Pipe cutting device

Abstract

To provide a pipe cutting device capable of efficiently cutting a pipe and ensuring excellent cut surface quality.SOLUTION: In a pipe cutting device in which a rotor ring 2 and a cam ring 3 that are disposed adjacent to each other in an axial direction and rotatably supported around a common rotation center O, with a pipe P passed through them are driven to rotate in the same direction at different rotational speeds, a blade block 5 swingably mounted on the rotor ring 2 rotates along the outer circumference of the pipe P and swings in a direction that brings its tip closer to the rotation center O; a blade of the blade block 5 bites into the pipe P; the blade block 5 is provided as one with a cutting blade 17 and one with a finishing blade 18; the finishing blade 18 has a tapered cutting edge; and the cutting blade 17 is formed thinner than the cutting edge of the finishing blade 18 along the entire length of the cutting edge.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a pipe cutting device used for cutting resin or metal pipes. [Background technology]

[0002] Among pipe cutting devices (hereinafter simply referred to as "cutting devices") used to cut plastic or metal pipes to a specified length, there is a type in which a special blade, selected according to the material, etc. of the pipe to be cut, is rotated along the outer periphery of a fixed pipe while cutting toward the center of the pipe (see, for example, Patent Document 1).

[0003] The pipe cutting device disclosed in Patent Document 1 includes a rotor ring (annular plate) and a cam ring (cam wheel) that are adjacent to each other in the axial direction and rotatably supported around a common center of rotation, a drive mechanism that rotates the rotor ring and the cam ring in the same direction at different rotation speeds, and a blade block (swing arm) whose base end is swingably attached to the surface of the rotor ring opposite to the surface facing the cam ring. The blade block has a blade that protrudes toward the pipe that is passed through the rotor ring and the cam ring, and a cam roller (a pin and a roller provided at its tip) that passes through a long hole provided in the rotor ring and is inserted into a cam groove provided in the cam ring. The cam groove of the cam ring extends along the circumferential direction of the cam ring and is formed so as to approach the center of rotation of the cam ring from one end to the other end.

[0004] The rotor ring and cam ring are rotated by a drive mechanism, so that the blade block rotates along the outer periphery of the pipe while the cam roller is guided by the cam groove and swings in a direction that brings the tip side closer to the center of rotation, causing the blade to bite into the pipe and cut it. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 57-42479 Summary of the Invention [Problem to be solved by the invention]

[0006] In the pipe cutting device as described in the above Patent Document 1, it is necessary to select a blade suitable for cutting depending on the material (physical properties such as hardness and toughness) of the pipe to be cut. For example, when the object to be cut is a resin pipe, a cutting tool such as a cutting tool for rigid polyvinyl chloride, a cutting tool for polypropylene or polyethylene, a cutting tool for glass fiber reinforced polypropylene, etc. are often used. It is common to attach one cutting tool, one to three cutting tools, and one knife. The cutting edge of these cutting tools is tapered so that it becomes thinner toward the tip, and the cut surface of the pipe is finished with the side of the cutting edge while cutting the pipe.

[0007] In addition, the amount and speed of cutting of the blade from the outer circumference of the pipe to the center varies depending on the shape of the cam groove in the cam ring, so a cam ring with a cam groove of an appropriate shape for each cutting condition (material of the pipe to be cut and type of blade) is designed and manufactured in advance, and a dedicated cam ring that suits the cutting conditions is used during cutting work.

[0008] As mentioned above, the reason why the blade and cam ring are used according to the material of the pipe is that, if they are not used, cutting may not be possible or the quality of the cut surface may be poor. Problems with the quality of the cut surface include waviness, roughness, poor perpendicularity of the cut surface, and the adverse effects on secondary processing due to melted cutting chips.

[0009] However, this method of use requires changing the blade and cam ring every time the material of the pipe to be cut is changed, which causes a problem of time and effort. In particular, changing the cam ring takes more than two days even for an experienced worker.

[0010] One possible solution to this problem in factories and other places is to install multiple cutting devices, each equipped with a cam ring dedicated to a different pipe material, and use different cutting devices depending on the material of the pipe to be cut.However, in this case, if there are multiple orders to cut pipes of the same material, only the cutting device equipped with a cam ring dedicated to that material can be used, which reduces the overall operating rate of the cutting equipment and creates waiting times for work, making it difficult to work efficiently.

[0011] For this reason, in practice, when the material of the pipe to be cut is changed, only the blade is replaced without replacing the cam ring, and the cutting speed is slowed down to prevent a decrease in the quality of the cut surface. However, this increases the time required for one cut, and a decrease in work efficiency is unavoidable.

[0012] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a pipe cutting device that can cut a pipe efficiently and ensure good cut surface quality. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention provides a rotary machine comprising a rotor ring and a cam ring adjacent to each other in the axial direction and supported rotatably around a common center of rotation, a drive mechanism that rotationally drives the rotor ring and the cam ring in the same direction at different rotational speeds, and a blade block having a base end that is swingably attached to a surface of the rotor ring opposite to the surface facing the cam ring, the blade block having blades that protrude toward the rotor ring and a pipe passed through the cam ring, and a cam roller that passes through an elongated hole provided in the rotor ring and is inserted into a cam groove provided in the cam ring, the cam groove of the cam ring extends along the circumferential direction of the cam ring and has an asymptotic portion that approaches the center of rotation as it moves from one end to the other end, and the rotor ring and In a pipe cutting device in which the blade block rotates along the outer periphery of the pipe by rotating the cam ring with the drive mechanism, while the cam roller is guided by the asymptotic portion of the cam groove and swings in a direction bringing the tip side closer to the rotation center, so that the blade bites into the pipe, the blade block is provided with at least one blade having a cutting blade as the blade and at least one blade having a finishing blade as the blade which bites into the pipe after the cutting blade, and the finishing blade is formed in a tapered shape such that the tip portion which bites into the pipe becomes thinner toward the tip, and the cutting blade is formed in such a way that the tip portion which bites into the pipe is thinner than the tip portion of the finishing blade over its entire length (configuration 1).

[0014] According to the above configuration 1, the cutting blade, which has a thinner cutting edge than the finishing blade and is specialized for cutting function, cuts the pipe while finishing the cut surface with the side of the tapered cutting edge of the finishing blade, so that the cutting ability and finishing ability can be improved compared to the case where only one type of blade is used for both cutting and finishing. Therefore, even when the material of the pipe to be cut is changed, the cam ring is not replaced, and only the blade is replaced as necessary, and the cutting work is performed at the normal cutting speed, so that the pipe can be cut efficiently while ensuring good cut surface quality.

[0015] In the above configuration 1, the specific combination of blades may be appropriately selected depending on the material of the pipe to be cut. For example, the cutting blade may be a bit having a constant thickness at the cutting edge, and the finishing blade may be a bit having a tapered cutting edge (configuration 2).

[0016] Alternatively, the cutting blade can be a round blade whose cutting edge is tapered so that it becomes thinner towards the tip, and the finishing blade can be a cutting tool whose cutting edge is tapered (configuration 3). Effect of the Invention

[0017] As described above, the pipe cutting device of the present invention performs the pipe cutting operation (cutting and finishing the cut surface) using a cutting blade whose cutting edge is thinner than that of a finishing blade and a finishing blade whose cutting edge is tapered, and therefore has higher cutting and finishing capabilities than a device that performs cutting operations using a single type of blade. Therefore, even when the material of the pipe to be cut is changed, it is not necessary to replace the cam ring, and cutting speed is not reduced, and cutting can be performed efficiently while ensuring good cut surface quality. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a front view of a pipe cutting device according to a first embodiment; [Diagram 2] Right side view of the main part of Figure 1 (excluding the stand) [Diagram 3] Right side view of the rotor ring in Figure 1 [Figure 4] Right side view of the cam ring in Figure 1 [Diagram 5] FIG. 2 is a cross-sectional view showing the mounting state of the blade block of FIG. [Figure 6] FIG. 3 is a side view showing a main part of a pipe cutting device according to a second embodiment, corresponding to FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 to Fig. 5 show a pipe cutting device of the first embodiment. This cutting device is intended to cut a resin pipe, and as shown in Fig. 1 and Fig. 2, includes a rotor ring 2 and a cam ring 3 that are adjacent to each other in the axial direction inside a base 1 and are supported rotatably around a common rotation center O, a drive mechanism 4 that drives the rotor ring 2 and the cam ring 3 to rotate, and two blade blocks 5 that are attached to one side of the rotor ring 2 (the side opposite to the side facing the cam ring 3). Although not shown, clamp devices that clamp the pipe P to be cut that is passed through the rotor ring 2 and the cam ring 3 are provided on both the front and rear sides of the base 1 (both the left and right sides in Fig. 1).

[0020] One end face of a cylindrical shaft 6 is fixed to the other side of the inner circumference of the rotor ring 2, and the cam ring 3 is fitted onto the outer circumference of one end of the cylindrical shaft 6 via a sliding bearing (not shown), and a rolling bearing 8 is incorporated between the outer circumference of the other end of the cylindrical shaft 6 and the inner circumference of the central hole of a support plate 7 fixed to the frame 1. In this way, the rotor ring 2 and the cam ring 3 are rotatably supported by the support plate 7. In addition, an annular protrusion 6a is provided on the outer circumference of the axial center of the cylindrical shaft 6 to restrict movement of the cam ring 3 in a direction away from the rotor ring 2.

[0021] A driving motor 9 is installed on a table 1a provided on the upper part of the stand 1, and two driving pulleys 10 of the same specifications are fixed to the outer periphery of the main shaft 9a of the driving motor 9 so as to be adjacent to each other in the axial direction. A toothed belt 11 is wound between the driving pulley 10 closer to the main body of the driving motor 9 and a gear formed on the outer periphery of the rotor ring 2, and between the other driving pulley 10 and a gear formed on the outer periphery of the cam ring 3. Here, the rotor ring 2 has a slightly larger diameter than the cam ring 3 and has a larger number of gear teeth, so that when the driving motor 9 is driven, the rotor ring 2 rotates at a slightly slower rotation speed than the cam ring 3. In other words, the driving motor 9, the two driving pulleys 10, the two toothed belts 11, and the gears on the outer peripheries of the rotor ring 2 and the cam ring 3 constitute a pulley-type driving mechanism 4 that rotates and drives the rotor ring 2 and the cam ring 3 in the same direction at different rotation speeds.

[0022] As shown in FIG. 3, the rotor ring 2 has two screw holes 2a for attaching the blade block 5 at positions that are rotationally symmetrical by 180 degrees, and elongated holes 2b that extend along an arc centered on the center of each screw hole 2a are formed in a shape that is rotationally symmetrical by 180 degrees.

[0023] As shown in Fig. 4, cam ring 3 is formed so that cam grooves 3a are continuous without interruption around the entire circumference. Cam grooves 3a extend along the circumferential direction of cam ring 3 and have two asymptotic portions 3a1 that approach center of rotation O from one end to the other, two arc portions 3a2 that connect to one end of asymptotic portion 3a1 and have a constant distance from center of rotation O, and two connecting portions 3a3 that connect the other end of asymptotic portion 3a1 to one end of arc portion 3a2.

[0024] 2 and 5, the blade block 5 has a first oscillating piece 12 and a second oscillating piece 13 overlapped with each other in the axial direction, and a screw portion 14a on the base end side of an oscillating shaft 14 that penetrates the base ends of both oscillating pieces 12, 13 is screwed into a screw hole 2a of the rotor ring 2. The oscillating shaft 14 has a cap 14b that prevents each of the oscillating pieces 12, 13 from coming off. A countersunk elongated hole 12a is formed in the first oscillating piece 12 along an arc centered on the oscillation center A of the oscillating shaft 14, and an adjustment screw 15 that is passed through the elongated hole 12a is screwed into a screw hole 13a provided in the second oscillating piece 13. As a result, the first oscillating piece 12 and the second oscillating piece 13 are connected in a freely oscillating state around a common oscillating center A, and the relative positions of the oscillating pieces in relation to each other can be adjusted by changing the position of the adjustment screw 15 within the long hole 12a of the first oscillating piece 12.

[0025] Further, the first oscillating piece 12 has a blade holder 16 attached to its tip surface, and the blade holder 16 holds a blade in a position in which it protrudes toward a pipe P passed through the rotor ring 2 and the cam ring 3. One of the blades held by the blade holder 16 is a cutting blade 17, and the other is a finishing blade 18.

[0026] Here, the cutting blade 17 is a (straight-shaped) cutting tool with a constant thickness at the tip that bites into the pipe P, and the finishing blade 18 is a tapered cutting tool with a tip that becomes thinner toward the tip, and the tip of the cutting blade 17 is formed thinner over its entire length than the tip of the finishing blade 18. The amount of protrusion of the finishing blade 18 from the blade holder 16 is adjusted so that it bites into the pipe P after the cutting blade 17.

[0027] The second oscillating piece 13 has a cam roller 19 at its tip end which passes through the long hole 2b of the rotor ring 2 and is inserted into the cam groove 3a of the cam ring 3. The cam roller 19 has a screw portion 19a at its base end which is screwed into the second oscillating piece 13, and a ring piece 19b which rolls in the cam groove 3a is rotatably supported at its tip end. As described below, as the position of the ring piece 19b of the cam roller 19 changes within the cam groove 3a, the blade block 5 swings, and the cutting blade 17 and the finishing blade 18 move towards and away from the pipe P.

[0028] Next, the cutting operation in this cutting device will be described. First, the pipe P to be cut is passed through the rotor ring 2 and cam ring 3 as shown in Fig. 1, and the front and rear portions of the stand 1 are clamped by the clamp device. At this time, the rotor ring 2 and cam ring 3 are set so that the cam rollers 19 of each blade block 5 are positioned in the arc portion 3a2 of the cam groove 3a of the cam ring 3 that is the farthest from the center of rotation O, and the cutting blades 17 and finishing blades 18 do not come into contact with the pipe P.

[0029] When the drive motor 9 of the drive mechanism 4 is driven with the pipe P fixed as described above, the rotation is transmitted to the rotor ring 2 and the cam ring 3 via the two drive pulleys 10 and the toothed belt 11, and the rotor ring 2 and the cam ring 3 rotate in the same direction (clockwise in Figures 2 to 4) along the outer periphery of the pipe P.

[0030] Here, because the rotation speed of the rotor ring 2 is slightly slower than that of the cam ring 3, the rotor ring 2 rotates relatively in the opposite direction (counterclockwise in Figs. 2 to 4) to the cam ring 3, and the cam rollers 19 of each blade block 5 are guided to leave the arc portion 3a2 of the cam groove 3a of the cam ring 3 and move along the asymptotic portion 3a1. As a result, each blade block 5 rotates around the pipe P, while swinging in a direction that brings the tip side closer to the center of rotation O, and the cutting blades 17 and finishing blades 18 bite into the pipe P.

[0031] At this time, as described above, the finishing blade 18 bites into the pipe P after the cutting blade 17, so while the pipe P is being cut by the cutting blade 17, the cut surface can be finished with the side of the cutting edge of the finishing blade 18. Moreover, since the cutting edge of the finishing blade 18 is tapered, as the finishing blade 18 bites into the pipe P, the cut surface of the pipe P is repeatedly subjected to finishing processing, ensuring good cut surface quality.

[0032] The cutting operation itself is completed when the tip of the cutting blade 17 reaches the inner circumference of the pipe P, but if the drive motor 9 continues to be driven after cutting is completed, the cam roller 19 will be guided by the cam groove 3a and will reach the arc portion 3a2 from its asymptotic portion 3a1 through the connection portion 3a3 (at this time the blade block 5 oscillates in the opposite direction to when cutting), so by stopping the drive motor 9 at that point, each blade block 5 can be set to the cutting preparation position where the cutting blade 17 and the finishing blade 18 are furthest from the rotation center O.

[0033] As described above, this cutting device cuts the pipe P with the cutting blade 17 while finishing the cut surface with the side of the tapered cutting edge of the finishing blade 18, and the cutting blade 17 has a thinner cutting edge than the finishing blade 18 and is specialized for cutting function, so that it is possible to maintain an appropriate cutting speed and ensure good cut surface quality at the same time. In other words, even when the material of the pipe to be cut is changed, the cam ring is not replaced, and only the blade is replaced as necessary, and the cutting work is performed at the normal cutting speed, making it possible to cut the pipe efficiently while ensuring good cut surface quality.

[0034] In addition, the cam groove 3a of the cam ring 3 is continuous without interruption around the entire circumference, and the blade block 5 can be set to the cutting preparation position by simply driving the drive motor 9 for a short period of time after cutting is completed. This means that preparation for the next cutting job can be completed in a short time, and there is no need to provide a separate mechanism for swinging the blade block 5 to the cutting preparation position.

[0035] Furthermore, the relative positions of the first oscillating piece 12 and the second oscillating piece 13 of the blade block 5 are adjustable in the swinging direction. Therefore, even when the outer diameter of the pipe to be cut is changed, the relative positions of the two oscillating pieces 12, 13 can be adjusted, and the blades 17, 18 of each blade block 5 can be easily set to appropriate positions according to the outer diameter of the pipe.

[0036] Fig. 6 shows a pipe cutting device of the second embodiment. In this second embodiment, instead of the straight-shaped cutting blade 17 of the first embodiment and the blade holder 16 that holds it, a cutting blade 20 made of a round blade and a blade holder 21 suitable for holding it are used. The cutting blade (round blade) 20 is formed in a tapered shape whose cutting edge becomes thinner toward the tip, but the thickness of the cutting edge is thinner over the entire length of the cutting edge than the cutting edge of the finishing blade 18. The configuration and operation of other parts are the same as in the first embodiment, and the same effects as in the first embodiment can be achieved.

[0037] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0038] For example, the combination of cutting blade and finishing blade types is not limited to those in each embodiment, but may be selected appropriately depending on the material of the pipe to be cut, etc., as long as the cutting edge of the finishing blade is tapered and the cutting edge of the cutting blade is thinner than the finishing blade over its entire length.

[0039] In addition, in each embodiment, a pulley type mechanism is used as the drive mechanism for rotating the rotor ring and the cam ring. However, instead of this, a gear type mechanism that transmits rotation by meshing gears may be used.

[0040] The present invention can be applied not only to cutting devices for cutting plastic pipes as in the above-described embodiments, but also to cutting devices for cutting metal pipes. [Explanation of symbols]

[0041] 1 Mount 2 Rotor Ring 2b long hole 3 Cam ring 3a Cam groove 3a1 Asymptote 4. Drive mechanism 5 Blade Block 9 Drive motor 17 Cutting tools (knives) 18 Finishing knives (knives) 19 Cam Roller O Rotation Center A Swing Center

Claims

1. The rotary knives include a rotor ring and a cam ring that are adjacent to each other in the axial direction and rotatably supported around a common center of rotation, a drive mechanism that rotates the rotor ring and the cam ring in the same direction at different rotation speeds, and a blade block whose base end is attached to a surface of the rotor ring opposite to the surface facing the cam ring and capable of swinging freely, the blade block has a blade protruding toward a pipe passing through the rotor ring and the cam ring, and a cam roller that passes through a long hole provided in the rotor ring and is inserted into a cam groove provided in the cam ring, the cam groove of the cam ring extends along a circumferential direction of the cam ring and has an asymptotic portion approaching the rotation center from one end to the other end, In the pipe cutting device, the rotor ring and the cam ring are rotationally driven by the drive mechanism, so that the blade block rotates along the outer periphery of the pipe, while the cam roller is guided by the asymptotic portion of the cam groove and swings in a direction in which the tip side approaches the rotation center, so that the blade bites into the pipe, The blade block is provided with at least one blade having a cutting blade as the blade, and at least one blade having a finishing blade as the blade, which bites into the pipe after the cutting blade, A pipe cutting device characterized in that the finishing blade is formed with a tapered tip that bites into the pipe and becomes thinner towards the tip, and the cutting blade is formed with a tip that bites into the pipe and is thinner than the tip of the finishing blade over its entire length.

2. 2. The pipe cutting device according to claim 1, wherein the cutting blade is a cutting tool having a blade tip with a constant thickness, and the finishing blade is a cutting tool having a tapered blade tip.

3. 2. The pipe cutting device according to claim 1, wherein the cutting blade is a round blade whose cutting edge is tapered toward the tip, and the finishing blade is a cutting tool whose cutting edge is tapered.

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