JP2005334993A - Pipe cutting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe cutting device easily and accurately cutting a pipe of approximately cylindrical shape from the inside while contributing to weight reduction and facilitation of maintenance. <P>SOLUTION: The pipe cutting device A for cutting a buried pipe T of approximately cylindrical shape into round slice shape from the inner peripheral side, comprises: a fixed part 1 fixed into a position near an opening of the buried pipe T integrally with the buried pipe T; a shaft part 2 extending forward inside the buried pipe T from the fixed part 1 with an axis O coinciding with the axis of the buried pipe T; a cutter pressing part 3 for moving a cutter C in the radial direction of the shaft part 2 while holding the position in the axis O direction of the shaft part 2 predeterminedly to press the cutter C to the inner peripheral side of the buried pipe T; and a motor M for transmitting rotational driving force to the shaft part 2 from the fixed part 1 side to rotate the cutter C around the axis O of the shaft part 2 together with the cutter pressing part 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pipe cutting device that cuts a pipe buried in the ground, for example, in a deep well method from the inside of the pipe.

  The deep well method (deep well method) excavates a deep well with a diameter of several tens of centimeters in a permeable layer, pumps groundwater, lowers the groundwater surface and groundwater level, prevents spring water, reduces water pressure, etc. It is widely implemented as a kind of drainage method. In this construction method, a long well is often formed by burying a long cylindrical tube up to a water permeable layer.

Such buried pipes are usually unnecessary after pumping up, and it becomes a hindrance when constructing various structures on the ground side, so it is often necessary to excise a few meters from the ground after pumping up. . In the past, the soil around the buried pipe was removed and the buried pipe was cut from the outside using a cutting means such as a burner. However, this method requires labor for excavating and refilling the sand. It was difficult to work with high efficiency. Therefore, it can be said that it is preferable if it can be cut from the inside of the buried pipe and pulled out from the soil. As described above, for example, a device described in Patent Document 1 is known as a device for cutting an embedded tube from the inside.
JP 2000-328570 A

  In those described in these documents, work is not easy because the weighted cutting device is suspended by a crane or the like and cut. In addition, since the structure is complicated by providing a hydraulic motor, a hydraulic cylinder, and the like, maintenance is not easy, resulting in an increase in maintenance cost.

  The present invention has been made in view of the above circumstances, and provides a tube cutting device capable of easily and accurately cutting a substantially cylindrical tube from the inside while contributing to weight reduction and ease of maintenance. With the goal.

  The invention according to claim 1 is a tube cutting device that cuts a substantially cylindrical tube into a ring shape from the inner peripheral side, and a fixing portion that is integrally fixed to the tube in the vicinity of the opening of the tube; While maintaining the position of the shaft portion in the axial direction of the shaft portion, the shaft portion extending from the fixed portion to the inner front side of the tube with the axis line being substantially the same as the axis line of the tube, A cutter pressing portion that moves the cutter in the radial direction of the shaft portion and presses it toward the inner peripheral side of the tube; a rotational driving force is transmitted from the fixed portion side to the shaft portion; And an actuator that rotates about the axis of the shaft portion together with the portion.

  Since such a configuration is adopted, the fixing portion is fixed at a position near the opening portion of the tube, and the cutter pressing portion is rotated in the tube through the shaft portion from the opening side, so that the tube is cut in a circle. Can be cut into shapes. Therefore, the configuration of the tube cutting device can be simplified without providing an actuator in the tube and without moving the shaft portion in the radial direction.

  Invention of Claim 2 is the pipe | tube cutting device of Claim 1, Comprising: The said cutter press part is mutually attached to the said axial part so that it can move relatively in the said axial direction, respectively, and attached to each other back and forth. First and second pivots, first and second links each having one end pivoted on the first pivot and the other end extending obliquely rearward, and the second pivot The first and third links each having one end side pivoted and the other end side obliquely extending forward, and the other end sides of the first and third links pivoted respectively. A horizontal movement part, and a second horizontal movement part that pivotally supports the other end side of each of the second and fourth links. A four-node phosphorus that enables a cutter attached to at least one of the moving parts to be in contact with and separated from the inner peripheral side of the tube When the one of the first and second pivots is moved in one direction on the axis, the other is equidistant in the opposite direction. It is characterized in that a moving mechanism unit for moving only is provided.

Thus, since the cutter pressing part is a four-bar link type expansion / contraction device, it can be expanded / contracted in the radial direction only by changing the distance between the first pivotal support part and the second pivotal support part. . Therefore, as a simple configuration, the cutter can be easily and accurately brought into contact with and separated from the inner peripheral side of the tube, and the tube can be cut while maintaining the pressing force of the cutter at a predetermined level. .
And since the moving mechanism part is provided in the cutter pressing part, the cutter pressing part can be rotated while holding the position of the cutter in the axial direction at a predetermined position, and it can be accurately cut into a ring shape at the position. it can.

  A third aspect of the present invention is the tube cutting device according to the second aspect, wherein the shaft portion has a double shaft structure including an outer shaft and an inner shaft, and the outer shaft has the first shaft. Two pivotal support portions are attached so as not to rotate relative to the axis and movable in the axial direction. A male screw threaded into a female screw hole formed in the first pivotal support portion is provided on the front side of the inner shaft. A screw portion is formed, and the first pivot portion is moved by rotating the inner shaft independently of the outer shaft rotating integrally with the second pivot portion.

  As described above, since the shaft portion has a double shaft structure and the inner shaft is rotated independently from the outer shaft, the first pivot portion and the second pivot portion are relatively moved. The cutter pressing portion can be easily and accurately expanded and contracted with a simple configuration without the need for an actuator or the like.

  A fourth aspect of the present invention is the tube cutting device according to the second or third aspect, wherein the moving mechanism part is a polygonal cylindrical body provided integrally with the shaft part. A telescopic slide mechanism in which a first cylindrical portion formed and a second cylindrical portion forming a cylindrical body with a polygonal cross-sectional view provided integrally with the second pivot support portion are engaged in a telescopic manner. It is characterized by that.

  Since the moving mechanism portion is an expansion / contraction slide mechanism having such a configuration, the shaft portion and the second pivotal support portion are coupled to each other so that they cannot be relatively rotated about the axis and can be relatively moved in the axial direction. Can do. Therefore, as a simple configuration, the rotational driving force from the fixed portion side can be accurately transmitted to the cutter pressing portion while the second pivotal support portion can be moved in the axial direction.

  In the tube cutting device according to the present invention, the above-described configuration is adopted, so that it contributes to weight reduction and ease of maintenance, and the workability is improved. It is possible to provide a tube cutting device that can be easily and accurately cut.

  Hereinafter, an embodiment of a tube cutting device according to the present invention will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, this pipe cutting device A cuts a substantially cylindrical pipe into a ring shape from the inner peripheral side. Here, a buried pipe (tube) T used in a deep well method or the like is used. Is taken as an example in the case of cutting at a position several m below the ground surface. The buried pipe T has a length of several tens of meters from the surface side and is buried substantially vertically in the ground, and functions as a deep well for introducing groundwater into the pipe.

  This pipe cutting device A includes a fixed portion 1 that is mounted and fixed at a position near the opening at the upper end of the buried pipe (tube) T, and an axial line that is substantially the same as the axis of the buried pipe T to the inside of the buried pipe T. The shaft portion 2 arranged so as to extend downward (forward), the cutter pressing portion 3 that presses the cutter C to the inside of the buried pipe T, and the rotational driving force is transmitted from the fixed portion 1 side to the shaft portion 2. And a motor (actuator) M.

  The fixed portion 1 includes a lid 11 having a substantially disk shape larger in diameter than the buried pipe T, and a speed reducer 16 and a brake 17 provided on the lid 11. The motor M is also provided on the lid 11. A plurality of protrusions 12 formed with female screw holes (not shown) are formed on the lower side of the lid 11 so as to surround the embedded pipe T, and are screwed into the female screw holes of the protrusions 12. By tightening the fixing bolt 12v, the lid 11 can be fixed to the upper side of the opening of the buried pipe T. That is, the projecting portion 12 and the fixing bolt 12v constitute a connecting and fixing mechanism to the buried tube T, whereby the lid 11 is attached integrally with the buried tube T so as to cover the opening of the buried tube T. It is fixed.

  The shaft portion 2 has a double shaft structure composed of a cylindrical outer shaft 21 and an inner shaft 22 arranged inside the outer shaft 21, and is fixed to be rotatable around the axis. 1 is attached. In addition, since the axis line of the shaft portion 2 and the axis line of the buried pipe T are substantially the same, both are shown as the axis line O. The upper end portion side of the shaft portion 2 penetrates the lid 11 and protrudes upward (rearward) so that the rotational driving force from the motor M is transmitted to the outer shaft 22 via the speed reducer 16. It has become. An appropriate frictional force acts between the outer shaft 21 and the inner shaft 22, and the outer shaft 21 is rotated in a normal state, that is, in a state where no mechanical load is applied to the inner shaft 22. And the inner shaft 22 are also rotated together.

  The upper end portion of the inner shaft 22 protrudes further upward than the upper end portion of the outer shaft 21, and a disk 17a is integrally attached to the upper end portion. The brake 17 is constituted by the disk 17a and a brake shoe 17b provided on the fixed portion 1 side and pressing the disk 17a. That is, when the brake shoe 17b is pressed against the disk 17a, a mechanical load, that is, a brake is applied to the inner shaft 22, and the inner shaft 22 tends to rotate in a direction opposite to the rotation direction of the outer shaft 21. For this reason, the inner shaft 22 slides with the outer shaft 21, that is, rotates independently from the outer shaft 21.

  The lower end portion of the outer shaft 21 is provided with a moving device rear portion 4 of a cutter pressing portion 3 described later, and the lower side (front side) of the inner shaft 22 is the moving device rear portion 4 and a cutter pressing portion described later. 3 protrudes further downward through the upper pivot support 34 of the third. The protruding portion of the inner shaft 22 is formed with a male screw portion 22v. The male screw portion 22v is a female screw formed on a lower pivot portion (first pivot portion) 31 of a cutter pressing portion 3 described later. Screwed into a screw hole (not shown in FIG. 1). The male screw and the female screw formed in the male screw portion 22v and the female screw hole are located on the lower pivot when the inner shaft 22 attempts to rotate in the direction opposite to the rotation direction of the lower pivot support portion 31. The support portions 31 are threaded to each other so as to have a screw direction that moves the support portion 31 upward, that is, upward on the axis O.

  The cutter pressing portion 3 is a four-bar link type expansion / contraction device having a configuration in which four links having substantially the same length are connected to each other so as to form a substantially rhombus in a side view. That is, as shown in FIGS. 1 to 3, a lower first link (first link) 32, a lower second link (second link) 33, an upper first link (third link) 35, and an upper side A lower pivot section (first pivot section) 31 and an upper pivot section that connect four links such as a second link (fourth link) 36 and the ends of these links so as to be able to rotate with each other. (Second pivot part) 34, a cutter support part (first lateral movement part) 37, a roller support part (second lateral movement part) 38, and a movement mechanism part 4 are provided as a schematic configuration. Yes. This cutter pressing part 3 can be expanded and contracted in the radial direction by changing the distance between the lower pivot part 31 and the upper pivot part 34, and thereby the cutter C attached to the cutter support part 37 can be expanded. It is possible to approach and separate from the inner peripheral surface of the buried pipe T.

  The lower pivot portion 31 and the upper pivot portion 34 are attached to the shaft portion 2 so as to be relatively movable in the direction of the axis O so as to be moved up and down (front and rear). A female screw hole 31n is formed in the lower pivot part 31, and the male screw part 22v of the inner shaft 22 is screwed into the female screw hole 31n. Further, the upper pivotal support portion 34 is integrally connected and fixed to an outer rectangular tube portion 42 of the moving mechanism portion 4 described later, and is movable in the vertical direction, that is, the axis O direction with respect to the outer shaft 21.

  The lower pivot 31 is provided with a pivot 31p that protrudes in a direction substantially orthogonal to the axis O. One end of the lower first link 32 and the lower second link 33 is provided on the pivot 31p. Each side is pivoted. The other end portions of the lower first link 32 and the lower second link 33 extend obliquely upward (obliquely rearward). Further, the upper pivot portion 34 is provided with a pivot shaft 34p that protrudes in a direction substantially parallel to the pivot shaft 31p. One end of the upper first link 35 and the upper second link 36 is provided on the pivot shaft 34p. Each side is pivotally supported. The other end portions of the upper first link 35 and the upper second link 36 are respectively extended obliquely downward (obliquely forward).

  On the other end side of the lower first link 32, there is a pivot shaft 32p protruding in a direction substantially parallel to the pivot shafts 31p, 34p, and on the other end side of the upper first link 35, a pivot shaft. The pivot shafts 35p projecting in a direction substantially parallel to 32p are integrally provided. With the pivot shafts 32p and 35p, the other end side of the lower first link 32 and the other end side of the upper first link 35 are pivotally supported by the cutter support portion 37 so as to be adjacent to each other vertically. Has been. A disk-shaped cutter C for cutting the buried tube T is attached to the outside of the cutter support portion 37 so as to be rotatable. A pivot shaft 33p that projects in a direction substantially parallel to the pivot shafts 32p and 35p is provided on the other end side of the lower second link 33, and a pivot shaft 33p that projects in a direction substantially parallel to the pivot shaft 32p is provided on the other end side of the upper second link 36. The pivot shafts 36p that project in a direction substantially parallel to the pivot shaft 33p are integrally provided. With these pivot shafts 33p, 36p, the other end side of the lower second link 33 and the other end side of the upper second link 36 are pivotally supported by the roller support portion 38 so as to be adjacent to each other vertically. Has been. A roller 38r that is in contact with the inner peripheral surface of the buried pipe T and rolls is attached to the outside of the roller support portion 38 so as to be rotatable.

  Note that gear portions 32g, 33g, 34g, and 35g are formed around the pivot shafts 32p, 33p, 34p, and 35p, respectively. The gear portion 32g and the gear portion 35g are meshed with each other in the cutter support portion 37, and the gear portion 33g and the gear portion 36g are meshed with each other in the roller support portion 38. For this reason, since the lower first link 32 and the upper first link 35 and the lower second link 32 and the upper second link 35 are interlocked with each other at the time of expansion / contraction of the cutter pressing portion 3, the cutter support portion 37 and The roller support portion 38 can be stably moved in the radial direction in a state where the predetermined posture is constantly maintained.

  The cutter pressing portion 3 is provided with a moving mechanism portion 4 that moves the upper pivot portion 34 by an equal distance in the opposite direction when the lower pivot portion 31 is moved in one direction on the axis O. As shown in FIGS. 1 and 4, the moving mechanism portion 4 includes an inner square tube portion (first tube portion) 41 that forms a tubular body having a quadrangular cross-sectional view provided integrally with the outer shaft 21, and an upper pivot. A telescopic slide mechanism is provided in which an outer rectangular tube portion (second tube portion) 42 provided integrally with the support portion 34 is engaged in a telescopic manner. As described above, since the rectangular tube portions are engaged with each other in a nested manner, the inner rectangular tube portion 41 and the outer rectangular tube portion 42 are not relatively rotatable around the axis O and are movable in the direction of the axis O. It is said that. Note that a pin 41p is projected from the inner square tube portion 41, and this pin 41p projects into a long hole 42h formed in the outer square tube portion 42 so as to extend in the vertical direction. This prevents the inner square tube portion 41 and the outer square tube portion 42 from coming off.

A flange 41f is formed at the upper end portion of the inner inner cylinder portion 41, and the flange 41f and the flange 21f formed at the lower end portion of the outer shaft 21 are integrally connected and fixed. Further, a flange 42f is formed at the lower end portion of the outer rectangular tube portion 42, and the flange 42f and the flange 34f formed at the upper end portion of the upper pivot support portion 34 are integrally connected and fixed. That is, the outer shaft 21 and the upper pivot support portion 34 are connected to each other by the moving mechanism portion 4 so as not to be relatively rotatable around the axis O and to be relatively movable in the direction of the axis O. Therefore, the rotational driving force from the outer shaft 21 can be accurately transmitted to the upper pivot portion 34 while allowing the upper pivot portion 34 to move in the vertical direction with respect to the outer shaft 21.
Note that a spring s for supporting a part of the weight of the upper pivotal support portion 34 and the like by the shaft portion 2 is appropriately provided between the flange 41f and the flange 42f.

  In such a cutter pressing part 3, the lower first link 32, the lower second link 33, the upper first link 35, the upper second link 6, the lower pivot part 31, the upper pivot part 34, the cutter support part 37, and As described above, each component such as the roller support portion 38 is connected to each other by pivot shafts 31p to 36p extending in a direction substantially orthogonal to the axis O so as to be rotatable. For this reason, these components can be displaced with respect to each other in the direction of the axis O and in the radial direction, but cannot be displaced with respect to each other around the axis O. That is, when the rotational driving force from the shaft portion 2 is transmitted to the upper pivot support portion 34, the cutter pressing portion 3 is integrally rotated around the axis O.

A procedure for cutting the buried pipe T using the pipe cutting apparatus A having such a configuration will be described below.
First, the length of the shaft portion 2 is adjusted in advance to the scheduled cutting position by adding the shaft portion 2 or the like. Then, the inner shaft 21 is rotated in a predetermined direction so that the cutter pressing portion 3 is sufficiently contracted, and the tube cutting device A is attached to the buried tube T. At this time, the fixing portion 1 is attached and fixed to the upper end of the embedded tube T while appropriately adjusting the tightness of the fixing bolt 12v so that the axis of the shaft portion 2 and the axis of the embedded tube T coincide with each other.

  Next, the shaft portion 2 is rotated by operating the motor M. When the rotation is stabilized, the brake 17 is operated to expand the cutter pressing portion 3 in the radial direction, and the cutter C and the roller 38r are connected to the inner peripheral surface of the buried tube T. Press on. At this time, the lower pivot 31 is moved upward, but the upper pivot 34 is moved downward by an equal distance by providing the moving mechanism 4. For this reason, the cutter C is immovable in the direction of the axis O, and rotates around the axis O while being pressed against the inner peripheral surface of the buried pipe T from a direction substantially orthogonal to the axis O. That is, an annular groove is formed on the inner peripheral surface of the buried pipe T at a predetermined position in the axis O direction. At this time, since the inner peripheral surface on the opposite side of the cutter C is pressed by the roller 38r, the pressing force of the cutter C can be further increased and the rotation of the cutter pressing portion 3 can be stabilized.

  While operating the brake 17 as it is, that is, while pressing the cutter C against the inner peripheral surface, the cutter pressing portion 3 is rotated. As a result, the groove gradually becomes deeper, and the buried tube T is finally cut into a circular shape.

  In the tube cutting device A according to the present embodiment, the fixed portion 1 fixed integrally with the embedded tube T near the opening of the embedded tube T, and the fixed portion 1 with the axis O being the same as the axis of the embedded tube T. The cutter C is moved in the radial direction of the shaft portion 2 while keeping the position of the shaft portion 2 extending downward from the inside of the tube and the axis O direction of the cutter C, and pressed toward the inner peripheral side of the buried tube T. And a motor M that transmits rotational driving force from the fixed portion 1 side to the shaft portion 2 and rotates the cutter C around the axis O of the shaft portion 2 together with the cutter pressing portion 3. Yes. Since such a configuration is adopted, the fixing portion 1 is fixed at a position in the vicinity of the opening of the buried pipe T, and the cutter pressing portion 3 is inserted into the buried pipe T from the opening via the shaft portion 2. By rotating, the buried pipe T can be cut into a ring shape. Therefore, the configuration of the tube cutting device A can be simplified without providing an actuator in the buried tube T and without moving the shaft portion 2 in the radial direction, while contributing to weight reduction and ease of maintenance. The substantially cylindrical buried tube T can be easily and accurately cut from the inside.

  Further, the cutter pressing portion 3 is relatively movable in the direction of the axis O, and is attached to the lower pivot portion 31 and the upper pivot portion 34 that are respectively attached back and forth on the shaft portion 2, and the lower pivot portion 31 has one end side. The lower first link 32 and the lower second link 33 that are pivotally supported and the other end side extends obliquely rearward, respectively, and one end side is pivotally supported by the upper pivotal support portion 34 and the other end side is obliquely forward. The extended upper first link 35 and upper second link 36, the cutter support portion 37 that pivotally supports the other end of the lower first link 32 and upper first link 35, and the lower first link 33 and a roller support portion 38 that pivotally supports the other end side of the upper second link 36, and the cutter C attached to the cutter support portion 37 is expanded or contracted in the radial direction by the inside of the buried tube T. 4-bar link type that allows contact and separation with the circumferential side It is a scaled system. Therefore, it is possible to expand and contract in the radial direction only by changing the distance between the lower pivot 31 and the upper pivot 34. Therefore, as a simple configuration, the cutter C can be easily and accurately brought into contact with and separated from the inner peripheral side of the embedded tube T, and the embedded tube T is cut while maintaining the pressing force of the cutter C at a predetermined level. Can continue.

  The cutter pressing portion 3 is provided with a moving mechanism portion 4 that moves the upper pivot portion 34 by an equal distance in the opposite direction when the lower pivot portion 31 is moved in one direction on the axis O. ing. For this reason, the cutter pressing portion 3 can be rotated while the position of the cutter C in the direction of the axis O is held at a predetermined position, and can be accurately cut into a ring shape at the position.

  Further, the shaft portion 2 has a double shaft structure comprising an outer shaft 21 and an inner shaft 22, and the upper pivot portion 34 is attached to the outer shaft 21 so as not to rotate around the axis O and to move in the direction of the axis O. On the front side of the inner shaft 22, a male screw portion 22v that is screwed into a female screw hole 31n formed in the lower pivot portion 31 is formed, and the inner shaft 22 is connected to the outer shaft 21 and the upper pivot portion 34. The lower pivot 31 is moved by rotating it in a direction opposite to the direction in which it rotates integrally. Thus, by rotating the inner shaft 22 independently of the outer shaft 21, the lower pivot portion 34 and the upper pivot portion 34 are moved relative to each other, so that no other actuator or the like is required. Moreover, as a simple configuration, the cutter pressing portion 3 can be expanded and contracted easily and accurately.

  Further, the moving mechanism section 4 has an inner rectangular tube portion 41 that forms a cylindrical body in a sectional view provided on the outer shaft 21 and a cylindrical body in a sectional view that is provided in the upper pivot support portion 34. Since the outer square tube portion 42 is a telescopic slide mechanism engaged in a telescopic manner, the outer shaft 21 and the upper pivot support portion 34 are relatively non-rotatable around the axis O and relatively movable in the direction of the axis O. Can be connected to each other. Therefore, as a simple configuration, the rotational driving force from the fixed portion 1 side can be accurately transmitted to the cutter pressing portion 3 while the upper pivot support portion 34 can be moved in the direction of the axis O.

It is a side view showing a tube cutting device concerning one embodiment of the present invention. It is a top view which shows the cutter press part of the same pipe cutting device. It is a side view which shows the cutter press part of the same pipe cutting device. It is a figure which shows the moving mechanism part of the tube cutting device, (a) is a side view, (b) is sectional drawing seen planarly.

Explanation of symbols

A pipe cutting device 1 fixing part 2 shaft part 21 outer shaft 22 inner shaft 22v male screw part 3 cutter pressing part 31 lower pivot part (first pivot part)
31n female screw hole 32 lower first link (first link)
33 Lower second link (second link)
34 Upper pivot (second pivot)
35 Upper first link (third link)
36 Upper second link (fourth link)
37 Cutter support part (first lateral movement part)
38 Rotor support part (second lateral movement part)
4 Movement mechanism part 41 Inner side square cylinder part (1st cylinder part)
42 Outer corner cylinder (second cylinder)
M motor (actuator)
T buried pipe (pipe)

Claims (4)

A tube cutting device for cutting a substantially cylindrical tube into a ring shape from the inner periphery side,
A fixing portion fixed integrally with the tube at a position near the opening of the tube;
A shaft portion extending substantially in front of the tube from the fixed portion with an axis substantially the same as the tube axis;
A cutter pressing portion that moves the cutter in the radial direction of the shaft portion and presses it toward the inner peripheral side of the tube while maintaining a predetermined position in the axial direction of the shaft portion of the cutter that cuts the tube; ,
An actuator for transmitting a rotational driving force from the fixed portion side to the shaft portion and rotating the cutter around the axis of the shaft portion together with the cutter pressing portion;
A tube cutting device comprising: The cutter pressing part is
First and second pivots attached to each other on the shaft part so as to be relatively movable in the axial direction;
A first link and a second link, each of which is pivotally supported at one end by the first pivot and the other end extends obliquely rearward;
Third and fourth links each having one end side pivoted to the second pivot portion and the other end side obliquely extending forward,
A first lateral movement unit that pivotally supports the other end side of each of the first and third links;
A second laterally moving portion that pivotally supports the other end sides of the second and fourth links,
4 and enabling the cutter attached to at least one of the first and second laterally moving portions to be in contact with and separated from the inner peripheral side of the tube by expanding and contracting in the radial direction. It is a link type expansion / contraction device,
The cutter pressing unit includes a moving mechanism unit that moves one of the first and second pivots in one direction on the axis and moves the other in the opposite direction by an equal distance. The tube cutting device according to claim 1, wherein the tube cutting device is provided. The shaft portion has a double shaft structure including an outer shaft and an inner shaft, and the second pivot support portion is attached to the outer shaft so as not to be relatively rotatable around the axis and movable in the axial direction. In addition, on the front side of the inner shaft, a male screw portion that is screwed into a female screw hole formed in the first pivot support portion is formed,
3. The tube according to claim 2, wherein the first pivot portion is moved by rotating the inner shaft independently of the outer shaft that rotates integrally with the second pivot portion. 4. Cutting device. The moving mechanism portion includes a first cylindrical portion that forms a cylindrical body in a sectional view provided integrally with the shaft portion, and a cylindrical shape in a sectional view that is provided integrally with the second pivotal support portion. The tube cutting device according to claim 2 or 3, wherein the second cylindrical portion constituting the body is a telescopic slide mechanism engaged in a telescopic manner.

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