JPH02217594A - Free-cross-section shield construction and shield machine - Google Patents

Abstract

PURPOSE:To freely form the cross section of excavated face by a method in which a center cutter is turned around the first shaft, an epicyclic cutter is turned around the second shaft, and while controlling the turning angles of them, the epicyclic cutter is rotated around the third shaft. CONSTITUTION:The center (third shaft) P3 of a drive shaft 17 passing through the center of an epicyclic cutter 22 is biased only by the length from the center (second shaft) P2 of a rotary shaft 15. The second shaft P2 is turned to contact or separate the third shaft P3 with or from the center P1 (first shaft) of a cutting wheel 2. The shaft 15 is properly operated by the action of a gear motor 24 to enable the distance from the center P1 of the wheel 2 to the center P3 of the cutter 22 to vary within a fixed range. Not only round but also desired cross sections of tunnels can thus be excavated continuously.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a free section shield construction method and a shield machine that can continuously excavate not only circular tunnels but also tunnels with irregular cross-sectional shapes other than circular shapes. be.

[Conventional technology]

In the conventional shield construction method, a cutter placed on the front of the shield machine is rotated around the central axis of the shield machine to excavate the front face in the direction of propulsion of the shield machine, and the shield machine is propelled by the excavated amount. It is common to dig by adding segment rings.

However, since such a construction method excavates only by rotating the front cutter, the excavation cross section is limited to a circular shape, and it is difficult to excavate a tunnel with a non-circular cross section. On the other hand, most of the actual cross-sectional shapes of tunnels such as sewers, power lines, subways, etc. are other than circular, so
Conventionally, it has been necessary to excavate a large circular cross-section that includes this irregular cross-sectional shape, which has been accompanied by inconveniences such as increased costs.

Therefore, the present applicant has previously proposed a shield method and a shield machine that can continuously excavate a cross section of a desired shape other than circular (see Japanese Patent Application No. 81829/1983). This is because the center cutter 101 is moved along the horizontal axis (
By rotating the center cutter 1 around the
A side cutter 102 disposed on the outer circumferential side of the circular portion 01 is excavated by rotating the side cutter 102 around the horizontal rotation axis 104 and revolving around the center cutter 101. 10
2 is a guide frame 10 having a similar shape to the desired excavation cross-sectional shape.
It is designed to revolve along 3.

According to such a shield construction method and shield machine, by appropriately setting the shape of the guide frame, it is possible to dig a tunnel having an irregular cross-sectional shape similar to the guide frame.

[Problem to be solved by the invention]

Since the above shield construction method and shield machine revolve the side cutter along a specially shaped guide frame, the following problems remain.

(1) In order to maintain the engagement between the rotating shaft 104 of the side cutter 102 and the circumferential surface of the guide frame 103, an engagement maintaining means such as the air cylinder 105 is required, so the structure becomes relatively complicated.

(2) Since the end of the rotating shaft 104 of the side cutter 102 is pressed against the guide frame 103, the rotating wheel 104
4, a large bending moment acts on the rotating shaft 104.
Not only that, but also the bearings and the like that support the rotating shaft 104 are required to have great strength.

(3) The revolution locus of the side cutter 102 is maintained by the engagement between the rotation shaft 104 of the side cutter 102 and the guide frame 103, and the revolution locus is uniquely determined by the shape of the guide frame 103. In this case, the orbit of the side cutter 102, that is, the cross-sectional shape of the excavation cannot be changed.

In view of these circumstances, the present invention makes it possible to obtain an irregularly shaped excavation cross-sectional shape with a simple structure, reduces the burden on the strength of the rotary shaft of the cutter, etc., and allows the above-mentioned cross-sectional shape to be easily changed. The purpose of the present invention is to provide a free section shield construction method and a shield machine that can be used.

[Means to solve the problem]

The shield construction method of the present invention is a shield construction method in which excavation is carried out by rotating a cutter around a predetermined axis and propelling it in a direction substantially parallel to the axis. A planetary cutter is made to revolve around a second axis that revolves around the first axis, and the planetary cutter is made to revolve around the first axis while drawing a trajectory corresponding to a desired cross-sectional shape. The planetary cutter is rotated about a third axis parallel to the first axis and the second axis, and the planetary cutter is rotated about a third axis parallel to the first axis and the second axis. It is something that makes you

In addition, as a shield machine that realizes this shield construction method,
A propulsion means for propelling the entire device, a center cutter that rotates around a first axis substantially parallel to the direction of propulsion, a large rotating body that rotates about the first axis, and rotationally driving the large rotating body and the center cutter. a first driving means for rotating the small rotating body; a small rotating body attached to the large rotating body so as to be rotatable about a second axis parallel to the first axis; and a second driving means for rotationally driving the small rotating body. a planetary cutter attached to the small rotating body so as to be rotatable around a third axis parallel to the first support and the second axis; and third driving means for rotationally driving the planetary cutter. Some cutters are equipped with a drive control system that controls the driving of the large rotating body and the small rotating body so that the planetary cutter revolves around the first axis while drawing a locus according to a preset cross-sectional shape.

[For production]

According to the shield construction method and shield machine configured as described above, the central circular part of the front surface of the excavation is excavated by the rotation of the center cutter, and the outer peripheral part is excavated by the second circular part revolving around the first axis while the planetary cutter rotates. It is excavated by revolving around the axis.

Furthermore, since this orbit corresponds to a desired excavation cross-sectional shape set in advance, the peripheral edge shape of the outer circumferential portion excavated by the planetary force pig has the desired excavation cross-sectional shape.

〔Example〕

A first embodiment of the present invention will be described based on FIGS. 1 to 13.

The shielding machine shown in FIGS. 1 to 8 includes a rectangular tube-shaped skin plate 1, and a cutting wheel (large rotating body) 2 is built into the tip of the skin plate 1. This cutting wheel 2 is connected to the front end (left end in FIG. 2) of a center shaft 3 extending in the direction of propulsion of the shield machine, so that both rotate together.

The outer periphery of the cutting wheel 2 and the end of the center shaft 3 are each supported by the skin plate 1 via bearings 4.5.

The bearing 5 supports radial load and thrust load, and the thrust load acting on the cutting wheel 2 during excavation is sequentially transferred to the center shaft 3, the bearing 5,
and is transmitted to the skin plate 1 via the bearing support frame 6 extending from the skin plate 1. That is, the cutting wheel 2 is supported in both the radial direction and the thrust direction by the bearing 4.5, and can freely rotate around the center shaft 3.

Rear end of the above center shaft 3 (right end in Figure 2)
A large gear 7 is fixed to. On the other hand, the bearing support frame 6 is provided with a gear casing 8, and a wheel drive geared motor (first drive means) 10 is attached to the lid 9 of the gear casing 8. 11 is meshed with the large gear 7. Therefore, by the operation of the wheel drive geared motor 10,
The cutting wheel 2 is rotationally driven.

The cutting wheel 2 is connected to a chamber 1 which is an internal space.
2, and a pair of bosses 1 having cylindrical holes at symmetrical positions sandwiching the center shaft 3 from both sides within the chamber 12.
3 is provided. These bosses 13 have eccentric holes 1
A rotating ring (small rotating body) 15 having a rotary ring 15 is rotatably inserted through a bearing 16, and a planetary cutter drive shaft 17 is rotatably inserted into the eccentric hole 14 through a bearing 18. A gear 19 is formed at the rear end of this planetary cutter drive shaft 17, and a planetary cutter 22 having a cutter bit 31 on the entire outer periphery of the front end is fixed to the front end.

A rotating wheel M20 is attached to the rear end of the rotating wheel 15,
This rotary wheel M20 is equipped with a geared motor for driving the planetary cutter (
A third driving means) 21 is attached, and a pinion 111 attached to the output shaft of the geared motor 21 for driving the planetary cutter is meshed with the gear 19. Therefore, the ahl cutter 22 is rotationally driven by the operation of the geared motor 21 for driving the planetary cutter. Further, a gear 23 having teeth is formed on the outer peripheral surface of the rear end portion of the rotary ring 15 over the entire circumference thereof.

Further, a rotary wheel drive device 26 is attached to the center shaft 3 via a bracket 27. This rotary wheel drive device 26 includes a rotary wheel drive geared motor (second
drive means) 24, a pinion 112 attached to the output shaft of this geared motor 24, an idle gear 25 meshed with this pinion 112, etc., and the idle gear 25 is connected to a gear 23 at the rear end of the rotating wheel 15. are engaged. Therefore, the rotation wheel 15 is rotationally driven via the binion 112 and the idle gear 25 by the operation of the rotary wheel drive geared motor 24 .

A planetary cutter 2 is installed on the front of the cutting wheel 2.
A face plate 30 is provided in which only the installation portion of the cutter 2 is cut out, and the front surface of the planetary cutter 22 and the front surface of the cutting wheel 2 (that is, the front surface of the face plate 30) are arranged on substantially the same level. . By arranging this face plate 30, only the planetary cutter 22 is prevented from protruding forward significantly, and the face (the surface where earth and sand is cut by the shield machine) is stabilized, thereby ensuring smooth excavation work of the shield machine. It looks like this.

A part of the face plate 30 has the planetary cutter 22
Similarly, cutter pits for cutting earth and sand) 31. L
312 are arranged in large numbers. Therefore, this face plate 30 and the cutter pit 31 disposed on its surface.
1 and 312 constitute a center cutter that rotates around the center shaft 3.

Further, the face plate 30 and the cutting wheel 2 are provided with a plurality of windows 32, and these windows 32 communicate with the chamber 12 of the cutting wheel 2. After being guided into the chamber 12, it is conveyed rearward by a screw conveyor (not shown) provided inside the center shaft 3, and then discharged outside the machine by a belt conveyor (not shown) or the like (not shown). It has become.

In addition to the above, a slip ring 33 is provided on the outer periphery of the center shaft 3 for transmitting power (electricity or hydraulic power) to the rotary wheel drive geared motor 24 and the planetary cutter drive geared motor 21. A shield jack (propulsion means) 34 for propelling the shield machine and an erector 35 for laying the segment 50 on the inner wall of the excavated tunnel are disposed.

Furthermore, a drive control system as shown in FIG. 9 (block diagram) is provided inside this shield machine.

Cutting wheel rotational position detector 80 shown in the figure
The reference rotational position of the cutting wheel 2 is determined, and the amount of rotational displacement (for example, angle) of the cutting wheel 2 with respect to this reference rotational position is detected. The reference rotation position is set, for example, to a position where the center P2 (see FIG. 5) of one of the two rotating wheels J5 is directly above the center P1 of the cutting wheel 2.

The rotating wheel rotational position detector 84 determines a reference rotational position of the rotating wheel 15 and detects the amount of rotational displacement of the rotating wheel 15 with respect to this reference rotational position. As the reference rotation position, for example, a position where the center P3 of the planetary cutter 22 approaches the center P1 of the cutting wheel 2 is set.

The calculation device 81 has a built-in program that calculates the amount of rotational displacement of the rotary wheel 15 that is necessary for the amount of rotational displacement of the cutting wheel 2 when obtaining a predetermined excavation cross section. The required amount of rotational displacement of the rotary wheel 15 is instantaneously calculated based on the amount of rotational displacement of the cutting wheel 2 inputted from the position detector 80. The contents of the calculation will be described in detail later.

The comparator 82 compares the amounts of rotational displacement inputted from the arithmetic device 81 and the rotary wheel rotational position detector 84, and controls the rotary wheel drive geared motor controller so that the rotary wheel 15 rotates in a direction in which both are equal. It gives a command to rotate forward or reverse, and when the difference between the two disappears, it gives a command to stop.

Note that when a hydraulic motor is used as the geared motor 24 for driving the rotating wheels, a servo valve may be used as the geared motor controller 83 for driving the rotating wheels.

Next, the operation of this shield machine will be explained.

First, the planetary cutter drive geared motor 21 is operated to rotate each of the two planetary cutters 22, and then the wheel drive geared motor 10 is driven to rotate the cutting wheel 2.

When the shield jack 34 is gradually extended, the tip of the shield jack 34 comes into contact with the laid segment 50, and the entire shield machine moves forward by taking a propulsive reaction force from the segment 50. In this state,
Since the cutting wheel 2 is rotating, the cutter bits 311 and 312 provided on the face plate 30
The cutter bit 31 provided on the planetary cutter 22 also cuts the earth and sand by rotating and revolving the planetary cutter 22 while rotating in a circular motion.

At this time, if the rotary wheel drive geared motor 24 is stopped, the earth and sand in front of the cutting wheel 2 will only be cut, and the earth and sand at a part of the corner of the skin plate 1 will not be cut at all. By driving the wheel drive geared motor 24, the rotating wheel 15 is rotationally driven via the binion 112 attached to its output shaft and the idle gear 25, so that the planetary cutter 2
The cutter bit 31 provided on the outer periphery of the skin plate 1 reaches a part of the corner of the skin plate 1, making it possible to excavate areas other than the above-mentioned circular shape.

The specific movement will be explained. As shown in FIG. 5, the planetary force lid drive shaft 1 passes through the center of the planetary cutter 22.
The center (third axis) P3 of the rotating shaft 15 is eccentric from the center (second axis) P2 of the rotating shaft 15 by a distance g1. Therefore, when the rotating wheel 15 rotates, the planetary force lid drive shaft 17
The center P3 of is the center of cutting wheel 2 (
1st axis) approaches and separates from Pl, resulting in the planetary cutter 2
2 approaches and separates from the center P1 of the cutting wheel 2.

Therefore, by operating the rotary wheel drive geared motor 24 and appropriately driving the rotary wheel 15, the center P1 of the cutting wheel 2 can be moved from the center P3 of the planetary cutter 22 to the center P3 of the planetary cutter 22.
The distance to can be changed within the range shown by the following formula.

#2-+ll≧g≧x2-Q1 Here, g2: Center P of cutting wheel 2
1 to the center P2 of the rotating wheel 15 = distance from the center P1 of the cutting wheel 2 to the center P3 of the planetary cutter 22 When cutting a square cross section as in this embodiment, the planetary cutter 22 is square The rotary wheel 15 may be rotated to a position where the distance a is the largest while passing through a part of the corner of the cross section.

For example, as shown in FIG. 7, in a state where a pair of rotating wheels 15 are located diagonally, each rotating wheel 15 is
By rotating from the position shown in the figure to a position reversed by 1800 degrees, the excavation area can be extended to a part of the corner of the rectangle. Conversely, when the cutting wheel 2 has rotated 900 times from the position shown in FIG. 5, as shown in FIG. Just rotate it. That is, by changing the rotational position of the rotary wheel 15 according to the rotation angle of the cutting wheel 2, a predetermined excavation cross section can be automatically obtained.

Therefore, in the drive control system shown in FIG. 9 above,
First, the calculation device 81 calculates the amount of rotational displacement of the rotating wheel 15 necessary to obtain a desired cross-sectional shape for each rotational position of the cutting wheel 2, and this calculated amount of rotational displacement is combined with the amount of rotational displacement actually detected. By controlling the rotational drive of the rotating wheel 15 based on the comparison with the rotational displacement amount, the planetary cutter 2
2 can be caused to revolve around the center P1 while drawing a trajectory corresponding to a desired excavation cross-sectional shape.

The rotation range of the rotating shaft 15 is shown in Fig. 5 and Fig. 7.8.
As is clear from the figure, it is sufficient to rotate forward and reverse within a rotation range of 1800 degrees.

Therefore, according to this shield machine and the shield construction method based on the shield machine, various excavated cross-sectional shapes can be automatically obtained in the container by appropriately converting the program installed in the computing device 81.

A few examples will be explained below.

A small circle 90 indicated by a dashed line in FIG. 10 represents the center P1 of the cutting wheel 2 and center shaft 3
This is the excavation cross-sectional shape obtained when the cutting wheel 2 is rotated with the center P2 of the planetary cutter 22 closest to the center P2.

Also, the great circle 91 shown in the same figure represents the cutting wheel 2 with the center 7P2 of the planetary cutter 22 farthest away from the center P1 of the cutting wheel 2.
This is the excavation cross-sectional shape obtained when rotating.

Therefore, the excavation cross section obtained by controlling the orbit of the planetary cutter 22 is limited to the range surrounded by the small circle 90 and the large circle 91. For example, the rectangular shape 92 indicated by a solid line in FIG. 10 illustrates the outer peripheral shape of the rectangular tube-shaped skin plate 1, but as is clear from the figure, the rectangular shape 92 is within the above-mentioned range. ing.

FIG. 11 is an example in which the horseshoe shape 93 is kept within the above-mentioned range. In this case, the skin plate 1 having the outer circumferential shape of the horseshoe shape 93 is used, and the computing device 81 runs a program that causes the orbit of the planetary cutter 22 to match the horseshoe shape.
You can incorporate it into

In addition, FIG. 12 shows an oval outer circumferential shape 94 within the above-mentioned range.
This is an example that includes.

As described above, according to the shielding machine and the shielding method based thereon, it is possible to simply change the program of the computing device 81 and change the shape of the skin plate 1 to a shape corresponding to the program of the computing device 81. Various excavation cross sections can be easily obtained with one shield machine.

Furthermore, even better effects can be obtained by performing so-called overcutting in this shield machine. This overcut will be explained based on FIG. 13.

In the figure, hatching portions A to D shown on the outside of the outer peripheral shape 92 of the skin plate 1 are overcut zones, respectively. During normal excavation, a program built into the computing device 81 controls the outer periphery of the planetary cutter 22 to move along the outer periphery shape 92. , a program for moving the planetary cutter 22 along an outer circumferential shape 92a, which is the outer circumferential shape 92 of the skin plate 1 plus a hatching part A, and an outer circumferential shape 92b, which is an outer circumferential shape 92b in which a hatching part shown as B is added, and a hatching part shown in C is added. outer peripheral shape 92
Outer circumferential shape 92 with hatched parts indicated by c1 and D
A program for moving the planetary cutter 22 along d is incorporated.

At the same time, by loading the arithmetic unit 81 with a selection circuit for arbitrarily selecting one of the five programs described above, one of the five types of excavation cross sections can be selected as needed. One can be arbitrarily selected, and thereby the effect of overcutting as described below can be obtained.

For example, if you select an excavation cross-section program that matches the outer circumference shape 92 of skin plate 1 and switch to an excavation cross-section program that matches the outer circumference shape 92a during excavation, the upper earth and sand of skin plate 1 It will be excavated beyond the outer circumference (overcut).

When excavation is continued in this state, a cross-sectional space corresponding to the hatching part A is formed in the upper part of the skin plate 1, and the frictional resistance between the skin plate 1 and the earth and sand in this part is reduced.

On the other hand, since the lower part of the skin plate 2 is still in contact with the earth and sand, the difference between the frictional resistance at the upper part of the skin plate 1 and the frictional resistance at the lower part of the skin plate 1 gradually increases. For this reason, the shield machine tries to escape to the side with lower frictional resistance, that is, to the upper side, and as a result, the direction of propulsion of the shield machine gradually becomes upward.

In this way, since the shield machine tries to change direction in the direction of the overcut, by arbitrarily selecting an excavation cross-section program that matches the outer peripheral shapes 92a to 92d shown in FIG. It can be easily changed vertically, horizontally, and horizontally, making it possible to dig around sharp curves. Furthermore, by incorporating a program that can overcut each of the four corners, posture righting control against rolling (inclination of the shield machine with respect to a horizontal or vertical line) can be easily performed.

Next, a second embodiment will be described based on FIGS. 14 and 15. Here, the rotary wheel 15 is rotationally driven by a hydraulic cylinder 40 instead of the rotary wheel drive device 26 in the previous embodiment.

Specifically, a cylinder support column 41 is provided on the belly plate 2a of the cutting hole 2, and a cylinder coupling bracket 421 is provided on the outer periphery of the end of the cylinder support column 41 and the rotary ring 15.
422 is provided, and both brackets 421.4
Both ends of a hydraulic cylinder 40 are connected to each of the hydraulic cylinders 22 in a rotationally neutral manner.

According to such a structure, the rotating wheel 15 can be driven in forward and reverse directions by expanding and contracting the hydraulic cylinder 40. In the case of this embodiment, although the rotation range of the rotating wheel 15 is narrowed, there is an advantage that the structure is very simple. As the drive control system in this embodiment, a hydraulic cylinder controller (servo valve) may be used as the rotary wheel drive geared motor controller 83 in FIG.

Note that the shield construction method and shield machine in the present invention are not limited to the above embodiments, but can also take the following embodiments as an example.

(1) In the present invention, the number of planetary cutters is not limited, and one or three or more may be provided depending on the case.

(2) In the above embodiment, the cutting wheel (large rotating body) 2 and the center cutter are rotated together, but they may be rotated separately.

(3) In the embodiment described above, the amount of rotational displacement of the rotating shaft (small rotating body) 15 is constantly detected and calculated. Control may also be performed to periodically correct the angle during excavation.

〔Effect of the invention〕

As described above, according to the shield construction method of the present invention, the central circular part at the front in the propulsion direction is excavated by the rotation of the center cutter, and the outer peripheral part is excavated by the second part which revolves around the first axis while rotating the planetary cutter. By revolving around the axis of the tunnel, it is possible to excavate in any shape, and as a result, it is possible to continuously excavate a tunnel with a desired cross-sectional shape, not just a circular one. Moreover, by simply changing the revolution angle of the planetary force/vine around the second axis with respect to the revolution angle of the second axis around the first axis, the orbit of the planetary force/vine around the first axis, That is, the cross-sectional shape of the excavation can be easily changed.

Further, according to the shielding machine of the present invention, the center cutter rotates around the first axis, and the small rotating body revolves around the first axis, and the center cutter rotates around the second axis and rotates around the third axis. The rotating planetary cutter allows you to obtain any desired excavation cross-sectional shape, not just circular, with a simple structure.
The above-mentioned excavation cross-sectional shape can be easily changed by simply changing the drive control details of the large rotary body and the small rotary body. Further, there is less burden on the rotation shaft of the planetary cutter in terms of strength.

[Brief explanation of the drawing]

Fig. 1 is a front view of a shield machine according to the first embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the line ■-■ in Fig. 1, Fig. 3 is a cross-sectional view taken along the line ■-■ in Fig. 2, and Fig. 4 is a sectional view taken along the line ■-■ in Fig. 2. The figure is a sectional view taken along the line IV-IV in Fig. 2, Fig. 5 is a sectional view taken along the line V-v in Fig. 2, Fig. 6 is a sectional view taken along the line Vl-Vl in Fig. 2, and Fig. 7 shows the Jffl cutter. Figure 9 is a cross-sectional view equivalent to Figure 5 showing a state where the cutter is on a diagonal line, Figure m8 is a cross-sectional view equivalent to Figure 5 showing a state where the planetary cutter is on both sides, and Figure 9 is a drive control system installed in the shield machine. 10 to 13 are diagrams showing examples of excavation cross-sectional shapes set in the shield machine, and FIG. 14 is a cross-sectional front view of the shield machine in the second embodiment. 15 is a sectional view taken along the line X--XV in FIG. 14, FIG. 16 is a sectional side view of the conventional shield machine, and FIG. 17 is a sectional view taken along the line X--XVn in FIG. 16. 2... Cutting wheel (large rotating body), 10...
・Gard motor for wheel drive (first drive stage),
15... Rotating wheel (small rotating body), 21... Geared motor for driving the planetary cutter (third drive means) 22... Planetary force pig, 24... Geared' motor for driving the rotating wheel (
second driving means), 30...face L,...-t(
), 311, 312... Cutter pit (consists of a center cutter), 8 (1...
Cutting wheel rotation position detector (constituting the drive control system), 81... Arithmetic device (constituting the drive control system), 82
... Comparator (constituting drive control system), 83... Geared motor controller for rotating wheel drive (constituting drive control system), 8
4...Rotating wheel rotation position detector (configuring the drive control system).

Claims (1)

[Claims] 1. In a shield construction method in which excavation is performed by rotating a cutter about a predetermined axis and propelling it in a direction substantially parallel to the axis, the center cutter is rotated about a first axis and A planetary cutter is caused to revolve around a second axis that revolves around the first axis, and the planetary cutter is caused to revolve around the first axis while drawing a trajectory corresponding to a desired cross-sectional shape. controlling the revolution angle of the planetary cutter around the second axis with respect to the revolution angle of the second axis around the axis, and rotating the planetary cutter around a third axis parallel to the first axis and the second axis. A free section shield construction method characterized by rotation. 2. A propulsion means for propelling the entire device, a center cutter that rotates around a first axis substantially parallel to the direction of propulsion, a large rotating body that rotates about the first axis, and this large rotating body and center cutter. a first driving means for rotationally driving;
a small rotating body attached to the large rotating body so as to be rotatable about a second axis parallel to the first axis; a second driving means for rotationally driving the small rotating body; a planetary cutter mounted to be rotatable around a third axis parallel to the first axis and the second axis; a third driving means for rotationally driving the planetary cutter; and a third drive means for rotating the planetary cutter; A free section shielding machine comprising: a drive control system that controls the driving of a large rotating body and a small rotating body so that the large rotating body and the small rotating body revolve around the first axis while drawing a trajectory according to a cross-sectional shape.