe mounting jig 173c is a straight pipe extending along the pipe axis direction. The secondary pipe mounting jig 173c of this embodiment is configured so that the state inside the pipe can be checked. Specifically, as shown in Fig. 8, the secondary pipe mounting jig 173c of this embodiment is formed with a window through which the internal state can be checked.

[0054] The dust collection and recovery unit 173e recovers dust (e.g., cutting chips and deposits X) generated in the adhesion removal step and the pipe cutting step. The dust collection and recovery unit 173e recovers the dust that has flowed toward the inlet 4 using airflow F sent from an airflow delivery unit 178 (described later). The dust collection and recovery unit 173e is disposed between the secondary pipe 173a and the existing pipe 1 in the pipe axial direction. As shown in FIG. 8 , the dust collection and recovery unit 173e of this embodiment is connected to the branching jig 173b via the branching pipe 173d, and is thereby disposed between the secondary pipe 173a and the secondary pipe attachment jig 173c. Therefore, after the dust flowing toward the secondary pipe 173a is confirmed through the window of the secondary pipe attachment jig 173c, the dust flows into the dust collection and recovery unit 173e. The branching pipe 173d is a pipe that connects the dust collection and recovery unit 173e and the branching jig 173b. The branch pipe 173d of this embodiment is flexible and arranged in a curved shape.

[0055] The pick-up section 174 includes a pick-up machine 175 that pulls the rope body, which will be described later, and a pick-up connection section 177 that connects the pick-up machine 175 to the outlet 5 of the existing piping 1. As shown in Fig. 8, the pick-up machine 175 of this embodiment is arranged so as to pull the opening of the outlet 5 of the existing piping 1 in the pipe axis direction.

[0056] The pick-up machine 175 is similar to the aforementioned feeder 171 and is a tool capable of moving the elongated body along the axial direction of the elongated body. The pick-up machine 175 of this embodiment is circular and includes a pair of pick-up main bodies 176 arranged to sandwich the cord body 23 from the sides, and the pick-up main bodies 176 are configured to rotate in opposite directions about an axis in the up-down direction. Therefore, in the pick-up machine 175, by rotating the pair of pick-up main bodies 176, the cord body sandwiched between the pair of pick-up main bodies 176 can be moved along the axial direction of the cord body.

[0057] Pick-up connecting portion 177 is configured to allow cord body 23, connecting portion 15, adhesion remover 13, and pipe cutting tool 21 to be inserted therethrough. Therefore, the inner diameter of pick-up connecting portion 177 is larger than the outer diameters of cord body 23, connecting portion 15, adhesion remover 13, and pipe cutting tool 21. Furthermore, pick-up connecting portion 177 in this embodiment is configured from a linear auxiliary pipe extending along the axial direction.

[0058] The welcoming section 174 of this embodiment includes an airflow sending section 178 that sends out the airflow F toward the sending section 170. The airflow sending section 178 of this embodiment is configured by a compressor. The airflow sending section 178 is also connected to the welcoming machine 175. Therefore, the air sent out from the airflow sending section 178 flows from the outlet 5 side to the inlet 4 side of the existing piping 1 via the welcoming section 174, allowing the collected dust to flow toward the sending section 170.

[0059] As shown in Fig. 8, the power supply unit 179 supplies electricity supplied from a power source to the pick-up unit 174. The power supply unit 179 of this embodiment is connected to the power source and the pick-up unit 174 via a connection line. The power supply unit 179 of this embodiment is configured as a transformer. In this embodiment, the sending machine 171 and the pick-up machine 175 are connected by a cable Y.

[0060] The adhesion removal process for removing adhesions inside the existing pipe 1 using the adhesion removal device 12 configured as described above will be described with reference to Figures 4(b) and 4(c). Note that in Figures 4(b) and 4(c), the transfer unit 17 and the drive unit 14 of the adhesion removal device 12 are not shown in order to focus on the inside of the existing pipe 1.

[0061] In the adhesion removal process of this embodiment, deposits are removed from the entire area in the axial direction of the old pipe 10. In the adhesion removal process, first, the adhesion removal device 12 is inserted into the existing pipe 1 from the inlet 4. Here, in the adhesion removal device 12 of this embodiment, the adhesion removal tool 13 is disposed at the front. Therefore, in this embodiment, the adhesion removal tool 13, which rotates in the rotation direction R by the rotational force of the drive unit 14, is inserted into the old pipe 10 from the front side in the front-to-rear direction L.

[0062] Incidentally, the length of the adhesion remover 13 of this embodiment in the first radial direction A is approximately the same as the inner diameter φA of the old pipe 10, and the length of the adhesion remover 13 in the second radial direction B is shorter than the inner diameter φA of the old pipe 10. Therefore, the adhesion remover 13 of this embodiment can be inserted into the old pipe 10.

[0063] Then, the attachment remover 13 rotating in the rotation direction R is inserted further into the old pipe 10. As a result, the removal blade edge 132a cuts and removes the attachment X. Specifically, the removal blade edge 132a, which is located at the leading end in the rotation direction R, moves in the rotation direction R while contacting the attachment X, thereby cutting and removing the attachment X. In addition, in the removal blade edge 132a of this embodiment, the linear front and rear removal blade edge 132b parallel to the front and rear direction L and the inclined removal blade edge 132c inclined so as to decrease in distance to the central axis of the front and rear direction L as it moves forward in the front and rear direction L move in the rotation direction R to cut and remove the attachment X. At this time, the inclined removal blade edge 132c cuts and removes the attachment X radially inward from the inner circumferential surface of the old pipe 10, and then the front and rear removal blade edge 132b cut and remove the attachment X on the inner circumferential surface side of the old pipe 10.

[0064] When the removal blade edge 132a removes the adhesion X, the removal target surface 134 scoops up the removed adhesion X. Then, the adhesion X is expelled from the existing piping 1 by air sent out from the air current sending unit 178. In this embodiment, as shown in FIG. 4(b), the air sent out from the air current sending unit 178 forms an air current F that flows from the outlet 5 side to the inlet 4 side of the existing piping 1, and this air current F blows the adhesion X toward the inlet 4 side of the existing piping 1. Specifically, air flows in the rotation direction R through an adhesion target separation portion formed between the removal target surface 134 and the removal front and rear portion 133 and a adhesion trailing separation portion formed between the removal support portion 139 and the leading side surface portion 137a, and the adhesion X is blown toward the inlet side.

[0065] 8, it is possible to check the insertion of connection part 18 into existing pipe 1 and the passage of deposits through the window of secondary pipe attachment jig 173c. Then, deposits X checked through the window of secondary pipe attachment jig 173c flow to dust collection and recovery part 173e via branch pipe 173d connected to branch jig 173b.

[0066] 4(c), the adhesion removal process is completed when the adhesion remover 13 is inserted into the old pipe 10. When the adhesion removal process is completed, the adhesion X is removed from the inner peripheral surface of the old pipe 10, and the inner diameter of the old pipe 10 becomes φA. In other words, the adhesion removal process can make the inner diameter of the entire old pipe 10 in the pipe axis direction φA.

[0067] Next, the pipe cutting step (3) will be described with reference to Figures 6(a) to 6(c). The pipe cutting step is a step of cutting the inner peripheral surface of the old pipe 10. To cut the inner peripheral surface of the old pipe 10, a pipe cutting device 20 is used that is equipped with a pipe cutting tool 21 that rotates in a rotation direction R around the pipe axis direction. For ease of explanation, the pipe cutting device 20 will be described before the pipe cutting step.

[0068] The pipe cutting device 20 is used to cut the old pipe 10 to remove a portion of the wall thickness from its inner surface. In addition to the pipe cutting tool 21 described above, the pipe cutting device 20 includes a drive unit 14 that generates a rotational force and a connecting unit 15 that transmits the rotational force generated by the drive unit 14 to the pipe cutting tool 21. The configurations of the connecting unit 15 and the drive unit 14 are as described above, so a description thereof will be omitted. That is, the pipe cutting device 20 is configured by connecting the pipe cutting tool 21 to the tip of the connecting unit 15 described above. The pipe cutting device 20 of this embodiment also includes the above-described transfer unit 17. The transfer unit 17 in the pipe cutting device 20 of this embodiment is used to transfer the pipe cutting tool 21 and the connecting unit from the inlet 4 side to the outlet 5 side.

[0069] 5, pipe cutting tool 21 is a cutting tool that cuts the thickness of the inner surface of old pipe 10 that is passed through protective material 9 by rotating about front-to-rear direction L along the pipe axis direction of existing pipe 1. Pipe cutting tool 21 can rotate in rotation direction R by receiving rotational force transmitted from connecting portion 15.

[0070] 5(a) and 5(b), the pipe cutting tool 21 includes a cutting base 210 extending in the front-rear direction L and a cutting forming portion 211 formed on the cutting base 210. The cutting base 210 is a columnar or cylindrical body with a central axis in the front-rear direction L, and is configured so that its radial size is smaller than the inner diameter φA of the old pipe 10. The cutting base 210 includes, as its outer periphery around the front-rear direction L, a first outer periphery 210a on which the cutting forming portion 211 is provided, and a second outer periphery 210b arranged on the rear side of the first outer periphery 210a in the rotational direction R. In this embodiment, a pair of first outer peripheries 210a are provided radially opposite each other, and a pair of second outer peripheries 210b are also provided radially opposite each other. Specifically, cutting base 210 has a first outer circumferential portion 210a and a second outer circumferential portion 210b that are respectively arranged in a first radial direction A and a second radial direction B that are perpendicular to each other among the radial directions of pipe cutting tool 21. Pipe cutting tool 21 also has a front end portion 210c that is arranged on the front side in the front-rear direction L, and a rear end portion 210d that is arranged on the rear side.

[0071] The first outer circumferential portion 210a and the second outer circumferential portion 210b extend in the front-rear direction L and are continuous with the front end portion 210c and the rear end portion 210d. As shown in FIG. 5(a), the first outer circumferential portion 210a is disposed on both sides of the cutting base portion 210 in the first radial direction A. In this embodiment, the first outer circumferential portion 210a is aligned with the second radial direction B. Specifically, the radial outer surface of the first outer circumferential portion 210a is a plane aligned with the front-rear direction L and is a surface on which the cutting forming portion 211 is provided. On the other hand, the second outer circumferential portion 210b is disposed on both sides of the cutting base portion 210 in the second radial direction B, and in this embodiment, the second outer circumferential portion 210b is aligned with the first radial direction A. Specifically, the radial outer surface of the second outer circumferential portion 210b is a plane aligned with the front-rear direction L and is a surface disposed perpendicular to the outer surface of the first outer circumferential portion 210a. 5(b) and 5(d), the first outer circumferential portion 210a and the second outer circumferential portion 210b in this embodiment extend along the front-rear direction L. The first outer circumferential portion 210a and the second outer circumferential portion 210b are arranged so as to be alternately aligned in the rotational direction R. In this embodiment, two each of the first outer circumferential portions 210a and second outer circumferential portions 210b are arranged so as to be alternately aligned in the rotational direction R.

[0072] The front end portion 210c is disposed on the front side of the cutting base portion 210. As shown in FIGS. 5(b) and 5(d), the radial length of the front end portion 210c is shorter than the inner diameter of the old pipe 10. In this embodiment, the front end portion 210c is configured in a curved shape that is convex on the front side in the front-rear direction L. A front connection portion a to which a cord body 23, which will be described later, is connected is formed on the front end portion 210c.

[0073] The rear end portion 210d is disposed on the rear side of the cutting base portion 210. In this embodiment, the rear end portion 210d is configured in a planar shape perpendicular to the front-to-rear direction L. The rear end portion 210d is provided with a rear connection portion b to which an attachment portion can be connected. In this embodiment, the rear connection portion b is configured as a female thread that can be threaded with a male thread serving as the attachment portion. Therefore, the pipe cutting tool 21 can be connected to the connecting portion 15 using the rear connection portion b.

[0074] The cutting forming portion 211 stands radially from the cutting base portion 210. In this embodiment, the cutting forming portion 211 stands in the first radial direction A from the first outer peripheral portion 210a. As shown in FIG. 5(a), the cutting forming portion 211 in this embodiment is disposed at the end of the first outer peripheral portion 210a in the second radial direction B, and is disposed on the trailing side in the rotational direction R on the outer surface of the first outer peripheral portion 210a. Specifically, the cutting forming portion 211 includes a trailing forming portion 212 on the trailing side in the rotational direction R and a leading forming portion 213 on the leading side in the rotational direction R, and is disposed so that the trailing forming portion 212 is continuous with the second outer peripheral portion 210b in the first radial direction A and the leading forming portion 213 is leading in the rotational direction R. As shown in FIG. 5(d), the trailing forming portion 212 and the leading forming portion 213 extend in the front-rear direction L. The cut-out portion 211 has a formed outer surface 211a as its radially outer surface, and the formed outer surface 211a is a curved surface along the rotation direction R.

[0075] The cutting forming portion 211 is arranged in the front-rear direction L on the first outer peripheral portion 210a. The cutting forming portion 211 of this embodiment is arranged over the entire area of ​​the first outer peripheral portion 210a in the front-rear direction L. A forming front portion 222, which is the front end of the cutting forming portion 211, is curved so as to be continuous with the front end portion 210c of the cutting base portion 210, and a rear inclined surface 226a, which is the rear end, is tapered so as to be continuous with the rear end portion of the cutting base 210. Furthermore, the cutting forming portion 211 of this embodiment includes an intermediate portion 214 provided on the first outer peripheral portion 210a, a rear side portion 224 arranged rearward of the intermediate portion 214, and a front side portion 220 arranged forward of the intermediate portion 214.

[0076] The intermediate portion 214 is disposed rearward of the front portion 220 in the front-rear direction L. As shown in FIGS. 5(b) and 5(c), the intermediate portion 214 extends radially outward further than the front portion 220. In this embodiment, the intermediate portion 214 is formed longer in the second radial direction B (rotational direction R) than the front portion 220 and the rear portion 224. Therefore, as shown in FIG. 5(d), of the forming leading portion 213, a forming intermediate leading portion 213a formed in the intermediate portion 214 extends further toward the leading side in the rotational direction R than a forming front leading portion 213b and a forming rear leading portion 213c, which will be described later.

[0077] The intermediate portion 214 is formed with a cutting portion 215 that cuts the inner peripheral surface of the old pipe 10. The cutting portion 215 is a portion of the intermediate portion 214 that is disposed radially outward from the front portion 220. The cutting portion 215 cuts the inner peripheral surface of the old pipe 10 by rotating around the front-rear direction L, with the front-rear direction L aligned with the pipe axis direction. The cutting portion 215 includes a cutting edge leading surface 215e that is an end face on the leading side of the cutting portion 215 in the rotational direction R, a cutting edge outer peripheral surface 215b that is formed from the radially outer end edge of the cutting edge leading surface 215e along the trailing side in the rotational direction R, and a blade end portion 215a that is formed on the ridge portion of the cutting edge leading surface 215e and the blade edge outer peripheral surface 215b. The blade tip 215a is the leading end in the rotation direction R of the cutting part 215 and the outer end in the radial direction, and is configured to cut the inner diameter φA of the old pipe from the inner peripheral side by rotating in the circumferential direction while abutting on the inner peripheral surface of the old pipe 10. The cutting part 215 includes a blade tip front part 215c that defines its front end, and a blade tip rear part 215d that defines its rear end.

[0078] The cutting edge leading surface 215e is a surface that intersects with the outer surface of the first outer peripheral portion 210a of the cutting base portion 210 and extends radially outward from the outer surface. In this embodiment, the cutting edge leading surface 215e is a plane that is perpendicular to the outer surface and parallel to the front-rear direction L. The cutting edge leading surface 215e constitutes the forming leading portion 213 of the cutting portion 211. Note that the cutting edge leading surface 215e may be any leading end surface in the rotational direction R of the cutting portion 215, and may be formed in a direction that intersects with the front-rear direction L, for example. That is, the cutting edge leading surface 215e in this embodiment is a surface that extends along the first radial direction A and the front-rear direction L and is perpendicular to the second radial direction B.

[0079] The blade tip outer peripheral surface 215b is the radial outer surface of the cutting portion 215 and is a curved surface along the rotational direction R. The blade tip outer peripheral surface 215b extends from the radial outer edge of the blade tip leading surface 215e toward the trailing side in the rotational direction R. That is, the blade tip outer peripheral surface 215b in this embodiment extends circumferentially between the blade tip end portion 215a and the trailing forming portion 212. Note that the blade tip outer peripheral surface 215b in this embodiment is configured to be longer in the circumferential direction than a front outer peripheral surface 221, which will be described later. In addition, a ridgeline is formed by the leading edge of the blade tip outer peripheral surface 215b in the rotational direction R and the radial outer edge of the blade tip leading surface 215e, and the blade tip 215a is formed on this ridgeline.

[0080] As described above, the blade tip 215a is formed on the ridge where the blade tip outer peripheral surface 215b and the blade tip leading surface 215e are continuous. That is, the blade tip 215a is a cutting edge formed on the leading edge of the blade tip outer peripheral surface 215b in the rotational direction R and on the radial outer edge of the blade tip leading surface 215e. Therefore, the blade tip 215a is located at the leading end in the rotational direction R. Furthermore, the blade tip 215a has the same distance from the central axis in the front-rear direction L (i.e., radius) over the entire length of the blade tip 215a. In this embodiment, the blade tip 215a is formed in a straight line parallel to the front-rear direction L. Note that the blade tip 215a may extend in a direction intersecting the front-rear direction L. In other words, the blade tip 215a extends in the front-rear direction L so that it can cut the wall thickness of the old pipe 10 from the inner peripheral surface side along the circumferential direction by rotating in contact with the inner peripheral surface of the old pipe 10.

[0081] The blade tip front portion 215c is located further forward in the front-rear direction L than the blade tip 215a. The blade tip front portion 215c extends radially inward from the blade tip 215a. As shown in FIGS. 5(b), 5(c), and 5(d), the blade tip front portion 215c of this embodiment is configured as a tapered surface that extends forward as it progresses radially inward. The blade tip front portion 215c is formed along the circumferential direction. The blade tip rear portion 215d is located further rearward in the front-rear direction than the blade tip 215a. The blade tip rear portion 215d extends radially inward from the blade tip 215a.

[0082] In this embodiment, the intermediate portion 214 includes a continuous portion 217 disposed forward of the cutting portion 215. The continuous portion 217 is disposed between the cutting portion 215 and the front portion 220 and includes a continuous leading surface 217a that continues forward of the cutting edge leading surface in the front-to-rear direction L, and a continuous outer peripheral surface 217b that extends from the continuous leading surface 217a to the rear side in the rotational direction R. The continuous leading surface 217a is flush with the cutting edge leading surface 215e. The continuous outer peripheral surface 217b is disposed forward of the cutting edge outer peripheral surface 215b via the cutting edge front portion 215c, and is therefore located radially inward of the cutting edge outer peripheral surface 215b. The radial difference in position between the cutting edge outer peripheral surface 215b and the continuous outer peripheral surface 217b is set to the cutting depth (cutting width) of the cutting portion 215.

[0083] 5(a) and 5(b), the forming intermediate leading portion 213a is the end portion of the intermediate portion 214 on the leading side in the rotational direction R. This forming intermediate leading portion 213a includes the cutting edge portion 215a described above. The forming intermediate leading portion 213a of this embodiment stands upright from the cutting base portion 210 along the first radial direction A. Furthermore, the forming intermediate leading portion 213a of this embodiment is positioned on the leading side in the rotational direction R relative to the forming front leading portion 213b and the forming rear leading portion 213c.

[0084] In this embodiment, the intermediate portion 214 includes an intermediate front portion 218a connecting the forming intermediate leading portion 213a and the forming front leading portion 213b, and an intermediate rear portion 218b connecting the forming intermediate leading portion 213a and the forming rear leading portion 213c. The intermediate front portion 218a defines the front end of the intermediate portion 214 in the front-to-rear direction L. In this embodiment, the intermediate front portion 218a is configured to extend along the radial direction. Therefore, in this embodiment, the intermediate portion 214 stands upright from the cutting base 210 so that its front side extends along the first radial direction A.

[0085] The intermediate rear portion 218b defines the rear end of the intermediate portion 214 in the front-to-rear direction L. As shown in FIG. 5(b), the intermediate rear portion 218b of this embodiment includes the cutting edge rear portion 215d described above and a circumferential rear surface portion 219 that is disposed radially inward of the cutting edge rear portion 215d. The intermediate rear portion 218b of this embodiment is configured to extend along the first radial direction. Therefore, the intermediate portion 214 of this embodiment has both ends in the front-to-rear direction L that rise from the cutting base portion 210 along the first radial direction A.

[0086] The front portion 220 is disposed forward of the intermediate portion 214. The front portion 220 is continuous with the intermediate portion 214 in the front-to-rear direction L. As shown in FIG. 5(c), the front portion 220 is disposed in the intermediate portion 214 radially inward of the cutting portion 215. The front portion 220 includes a front outer peripheral surface 221 formed along the rotational direction R, a forming front portion 222 that defines the front end of the cutting forming portion 211, and a forming front leading portion 213b that is defined as the leading end in the rotational direction R.

[0087] The front outer peripheral surface 221 abuts against the inner peripheral surface of the existing pipe 1 forward of the cutting portion 215 in the front-rear direction L. As shown in FIG. 5(d), the front outer peripheral surface 221 of this embodiment is a curved surface that follows the rotational direction R and is configured to fit along the inner peripheral surface of the old pipe 10. Furthermore, the front outer peripheral surface 221 of this embodiment has its leading end in the rotational direction R positioned on the trailing side of the cutting edge 215a in the rotational direction R, and is therefore positioned on the trailing side of the cutting edge 215a in the rotational direction R. The front outer peripheral surface 221 is positioned forward of the cutting edge outer peripheral surface 215b. The front outer peripheral surface 221 is also positioned radially inward of the cutting edge outer peripheral surface 215b and the cutting edge 215a. Specifically, the front outer peripheral surface 221 is positioned radially inward by the cutting width of the cutting edge 215a. In other words, the cutting edge 215a and the cutting edge outer peripheral surface 215b protrude radially outward from the front outer peripheral surface 221 by an amount corresponding to the cutting width.

[0088] The forming front portion 222 defines the front end of the cutting forming portion 211. As shown in FIG. 5(b), the forming front portion 222 of this embodiment is configured in a curved shape that slopes radially inward as it progresses toward the front. Furthermore, the forming front portion 222 of this embodiment is continuous from the front outer peripheral surface 221 to the front side. Furthermore, the forming front portion 222 of this embodiment is curved so as to be continuous with the front end portion 210c.

[0089] The forming front leading portion 213b is a leading end portion of the front portion 220 in the rotational direction R. This forming front leading portion 213b stands in the first radial direction A from the outer surface of the first outer circumferential portion 210a. Furthermore, the forming front leading portion 213b extends in the front-rear direction L. Therefore, the forming front leading portion 213b is a surface that extends in the first radial direction A and the front-rear direction L. Note that the forming front leading portion 213b of this embodiment is configured as a surface that extends along the first radial direction A and the front-rear direction L.

[0090] The rear side portion 224 includes a forming rear portion 225 that defines the rear end of the cutting forming portion 211, a rear outer peripheral surface 226 that is the radial outer peripheral surface of the rear side portion 224, a forming rear leading portion 213c that is the leading end in the rotational direction R, and a rear inclined surface 226a that is inclined in the front-rear direction. As shown in FIG. 5(b), the forming rear portion 225 in this embodiment is a surface that intersects with the front-rear direction L. This forming rear portion 225 extends between the forming rear portion 212 and the forming rear leading portion 213c. This forming rear portion 225 is also configured to be flush with the rear end portion 210d. The forming rear portion 225 is a curved surface that extends along the circumferential direction. This forming rear portion 225 extends between the forming rear leading portion 213c and the forming rear portion 212. Additionally, the rear outer peripheral surface 226 is continuous with the rear forming portion 225 and the cutting edge outer peripheral surface 215b in the front-to-rear direction L. The rear forming leading portion 213c is a surface that extends in the first radial direction A and the front-to-rear direction L. This rear forming leading portion 213c is configured to extend along the front-to-rear direction L. In this embodiment, the rear forming leading portion 213c is positioned further rearward in the rotational direction R than the intermediate forming leading portion 213a.

[0091] The pipe cutting tool 21 includes a leading separation portion 21B that is disposed on the leading side of the cutting and forming portion 211 in the rotational direction R and spaced apart from the inner circumferential surface of the old pipe 10. The leading separation portion 21B is disposed on the leading side of the forming leading portion 213 of the cutting and forming portion 211 in the rotational direction R, and is formed between the forming leading portion 213 and the first outer circumferential portion 210a of the cutting base portion 210 in the rotational direction R. Specifically, the leading separation portion 21B is formed between the forming leading portion 213b of the front portion 220 of the cutting and forming portion 211, the cutting edge leading surface 215e of the cutting portion 215, the continuous leading surface 217a of the continuous portion 217, the forming rear leading portion 213c of the rear portion 224, and the first outer circumferential portion 210a. In other words, the leading separation portion 21B is a space that penetrates in the front-to-rear direction L.

[0092] Furthermore, since the front-side forming leading portion 213b is located on the rear side in the rotational direction R with respect to the cutting edge leading surface 215e, the width of the leading separating portion 21B in the rotational direction R at the front portion 220 is greater than the width at the cutting portion 215. Furthermore, since the rear-side forming leading portion 213c is located on the rear side in the rotational direction R with respect to the cutting edge leading surface 215e, the width of the leading separating portion 21B in the rotational direction R at the rear portion 224 is greater than the width at the cutting portion 215. In this way, the width of the leading separating portion 21B in the rotational direction R is greater than the width of the cutting portion 215 on at least one side, front and rear in the front-rear direction L, of the cutting portion 215.

[0093] The pipe cutting tool 21 includes a trailing separation portion 21A that is disposed at a distance from the inner peripheral surface of the old pipe 10 on the trailing side in the rotational direction R of the cutting and forming portion 211. The trailing separation portion 21A is disposed on the trailing side in the rotational direction R of the forming trailing portion 212, and is formed between the forming trailing portion 212 and the second outer peripheral portion 210b of the cutting base portion 210 in the rotational direction R. In other words, the trailing separation portion 21A is a space that penetrates in the front-rear direction L.

[0094] The traction portion 22 includes a rope 23 extending from the pipe cutting tool 21 toward the tip side (the opposite side to the connecting portion in the axial direction), and an intermediate guide portion 24 provided midway in the extending direction of the rope 23. Such a traction portion 22 transmits a pulling force pulled from the outlet 5 side to the cutting portion 215, and pulls the cutting portion 215 toward the outlet 5. In this embodiment, the traction portion 22 is pulled from the outlet 5 side by the welcoming portion 174.

[0095] The rope 23 is a rope-like body having an outer diameter smaller than the inner diameter of the existing pipe 1. The rope-like body is also capable of withstanding the tensile force that pulls the pipe cutting tool 21 and the connection portion 18. The rope 23 of this embodiment is made of a metal wire. The rope 23 also includes a front-end rope 230 located on the front side of the intermediate guide portion 24 (the opposite side to the cutting portion 215 in the axial direction of the existing pipe 1), and a rear-end rope 231 located on the rear-end side of the intermediate guide portion 24 (the pipe cutting tool 21 side). In this embodiment, the rear-end rope 231 is connected to the pipe cutting tool 21.

[0096] The intermediate guide portion 24 is a portion provided midway in the extension direction of the rope 23. The intermediate guide portion 24 has an outer diameter larger than that of the rope 23. Specifically, the intermediate guide portion 24 is a cylindrical or columnar body whose outer diameter is approximately the same as the inner diameter of the existing pipe 1. The intermediate guide portion 24 in this embodiment is a cylindrical body. Note that "approximately the same as the inner diameter of the existing pipe 1" does not mean the same diameter as the inner diameter of the existing pipe 1, but means a diameter small enough relative to the inner diameter of the existing pipe 1 to allow movement within the existing pipe 1. In other words, the intermediate guide portion 24 is a cylindrical or columnar body whose outer diameter is small enough relative to the inner diameter of the existing pipe 1 to prevent clogging or getting caught when inserted into the existing pipe 1. The intermediate guide portion 24 in this embodiment is disposed midway in the extension direction of the rope 23 by connecting the rope 23 to one end and the other end in the axial direction. Furthermore, the intermediate guide portion 24 is configured such that one axial end and the other axial end thereof rotate relatively around the axial center. Specifically, the portion of the intermediate guide portion 24 to which the rope 23 is connected at one end and the portion to which the rope 23 is connected at the other end are configured to rotate relatively around the axial center. The intermediate guide portion 24 of this embodiment is equipped with a bearing therein (not shown). Such an intermediate guide portion 24 is a rotation insulating portion configured to prevent the rotation of the cutting portion 215 from being transmitted to the rope 23 (the tip-side rope 230) disposed further distal than the intermediate guide portion 24. That is, in the rope 23, rotation is only apparent at the surface in the portion rearward of the intermediate guide portion 24 (the rear-side rope 231).

[0097] The pipe cutting process is a process of cutting a portion of the wall thickness of the existing pipe 1 using pipe cutting tool 21 over the entire area to be cut in the pipe axis direction of the existing pipe 1. The pipe cutting process of this embodiment includes a cutting preparation process of inserting towing portion 22 from the outlet 5 side to the inlet 4 side of the existing pipe 1 and connecting pipe cutting device 20 to rear end portion 210d of towing portion 22 exposed from the inlet 4 side, and a cutting execution process of cutting the wall thickness of the existing pipe 1 while moving pipe cutting device 20 from the inlet 4 side to the outlet 5 side.

[0098] In the cutting preparation step, first, as shown in FIG. 6( a), the towing section 22 is inserted from the exit 5 of the existing pipe 1 toward the entrance 4. Specifically, a cord-like call wire (not shown) is inserted into the existing pipe 1 in advance, and the cord 23 is pulled and inserted from the exit 5 of the existing pipe 1 to the entrance 4 using the call wire. After the cord 23 is exposed from the entrance 4, the intermediate guide section 24 and the rear end cord 231 are connected to the rear end of the cord 23. Note that, as described above, the case where only the cord 23 is inserted into the existing pipe 1 using the call wire and then the intermediate guide section 24 and the rear end cord 231 are connected at the entrance 4 side has been described. However, this is not limiting, and the intermediate guide section 24 and the rear end cord 231 may be pulled and inserted into the existing pipe 1 using the call wire. Furthermore, when inserting the towing section 22, it is not limited to inserting it using the call wire, and the towing section 22 may also be inserted into the existing pipe 1 by pushing it from the exit 5 side.

[0099] Thereafter, the pulling portion 22 exposed from the inlet 4 of the existing pipe 1 is connected to the pipe cutting device 20 (not shown). Specifically, the rear end rope body 231 is connected to the front connection portion a. In this embodiment, the cutting preparation step is completed when the pulling portion 22 is connected to the pipe cutting device 20.

[0100] In the cutting process, pipe cutting device 20 is inserted into existing pipe 1 from the inlet 4 side, and the wall thickness of existing pipe 1 is cut. As shown in FIG. 6(b), in this embodiment, pipe cutting tool 21 is inserted into old pipe 10, and pipe cutting tool 21 is rotated by the rotational force of drive unit 14, and cutting unit 215 cuts the inner diameter of old pipe 10. Also, in this embodiment, while pipe cutting tool 21 is pulled by pulling unit 22 from the outlet 5 side using picker 174, a pair of feed main bodies 172 rotate on the inlet 4 side, and connecting unit 18 sandwiched between the pair of feed main bodies 172 is fed axially into existing pipe 1, whereby pipe cutting tool 21 moves from the inlet 4 side to the outlet 5 side.

[0101] Specifically, the pipe cutting tool 21, which is connected to the drive unit 14 via the connecting unit 15, rotates around the pipe axis direction as a rotation center. The tool is inserted into the old pipe 10 while being pushed toward the outlet 5 by the connecting unit 18 and pulled by the towing unit 22 via the rope 23. When inserted into the old pipe 10, the pipe cutting tool 21 is inserted from the front end 210c side. Here, the radial length of the front end 210c is shorter than the inner diameter of the old pipe 10. As shown in FIGS. 5(b) and 5(d), the front end 210c of this embodiment is curved so as to be convex forward in the front-to-rear direction L. Furthermore, of the cutting and forming portion 211, which stands from the cutting base 210 in the first radial direction A, the forming front portion 222 is curved so as to be inclined radially inward as it extends forward. Therefore, the pipe cutting tool 21 can be easily inserted into the old pipe 10 from the front side.

[0102] When the pipe cutting tool 21 is inserted into the old pipe 10 from the front side in the front-to-rear direction L, the front outer peripheral surface 221, which is forward of the cutting portion 215, abuts against the inner peripheral surface of the old pipe 10. Here, in this embodiment, the front outer peripheral surface 221 is a curved surface along the rotation direction R and is configured to fit along the inner peripheral surface of the old pipe 10. Therefore, the front outer peripheral surface 221 abuts against the inner peripheral surface of the old pipe 10 while fitting along the inner peripheral surface of the old pipe 10. Then, as the front outer peripheral surface 221 fits along the inner peripheral surface of the old pipe 10, the pipe cutting tool 21 moves in the pipe axis direction within the existing pipe 1 while being guided by the inner peripheral surface of the old pipe 10. Thereafter, when the pipe cutting tool 21 moves until the cutting portion 215 is inserted into the old pipe 10, the cutting portion 215 cuts the inner peripheral surface of the old pipe 10.

[0103] In this embodiment, the pipe cutting tool 21 rotates in the rotational direction R with the cutting edge 215a in contact with the inner circumferential surface of the old pipe 10, causing the cutting edge 215a to cut the inner diameter φA of the old pipe 10 from the inner circumferential side. Specifically, the cutting edge 215a, which is located at the leading end in the rotational direction R, moves in the rotational direction R while in contact with the inner circumferential surface of the old pipe 10, thereby cutting the thickness of the inner circumferential surface of the old pipe 10 in the circumferential direction. Therefore, as the inner circumferential surface of the old pipe 10 is cut, the inner diameter of the old pipe 10 changes from φA to φB. Furthermore, as shown in FIG. 5(c), when the pipe cutting tool 21 is inserted into the old pipe 10, the inner diameter of the old pipe 10 becomes φB throughout the entire axial direction of the old pipe 10.

[0104] When the cutting edge 215a cuts the inner circumferential surface of the old pipe 10, the cutting edge leading surface 215e, which intersects with the outer surface of the first outer circumferential portion 210a, scoops up chips generated by the cutting. The chips are then blown away by air delivered from the airflow delivery portion 178 at the leading separating portion 21B and discharged from the existing pipe 1. In this embodiment, airflow F flows from the outlet 5 side to the inlet 4 side. Therefore, the chips flow toward the inlet side. In the pipe cutting tool 21 of this embodiment, the forming front leading portion 213b is positioned on the trailing side of the rotational direction R, so that the width of the leading separating portion 21B in the rotational direction R is greater than the width at the cutting portion 215 and the width at the front portion 220. Therefore, air flowing toward the inlet side collides with the intermediate front portion 218a, disrupting the airflow F within the existing pipe 1, allowing chips to be efficiently removed. Then, the cutting chips flow toward the inlet side due to the air flow F, so that the insertion state and the discharge state of the cutting chips can be checked through the window of the secondary pipe attachment jig 173c. Thereafter, the cutting chips flow to and are collected in the dust collection and recovery section 173e.

[0105] Next, the insertion process (4) will be described. In the insertion process, the pipe insertion tool 25 attached to the rear end 210d of the rope 31 is attached to the tip end of the new pipe 11, and the rope 31 is pulled, thereby pulling the new pipe 11 from the inlet 4 side to the outlet 5 side, and inserting the new pipe 11 into the existing pipe 1.

[0106] 7(a), in the insertion process, first, a cord-like call wire is inserted into the existing pipe 1, and the call wire is used to pull and insert the cord 31 from the exit 5 of the existing pipe 1 to the entrance 4, and a pipe insertion tool 25 is attached to the cord 31 exposed from the entrance 4 side. After the pipe insertion tool 25 is attached to the cord 31 on the entrance 4 side, the tip of the new pipe 11 is fixed to the pipe insertion tool 25. Note that various pipe insertion tools 25 that can fix the tip of the new pipe 11 and connect the new pipe 11 and the cord 31 can be used as the pipe insertion tool 25.

[0107] After the tip of the new pipe 11 is fixed to the pipe insertion tool 25, the rope 31 is pulled from the outlet 5 by the receiving main body 176, and the new pipe 11 is moved from the inlet 4 to the outlet 5. Then, when the tip of the new pipe 11 is exposed from the outlet 5, the insertion process is completed.

[0108] The above steps complete the piping renewal of this embodiment.

[0109] As described above, according to the pipe cutting tool 21 of this embodiment, when the cutting portion 215 is rotated and advanced within the existing pipe 1, the front outer peripheral surface 221 of the front portion 220 abuts against the inner peripheral surface of the existing pipe 1 at the front side of the cutting portion 215, thereby maintaining the blade end 215a of the cutting portion 215 at a predetermined cutting position relative to the inner peripheral surface of the existing pipe 1, and the blade end outer peripheral surface 215b stabilizes rotation at the cutting position.

[0110] Furthermore, according to the pipe cutting tool 21 of this embodiment, the front outer peripheral surface 221 maintains the cutting position of the blade end 215a relative to the inner peripheral surface of the existing pipe 1, while not interfering with the cutting by the blade end 215a, allowing for stable cutting.

[0111] Furthermore, according to the pipe cutting tool 21 of this embodiment, a trailing separation portion 21A is provided at a position offset in the rotational direction R of the cutting portion 215, and is positioned at a distance from the inner surface of the existing pipe 1. This reduces the cutting area between the pipe cutting tool 21 and the inner surface of the existing pipe 1, making it easier to move the pipe cutting tool 21 inside the existing pipe 1, for example.

[0112] Furthermore, according to the pipe cutting tool 21 of this embodiment, cutting chips generated by cutting the inner peripheral surface of the existing pipe 1 with the blade end 215a can be efficiently removed by the preceding separating portion 21B.

[0113] Furthermore, in the pipe cutting tool 21 of this embodiment, the forming front leading portion 213b and the forming rear leading portion 213c are positioned to the rear side of the forming intermediate leading portion 213a in the rotational direction R, so that the width of the leading separation portion 21B in the rotational direction R is greater than the width at the cutting portion 215 and the width at the front portion 220 and the rear portion 224.Therefore, air flowing in the axial direction of the existing pipe 1 collides with the intermediate front portion 218a or the intermediate rear portion 218b, disrupting the air flow F within the existing pipe 1 and enabling cutting chips to be removed efficiently.

[0114] In addition, in the pipe cutting tool 21 of this embodiment, the cutting portions 215 are arranged on both sides of the first radial direction A, so that by rotating the pipe cutting tool 21 halfway around, the entire circumference of the inner surface of the old pipe 10 can be cut.

[0115] The above describes an embodiment of the present invention using one example, but the present invention is not limited to the above embodiment, and various modifications can be made within the scope that does not deviate from the gist of the present invention.

[0116] For example, in the above embodiment, for the sake of convenience of explanation, the side where the adhesion removal device or pipe cutting device is inserted is designated as the entrance and the opposite side as the exit, but this is not limited to this, and the adhesion removal device or pipe cutting device may be inserted from the exit toward the entrance.

[0117] For example, in the above embodiment, the existing piping is formed by inserting the piping into the protective material, but this is not limiting, and the existing piping may be formed of piping that is not inserted into the protective material. In other words, the existing piping may be formed of only the old piping.

[0118] In the above embodiment, the pipe inserting step is performed separately from the pipe cutting step. However, for example, the new pipe may be positioned behind the pipe cutting tool, and the pipe inserting step may be performed while the pipe cutting step is being performed. Furthermore, the pipe cutting step and the pipe inserting step do not need to be performed consecutively. For example, a pipe cutting step, in which the pipe is cut in the radial direction, may be performed between the pipe cutting step and the pipe inserting step. In this case, the new pipe may be inserted into the supply pipe while the old pipe is being cut, or the new pipe may be inserted into the old pipe after the old pipe is cut.

[0119] In the above embodiment, the feed section 170 and the welcoming section 174 were used as the transfer section 17 in the cutting execution process, but this is not limited to this. For example, the pipe cutting device may be inserted into the existing pipe by using only the feed section 170 or the welcoming section 174 of the transfer section 17.

[0120] In the above embodiment, the blade tip extends along the tube axis direction, but this is not limiting. For example, the blade tip may be tapered so that its diameter increases toward the rear.

[0121] In the above embodiment, the cutting part is disposed in one of the first and second radial directions of the existing pipe, which intersect with each other. However, the pipe cutting tool may have cutting parts disposed in both the first and second radial directions. In this case, the cutting load on one blade end can be reduced.

[0122] In the above embodiment, as shown in FIG. 5(a), the blade end and the outer peripheral surface of the blade end are arranged so that the pipe cutting tool rotates clockwise in the rotation direction R. However, this is not limited to this, and the blade end and the outer peripheral surface of the blade end may be arranged so that the pipe cutting tool rotates counterclockwise.

[0123] In the above embodiment, the front end of the pipe cutting tool is configured to have a curved shape, but this is not limiting, and for example, the front end of the pipe cutting tool may be configured to have a flat shape. Furthermore, the pipe cutting tool may be formed into an overall cone shape.

[0124] In the above embodiment, a case has been described in which the outer peripheral surface of the cutting edge is formed to be longer in the circumferential direction than the front outer peripheral surface. However, this is not limited to this. For example, the outer peripheral surface of the cutting edge may be formed to be approximately the same length in the circumferential direction as the front outer peripheral surface, or shorter than the front outer peripheral surface.

[0125] In the above embodiment, the case where the front portion is continuous with the intermediate portion in the front-to-rear direction has been described, but this is not limiting. For example, the front portion and the intermediate portion may be arranged to be offset in the circumferential direction, so that they are not continuous in the front-to-rear direction. In this case, for example, the front portion of the cutting-formed portion may stand up from the first base diameter portion, and the intermediate portion may stand up from the second base diameter portion. In this way, the front portion and the intermediate portion may be arranged to be offset in the circumferential direction, so that the cutting portion and the front portion may be arranged to be offset in the circumferential direction.

[0126] In the above embodiment, the front portion and the intermediate portion are continuous in the front-to-rear direction, but for example, the intermediate portion and the front portion may be spaced apart in the front-to-rear direction. In this case, it is conceivable that the cutting portion and the front portion are spaced apart in the front-to-rear direction.

[0127] In the above embodiment, the cutting base is provided on the first outer periphery, but this is not limiting. The cutting base can also be provided on the second outer periphery. In this case, for example, the cutting forming portion can be provided on the trailing side in the rotational direction of the second outer periphery, and can have three or four blades. Also, in this case, a leading separation portion is formed on the leading side in the rotational direction of the cutting forming portion provided on the second outer periphery. Furthermore, in this case, a trailing separation portion relative to the cutting forming portion provided on the first outer periphery, which is located on the leading side in the rotational direction of the second outer periphery, is formed between the second outer periphery and the leading formation portion of the cutting forming portion provided on the second outer periphery.

[0128] In the above embodiment, the cutting edge outer surface protrudes radially outward relative to the front outer surface. However, this is not limiting. For example, the front outer surface may be flush with the cutting edge outer surface in the front-to-rear direction.

[0129] In the above embodiment, the leading end of the front outer peripheral surface in the rotational direction is positioned on the trailing side of the blade end in the rotational direction, but this is not limiting, and the front outer peripheral surface may be positioned on the leading side of the blade end in the rotational direction. Also, the leading end of the front outer peripheral surface in the rotational direction may be positioned at the same position as the blade end in the rotational direction.

[0130] In the above embodiment, the case where the pipe cutting tool is connected to the tip of the connecting part using the rear connecting part and to the rear end rope using the front connecting part has been described, but this is not limiting, and for example, a shaft serving as a connecting part may be connected to the front side of the pipe cutting tool, and the rope may be connected to the rear side of the pipe cutting tool. In this case, for example, the rotational force of the drive unit may be transmitted from the front side to the pipe cutting tool via the connecting part.

[0131] In the above embodiment, the feed portion and the greeter portion are disposed at the front and rear of the pipe cutting tool in the fore-and-aft direction, respectively, but this is not limiting, and for example, the pipe cutting tool may be fed into the old pipe by only the feed portion so that the fore-and-aft direction is along the pipe axial direction. In other words, in this case, the front end of the pipe cutting tool does not need to be formed with a front connection portion. [Explanation of symbols]

[0132] 1: Existing pipe, 3: Floor, 4: Inlet, 5: Outlet, 6: Header material, 7: Faucet, 8: Curved portion, 9: Protective material, 10: Old pipe, 11: New pipe, 12: Adhesion removal device, 13: Adhesion removal tool, 14: Drive unit, 15: Connecting part, 16: Handle, 17: Transfer part, 18: Connection part, 19: Shaft, 20: Pipe cutting device, 21: Pipe cutting tool, 22: Towing part, 23: Rope body, 24: Intermediate guide part, 25: Pipe insertion tool, a: Front connection part, b: Rear connection part, A: First radial direction, B: Second radial direction, F: Air flow, R: Rotation direction, L: Forward / backward direction, X: Adhesion, Y: Cable, φA: Inner diameter of old pipe, φB: Inner diameter of old pipe

Claims

1. a cutting unit that cuts an inner circumferential surface of the existing pipe by rotating around the front-rear direction with the front-rear direction aligned with the pipe axis direction; a front portion disposed forward of the cutting portion in the front-to-rear direction; a front end portion located forward of the front side portion, the cutting portion includes a blade end portion disposed at an end portion on a leading side in a rotational direction of the cutting portion and extending in the front-rear direction, and a blade end outer peripheral surface formed along a trailing side in the rotational direction from the blade end portion, the front portion includes a front outer peripheral surface formed along the rotation direction, The front outer peripheral surface is configured to abut against the inner peripheral surface of the existing piping, The front end portion has a curved shape that is convex toward the front, The pipe cutting tool is characterized in that the front side portion is curved so as to be continuous with the front end portion.

2. a cutting unit that cuts an inner circumferential surface of the existing pipe by rotating around the front-rear direction with the front-rear direction aligned with the pipe axis direction; a front portion disposed forward of the cutting portion in the front-to-rear direction, the cutting portion includes a blade end portion disposed at a leading end portion in a rotational direction of the cutting portion and extending in the front-rear direction, a blade end outer circumferential surface formed along a trailing side in the rotational direction from the blade end portion, and a blade end front portion defining a front end portion of the cutting portion, the front portion includes a front outer peripheral surface formed along the rotation direction, The front outer peripheral surface is configured to abut against the inner peripheral surface of the existing piping, the cutting edge front portion has a tapered shape with the radially inner side positioned forward, A pipe cutting tool comprising a continuous portion extending in the front-to-rear direction from the front portion of the cutting edge to the front side portion.

3. an intermediate portion having a cutting portion formed therein that cuts an inner peripheral surface of an existing pipe by rotating around the longitudinal direction with the longitudinal direction aligned with the pipe axis direction; a front portion disposed forward of the intermediate portion in the front-to-rear direction, the front portion includes a formed front leading portion that is an end portion on a leading side in a rotational direction of the front portion, the cutting portion includes a blade end portion disposed at an end portion on a leading side in a rotational direction of the cutting portion and extending in the front-rear direction, and a blade end outer peripheral surface formed along a trailing side in the rotational direction from the blade end portion, the intermediate portion includes a formed intermediate leading portion that is an end portion on a leading side in a rotational direction of the intermediate portion, the forming intermediate leading portion includes the blade end portion, the front portion includes a front outer peripheral surface formed along the rotation direction, The front outer peripheral surface is configured to abut against the inner peripheral surface of the existing piping, The pipe cutting tool is characterized in that the forming intermediate leading portion is located further to the leading side in the rotation direction than the forming front leading portion.

4. A cutting device comprising: a cutting base portion extending in the front-rear direction; and a cutting forming portion provided on the cutting base portion; The cutting base includes a first outer circumferential portion extending in a second radial direction of the cutting base and on which the cutting forming portion is provided, and a second outer circumferential portion extending in a first radial direction of the cutting base perpendicular to the second radial direction and disposed on the trailing side of the first outer circumferential portion in a rotational direction, The cutting and forming unit includes a cutting unit that cuts the inner circumferential surface of the existing pipe by rotating around the front-rear direction with the front-rear direction aligned with the pipe axis direction, and a front side unit that is arranged forward of the cutting unit in the front-rear direction, the cutting portion includes a blade end portion disposed at an end portion on a leading side in a rotational direction of the cutting portion and extending in the front-rear direction, and a blade end outer peripheral surface formed along a trailing side in the rotational direction from the blade end portion, the front portion includes a front outer peripheral surface formed along the rotation direction, The front outer peripheral surface is configured to abut against the inner peripheral surface of the existing piping, A pipe cutting tool characterized in that a trailing forming portion, which is located on the trailing side in the rotational direction of the cutting and forming portion, extends continuously with the second outer peripheral portion in the first radial direction.

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