Piping cutting method, piping cutting device

Abstract

To provide a pipe cutting method and a pipe cutting device with which a pipe is surely cut.SOLUTION: A pipe cutting method uses a pipe cutting device 20 comprising: a flexible shaft part 29 having flexibility that allows its center axis to be bent and deflected; a cutting part 22 for cutting a pipe in its circumferential direction, that is attached to a tip of the flexible shaft part 29; and a driving part 23 which applies rotary driving force to the cutting part 22 via the flexible shaft part 29. In the pipe cutting method, rotary driving force from the driving part 23 is applied to the cutting part 22 inserted into a pipe with the center axis of the flexible shaft part 29 placed along the center axis of the pipe, and the flexible shaft part 29 deflects at least its tip, while rotating about the center axis of the flexible shaft part 29 according to the rotary driving force, whereby the cutting part 22 separates by a deflected portion of the flexible shaft part 29 relative to the center axis of the pipe while rotating together with rotation of the flexible shaft part 29, and turns around the center axis of the pipe.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a pipe cutting method and a pipe cutting device for cutting a pipe. [Background technology]

[0002] Patent Document 1 discloses a cutting device for existing pipes. The cutting device includes a cutter, a rotary drive source for the cutter, and a flexible shaft that rotates and drives the cutter blade. The cutter includes a cutter blade, a rotary support member that pivots to allow the cutter blade to expand and contract in diameter, and a drive member that expands and contracts the cutter blade.

[0003] In this cutting device, the cutter is rotated via a flexible shaft by the power of a rotary drive source, and the diameter of the cutter blade is expanded by driving the drive member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-153266 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in such a cutting device, if the cutter drive does not operate properly within the existing pipe to be cut, it will not be possible to cut the existing pipe.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a pipe cutting method and apparatus that can reliably cut a pipe. [Means for solving the problem]

[0007] The pipe cutting method of the present invention is a pipe cutting method using a pipe cutting device comprising: a flexible shaft portion having flexibility such that its central axis curves and bends; a cutting portion attached to the flexible shaft portion and cutting the pipe circumferentially; and a drive portion that applies a rotational drive force to the cutting portion via the flexible shaft portion. The cutting portion is inserted into the pipe with the central axis of the flexible shaft aligned with the central axis of the pipe, and the drive portion applies a rotational drive force to the cutting portion, causing the flexible shaft portion to bend, and the cutting portion rotates together with the flexible shaft portion, rotating around the central axis of the pipe and away from the central axis of the pipe by an amount equal to the bending of the flexible shaft portion.

[0008] According to the pipe cutting method of the present invention, the flexible shaft is bent by the rotational driving force of the drive unit, and the cutting part attached to the flexible shaft is rotated by the amount of bending, so that it can be reliably applied to the inside of the pipe, thereby reliably cutting the pipe.

[0009] The pipe cutting device of the present invention is characterized by comprising a flexible shaft portion having flexibility such that the central axis thereof bends and flexes; a cutting portion attached to the flexible shaft portion and cutting the pipe in the circumferential direction; a drive portion that applies a rotational drive force to the cutting portion via the flexible shaft portion; and a configuration in which the flexible shaft portion is bent by the rotational drive force from the drive portion, and the cutting portion rotates together with the flexible shaft portion, moving away from the flexible shaft portion by the amount of the bend and rotating around the central axis of the flexible shaft portion.

[0010] According to the pipe cutting device of the present invention, the flexible shaft is bent by the rotational driving force of the drive unit, and the cutting part attached to the flexible shaft is rotated by the amount of bending, so that it can be reliably applied to the inside of the pipe, thereby reliably cutting the pipe.

[0011] The pipe cutting device of the present invention may also include a support section between the drive section and the cutting section, the support section being configured to have a larger diameter than the flexible shaft section and being positioned within the pipe to be cut so as to support the flexible shaft section.

[0012] According to the pipe cutting device of the present invention, the support portion serves as a fulcrum for the bending of the flexible shaft portion, and the flexible shaft portion bends while rotating reliably, thereby cutting the pipe. [Effects of the Invention]

[0013] According to the pipe cutting method and pipe cutting device of the present invention, the flexible shaft is bent by the rotational driving force of the drive unit, and the cutting part attached to the flexible shaft is rotated by the amount of bending, so that it can be reliably applied to the inside of the pipe, thereby reliably cutting the pipe. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view showing an insertion step of a pipe cutting method according to an embodiment of the present invention. [Figure 2] 10 is a cross-sectional view showing the arrangement process and the pipe cutting device. FIG. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] 1A, 1B, 1C, 1D, and 1E show the cut section, with (a) being a front view, (b) being a rear view, (c) being a side view, and (d) being a plan view. [Figure 7] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] A pipe cutting method and a pipe cutting device according to one embodiment of the present invention will be described with reference to Figures 1 to 7. The pipe cutting method of this embodiment is used as a pipe renewal method in which an old internal pipe, which is an existing pipe (hereinafter simply referred to as pipe) 10, is cut in the circumferential direction of the pipe 10 by a pipe cutting device 20 (see Figure 2), divided in the central axis direction, and removed, and then renewed with a new pipe 11 that is placed inside a protective pipe 9 in place of the pipe 10, as shown in Figure 7.

[0016] As shown in Fig. 1, hot water supply piping and cold water supply piping generally used in buildings are composed of a protective pipe 9 and a pipe 10 arranged inside the protective pipe 9. The hot water supply piping and the cold water supply piping have the same configuration. In this embodiment, the protective pipe 9 and the pipe 10 arranged inside it are referred to as existing pipe 1.

[0017] Protective pipe 9 is made of a heat insulating material such as foamed resin. Pipe 10 is tubular and is formed by inserting flexible pipe 10 made of a polyethylene pipe, cross-linked polyethylene pipe, aluminum three-layer pipe, etc. into protective pipe 9. Pipe 10 is flexible and can be bent. New pipe 11, like pipe 10, is made of a polyethylene pipe, cross-linked polyethylene pipe, polybutene pipe, aluminum three-layer pipe, etc., and is a flexible pipe that can be bent in the axial direction.

[0018] In this embodiment, the inlet 4 and the outlet 5 of the pipe 10 are arranged in the pipe axial direction, with the inlet 4 being on the side where the pipe cutting device 20 is inserted and the outlet 5 being on the opposite side. Note that in the insertion step shown in FIG. 7 and described below, the inlet 4 and the outlet 5 are the inlet 4 and the outlet 5 of the protective pipe 9.

[0019] The piping renewal method according to this embodiment will be specifically described as follows: (1) a pipe cutting step of cutting the pipe 10 from the inside at a midpoint between the inlet 4 and the outlet 5 in the pipe axial direction; (2) After the pipe cutting process, a removal process is performed to remove the pipe 10 from the protective pipe 9. (3) After the removal step, an insertion step of inserting the new pipe 11 by pulling it through the outlet 5 using an insertion tool. In this pipe renewal method, the protective pipe 9, the pipe 10, and the new pipe 11 have a circular cross section.

[0020] (1) The pipe cutting step will be described in more detail. The pipe cutting step is performed by applying a pipe cutting method. The pipe cutting step further includes the following steps: (1-1) Removal process as a preparation step for cutting, (1-2) An insertion process (see FIG. 1) performed after the removal process, in which the cable body main body 31 is passed through the pipe 10. (1-3) A placement step (see FIG. 2) performed after the insertion step, in which the cutting portion 22 is inserted into the inside of the pipe 10 and placed at a predetermined position inside the pipe 10; (1-4) a cutting blade cutting step (see FIG. 3) performed after the placement step, in which the pipe 10 is cut at a predetermined position by the cutting unit 22; This includes the following.

[0021] (1-1) The removal process will be described. The removal process is a process for making the area of ​​the existing pipe 1 that is exposed on the floor surface 3 into a free end for one existing pipe 1. The removal process is a process for removing one end (the end on the inlet 4 side) of the pipe 10 in the existing pipe 1 from the header member (not shown) to make it the inlet 4, and removing the other end of the pipe 10 in the existing pipe 1 from the faucet (not shown) to make it the outlet 5, thereby making the inlet 4 and the outlet 5 into a single protective pipe 9 and pipe 10 that include straight and curved areas into free ends.

[0022] Before describing (1-2) the insertion step, (1-3) the placement step, and (1-4) the cutting blade cutting step, the pipe cutting device 20 will be described.

[0023] The pipe cutting device 20 has the following configuration: As shown in Figures 2 and 3, a drive unit 23, a transmission shaft 24, a cutting unit 22, and a leading unit 25 are provided parallel to each other from the inlet 4 to the outlet 5 of the pipe 10.

[0024] The drive unit 23 is a device that applies a rotational force to the cutting unit 22 via a transmission shaft 24. A general rotary power tool is used as the drive unit 23, and a drive connecting shaft (handle) 27 is detachably connected to the tip of the main body 26 of the drive unit 23.

[0025] The transmission shaft 24 includes a drive connecting shaft portion 27, a multiple shaft portion 28, and a flexible shaft portion 29. As described above, the drive connecting shaft portion 27 is located at the tip of the drive unit 23 and is configured to be detachable from the drive unit 23.

[0026] The multiple shaft portion 28 is a rod-shaped member extending in the axial direction of the drive connecting shaft portion 27. The multiple shaft portion 28 includes a shaft (outer shaft portion) 19 and a rod-shaped connecting rod portion (inner shaft portion) 19A provided inside the shaft 19. The shaft 19 is formed of a flexible metal tube and is flexible in the axial direction. A first support portion 35, which will be described later, configured to support the flexible shaft portion 29 is disposed at the tip of the shaft 19. This first support portion 35 is configured to have a larger diameter than the flexible shaft portion 29 and is disposed inside the pipe 10 to be cut, so as to support the flexible shaft portion 29. Specifically, the outer diameter of the first support portion 35 is approximately the same as the inner diameter of the pipe 10, and is configured so that radial movement is restricted by the inner circumferential surface of the pipe 10. The first support portion 35 supports the flexible shaft portion 29 at its radial center, and is supported so that at least the tip end of the flexible shaft portion 29 protrudes toward the tip side. In this embodiment, the first support portion 35 supports the base end of the flexible shaft portion 29.

[0027] The connecting rod portion 19A is provided from the tip of the drive connecting shaft portion 27 to the tip of the shaft 19 and is connected to the tip of the drive connecting shaft portion 27. In this embodiment, the connecting rod portion 19A is made of a torsion coil spring that is linear in its natural state. Although the connecting rod portion 19A is made of a torsion coil spring, because it is disposed inside the shaft 19, even when it rotates in response to the rotational drive from the drive unit 23, the range of its flexibility is limited to the amount of deflection formed by the gap between the inner peripheral surface of the shaft 19 and the outer peripheral surface of the connecting rod portion 19A.

[0028] The flexible shaft portion 29 has flexibility so that its central axis can bend and flex, and is arranged within a certain range in the tube axis direction on the tube axis direction side (outlet 5 side) of the first support portion 35. In this embodiment, the flexible shaft portion 29 is a portion that extends in the tube axis direction from the connecting rod portion 19A, and is formed integrally with the connecting rod portion 19A. In other words, the flexible shaft portion 29 is made of a torsion coil spring. Alternatively, the flexible shaft portion 29 can be configured as a separate member with a different length in the tube axis direction, and the connecting rod portion 19A can be connected to it by a screw.

[0029] Since the flexible shaft 29 is free to rotate radially outward, it rotates by an amount corresponding to the rotation from the drive unit 23. A support ring 36 for attaching the cutting unit 22 is fitted onto the tip of the flexible shaft 29. A rod-shaped member 37 for supporting the cutting unit 22 on the inlet 4 side is disposed at the center of the tip of the support ring 36 (flexible shaft 29) (see FIG. 6(a)). A male thread that screws onto the cutting unit 22 is formed on the outer periphery of the rod-shaped member 37.

[0030] As shown in Fig. 6, the cutting section 22 includes a base 38 and a cutting blade 39. The base 38 is cylindrical and extends in the pipe axis direction. As shown in Fig. 6(a), one base end face 40 and the other base end face 41 on both sides are formed parallel to each other and perpendicular to the pipe axis direction. A central hole 42 is formed in the center of the base 38 (between the one base end face 40 and the other base end face 41), and a female thread is formed in the central hole 42. The male thread of the rod-shaped member 37 is threaded into the inlet 4 side of the central hole 42. The male thread of one connector 43 (described later) is threaded into the outlet 5 side of the central hole 42.

[0031] The cutting blade portion 39 is integrally formed and protrudes radially from the outer peripheral surface of one side of the base portion 38 in the central axial direction, i.e., from one base end face 40 side. As shown in Figure 6(c), the cutting blade portion 39 is composed of an outer diameter surface 44, a leading side surface (rake face) 45 that leads the rotation of the cutting portion 22 in the rotation direction R of the outer diameter surface 44, a trailing side surface 46 that faces the leading side surface 45 in the counter-rotation direction R1 of the outer diameter surface 44, and one blade end face 47 and another blade end face 48 on both sides in the axial direction of the tube. The leading side surface 45 is a surface that stands in the radial direction of the base portion 38.

[0032] The contact area between the outer diameter surface 44 and the leading side surface 45 forms a cutting edge 49 that cuts the pipe 10 from the inside. The outer diameter surface 44 forms an inclined surface that slopes in the counter-rotation direction R1 from the cutting edge 49. The outer diameter surface 44 including the cutting edge 49 and a portion of the one blade end surface 47 and the other blade end surface 48 are set as a bit (formed from cemented carbide, for example) separate from the other cutting blade portion 39.

[0033] The leading portion 25 is inserted into the pipe 10 prior to the cutting portion 22. The leading portion 25 includes a leading connecting portion 50 and a cord body 51.

[0034] The leading connection section 50 further includes a flexible connection section 52 and a second support section 53. The flexible connection section 52 includes the first connection body 43 attached to the axial side of the cutting section 22, a flexible connection section main body 54 attached to the first connection body 43, and a second connection body 55 attached to the flexible connection section main body 54, arranged from the inlet 4 to the outlet 5 of the piping 10. In this embodiment, the flexible connection section main body 54 is composed of a single wire with the same central axis. The flexible connection section main body 54 also includes, on both sides in the axial direction of the piping, the first connection body 43 located on the inlet 4 side and the second connection body 55 located on the outlet 5 side, as described above. The flexible connection section main body 54 includes annular members 56, 56 on the first connection body 43 side and the second connection body 55 side, which fit around the flexible connection section main body 54. The annular members 56, 56 have circular outer circumferential surfaces. Because the flexible connection body 54 is made of wire, it is flexible between the annular members 56, 56, but is not flexible between the one connecting body 43 and the annular members 56, 56, and between the other connecting body 55 and the annular members 56, 56. Here, the flexible portion of the flexible connection body 54 between the annular members 56, 56 is referred to as the flexible portion 56A.

[0035] The one-way connector 43 is a member attached to the cutting part 22 in the pipe axis direction (on the outlet 5 side) and connects the flexible connecting part main body 54. The one-way connector 43 is formed with a central rod 57 that screws into the female thread of the central hole 42 of the cutting part 22 (see FIG. 6(a)). Also, a one-way hole 58 for connecting the end of the flexible connecting part main body 54 is formed.

[0036] The other connector 55 is a member that supports the flexible connector main body 54 in the pipe axis direction (on the outlet 5 side), and is connected to the second support part 53, which will be described later. The other connector 55 is also formed with another hole part 59 for connecting the end part of the flexible connector main body 54.

[0037] The second support part 53 is composed of a bearing jig. The second support part 53 includes a lid part 60 and a jig body 61. The jig body 61 is connected to the connector 62 in the pipe axial direction on the outlet 5 side. The jig body 61 is connected to the lid part 60 by a bearing, and the lid part 60 and the jig body 61 are configured to be rotatable relative to each other in the pipe axial direction. The second support part 53 has a circular outer periphery and is configured to have a larger diameter than the flexible connection part body 54. The second support part 53 is configured to be placed inside the pipe 10 to be cut and to support the flexible connection part body 54. Specifically, the outer diameter of the second support part 53 is approximately the same as the inner diameter of the pipe 10, and its radial movement is restricted by the inner peripheral surface of the pipe 10. The second support part 53 also supports the flexible connection part 52 at its radial center.

[0038] Rope body 51 includes a connector 62 attached to jig body 61 of second support portion 53, and rope body main body 31 connected to connector 62. Rope body main body 31 is made of wire and is formed with an outer diameter smaller than the inner diameter of pipe 10. Rope body main body 31 extends to outlet 5, and the portion extending to outlet 5 is wound around a drivable winch or the like (not shown).

[0039] Next, (1-2) the insertion process, (1-3) the placement process, and (1-4) the cutting blade cutting process will be described. First, as described above, the insertion process is a process of passing the rope body main body 31 through the pipe 10. In this case, the insertion process is a process of passing the rope body main body 31 from the outlet 5 of the pipe 10 toward the inlet 4 (see FIG. 1). The rope body main body 31 is formed with an outer diameter smaller than the inner diameter of the pipe 10. This allows for smooth insertion.

[0040] (1-3) The placement process will be described. The placement process is a process of placing the cutting part 22 at a cutting position, which is a midpoint in the central axial direction of the pipe 10 to be cut. This is performed by inserting an assembly in which the cutting part 22 is attached to the tip of the flexible shaft part 29 into the pipe 10 from the inlet 4 side. Specifically, as shown in FIG. 2 above, the placement process is a process of attaching the cutting part 22 to the cord body main body 31 and placing it at a predetermined position 10c inside the pipe 10. In the placement process, an assembly of the transmission shaft 24 (drive connecting shaft part 27, multiple shaft part 28, and flexible shaft part 29), the cutting part 22 at the tip of the flexible shaft part 29, and the preceding connecting part 50 (flexible connecting part 52, second support part 53) is attached to the end of the cord body main body 31 protruding from the inlet 4. Note that the transmission shaft 24, cutting part 22, and preceding connecting part 50 are preferably assembled together in advance of the pipe cutting process. At this time, the male thread of the rod-shaped member 37 is screwed into the central hole 42 of the base 38 of the cutting portion 22 on the inlet 4 side, and the male thread of the one connector 43 is screwed into the central hole 42 on the outlet 5 side.

[0041] In the placement step, the jig body 61 is directly attached to the second support portion 53 via the connector 62 on the rope body main body 31 protruding from the inlet 4. Then, the winch is driven to pull the rope body main body 31 into the inside of the pipe 10, and the second support portion 53, the flexible connecting portion 52, the cutting portion 22, the flexible shaft portion 29, and the multiple shaft portion 28 are inserted into the pipe 10. The pulling direction (also referred to as the insertion direction) is indicated by the arrow in FIG. 2. The rope body main body 31 is further pulled to place the cutting portion 22 at a predetermined position in the pipe 10. At this time, by knowing in advance the axial lengths of the second support portion 53, the flexible connecting portion 52, the cutting portion 22, the flexible shaft portion 29, and the multiple shaft portion 28, it can be determined whether the cutting portion 22 is in the predetermined position. Then, when the cutting portion 22 reaches the predetermined position, the cable body 31 stops pulling, and the cutting portion 22 is now in a tensioned state by the flexible shaft portion 29 and the flexible connecting portion 52. This completes the placement process.

[0042] (1-4) The cutting blade cutting step will be described. As shown in Fig. 3, the cutting blade cutting step is a step of cutting a predetermined position of the pipe 10 with the cutting unit 22. In the cutting blade cutting step, the drive unit 23 is attached to the drive connecting shaft 27.

[0043] By attaching the driving unit 23 to the driving connecting shaft 27, the connecting rod 19A becomes rotatable while the shaft 19 of the multiple shaft unit 28 remains fixed, and therefore the flexible shaft 29, which is integral with the connecting rod 19A, becomes rotatable. Furthermore, in the disposing step, the cable body 31 is no longer pulled, and the flexible connecting body 54 of the flexible connecting unit 52 is made of a wire and therefore is flexible. Therefore, when the flexible shaft 29 rotates due to the rotational driving force of the driving unit 23, the cutting unit 22 rotates around the central axis of the flexible shaft 29. The flexible portion 56A of the flexible connecting body 54 rotates around the central axis in conjunction with the rotation of the flexible shaft 29. In this way, the cutting portion 22 is held by the flexible shaft portion 29 on the inlet 4 side and by the flexible connecting portion main body 54 (flexible connecting portion 52) on the outlet 5 side, and rotates around the rotation center CL of the cutting portion 22 within the piping 10.

[0044] A central hole 42 is formed in the center of the base 38, and the cutting blade 39 protrudes from one base end surface 40 of the base 38, so the center of gravity of the cutting portion 22 is not at the center of the base 38 but is offset from the center of the central hole 42. However, because the cutting portion 22 rotates around the rod-shaped member 37 and one connector 43 that pass through the central hole 42, the position of the center of gravity of the cutting portion 22 is unrelated to the rotation of the cutting portion 22 around the rotation direction R. In other words, the center of rotation CL of the cutting portion 22 and the center of gravity are offset in the radial direction.

[0045] In other words, the pipe cutting method according to this embodiment is the following: A rotational driving force is applied from driving unit 23 located on the inlet 4 side to cutting unit 22, which is inserted into pipe 10 with the central axis of flexible shaft 29 aligned with the central axis of pipe 10, causing flexible shaft 29 to rotate about the central axis due to the rotational driving force, and flexible connecting unit main body 54, located on the outlet 5 side, rotates about the central axis of flexible connecting unit main body 54 relative to cutting unit 22, causing cutting unit 22 to rotate about its own center of rotation together with the rotation of flexible shaft 29 and flexible connecting unit main body 54. The centrifugal force of the rotation then causes the flexible shaft portion 29 and the flexible connecting portion main body 54 to bend so that the central axis is curved, and as a result, the center of rotation of the cutting portion 22 moves radially outward from the central axis (pipe axis) of the piping 10 by the amount of bending of the flexible shaft portion 29 and the flexible connecting portion main body 54, and the cutting portion 22 rotates around the central axis of the piping 10.

[0046] Furthermore, the male thread of the rod-shaped member 37 is threadedly engaged with the inlet 4 side of the central hole 42 formed in the base 38 of the cutting part 22, and the male thread of the one-side connector 43 is threadedly engaged with the outlet 5 side of the central hole 42. The cutting part 22 is configured to rotate in the rotation direction R, and the cutting edge 49 of the cutting part 22 protrudes from the base 38. When the cutting part 22 is rotated by the rotational driving force of the drive part 23, it can cut the piping 10 at a predetermined position on the inlet 4 side and the outlet 5 side.

[0047] Then, the rotational driving force of the drive unit 23 causes the flexible shaft portion 29 and the flexible connecting portion main body 54 to bend, and the cutting portion 22 attached to the tip of the flexible shaft portion 29 is shifted radially outward by the amount of bending and rotated, so that it can be reliably brought into contact with the inside of the pipe 10, thereby reliably cutting the pipe 10.

[0048] Meanwhile, pipe cutting device 20 is provided with a first support part 35 between drive part 23 and cutting part 22, which has a larger diameter than flexible shaft part 29, is disposed within pipe 10 to be cut, and is configured to support flexible shaft part 29. Pipe cutting device 20 also includes a second support part 53 which is disposed within pipe 10 to be cut, and is configured to support flexible connecting part main body 54.

[0049] Therefore, in the cutting blade cutting step, when the flexible shaft 29 and the flexible connection body 54 are rotated around the central axis, the first support portion 35 acts to support the flexible shaft 29, and the second support portion 53 acts to support the flexible connection body 54. Therefore, the first support portion 35 and the second support portion 53 serve as fulcrums for the bending of the flexible shaft 29 and the flexible connection body 54, so that the flexible shaft 29 and the flexible connection body 54 bend and rotate reliably, and the pipe 10 can be cut.

[0050] The second support member 53 is composed of a bearing jig, and the lid member 60 and the jig body 61 are connected to the lid member 60 by a bearing. The lid member 60 and the jig body 61 are configured to be rotatable relative to each other in the pipe axial direction, so that rotation of the flexible connection member body 54 does not apply a rotational force to the cord body body 31. Even if the first support member 35 and the second support member 53 are held in position, the cutting member 22 is held by flexible shafts on the inlet 4 side and the outlet 5 side, so that it bends sufficiently within the pipe 10, and the cutting member 22 rotates, thereby cutting the pipe 10 at the predetermined location 10c. In other words, the first support member 35 and the second support member 53 (jig body 61) are non-rotating relative to the rotation of the flexible shaft member 29 and the flexible connection member body 54, and support the flexible shaft member 29 and the flexible connection member body 54 in a non-rotating state within the pipe. The second support portion 53 is configured to isolate the rotation of the flexible shaft portion 29 and the flexible connecting portion main body 54 from being transmitted to the rope body main body 31 .

[0051] This completes the (1-2) insertion step, (1-3) placement step, and (1-4) cutting blade cutting step.

[0052] Next, (2) the removal step will be described. The removal step is performed after the pipe cutting step (cutting blade cutting step), and is a step of removing the pipe 10 from the protective pipe 9. The removal step further includes the following steps: (2-1) a one-side tube removal step (see FIG. 4 ) of removing the cut pipe 10a on the inlet 4 side from the inlet 4 of the protective pipe 9; (2-2) a one-side pipe removal step (see FIG. 5 ) performed after the one-side pipe removal step, in which the cut pipe 10b on the outlet 5 side is removed from the outlet 5 of the protective pipe 9; Equipped with.

[0053] (2-1) The one-side tube removal process will be described. The one-side tube removal process is a process in which the rope body main body 31 is fed toward the inlet 4, and the transmission shaft 24, cutting section 22, and preceding connecting section 50 are removed from the inlet 4 side, and the cutting pipe 10a is removed from the inlet 4 side. In this case, the transmission shaft 24, cutting section 22, preceding connecting section 50, and cutting pipe 10a are removed from the inlet 4 side. The removal direction is indicated by the arrows in Figure 4.

[0054] Alternatively, the cable body 31 can be fed toward the inlet 4, and the transmission shaft 24, cutting portion 22, and leading connecting portion 50 can be removed from the inlet 4. For example, the other connecting body 55 can be replaced with a different tool. This tool is configured to be able to pass through the pipe 10 and has an expanded outer diameter at the predetermined portion 10c. This tool can then be inserted up to the predetermined portion 10c, and the cut pipe 10a can be removed from the inlet 4. In other words, the one-side pipe removal process is a process in which the cut end of the cut pipe 10a on the inlet 4 side is removed toward the inlet 4 by engaging a pipe removal tool with the cut end of the cut pipe 10a. This completes the (2-1) one-side pipe removal process. Alternatively, the inlet end of the cut pipe 10a can be grasped and removed by the operator.

[0055] (2-2) The other pipe removal process will be described. In the other pipe removal process, a other pipe removal body 67 is attached to the rope body main body 31 that protruded from the inlet 4 side in the one pipe removal process, and the cut pipe 10b is removed from the outlet 5. The other pipe removal body 67 is equipped with a disk-shaped removal ring 68. The other pipe removal body 67 is composed of the removal ring 68, a rope body attachment part 69 that is formed integrally with the removal ring 68 and is arranged on the outlet 5 side of the removal ring 68, and a cover part 60 and other pipe connection body 55 that are arranged on the inlet 4 side of the removal ring 68 and are used in the second support part 53. The rope body main body 31 is attached to the rope body attachment part 69, and the flexible connection part main body 54 is attached to the other pipe connection body 55.

[0056] Of these components constituting the other pipe extractor 67, the extractor ring 68 has the largest outer diameter, which is set to be larger than the outer diameter of the pipe 10 (pipe 10b) and smaller than the inner diameter of the protective tube 9. The inner peripheral portion of the extractor ring 68 of the other pipe extractor 67 is hooked to a predetermined portion 10c of the cut pipe 10b, and the rope body 31 is pulled with a winch or the like to extract the cut pipe 10b from the outlet 5 side. The extraction direction is indicated by the arrow in Figure 5. That is, the other pipe extractor step is a step in which the cut pipe 10b on the outlet 5 side is extracted toward the outlet 5 side by engaging a pipe extractor tool with the cut end of the cut pipe 10b. Next, the flexible connecting portion main body 54 on the outlet 5 side is removed from the other hole portion 59 of the other connecting body 55, and the flexible connecting portion main body 54 is then extracted from the inlet 4 side. This completes the (2-2) other pipe removal step, and by this step, the pipe 10b is removed from the protective pipe 9 while the protective pipe 9 remains fixed. Note that the worker can also grasp the outlet side end of the cut pipe 10b and remove it.

[0057] Next, (3) the insertion step will be described. In the insertion step, as shown in Fig. 7, the new pipe 11 is inserted into the protective pipe 9. In this embodiment, the new pipe 11 has the outer diameter of the pipe 10 and is inserted into the protective pipe 9. In this embodiment, the new pipe 11 is inserted into the protective pipe 9 using a pipe insertion tool that can fix the cable body main body 31 and the end of the new pipe 11.

[0058] The pipe insertion tool is composed of a tip attachment part 34 and a relay member 66. The tip attachment part 34 is attached to the tip of the cable body main body 31. The tip attachment part 34 is ring-shaped and is crimped using a crimping ring or the like, thereby being integrated with the relay member 66.

[0059] The relay member 66 includes an insertion portion 65 and a truncated cone surface 65c. The insertion portion 65 is connected to the tip of the new pipe 11 and is a joint with an outer diameter equal to that of the new pipe 11. The truncated cone surface 65c is configured so that the outer circumference gradually increases toward the rear, and the maximum diameter of the truncated cone surface 65c is slightly smaller than that of the insertion portion 65. A screw is formed at the rear of the truncated cone surface 65c to be threaded into a screw hole located at the radial center of the relay member 66.

[0060] In the insertion process, the pipe insertion tool attached to the rear end of the rope body main body 31 is attached to the tip end of the new pipe 11, and by pulling the rope body main body 31, the new pipe 11 is pulled from the inlet 4 side to the outlet 5 side, and the new pipe 11 is inserted inside the protective tube 9.

[0061] 8(a), in the insertion step, first, a cord-like call wire is inserted into the protective pipe 9, and the cord body 31 is pulled and inserted by the call wire from the outlet 5 of the protective pipe 9 to the entrance 4, and a pipe insertion tool is attached to the cord body 31 exposed from the entrance 4 side. After the pipe insertion tool is attached to the cord body 31 on the entrance 4 side, the tip of the new pipe 11 is fixed to the pipe insertion tool.

[0062] As shown in Figure 8(b), after the tip of the new pipe 11 is fixed to the pipe insertion tool, the rope body main body 31 is pulled from the outlet 5 by driving the winch, and the tip of the new pipe 11 is moved from the inlet 4 to the outlet 5. When the tip of the new pipe 11 is exposed from the outlet 5, the insertion process is completed. With the above process, the pipe renewal of this embodiment is completed.

[0063] The present invention is not limited to the above embodiment. For example, in the above embodiment, the pipe 10 is divided into two parts, the cut pipe 10a and the cut pipe 10b, but it can also be divided into three or more parts. When dividing the pipe 10 into three parts, the cutting portion 22 is positioned at each of the two predetermined positions 10c, and the pipe 10 is cut using the pipe cutting method used in the first embodiment. Then, in the one-side pipe removal process, the pipe is removed from the inlet 4 side, and the remaining two pipes are removed from the outlet 5 side as described in the other-side pipe removal process.

[0064] In the above embodiment, flexible shafts are arranged on the inlet 4 side and outlet 5 side of cutting unit 22, but for example, even if the flexible shaft (wire in the above embodiment) is omitted on the outlet 5 side and only flexible shaft 29 that applies a driving force on the inlet 4 side is used, flexible shaft 29 will bend due to the rotational driving force of drive unit 23, and cutting unit 22 attached to the tip of flexible shaft 29 will rotate by the amount of bending, so that it can reliably hit the inside of pipe 10, thereby cutting pipe 10. Furthermore, when drive unit 23 is arranged on the outlet 5 side, the pipe can also be cut with only a flexible shaft that applies a driving force provided on the outlet 5 side.

[0065] In the above embodiment, an example was given in which the cutting blade 39 is a single cutting blade 39 that is integrally formed and protrudes from the outer peripheral surface on one side of the base 38 along the radial direction of the base 38. However, two cutting blades 39 may be provided so that they protrude from the outer peripheral surface on one side of the base 38 along both radial sides of the base 38. In this case, the leading sides 45 of both cutting blades 39 are disposed on both radial sides. Furthermore, by forming two cutting blades 39, cutting of the pipe 10 can be completed in a short time when the same rotational drive is performed. In this way, the number of cutting blades 39 is not limited to one, and multiple cutting blades 39 may be provided.

[0066] In the above embodiment, one shaft 19 is provided on the drive connecting shaft portion 27. However, if a long distance must be provided from the entrance 4 to the predetermined portion 10c, the shaft 19 and the connecting rod portion 19A disposed inside the shaft 19 can be added.

[0067] In the above embodiment, the cutting blade portion 39 is integrally formed by protruding from the outer peripheral surface on one side of the base portion 38 along the radial direction of the base portion 38, but the cutting blade portion 39 can also protrude from the middle of the axial direction of the base portion 38 relative to the base portion 38.

[0068] In the above embodiment, the support ring 36, the cutting blade 39, and the one-side connector 43 are attached by screwing the rod-shaped member 37 on the support ring 36 side and the central rod 57 on the one-side connector 43 side into the central hole 42 of the cutting blade 39. However, the present invention is not limited to this. For example, the support ring 36, the cutting blade 39, and the one-side connector 43 can be attached by forming the rod-shaped member 37 (external thread) of the support ring 36 to be longer in the pipe axial direction than the central hole 42 (internal thread) of the cutting blade 39, and by forming an internally threaded hole in the one-side connector 43 that screws into the end side of the rod-shaped member 37.

[0069] In this embodiment, the pipe 10 is disposed inside the protective pipe 9, but the protective pipe 9 does not have to be provided, and the pipe cutting method and pipe cutting device of the present invention can be employed even for the pipe 10 that is fixed in a predetermined location, such as when it is buried in the ground or concrete, or when it is fixed to a wall or floor. In this case, the insertion step in the above embodiment is not necessary. [Explanation of symbols]

[0070] 1...existing pipe, 4...inlet, 5...outlet, 9...protective pipe, 10...pipe, 10a...cutting pipe, 10b...cutting pipe, 11...new pipe, 19...shaft, 19A...connecting rod portion, 20...pipe cutting device, 22...cutting portion, 23...drive portion, 24...transmission shaft, 25...leading portion, 27...drive connecting shaft portion, 28...multiple shaft portion, 29...flexible shaft portion, 31...rod body main body, 34...tip mounting portion, 35...first support portion, 37...rod-shaped member, 38...base portion, 39...cutting blade portion, 4 2...center hole, 43...one-side connector, 45...leading side surface, 46...following side surface, 49...cutting edge, 50...leading connector, 51...rod, 52...flexible connector, 53...second support portion, 54...flexible connector body, 55...other-side connector, 56, 56...annular member, 56A...flexible portion, 57...center rod, 60...lid portion, 61...jig body, 62...connector, 65...insertion portion, 66...relay member, 67...pulling body, 68...pulling ring, 69...rod mounting portion, R...rotation direction

Claims

1. a flexible shaft portion having flexibility such that the central axis line is curved and bent; a flexible connection body having flexibility such that the central axis line is curved and bent; a cutting portion attached to the flexible shaft portion and the flexible connecting portion main body, and configured to cut the pipe in a circumferential direction; a driving unit that applies a rotational driving force to the cutting unit via the flexible shaft, the flexible shaft portion, the cutting portion, and the flexible connecting portion main body are inserted into the pipe in this order along the central axis of the pipe with the central axes of the flexible shaft portion and the flexible connecting portion main body aligned with the central axis of the pipe, and a rotational driving force is applied from the driving unit to the cutting portion; A pipe cutting method characterized in that the rotational driving force causes the flexible shaft and the flexible connecting body to bend, causing the cutting section to rotate together with the flexible shaft and the flexible connecting body, and to rotate around the central axis of the pipe, away from the central axis of the pipe by an amount equal to the bending of the flexible shaft and the flexible connecting body.

2. a flexible shaft portion having flexibility such that the central axis line is curved and bent; a flexible connection body having flexibility such that the central axis line is curved and bent; a cutting portion attached to the flexible shaft portion and the flexible connecting portion main body, and configured to cut the pipe in a circumferential direction; a drive unit that applies a rotational drive force to the cutting unit via the flexible shaft unit, a cutting section for cutting a pipe, the cutting section being configured to rotate around the central axis of the flexible shaft and the flexible connecting body by an amount corresponding to the deflection while rotating together with the flexible shaft and the flexible connecting body due to the rotational driving force from the driving section;

3. 3. The pipe cutting device according to claim 2, further comprising: a first support section between the drive section and the cutting section, the first support section having a larger diameter than the flexible shaft section, being positioned within the pipe to be cut and configured to support the flexible shaft section; and a second support section having a larger diameter than the flexible connecting section main body, being positioned within the pipe to be cut and configured to support the flexible connecting section main body.

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