Jig for pipe cutting and pipe cutting device

Abstract

To provide a jig for pipe cutting which enables a pipe to be easily cut, and a pipe cutting device which can easily cut a pipe.SOLUTION: A jig 28 for cutting a large-diameter pipe is inserted from the end of the pipe P2 into the inside of the large-diameter pipe P2, and is disposed on both sides of a planned cutting position of the large-diameter pipe P2. The jig 28 for cutting the large-diameter pipe includes a pair of large-diameter suppression portions 23 which support the large-diameter pipe P2 from the inside of the large-diameter pipe P2 and suppress deformation of the large-diameter pipe P2 caused by pressurization of a cutting blade which cuts the large-diameter pipe P2. The pair of large-diameter suppression portions 23 are arranged in an axial direction of the large-diameter pipe P2, and the pair of large-diameter suppression portions 23 are spaced apart from each other in the axial direction of the large-diameter pipe P2. In the jig 28 for cutting a large-diameter pipe, a large-diameter avoidance space S2 which avoids interference with the cutting blade when the large-diameter pipe P2 is cut, is formed between the pair of large-diameter suppression portions 23 in the axial direction of the large-diameter pipe P2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] For example, Patent Document 1 discloses a pipe cutting jig used to cut a plastic pipe straight in the radial direction. The pipe cutting jig has a clamping portion, an extending portion, and a cutting guide portion. The clamping portion has a pair of frame bodies, and one end of the pair of frame bodies is axially attached to each other. The clamping portion forms a circular space on its inner circumferential surface to clamp the pipe. The extending portion is provided on the other end of each frame body and engages with the other end of the other frame body. The cutting guide portion protrudes from the side edge of the inner circumferential surface of each frame body toward the outer periphery at approximately a right angle.

[0003] When using the pipe cutting jig, the frame is closed and the extension is engaged to secure the pipe to the jig. This clamps the cutting guide to the pipe, and the cutting guide surface is attached perpendicular to the longitudinal direction of the pipe. In this state, a cutting tool such as a saw blade is placed along the cutting guide surface to cut the pipe. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-177949 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when cutting a pipe using the pipe cutting tool disclosed in Patent Document 1, if the cutting tool presses the pipe from the radial outside of the pipe, the pipe will bend and deform radially inward, making it difficult to cut the pipe. [Means for solving the problem]

[0006] The gist of the pipe cutting jig for solving the above problems is that it is inserted into the inside of the pipe from the end of the pipe, and has a pair of restraining parts that are positioned on both sides of the intended cutting position of the pipe, support the pipe from the inside, and restrain deformation of the pipe due to the pressure of the cutting blade that cuts the pipe, one of the restraining parts and the other of the restraining parts are aligned in the axial direction of the pipe, and the pair of restraining parts are spaced apart from each other in the axial direction of the pipe, and an avoidance space is formed between the pair of restraining parts in the axial direction of the pipe to avoid interference with the cutting blade when cutting the pipe.

[0007] In a pipe cutting jig, each of the pair of suppression portions may have a contact portion on the side of the avoidance space in the axial direction of the pipe, and the contact portion may be capable of coming into contact with the pipe that has been bent as the cutting blade presses against the pipe.

[0008] With regard to a pipe cutting jig, when the pipe is cut by the cutting blade, a divided portion is produced that is severed and removed from the pipe, and a preventing portion may be formed on the end side of the suppression portion in the axial direction of the pipe, which contacts the inner surface of the dividing portion and prevents the dividing portion from falling.

[0009] The gist of the pipe cutting device for solving the above problems is that it comprises a pipe cutting tool as set forth in any one of claims 1 to 3, and an operating tool for moving the pipe cutting tool inserted inside the pipe to the intended cutting position, wherein the operating tool and the pipe cutting tool are magnetically attachable, and the operating tool is capable of operating the pipe cutting tool inserted inside the pipe from the outer surface side of the pipe to move it in the axial direction of the pipe.

[0010] In the pipe cutting device, the operating tool may have a positioning portion that determines the position of the cutting blade relative to the pipe cutting jig inserted inside the pipe. [Effects of the Invention]

[0011] The present invention allows pipes to be easily cut. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is an exploded perspective view showing a pipe cutting device. [Figure 2] FIG. 2 is a side cross-sectional view showing the pipe cutting device. [Figure 3] FIG. 3 is an exploded perspective view showing the pipe cutting tool. [Figure 4] FIG. 4 is a front view showing the large diameter jig forming section. [Figure 5] FIG. 5 is a front view showing the small diameter jig forming section. [Figure 6] FIG. 6 is an exploded perspective view showing the operating tool. [Figure 7] FIG. 7 is a diagram showing the pipe cutting jig inserted into a large diameter pipe. [Figure 8] FIG. 8 is a plan view showing the operating tool placed on the large diameter pipe. [Figure 9] FIG. 9 is a diagram showing a state in which the pipe cutting tool is moved by the operating tool. [Figure 10] FIG. 10 is a diagram showing the state in which the large diameter pipe has been cut by the cutting blade. [Figure 11] FIG. 11 is a diagram showing a state in which the separation portion is prevented from falling off by the prevention portion. [Figure 12] FIG. 12 is a diagram showing the pipe cutting jig inserted into a small diameter pipe. [Figure 13] FIG. 13 is a diagram showing a state in which the separation portion is prevented from falling off by the prevention portion. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, a specific embodiment of a pipe cutting jig and a pipe cutting device will be described with reference to FIGS. <Pipe cutting device> As shown in FIG. 1, the pipe cutting device 10 has a pipe cutting jig 20 that is inserted inside the pipe P, and an operating tool 60 that operates the pipe cutting jig 20 from outside the pipe P.

[0014] <pipe> The pipe P is a thin-walled resin pipe such as an air conditioning pipe. Therefore, when the pipe P is pressed with a cutting blade or the like to cut it at a midpoint in the axial direction, the pipe P easily bends and deforms inward. There are two types of pipe P: a small-diameter pipe P1 shown in Figures 12 and 13, and a large-diameter pipe P2 shown in Figure 1. The inner and outer diameters of the small-diameter pipe P1 are smaller than those of the large-diameter pipe P2.

[0015] <Pipe cutting jig> The pipe cutting jig 20 is inserted into the inside of the pipe P from the end of the pipe P when in use.

[0016] 1 and 11, the pipe cutting jig 20 can be selectively used as a large-diameter pipe cutting jig 28 or a small-diameter pipe cutting jig 38. The pipe cutting jig 20 can be assembled integrally with the large-diameter pipe cutting jig 28 and the small-diameter pipe cutting jig 38. The pipe cutting jig 20 can also accommodate at least a portion of the small-diameter pipe cutting jig 38 within the large-diameter pipe cutting jig 28.

[0017] <Large diameter pipe cutting jig> The large diameter pipe cutting jig 28 is a pipe cutting jig 20 used when cutting the large diameter pipe P2. The large diameter pipe cutting jig 28 has a pair of large diameter jig forming portions 21.

[0018] <Large diameter jig forming section> The pair of large diameter jig forming units 21 have the same configuration, so one of the large diameter jig forming units 21 will be used for explanation.

[0019] 3 and 4, the large diameter jig forming portion 21 has a large diameter substrate 22, a large diameter suppressing portion 23 extending from the large diameter substrate 22, a large diameter connecting wall portion 24, and a fitting wall portion 25. The large diameter jig forming portion 21 also has a plurality of ribs 26 and a large diameter boss 27.

[0020] The large diameter substrate 22 is disk-shaped. The large diameter suppression portion 23 protrudes from a portion of the peripheral edge of the large diameter substrate 22 in the thickness direction of the large diameter substrate 22. When the large diameter jig forming portion 21 is viewed in the thickness direction of the large diameter substrate 22, the large diameter suppression portion 23 is an arc-shaped plate having a length exceeding half of the entire peripheral edge of the large diameter substrate 22. Therefore, the external shape of the large diameter jig forming portion 21 has a shape in which a portion in the circumferential direction is cut out, and an opening 23a is formed between both ends of the large diameter suppression portion 23 in the circumferential direction.

[0021] Furthermore, the large diameter suppression portion 23 is in the shape of an elongated plate having a dimension in the thickness direction of the large diameter substrate 22. The thickness of the large diameter suppression portion 23 is constant in the direction in which the arc of the large diameter suppression portion 23 extends. As shown in FIG. 2, the dimension of the large diameter suppression portion 23 in the thickness direction of the large diameter substrate 22 is designated as "M1."

[0022] As shown in FIG. 4, the diameter R1 of a first imaginary circle C1 along the outer peripheral surface of the large diameter suppression portion 23 is the same as the diameter of the large diameter substrate 22. Since the first imaginary circle C1 coincides with the periphery of the large diameter substrate 22, the first imaginary circle C1 coincides with the outline of the large diameter substrate 22. The diameter R1 of the first imaginary circle C1 is slightly smaller than the inner diameter N2 of the large diameter pipe P2. Therefore, as shown in FIG. 2, the large diameter jig forming portion 21 can be inserted into the large diameter pipe P2.

[0023] When the large diameter jig forming portion 21 is inserted into the large diameter pipe P2, a gap is formed between the inner peripheral surface of the large diameter pipe P2 and the outer peripheral surface of the large diameter suppression portion 23 and the peripheral edge of the large diameter substrate 22. The maximum value of this gap is the difference between the inner diameter N2 and the diameter R1. The dimension M1 of the large diameter suppression portion 23 is sufficiently larger than the maximum value of the gap.

[0024] As shown in FIG. 10, the large diameter pipe P2 is cut by the cutting blade 80. Also, as shown in FIG. 11, when the large diameter pipe P2 is cut by the cutting blade 80, a divided portion PH is generated, which is separated and removed from the large diameter pipe P2. The divided portion PH is the shorter end portion of the large diameter pipe P2, i.e., the portion that will become the scrap material. This divided portion PH tilts by the amount of the gap due to its own weight. At this time, because the dimension M1 of the large diameter suppression portion 23 is sufficiently larger than the gap, the inner surface of the divided portion PH comes into contact with the outer surface of the large diameter suppression portion 23.

[0025] As shown in Figures 2, 3, and 4, the large diameter connecting wall portion 24 protrudes in the thickness direction of the large diameter substrate 22 from inside the large diameter suppression portion 23. When looking at the large diameter jig forming portion 21 in the thickness direction of the large diameter substrate 22, the large diameter connecting wall portion 24 is a semicircular plate. The large diameter connecting wall portion 24 is also a long plate having a dimension in the thickness direction of the large diameter substrate 22. The diameter R2 of a second imaginary circle C2 along the circumferential surface of the large diameter connecting wall portion 24 is smaller than the diameter R1 of the first imaginary circle C1 including the large diameter suppression portion 23. The second imaginary circle C2 is a concentric circle centered at the center of the first imaginary circle C1. The dimension M2 of the large diameter connecting wall portion 24 in the thickness direction of the large diameter substrate 22 is longer than the dimension M1 of the large diameter suppression portion 23. Therefore, the large diameter connecting wall portion 24 protrudes further than the large diameter suppressing portion 23 in the thickness direction of the large diameter base plate 22.

[0026] The fitting wall portion 25 protrudes in the thickness direction of the large diameter substrate 22 from inside the large diameter connecting wall portion 24. When looking at the large diameter jig forming portion 21 in the thickness direction of the large diameter substrate 22, the fitting wall portion 25 is an arc-shaped plate. The fitting wall portion 25 is also an elongated plate having a dimension in the thickness direction of the large diameter substrate 22. The diameter R3 of a third imaginary circle C3 along the circumferential surface of the fitting wall portion 25 is slightly larger than the diameter R2 of the second imaginary circle C2 including the large diameter connecting wall portion 24. Both ends of the fitting wall portion 25 in the longitudinal direction are connected to both ends of the arc of the large diameter connecting wall portion 24. The fitting wall portion 25 also has a fitting protrusion 25a that protrudes in an arc shape from the connection point with the large diameter connecting wall portion 24.

[0027] When viewing the large diameter jig forming portion 21 in the thickness direction of the large diameter substrate 22, the fitting wall portion 25 has an extending portion 25b in a portion located between both ends of the arc of the large diameter connecting wall portion 24. When viewing the large diameter jig forming portion 21 in the thickness direction of the large diameter substrate 22, the extending portion 25b is arc-shaped. The dimension M3 of the extending portion 25b in the thickness direction of the large diameter substrate 22 is the same as the dimension M2 of the large diameter connecting wall portion 24, but the dimension of the portion other than the extending portion 25b is the same as the dimension M1 of the large diameter suppressing portion 23. Therefore, the extending portion 25b and the large diameter connecting wall portion 24 protrude more than the large diameter suppressing portion 23 in the thickness direction of the large diameter substrate 22.

[0028] A plurality of ribs 26 are provided between the opposing surfaces of the large diameter suppression portion 23 and the large diameter connecting wall portion 24, and between the opposing surfaces of the fitting wall portion 25 and the large diameter suppression portion 23. Each rib 26 extends in the radial direction of the large diameter base plate 22, and connects the opposing surfaces of the large diameter suppression portion 23 and the large diameter connecting wall portion 24, and the opposing surfaces of the fitting wall portion 25 and the large diameter suppression portion 23.

[0029] The large diameter boss 27 is disposed between the large diameter connecting wall portion 24 and the fitting wall portion 25. The large diameter boss 27 protrudes cylindrically in the plate thickness direction from the large diameter base plate 22. The inside of the large diameter boss 27 communicates with a through hole 22a that penetrates the large diameter base plate 22 in the plate thickness direction.

[0030] <Small diameter pipe cutting jig> 12, the small diameter pipe cutting jig 38 is a pipe cutting jig 20 used when cutting a small diameter pipe P1. The small diameter pipe cutting jig 38 is also used as part of the large diameter pipe cutting jig 28 when cutting a large diameter pipe P2. The small diameter pipe cutting jig 38 has a pair of small diameter jig forming parts 31.

[0031] <Small diameter jig forming part> The pair of small diameter jig forming units 31 have the same configuration, so one of the small diameter jig forming units 31 will be used for explanation.

[0032] 2, 3, and 5, the small diameter jig forming portion 31 has a small diameter base plate 32, and a small diameter suppressing portion 33 and a small diameter connecting wall portion 34 extending from the small diameter base plate 32. The small diameter jig forming portion 31 also has a plurality of ribs 36 and a small diameter boss 37.

[0033] The small diameter substrate 32 is disk-shaped. The diameter of the small diameter substrate 32 is smaller than the diameter of the large diameter substrate 22. The small diameter suppression portion 33 protrudes cylindrically from the peripheral edge of the small diameter substrate 32 in the thickness direction of the small diameter substrate 32. The small diameter suppression portion 33 also has a dimension in the thickness direction of the small diameter substrate 32. The dimension H1 of the small diameter suppression portion 33 in the thickness direction of the small diameter substrate 32 is shorter than the dimension M1 of the large diameter suppression portion 23.

[0034] The outer diameter R4 of the small diameter suppression portion 33 is smaller than the diameter R1 of the first imaginary circle C1 that includes the large diameter suppression portion 23, and is slightly smaller than the diameter R3 of the third imaginary circle C3 that includes the fitting wall portion 25. The outer diameter R4 of the small diameter suppression portion 33 is also slightly smaller than the inner diameter N1 of the small diameter pipe P1. Therefore, the small diameter jig forming portion 31 can be inserted into the small diameter pipe P1.

[0035] When the small diameter jig forming portion 31 is inserted into the small diameter pipe P1, a gap is formed between the inner peripheral surface of the small diameter pipe P1 and the outer peripheral surface of the small diameter jig forming portion 31. The maximum value of this gap is the difference between the inner diameter N1 and the outer diameter R4. The dimension H1 of the small diameter suppression portion 33 is larger than the maximum value of the gap.

[0036] 13, when the small diameter pipe P1 is cut by the cutting blade 80, a separated portion PH is generated, which is separated and removed from the small diameter pipe P1. This separated portion PH tilts by the amount of the gap due to its own weight. At this time, because the dimension H1 of the small diameter suppression portion 33 is sufficiently larger than the gap, the inner peripheral surface of the separated portion PH comes into contact with the outer peripheral surface of the small diameter suppression portion 33.

[0037] As shown in Figures 2, 3, and 5, the small diameter connecting wall portion 34 protrudes cylindrically from inside the small diameter suppression portion 33 in the thickness direction of the small diameter base plate 32. The small diameter connecting wall portion 34 also has a dimension in the thickness direction of the small diameter base plate 32. The outer diameter R5 of the small diameter connecting wall portion 34 is smaller than the outer diameter R4 of the small diameter suppression portion 33. The dimension H2 of the small diameter connecting wall portion 34 in the thickness direction of the small diameter base plate 32 is longer than the dimension H1 of the small diameter suppression portion 33. Therefore, the small diameter connecting wall portion 34 protrudes from the tip of the small diameter suppression portion 33 in the thickness direction of the small diameter suppression portion 33. The dimension H2 of the small diameter connecting wall portion 34 is slightly shorter than the dimension M3 at the extension portion 25b described above.

[0038] The small diameter boss 37 is disposed in the center of the small diameter base plate 32. The small diameter boss 37 protrudes cylindrically in the plate thickness direction from the small diameter base plate 32. The inside of the small diameter boss 37 communicates with the through hole 32a that penetrates the small diameter base plate 32 in the plate thickness direction.

[0039] A plurality of ribs 36 are provided between the opposing surfaces of the small diameter suppression portion 33 and the small diameter connecting wall portion 34, and between the opposing surfaces of the small diameter connecting wall portion 34 and the small diameter boss 37. Each rib 36 extends in the radial direction of the small diameter base plate 32, and connects the opposing surfaces of the small diameter suppression portion 33 and the small diameter connecting wall portion 34, and the opposing surfaces of the small diameter connecting wall portion 34 and the small diameter boss 37.

[0040] Each small diameter jig forming portion 31 has a magnet 31a. The magnet 31a is held between the inner peripheral surface of the small diameter suppressing portion 33 and the outer peripheral surface of the small diameter connecting wall portion 34. When a pair of small diameter jig forming portions 31 and a pair of large diameter jig forming portions 21 are assembled to form a large diameter pipe cutting jig 28, the large diameter pipe cutting jig 28 will have the magnet 31a.

[0041] <Details of small diameter pipe cutting jig> As shown in Figures 2 and 3, the small diameter pipe cutting jig 38 is formed by forcibly screwing an attachment screw 39 inserted into the through hole 32a of one of the small diameter jig forming portions 31 into the small diameter bosses 37 of both small diameter jig forming portions 31.

[0042] As shown in FIG. 12, in a small diameter pipe cutting jig 38, a pair of small diameter jig forming portions 31 are assembled with the tips of the small diameter connecting wall portions 34 butted against each other. The small diameter pipe cutting jig 38 has a small diameter connecting portion 51 formed by integrating a pair of small diameter connecting wall portions 34. As described above, the small diameter connecting wall portions 34 protrude from the small diameter suppressing portion 33. Therefore, when the small diameter pipe cutting jig 38 is viewed from the outside in the radial direction, the center portion of the small diameter connecting portion 51 is exposed from between the pair of small diameter suppressing portions 33, and the center portion of the small diameter connecting portion 51 is sandwiched between the pair of small diameter suppressing portions 33.

[0043] When the small diameter pipe cutting jig 38 is viewed from the outside in the radial direction, one small diameter suppression portion 33, the center of the small diameter connecting portion 51, and the other small diameter suppression portion 33 are arranged in this order in the small diameter pipe cutting jig 38. In the small diameter pipe cutting jig 38, the direction in which one small diameter suppression portion 33, the small diameter connecting portion 51, and the other small diameter suppression portion 33 are arranged is defined as the axial direction. In the small diameter pipe cutting jig 38, the one small diameter suppression portion 33 and the other small diameter suppression portion 33 are arranged in the axial direction of the small diameter pipe cutting jig 38, and the pair of small diameter suppression portions 33 are spaced apart from each other in the axial direction. When the small diameter pipe cutting jig 38 is inserted inside the small diameter pipe P1, one small diameter suppression portion 33 and the other small diameter suppression portion 33 are aligned in the axial direction of the small diameter pipe P1, and the pair of small diameter suppression portions 33 are spaced apart from each other in the axial direction of the small diameter pipe P1.

[0044] The small diameter pipe cutting jig 38 defines a small diameter avoidance space S1 between the pair of small diameter suppression parts 33 in the axial direction and outside the outer peripheral surface at the center of the small diameter connecting part 51. The small diameter avoidance space S1 is located between the pair of small diameter suppression parts 33 in the axial direction. This small diameter avoidance space S1 is provided to prevent interference between the cutting blade 80 and the small diameter pipe cutting jig 38 when the small diameter pipe P1 is cut with the cutting blade 80. The small diameter avoidance space S1 is an annular space surrounding the center of the small diameter connecting part 51. The dimension of the small diameter avoidance space S1 in the radial direction of the small diameter connecting part 51 is defined as a depth F1. The depth F1 of the small diameter avoidance space S1 is constant in the circumferential direction of the small diameter pipe cutting jig 38.

[0045] 2, the width W1 of the small diameter avoidance space S1 in the axial direction of the small diameter pipe cutting jig 38 is shorter than the length of the small diameter suppression portion 33 in the axial direction of the small diameter pipe cutting jig 38, i.e., the dimension H1 of the small diameter suppression portion 33. As described above, the small diameter pipe cutting jig 38 is formed by connecting a pair of small diameter jig forming portions 31 with the mounting screws 39. Therefore, the pair of small diameter suppression portions 33 are suppressed from moving in the axial direction of the small diameter pipe cutting jig 38, and the width W1 of the small diameter avoidance space S1 remains unchanged.

[0046] Furthermore, the width W1 of the small diameter avoidance space S1 is sufficiently wider than the thickness of the cutting blade 80. Specifically, the width W1 is set to a width that can accommodate the bending deformation of the ends of the small diameter pipe P1 located on both sides of the cutting blade 80 when the small diameter pipe P1 is cut by the cutting blade 80. Here, the width W1 of the small diameter avoidance space S1 is set to a width that can accommodate the bending deformation of the ends of the small diameter pipe P1 not only when the cutting blade 80 is located at the center of the width W1 in the axial direction of the small diameter pipe cutting jig 38, but also when the cutting blade 80 is positioned offset to one side from the center. Furthermore, the width W1 of the small diameter avoidance space S1 is shorter than the dimension H1 of the small diameter suppression portion 33. In other words, the dimension H1 of the small diameter suppression portion 33 is longer than the width W1 of the small diameter avoidance space S1.

[0047] 12, each small diameter suppression part 33 has a small diameter contact part 53 on the small diameter avoidance space S1 side in the axial direction of the small diameter pipe cutting jig 38. The small diameter contact part 53 is formed by the end face of each small diameter suppression part 33 on the small diameter avoidance space S1 side.

[0048] 2, the small diameter pipe cutting jig has two magnets 31a. The two magnets 31a face each other in the axial direction of the small diameter pipe cutting jig . The small diameter pipe cutting jig 38 is used by being inserted into the inside of the small diameter pipe P1. How to use the small diameter pipe cutting jig 38 will be explained later.

[0049] <Details of the large diameter pipe cutting jig> 1 to 3, one small diameter suppression portion 33 is fitted inside one fitting wall portion 25 of large diameter pipe cutting jig 28, and the other small diameter suppression portion 33 is fitted inside the other fitting wall portion 25. Small diameter suppression portion 33 fitted into each fitting wall portion 25 is suitably held by a pair of fitting protrusions 25a of each fitting wall portion 25.

[0050] The dimension H1 of the small diameter suppression portion 33 is slightly shorter than the dimension M1 of the large diameter suppression portion 23. The dimension H2 of the small diameter connecting wall portion 34 is longer than the dimension H1. Therefore, when the small diameter suppression portion 33 is fitted into the fitting wall portion 25, the tip side of the small diameter connecting wall portion 34 protrudes beyond the large diameter suppression portion 23. The dimension H2 of the small diameter connecting wall portion 34 is also slightly shorter than the dimension M3 of the extension portion 25b described above. When the small diameter suppression portion 33 is fitted into the fitting wall portion 25, the tip of the small diameter connecting wall portion 34 is located on the same plane as the tip of the extension portion 25b of the fitting wall portion 25.

[0051] The large diameter pipe cutting jig 28 is formed by forcibly screwing an attachment screw 39 inserted into the through hole 22a of one of the large diameter jig forming portions 21 into the large diameter bosses 27 of both large diameter jig forming portions 21.

[0052] 7, in the large diameter pipe cutting jig 28, the pair of large diameter jig forming portions 21 are assembled by butting together the tips of the large diameter connecting wall portions 24. The pair of large diameter connecting wall portions 24 surround a portion of the small diameter connecting portion 51 in the circumferential direction from the outer circumferential side.

[0053] The large diameter pipe cutting jig 28 has a large diameter connecting portion 54 consisting of a pair of large diameter connecting wall portions 24 and a circumferential portion of a small diameter connecting portion 51. As described above, the large diameter connecting wall portion 24 and the extension portion 25b of the fitting wall portion 25 protrude from the large diameter suppressing portion 23. Therefore, when the large diameter pipe cutting jig 28 is viewed from the outside in the radial direction, the central portion of the large diameter connecting portion 54 is exposed from between the pair of large diameter suppressing portions 23, and is also sandwiched between the pair of large diameter suppressing portions 23. The portion of the large diameter connecting portion 54 formed by the small diameter connecting portion 51 has a smaller diameter than the portion formed by the large diameter connecting wall portions 24.

[0054] In the large diameter pipe cutting jig 28, a circumferential portion of the small diameter suppression portion 33 is exposed from the opening 23a of each large diameter suppression portion 23. A portion of the outer circumferential surface of each small diameter suppression portion 33 is positioned on the first imaginary circle C1. Therefore, it can be said that the small diameter suppression portion 33 forms a part of the large diameter suppression portion 23.

[0055] When the large diameter pipe cutting jig 28 is viewed from the outside in the radial direction, one large diameter suppression portion 23, the center portion of the large diameter connecting portion 54, and the other large diameter suppression portion 23 are arranged in this order in the large diameter pipe cutting jig 28. In the large diameter pipe cutting jig 28, the direction in which one large diameter suppression portion 23, the large diameter connecting portion 54, and the other large diameter suppression portion 23 are arranged is defined as the axial direction. In the large diameter pipe cutting jig 28, the one large diameter suppression portion 23 and the other large diameter suppression portion 23 are arranged in the axial direction of the large diameter pipe cutting jig 28, and the pair of large diameter suppression portions 23 are spaced apart from each other in the axial direction. When the large diameter pipe cutting jig 28 is inserted inside the large diameter pipe P2, one large diameter suppression portion 23 and the other large diameter suppression portion 23 are aligned in the axial direction of the large diameter pipe P2, and the pair of large diameter suppression portions 23 are spaced apart from each other in the axial direction of the large diameter pipe P2.

[0056] The large diameter pipe cutting jig 28 defines a large diameter avoidance space S2 between the pair of large diameter restraining portions 23 in the axial direction and outside the outer peripheral surfaces of the small diameter connecting portion 51 and the large diameter connecting portion 54. The large diameter avoidance space S2 is located between the pair of large diameter restraining portions 23 in the axial direction. This large diameter avoidance space S2 is provided to prevent interference between the cutting blade 80 and the large diameter pipe cutting jig 28 when the cutting blade 80 cuts the large diameter pipe P2. The large diameter avoidance space S2 is a space surrounding the small diameter connecting portion 51 and the large diameter connecting portion 54. As shown in FIG. 7 , the depth F2 of the large diameter avoidance space S2 is different around the small diameter connecting portion 51 and around the large diameter connecting portion 54. In other words, the depth F2 of the large diameter avoidance space S2 is deeper around the small diameter connecting portion 51 than around the large diameter connecting portion 54.

[0057] 2, the width W2 of the large diameter avoidance space S2 in the axial direction of the large diameter pipe cutting jig 28 is shorter than the length of the large diameter suppression portion 23 in the axial direction of the large diameter pipe cutting jig 28, i.e., the dimension M1 of the large diameter suppression portion 23. In other words, the dimension M1 of the large diameter suppression portion 23 is longer than the width W2 of the large diameter avoidance space S2.

[0058] As described above, the large diameter pipe cutting jig 28 is formed by connecting a pair of large diameter jig forming portions 21 with the mounting screws 39. In addition, the pair of small diameter jig forming portions 31 of the small diameter pipe cutting jig 38 are also connected with the mounting screws 39. Therefore, the pair of large diameter restraining portions 23 are restrained from moving in the axial direction of the large diameter pipe cutting jig 28, and the width W2 of the large diameter avoidance space S2 remains unchanged.

[0059] Furthermore, the width W2 of the large diameter avoidance space S2 is sufficiently wider than the thickness of the cutting blade 80. Specifically, the width W2 is set to a width that can accommodate bending deformation of the ends of the large diameter pipe P2 located on both sides of the cutting blade 80 when the large diameter pipe P2 is cut by the cutting blade 80. Here, the width W2 of the large diameter avoidance space S2 is set to a width that can accommodate bending deformation of the ends of the large diameter pipe P2 not only when the cutting blade 80 is located at the center of the width W2 in the axial direction of the large diameter pipe cutting jig 28, but also when the cutting blade 80 is positioned off to one side from the center.

[0060] 7, each large diameter suppression part 23 has a large diameter contact part 55 on the large diameter avoidance space S2 side in the axial direction of the large diameter pipe cutting jig 28. The large diameter contact part 55 is formed by the end face on the large diameter avoidance space S2 side of each large diameter suppression part 23. Note that since the large diameter avoidance space S2 is also defined between the pair of small diameter suppression parts 33, the part of the small diameter contact part 53 located on the large diameter avoidance space S2 side also serves as the large diameter contact part 55.

[0061] A part of the small diameter connecting portion 51 is exposed at a part in the circumferential direction of the large diameter connecting portion 54. The magnet 31a held by the small diameter jig forming portion 31 is located inside the small diameter connecting portion 51 exposed from the large diameter connecting portion 54. Therefore, a magnetic member can be magnetically attracted to the outer peripheral surface of the large diameter connecting portion 54 by the magnetic force of the pair of magnets 31a.

[0062] The large diameter pipe cutting jig 28 is used by being inserted into the inside of the large diameter pipe P2. How to use the large diameter pipe cutting jig 28 will be explained later. <Operating tools> As shown in Fig. 7, the operating tool 60 moves the pipe cutting jig 20 inserted inside the pipe P to a scribe line L as a planned cutting position. The planned cutting position is set in advance.

[0063] As shown in FIGS. 1 and 6, the operating tool 60 is formed by assembling a pair of operating tool forming parts 61 together. <Operation tool forming part> The pair of operating tool forming portions 61 have the same configuration, so description will be given using one of the operating tool forming portions 61. The operating tool forming portion 61 has a semi-cylindrical main body forming portion 62 and a plate-shaped contact plate forming portion 64 extending from the main body forming portion 62. The operating tool forming portion 61 also has a first rib 661 and a second rib 662 provided inside the main body forming portion 62, and an operating tool boss 67.

[0064] The main body forming portion 62 has a semicircular top plate 62a and a peripheral wall portion 62b extending from the edge of the top plate 62a, and the contact plate forming portion 64 is provided on the peripheral wall portion 62b on the opposite side to the top plate 62a. The contact plate forming portion 64 functions as the bottom plate of the main body forming portion 62.

[0065] As shown in Figures 1 and 8, when a pair of operating tool forming parts 61 are assembled, a cylindrical main body 71 is formed by a pair of main body forming parts 62, and a rectangular contact plate 72 is formed by a pair of contact plate forming parts 64.

[0066] As shown in Fig. 6, the first rib 661 has a semicircular shape similar to that of the top plate 62a. The first rib 661 is provided between the top plate 62a and the contact plate forming portion 64. The first rib 661 extends from the inner surface of the peripheral wall portion 62b. The second rib 662 has a rectangular plate shape. The second rib 662 is provided between the top plate 62a and the contact plate forming portion 64.

[0067] The operating tool boss 67 is provided at the intersection of the first rib 661 and the second rib 662. The operating tool boss 67 protrudes cylindrically from the peripheral wall portion 62b in the thickness direction. The inside of the operating tool boss 67 communicates with a through-hole 62c that penetrates the peripheral wall portion 62b in the thickness direction.

[0068] The contact plate forming portion 64 has a rectangular plate shape when the operating tool forming portion 61 is viewed from the top plate 62a. The dimension of the short side of the contact plate forming portion 64 is longer than the radius of the main body 71, and the dimension of the long side of the contact plate forming portion 64 is longer than the diameter of the main body 71. The contact plate forming portion 64 has an arcuate surface 65 on the surface opposite the main body forming portion 62. The arcuate surface 65 has a radius of curvature larger than that of the first imaginary circle C1.

[0069] Each operating tool forming portion 61 has two magnet holding portions 66 on the surface opposite to the arc surface 65. The magnet holding portions 66 are rectangular tubular and open on the opening side of the main body forming portion 62. Each magnet holding portion 66 holds a magnet 69. Therefore, the operating tool forming portion 61 has the magnet 69 integrally therewith.

[0070] The operating tool forming portion 61 has a slit forming portion 68 formed at a position that bisects the main body forming portion 62 and the contact plate forming portion 64. The slit forming portion 68 is formed on the outer surfaces of the top plate 62a and the peripheral wall portion 62b. The slit forming portion 68 is provided so as to avoid the through-hole 62c.

[0071] The contact plate forming portion 64 has a positioning portion 64a formed on the long edge portion opposite the opening side of the main body forming portion 62. The positioning portion 64a is formed in the center portion in the longitudinal direction of the contact plate forming portion 64. The positioning portion 64a is groove-shaped and communicates with the slit forming portion 68. The positioning portion 64a is V-groove-shaped and becomes narrower from the outer edge of the contact plate forming portion 64 toward the main body forming portion 62.

[0072] The operating tool 60 is formed by assembling a pair of operating tool forming parts 61. The operating tool 60 is formed by forcibly screwing the mounting screw 39 inserted through the through hole 62c of one of the operating tool forming parts 61 into the operating tool bosses 67 of both operating tool forming parts 61.

[0073] As shown in FIG. 1, the operating tool 60 has a main body 71 formed by a pair of main body forming portions 62, a contact plate 72 formed by a pair of contact plate forming portions 64, and a guide slit 73 formed by a pair of slit forming portions 68.

[0074] The main body 71 is cylindrical, and the contact plate 72 is rectangular. The contact plate 72 has a contact surface 74 formed in an arc shape by a pair of arc surfaces 65. The four sides of the rectangle of the contact plate 72 have the same length. The dimension of the contact plate 72 in the first direction X is the same as the dimension of the pipe cutting jig 20 in the axial direction.

[0075] As shown in Fig. 8, a plan view is when the operating tool 60 is viewed from the axial direction of the main body 71. In the plan view of the operating tool 60, the direction in which the longer sides of each contact plate forming portion 64 extend is defined as a first direction X of the operating tool 60, and the direction in which the shorter sides of each contact plate forming portion 64 extend is defined as a second direction Y of the operating tool 60. The first direction X and the second direction Y are perpendicular to each other.

[0076] The positioning portions 64a are located at both ends in the second direction Y, and the guide slit 73 extends in the second direction Y. The positioning portions 64a and the guide slit 73 are located in the center of the contact plate 72 in the first direction X. The pair of magnets 69 are also positioned to sandwich the guide slit 73 from both sides in the first direction X.

[0077] 1, the contact surface 74 is an arcuate surface that curves in the second direction Y. The dimension of the contact plate 72 in the first direction X is the same as the dimension in the second direction Y. In addition, the dimension of the contact plate 72 in the first direction X is approximately the same as the axial length of the pipe cutting jig 20.

[0078] <How to use the pipe cutting device> Next, a method of using the pipe cutting device 10 will be described, as well as the operation of the pipe cutting device 10 and the pipe cutting jig 20.

[0079] First, a description will be given of the case where the large diameter pipe P2 is cut. Note that a marking line L is marked on the outer circumferential surface of the large diameter pipe P2 at the intended cutting position. The worker assembles a pair of small diameter jig forming parts 31 to form a small diameter pipe cutting jig 38, and assembles a pair of large diameter jig forming parts 21 to the small diameter pipe cutting jig 38 to form a large diameter pipe cutting jig 28.

[0080] The worker inserts the large diameter pipe cutting jig 28 into the inside of the large diameter pipe P2 from the end of the large diameter pipe P2. 7 and 8, the worker places the operating tool 60 radially outward of the large-diameter pipe P2. At this time, the worker aligns the first direction X of the operating tool 60 with the axial direction of the large-diameter pipe P2 and the second direction Y with the radial direction of the large-diameter pipe P2. Then, the direction in which the arc of the contact surface 74 of the contact plate 72 extends is aligned with the circumferential direction of the large-diameter pipe P2. In addition, the guide slit 73 and the positioning portion 64a are arranged to extend in a direction perpendicular to the axial direction of the large-diameter pipe P2.

[0081] 9, the operator moves the operating tool 60 in the circumferential and axial directions of the large diameter pipe P2. When the operating tool 60 is moved to the position of the large diameter pipe cutting jig 28 within the large diameter pipe P2, the magnet 31a of the large diameter pipe cutting jig 28 is magnetically attracted to the magnet 69 of the operating tool 60, and the large diameter pipe cutting jig 28 is magnetically attracted to the operating tool 60. Therefore, it can be said that the operating tool 60 and the large diameter pipe cutting jig 28 are magnetically attractable to each other.

[0082] The operator then moves the operating tool 60 in the axial direction along the outer peripheral surface of the large diameter pipe P2 toward the scribe line L. As a result, the pipe cutting jig 20 moves together with the operating tool 60 in the axial direction of the large diameter pipe P2 toward the scribe line L. Therefore, the operating tool 60 operates the pipe cutting jig 20 inserted inside the pipe P from the outer peripheral surface side of the pipe P, making it possible to move it in the axial direction of the pipe P.

[0083] The operator positions the positioning portion 64a and the guide slit 73 on the same straight line as the marking line L. The positioning portion 64a and the guide slit 73 are arranged at a position that bisects the operating tool 60. Furthermore, the dimension of the contact plate 72 of the operating tool 60 in the first direction X is the same as the dimension of the pipe cutting jig 20 in the axial direction. Therefore, when the positioning portion 64a is aligned with the marking line L, the positioning portion 64a is located in the axial center of the large diameter pipe cutting jig 28, that is, in the large diameter avoidance space S2.

[0084] Furthermore, portions of the large diameter suppression portion 23 and the small diameter suppression portion 33 are disposed on both sides of the large diameter avoidance space S2 in the axial direction of the large diameter pipe cutting jig 28. Therefore, the pair of large diameter suppression portion 23 and portions of the small diameter suppression portion 33 are disposed on both sides of the scribe line L, which is the intended cutting position of the large diameter pipe P2. Therefore, the operating tool 60 has a positioning portion 64a that determines the position of the cutting blade 80 relative to the large diameter pipe cutting jig 28 inserted inside the large diameter pipe P2.

[0085] As shown in Figure 10, the operator presses the cutting blade 80 against the large diameter pipe P2. Then, the cutting blade 80 pressed against the outer surface of the large diameter pipe P2 bends and deforms the large diameter pipe P2 radially inward until just before it is cut. The large diameter pipe P2 itself, bent and deformed radially inward, urges the pair of large diameter suppression parts 23 or small diameter suppression parts 33 toward both ends in the axial direction. Therefore, when the cutting blade 80 is positioned in the cutting start state and pressed against the large diameter pipe P2, the bent large diameter pipe P2 prevents the large diameter pipe cutting jig 28 from moving from the cutting position, even without the operating tool 60.

[0086] Then, after removing the operating tool 60, the cutting blade 80 is moved along the scribed line L. Specifically, while the cutting blade 80 is pressed against the large-diameter pipe P2, the cutting blade 80 is moved around the outside of the large-diameter pipe P2 around the large-diameter pipe P2 as an axis. The large-diameter pipe P2 is then cut while being pressed from the outside to the inside by the cutting blade 80. The large-diameter pipe P2 is pressed inward in the radial direction by the cutting blade 80, and the large-diameter suppression parts 23 are disposed at positions sandwiching the pressed part. Therefore, on both sides of the intended cutting position of the large-diameter pipe P2 by the cutting blade 80, the large-diameter suppression parts 23 or the small-diameter suppression parts 33 that support the large-diameter pipe P2 from the inside of the large-diameter pipe P2 are disposed. The pair of large-diameter suppression parts 23 or the small-diameter suppression parts 33 suppress deformation of the large-diameter pipe P2 due to the pressure of the cutting blade 80.

[0087] The cutting blade 80 that penetrates the large diameter pipe P2 in the thickness direction enters the large diameter avoidance space S2. In other words, the large diameter avoidance space S2 prevents the cutting blade 80 from interfering with the large diameter pipe cutting jig 28. Therefore, in the large diameter pipe cutting jig 28, the large diameter avoidance space S2 that prevents interference with the cutting blade 80 when cutting the large diameter pipe P2 is formed between the pair of large diameter suppressing parts 23 in the axial direction of the large diameter pipe P2.

[0088] Furthermore, a portion of the circumferential portion of the large diameter pipe P2 pressed by the cutting blade 80 is bent and deformed toward the large diameter avoidance space S2. The bent and deformed portion of the large diameter pipe P2 comes into contact with the leading edge of the large diameter suppressing portion 23, i.e., the large diameter contact portion 55. Therefore, each of the pair of large diameter suppressing portions 23 has a large diameter contact portion 55 on the large diameter avoidance space S2 side in the axial direction of the large diameter pipe P2, and this large diameter contact portion 55 can come into contact with the large diameter pipe P2 that has been bent as the large diameter pipe P2 is pressed by the cutting blade 80. Note that in FIG. 10 , a portion of the large diameter pipe P2 is in contact with the small diameter suppressing portion 33, but because the small diameter suppressing portion 33 also serves as the large diameter contact portion 55, a portion of the large diameter pipe P2 is in contact with the large diameter contact portion 55. Therefore, each of the pair of large diameter jig forming portions 21 has a large diameter contact portion 55 on the large diameter avoidance space S2 side in the axial direction of the large diameter pipe P2.

[0089] As shown in FIG. 11 , when cutting of the large-diameter pipe P2 is completed, a divided portion PH is generated in the large-diameter pipe P2 at a portion closer to the end than the cut portion. The divided portion PH is the portion that is cut and removed from the large-diameter pipe P2. The divided portion PH is so-called scrap material. Even if the divided portion PH is generated, the inner circumferential surface of the divided portion PH contacts the outer circumferential surface of one of the large-diameter restraining portions 23. This contact prevents the divided portion PH from falling off the large-diameter pipe cutting jig 28. Therefore, the large-diameter restraining portion 23 is formed with a large-diameter blocking portion 23b on the end side in the axial direction of the large-diameter pipe P2, which contacts the inner circumferential surface of the divided portion PH and prevents the divided portion PH from falling off. The large-diameter blocking portion 23b may be formed by the large-diameter restraining portion 23 itself, or may be formed by the small-diameter restraining portion 33 depending on the cutting position of the large-diameter pipe P2.

[0090] Next, the case of cutting the small diameter pipe P1 will be described. The worker removes the pair of large diameter jig forming parts 21 from the small diameter pipe cutting jig 38. Then, as shown in FIG. 12, the pipe cutting jig 20 made up of the small diameter pipe cutting jig 38 is formed.

[0091] The worker inserts the small diameter pipe cutting jig 38 into the inside of the small diameter pipe P1 from the end of the small diameter pipe P1. Next, in the same manner as when using the large diameter pipe cutting jig 28, the operator places the operating tool 60 radially outward of the small diameter pipe P1 and operates the operating tool 60 to move it toward the scribe line L. The operator then positions the positioning part 64a in the same straight line as the scribe line L. This positions the positioning part 64a in the axial center of the small diameter pipe cutting jig 38, that is, in the small diameter avoidance space S1.

[0092] The operator presses the cutting blade 80 against the small diameter pipe P1 from the radially outer side of the small diameter pipe P1, just as when using the large diameter pipe cutting jig 28. Then, the cutting blade 80 pressed against the outer surface of the small diameter pipe P1 causes the small diameter pipe P1 to bend radially inward until just before it is cut. Therefore, when the cutting blade 80 is positioned in a cutting start state and pressed against the small diameter pipe P1, the bent small diameter pipe P1 prevents the small diameter pipe cutting jig 38 from moving from the cutting position, even without the operating tool 60.

[0093] Then, after removing the operating tool 60, the worker moves the cutting blade 80 around the outside of the small diameter pipe P1, with the small diameter pipe P1 as its axis, while pressing the cutting blade 80 against the small diameter pipe P1 along the scribe line L. As a result, the small diameter pipe P1 is cut while being pressed from the outside in the radial direction by the cutting blade 80.

[0094] The small diameter pipe P1 is pressed radially inward by the cutting blade 80, and small diameter suppression parts 33 are arranged at positions sandwiching the pressed point. Therefore, on the small diameter pipe P1, small diameter suppression parts 33 that support the small diameter pipe P1 from the inside are arranged on both sides of the position on the small diameter pipe P1 that is intended to be cut by the cutting blade 80. The pair of small diameter suppression parts 33 suppress deformation of the small diameter pipe P1 due to the pressing of the cutting blade 80.

[0095] The cutting blade 80 that penetrates the small diameter pipe P1 in the thickness direction enters a small diameter avoidance space S1 defined between a pair of small diameter suppression parts 33. In other words, the small diameter avoidance space S1 prevents the cutting blade 80 from interfering with the small diameter pipe cutting jig 38. Therefore, in the small diameter pipe cutting jig 38, a small diameter avoidance space S1 that prevents interference with the cutting blade 80 when cutting the small diameter pipe P1 is formed between the pair of small diameter suppression parts 33 in the axial direction of the small diameter pipe P1.

[0096] Furthermore, a portion of the circumferential portion of the small diameter pipe P1 pressed by the cutting blade 80 is bent and deformed toward the small diameter avoidance space S1. The bent and deformed portion of the small diameter pipe P1 comes into contact with the leading edge of the small diameter suppressing portion 33, i.e., the small diameter contact portion 53. Therefore, each of the pair of small diameter jig forming portions 31 has the small diameter contact portion 53 on the small diameter avoidance space S1 side in the axial direction of the small diameter pipe P1. Therefore, each of the pair of small diameter suppressing portions 33 has the small diameter contact portion 53 on the small diameter avoidance space S1 side in the axial direction of the small diameter pipe cutting jig 38, and this small diameter contact portion 53 can come into contact with the small diameter pipe P1 that has been bent as the cutting blade 80 presses the small diameter pipe P1.

[0097] As shown in FIG. 13, when cutting of the small diameter pipe P1 is completed, a divided portion PH is generated in the small diameter pipe P1 at a portion closer to the end than the cut portion. The divided portion PH is the portion that is cut and removed from the small diameter pipe P1. The divided portion PH is what is called a scrap material. Even if the divided portion PH is generated, the inner circumferential surface of the divided portion PH contacts the outer circumferential surface of one of the small diameter suppressing portions 33. This contact prevents the divided portion PH from falling off the small diameter pipe cutting jig 38. Therefore, the small diameter suppressing portion 33 is formed with a small diameter preventing portion 33a on the end side in the axial direction of the small diameter pipe P1, which contacts the inner circumferential surface of the divided portion PH and prevents the divided portion PH from falling off.

[0098] [Effects of the embodiment] According to the above embodiment, the following effects can be obtained. (1) The large diameter pipe cutting jig 28 has a pair of large diameter suppressing parts 23. When the large diameter pipe P2 is cut by the cutting blade 80, the pair of large diameter suppressing parts 23 support the large diameter pipe P2 from inside at positions that sandwich the pressed part when the large diameter pipe P2 is pressed by the cutting blade 80. As a result, the large diameter pipe P2 can be prevented from being significantly deformed inward when pressed by the cutting blade 80.

[0099] Similarly, the small diameter pipe cutting jig 38 has a pair of small diameter suppression parts 33. When the small diameter pipe P1 is cut by the cutting blade 80 and the small diameter pipe P1 is pressed by the cutting blade 80, the pair of small diameter suppression parts 33 support the small diameter pipe P1 from inside at positions that sandwich the pressed part. As a result, the small diameter pipe P1 can be prevented from being significantly deformed inward due to the pressure from the cutting blade 80.

[0100] As described above, the pipe cutting jig 20 makes it easy to cut even a thin-walled pipe P with the cutting blade 80. (2) In the large diameter pipe cutting jig 28, a large diameter avoidance space S2 is formed between the pair of large diameter suppression parts 23. The large diameter avoidance space S2 is recessed from the circumferential surface of the large diameter suppression parts 23. This allows the cutting blade 80 to penetrate the large diameter pipe P2 in the thickness direction, and prevents the cutting blade 80 from coming into contact with the large diameter pipe cutting jig 28.

[0101] Similarly, in the small diameter pipe cutting jig 38, a small diameter avoidance space S1 is formed between the pair of small diameter suppression parts 33. The small diameter avoidance space S1 is recessed from the circumferential surface of the small diameter suppression parts 33. This allows the cutting blade 80 to penetrate the small diameter pipe P1 in the thickness direction, while preventing the cutting blade 80 from coming into contact with the small diameter pipe cutting jig 38.

[0102] As described above, the pipe cutting jig 20 does not come into contact with the cutting blade 80 and interfere with the movement of the cutting blade 80, making it easier to cut the pipe P using the pipe cutting jig 20. (3) As described above, the pipe cutting jig 20 can suppress large bending deformation of the pipe P caused by the pressing force of the cutting blade 80 using the large diameter suppressing portion 23 or the small diameter suppressing portion 33, thereby reducing the pressing force on the cutting blade 80 caused by the return of the bent and deformed pipe P to its original shape. Therefore, the pipe cutting jig 20 facilitates the movement of the cutting blade 80 while the pipe P is being cut with the cutting blade 80 and the movement of the cutting blade 80 after cutting of the pipe P is completed.

[0103] (4) The large diameter pipe cutting jig 28 has a large diameter contact portion 55 that comes into contact with a deflected portion of the large diameter pipe P2 when the large diameter pipe P2 is cut by the cutting blade 80. The small diameter pipe cutting jig 38 has a small diameter contact portion 53 that comes into contact with a deflected portion of the small diameter pipe P1 when the small diameter pipe P1 is cut by the cutting blade 80. These contact portions 53, 55 make it possible to keep the deflection of the pipe P small.

[0104] Furthermore, by contacting the pipe P with each of the contact portions 53, 55, movement of the pipe cutting jig 20 in the axial direction of the pipe P can be suppressed after a portion of the pipe P is cut by the cutting blade 80. As a result, the cutting operation of the pipe P using the pipe cutting jig 20 can be maintained, and cutting of the pipe P along the score line L can be maintained.

[0105] (5) The large diameter jig forming portion 21 or the small diameter jig forming portion 31 has a predetermined length so as to function as the blocking portion 23b, 33a. Even if a divided portion PH occurs when the pipe P is cut, the inner circumferential surface of the divided portion PH comes into contact with the large diameter blocking portion 23b or the small diameter blocking portion 33a, thereby preventing the divided portion PH from falling. As a result, damage caused by the divided portion PH falling can be prevented.

[0106] (6) The pipe cutting device 10 has a pipe cutting jig 20 and an operating tool 60. The pipe cutting jig 20 and the operating tool 60 can be magnetically attached to each other. The operating tool 60 can be magnetically attached to the pipe cutting jig 20 from the outer peripheral surface side of the pipe P, so that the pipe cutting jig 20 can be moved axially within the pipe P by operating the operating tool 60 from the outer peripheral surface side of the pipe P. As a result, the pipe cutting jig 20 can be moved and positioned even in a position that is out of reach from the end of the pipe P.

[0107] (7) The operating tool 60 has a positioning portion 64a and a guide slit 73 that determine the position of the cutting blade 80 relative to the pipe cutting jig 20. When the positioning portion 64a and the guide slit 73 are aligned with the scribe line L, the small diameter avoidance space S1 or the large diameter avoidance space S2 can be positioned on the inner periphery of the scribed position of the scribe line L on the pipe P. Therefore, the pipe cutting device 10 having the operating tool 60 can easily perform the cutting operation of the pipe P with the cutting blade 80 using the pipe cutting jig 20.

[0108] (8) The pipe cutting jig 20 can be used as either a large diameter pipe cutting jig 28 formed by assembling a pair of large diameter jig forming parts 21, or a small diameter pipe cutting jig 38 formed by assembling a pair of small diameter jig forming parts 31. Therefore, one pipe cutting jig 20 can easily cut two types of pipe P with different pipe diameters. This eliminates the need to carry two types of pipe cutting jigs 20 to the pipe P installation site.

[0109] (9) The small diameter avoidance space S1 extends over the entire circumferential direction of the small diameter pipe cutting jig 38, and the large diameter avoidance space S2 extends over the entire circumferential direction of the large diameter pipe cutting jig 28. Therefore, the cutting blade 80 can be moved around the small diameter pipe P1 or the large diameter pipe P2 as an axis. Therefore, even if the pipe cutting jig 20 is positioned inside the pipe P, the pipe P can be easily cut by the cutting blade 80.

[0110] (10) The large diameter jig forming portion 21 has a fitting wall portion 25 and a fitting protrusion 25a protruding from the fitting wall portion 25. The large diameter jig forming portion 21 can hold the small diameter jig forming portion 31 by means of the fitting wall portion 25 and the fitting protrusion 25a. This allows the large diameter jig forming portion 21 and the small diameter jig forming portion 31 to be easily integrated together. As a result, the large diameter pipe cutting jig 28 formed by integrating the large diameter jig forming portion 21 with the small diameter pipe cutting jig 38 can be easily formed.

[0111] (11) The small diameter suppression portion 33 forms a part of the large diameter suppression portion 23. In other words, the small diameter suppression portion 33 also serves as the large diameter suppression portion 23. For example, compared to when the large diameter suppression portion 23 is formed cylindrically and the large diameter suppression portion 23 is formed solely by the large diameter suppression portion 23, the material cost of the large diameter suppression portion 23 and therefore the material cost of the large diameter jig forming portion 21 can be reduced, and the large diameter pipe cutting jig 28 can be made lighter.

[0112] [Example of change] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0113] The operating tool 60 does not necessarily have to have either the positioning portion 64a or the guide slit 73. The pipe cutting jig 20 may be moved to the position of the scribe line L without using the operating tool 60. For example, the pipe cutting jig 20 inserted into the pipe P may be pushed with a rod or the like to move it to the position of the scribe line L.

[0114] The dimension H1 of the small diameter suppression portion 33 that forms the small diameter suppression portion 33 and the dimension M1 of the large diameter suppression portion 23 that forms the large diameter suppression portion 23 may be changed as appropriate. The end face of the small diameter suppression portion 33 that forms the small diameter suppression portion 33 on the small diameter avoidance space S1 side may be curved in an arc shape. Similarly, the end face of the large diameter suppression portion 23 that forms the large diameter suppression portion 23 on the large diameter avoidance space S2 side may be curved in an arc shape.

[0115] The pipe cutting jig 20 may be a single large diameter pipe cutting jig 28 consisting of a pair of large diameter jig forming portions 21, or a single small diameter pipe cutting jig 38 consisting of a pair of small diameter jig forming portions 31.

[0116] The intended cutting position does not have to be indicated by the scribed line L. For example, it may be a groove or a dot on the pipe P. [Explanation of symbols]

[0117] P...pipe, P1...small diameter pipe, P2...large diameter pipe, PH...separating portion, S1...small diameter avoidance space, S2...large diameter avoidance space, 10...pipe cutting device, 20...pipe cutting jig, 23...large diameter suppression portion, 23b...large diameter blocking portion, 28...large diameter pipe cutting jig, 33...small diameter suppression portion, 33a...small diameter blocking portion, 38...small diameter pipe cutting jig, 53...small diameter contact portion, 55...large diameter contact portion, 60...operating tool, 64a...positioning portion, 80...cutting blade.

Claims

1. The cutting blade is inserted into the inside of the pipe from the end thereof, and is disposed on both sides of the intended cutting position of the pipe, supporting the pipe from the inside and suppressing deformation of the pipe due to pressure from a cutting blade that cuts the pipe. one suppression portion and the other suppression portion are aligned in the axial direction of the pipe, and the pair of suppression portions are spaced apart from each other in the axial direction of the pipe, A pipe cutting jig characterized in that an avoidance space is formed between the pair of suppression portions in the axial direction of the pipe to avoid interference with the cutting blade when cutting the pipe.

2. A pipe cutting jig as described in claim 1, wherein each of the pair of suppression portions has a contact portion on the side of the avoidance space in the axial direction of the pipe, and the contact portion is capable of contacting the pipe that has been bent as the pipe is pressed by the cutting blade.

3. 3. A pipe cutting jig as described in claim 2, wherein when the pipe is cut by the cutting blade, a divided portion is produced that is separated and removed from the pipe, and a preventing portion is formed on the end side of the suppression portion in the axial direction of the pipe, which contacts the inner surface of the divided portion and prevents the divided portion from falling.

4. A pipe cutting jig according to any one of claims 1 to 3, an operating tool for moving the pipe cutting tool inserted into the inside of the pipe to the intended cutting position, The operating tool and the pipe cutting jig are magnetically attachable to each other, The operating tool is a pipe cutting device in which the pipe cutting jig inserted inside the pipe can be operated from the outer peripheral surface side of the pipe to move in the axial direction of the pipe.

5. 5. The pipe cutting device according to claim 4, wherein the operating tool has a positioning portion for determining the position of the cutting blade relative to the pipe cutting jig inserted inside the pipe.

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