JPH09250248A - Recessed part formation method and cutting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently form a recessed part in relation to a structure. SOLUTION: Wire insertion grooves are hollowed out along outer circumferential lines of recessed part formation areas 111 developed on the top surface of a ballast 101. A column part is formed in the recessed part formation area 111 by boring a wire insertion groove. A cutting part 27α of a cutting wire 27 provided in a cutting device 11 is inserted into the wire insertion groove so as to be wound around the outer circumference of the base part of the column part. A drive pulley 21 is slidably moves, while turning round the cutting wire 27 so that the column part is cut. The column part cut from the ballast 101 is removed from the recessed part formation area 111 as that the recessed part 105 is formed on the top face of the ballast 101 matched with a sleeper trace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a recess forming method used in a construction in which an anti-vibration sleeper system is applied to an existing railway track, and a cutting device used in the method.

[0002]

2. Description of the Related Art FIG. 7 (a) is a diagram showing a railway track,
A concrete roadbed 101 as a structure is cast on a roadbed. The drainage groove 102 is recessed in the central portion of the roadbed 101 along the extending direction thereof, and divides the roadbed 101 into right and left. A pair of short sleepers 103A is the base 101
Are fixed to both sides of the drainage groove 102 on the upper surface of the rail, and a pair of rails 104 are arranged in parallel along the extending direction of the roadbed 101 on the sleeper 103A.

In recent years, railroad tracks have been proposed that incorporate a vibration-proof sleeper system. That is, as shown in FIG. 8, the recess 105 is formed on the upper surface of the roadbed 101, and the vibration isolator 106 having a rubber pad or the like is housed in the recess 105. And PC (Prestressed Co
By mounting and fixing the sleeper 103B on the vibration isolator 106, it is intended to absorb vibration when the vehicle is running.

Conventionally, when the above-mentioned vibration-proof sleeper system is applied to an existing railway track, as shown in FIG.
No. 01 was removed, and the roadbed 101 having the above-mentioned recess 105 was re-installed.

[0005]

However, the following problems have occurred in the above-mentioned prior art. (1) For example, in a subway or the like, it is not suitable to operate a heavy machine for removing the roadbed 101 in the narrow premises. Therefore, it is necessary to rely on small-sized equipment and human power of workers, resulting in a long construction period.

(2) It takes a long time to cure and solidify after pouring concrete, which also leads to a longer construction period. (3) Noise, vibration, and dust were generated when the roadbed 101 was crushed, and the working environment of the worker was particularly poor in the subway yard, which is a closed space.

(4) It took a lot of time to discharge the innumerable pieces of the crushed roadbed 101 to the outside of the construction area (for example, aboveground in the case of a subway). As described above, in order to apply the anti-vibration sleeper system to the existing railway track, more specifically, in order to form the recess 105 for accommodating the anti-vibration device 106 on the roadbed 101, Was doing inefficient work.

The present invention has been made by paying attention to the problems existing in the above-mentioned prior art, and its purpose is to use in a recess forming method and the same which can efficiently form recesses in a structure. The present invention is to provide a cutting device.

[0009]

In order to achieve the above object, in the invention of claim 1, a wire insertion groove is bored along an outer peripheral line of a recess forming area in a structure, and a columnar portion is formed in the recess forming area. Forming a wire insertion groove, forming a wire into the wire insertion groove and winding the wire around the columnar portion, and cutting the wire by driving means to cut the columnar portion. And a columnar portion removing step of removing the columnar portion separated from the structure from the recessed portion forming area.

According to a second aspect of the present invention, the columnar portion has a corner portion on its outer periphery, and a chamfering step of chamfering the same corner portion between the wire insertion groove drilling step and the wire winding step is performed. Be prepared.

In the invention of claim 3, the chamfering step is
A corner separating step of making a notch near the corner of the columnar portion in the recess forming area to separate the same corner into a columnar shape, and a corner for removing the corner separated from the columnar portion from the recess forming area. Part removal step.

In the invention of claim 4, in the chamfering step, at least the corner separating step is repeated a plurality of times. According to the invention of claim 5, there is provided a cutting device in which the cutting portions of the cutting wire are arranged symmetrically on both sides of the support base.

According to the invention of claim 6, the wire saw mechanism for arranging the cutting portion on one side of the support base and the wire saw mechanism for arranging the cutting portion on the other side are independent mechanisms. (Operation) In the invention of claim 1 having the above-mentioned configuration, in the wire insertion groove punching step, the wire insertion groove is bored along the outer peripheral line of the recess forming area in the structure, and the columnar portion is formed in the recess forming area. It is formed. In the wire winding step, the cutting wire is inserted and arranged in the wire insertion groove and wound around the columnar portion. In the columnar section cutting process,
The cutting wire is driven by the driving means to cut the columnar portion. In the columnar portion removing step, the columnar portions separated from the construct are removed from the recess forming area.
Therefore, in the concave portion forming area where the columnar portion is removed, a concave portion which is a space corresponding to the outer shape of the columnar portion is formed.

According to the second aspect of the invention, the corners of the columnar portion are chamfered in the chamfering step between the wire insertion groove drilling step and the wire winding step. In the invention of claim 3, in the corner separating step, a notch is made in the vicinity of the corner of the columnar portion in the recess forming area, and the same corner is separated from the columnar portion into a columnar shape. By the corner removing step, the corner separated from the columnar part is removed from the recess forming area. Therefore, the bending radius near the corner of the cutting wire inserted and arranged in the wire insertion groove can be increased.

In the invention of claim 4, the bending radius in the vicinity of the same corner of the cutting wire can be further increased by repeating the corner separating step a plurality of times. In the invention of claim 5, the cutting wire wound around the cutting target cuts the cutting target by running the cutting wire. Here, the cutting portions are arranged at symmetrical positions on both sides of the support base. For this reason,
It is possible to cut the objects to be cut located on both sides of the support table at the same working position substantially at the same time.

According to the sixth aspect of the present invention, the operation of one of the wire saw mechanisms cuts the cutting object located on one side of the support base. Further, the operation of the other wire saw mechanism cuts the cutting object located on the other side of the support base. That is, each cutting wire runs independently.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A recess forming method of the present invention and a cutting device used in the method are embodied as a construction for applying an anti-vibration sleeper system to an existing subway track and an equipment used for the construction. An embodiment will be described. Since the structure of the existing subway track is substantially the same as that of the above-mentioned "prior art" rail track (Fig. 7 (a)), the description thereof will be omitted and the member numbers will be quoted as they are.

First, the overall structure of the cutting device 11 will be described with reference to FIGS. 1 and 2, the right side is the front part and the left side is the rear part. The carriage 12 as a support is provided with a pair of left and right wheels 14 rotatably provided at the front and rear of the lower portion of the frame 13. The two wire saw mechanisms 15A and 15B are provided on the left and right sides of the frame 13, respectively. Then, the cutting device 11 is provided with wheels 14 for rail 104 of the subway track.
Can be moved on the rail 104 by being connected to a starting vehicle (not shown).

Next, the wire saw mechanism 15A, 15B
Will be described. The two wire saw mechanisms 15
Since A and 15B are the same mechanism, the wire saw mechanism 15A arranged on the left side of the carriage 12 will be described, and the wire saw mechanism 15B arranged on the right side will be described only on the difference in their arrangement.

The guide rails 16 are arranged on the frame 13 in the front-rear direction. The guide table 17 is slidably engaged with the guide rail 16. The hydraulic unit 18 is arranged on the rear side of the guide rail 16, and the rod 19α of the hydraulic cylinder 19 is attached to the guide base 1.
7. Therefore, the hydraulic cylinder 19 is expanded and contracted by driving the hydraulic unit 18, and the guide base 17 is linearly moved reciprocally on the guide rail 16 accordingly. The operation of the hydraulic unit 18 is performed via the operation valve 18α on the hydraulic circuit arranged on the side of the frame 13.

The drive unit 20 as a drive means is mounted and fixed on the guide base 17. Drive pulley 2
1 is fixed to an output shaft 20α of the drive unit 20 and is positively rotated by a hydraulic motor 20β.

The arm 22 is fixed to the center of the back surface of the frame 13 and extends vertically downward. The pulley support 22a is provided at the lower end of the arm 22 and extends horizontally toward the left outside of the carriage 12 (the arm 22 of the wire saw mechanism 15B is outside right).

A pair of first guide pulleys 23, which are vertical pulleys, are arranged on the frame 13 near the upper end of the arm 22 and are rotated in the same plane as the drive pulley 21. A pair of second guide pulleys 24, which are vertical pulleys, are arranged at the lower end of the arm 22 and are rotated in a vertical plane orthogonal to the first guide pulley 23. A pair of third guide pulleys 25, which are horizontal pulleys, are arranged on the pulley supporting portion 22α and rotated in a horizontal plane orthogonal to the second guide pulley 24. The receiving roller 26 is arranged between the third guide pulleys 25 on the pulley supporting portion 22α.

Although not shown, the cutting wire 27 is a bead saw constituted by fixing beads made of diamond grains or the like at a predetermined interval on the outer circumference of a steel wire. The cutting wire 27 is wound around the drive pulley 21. The cutting wire 27 is guided vertically downward by the first guide pulley 23. And
The cutting wire 27 is horizontally guided to the left outside of the carriage 12 by the second guide pulley 24, and is connected between the third guide pulleys 25 to form an endless shape. A portion of the cutting wire 27 located between the third guide pulleys 25 is referred to as a cutting portion 27α. The wire saw mechanism 15
The cutting portion 27α of B is arranged on the right side of the carriage 12 at a position symmetrical to the cutting portion 27α of the wire saw mechanism 15A.

As shown in FIG. 4, when the cutting device 11 having the above-mentioned structure is used for cutting work, the hydraulic unit 18 is operated to drive the drive unit 20 (drive pulley 2).
1) is arranged at the rearmost portion on the guide rail 16 (indicated by a chain double-dashed line in the figure). In this state, the cutting portion 27α of the cutting wire 27 is the longest, and the cutting target (11
Make it easy to wrap around 3). Then, the drive pulley 20 is rotated by the drive unit 20 in a state where the cutting portion 27α is wound around the cutting target (113). Therefore, the cutting wire 27 is circulated between the drive pulley 21 and the object to be cut (113) while being guided by the pulleys 23 to 25. At the same time, the hydraulic unit 18
Is operated to move the drive pulley 21 forward along the guide rail 16. Therefore, a predetermined cutting tension is applied to the cutting wire 27, and the cutting target (113) is horizontally cut by the cutting portion 27α.

Further, in the present embodiment, the cutting portions 27α of the wire saw mechanisms 15A and 15B are connected to each other by the carriage 12.
Are arranged at symmetrical positions on both sides of. Therefore,
The objects to be cut located on both the left and right sides of the carriage 12 (11
It is possible to cut 3) at substantially the same working position.

The receiving roller 26 is for receiving the cutting wire 27 released from the object to be cut at the end of cutting. By the receiving roller 26,
It is possible to prevent the cutting wire 27 from jumping toward the dolly 12 side due to the given tension, and to prevent the dolly 12 and the wire saw mechanisms 15A and 15B from being damaged.

Next, a recess forming method using the above cutting device 11 will be described in accordance with a construction in which an existing anti-vibration sleeper system is applied to an existing railway track, which mainly uses the recess forming method. Note that, in FIGS. 5 and 6, the concave portion 101α of the short sleeper 103A on the roadbed 101 is deleted for the sake of clarity.

First, the fixed relationship between the rail 104 and the short sleeper 103A in the predetermined work area is released, and the rail 104 is supported by a jack or the like not shown. In this state, the fixed relationship between the short sleepers 103A and the ballast 101 is released, and all the sleepers 103A are removed from the track 101. Then, by using the recess forming method of the present embodiment, the roadbed 1
The concave portion 105 is provided at a position corresponding to the sleeper trace on the upper surface of 01
Is formed.

That is, as shown in FIG. 5A, the wire insertion groove 112 is bored along the outer peripheral line of the recess forming area 111 which appears in a square shape on the upper surface of the road bed 101 by using a chain saw, a cutter or the like. To be done. The depth of the wire insertion groove 112 corresponds to the desired depth of the recess 105. Further, in the present embodiment, the drainage groove 102 is bored in the central portion of the roadbed 101, and one side of the quadrangle that is the outer peripheral line of the recess forming area 111 is opened from the beginning. Therefore, the wire insertion groove 112 is formed along the remaining three sides of the quadrangle.

Since the wire insertion groove 112 is formed along the outer peripheral line of the recess forming area 111 as described above, the wire inserting groove 112 in the recess forming area 111 corresponds to the internal space shape and is to be cut. The columnar portion 113-1 forming a rectangular parallelepiped is formed (wire insertion groove drilling step).

Next, the corner portion 113α of the columnar portion 113-1 on the side around which the cutting wire 27 is wound is chamfered (chamfering step). That is, as shown in FIG. 5B, the columnar portion 11 in the recess forming area 111 is formed.
A notch 114α having substantially the same depth as the wire insertion groove 112 is formed near the corner 113α of 3-1 to separate the same corner 113α into a triangular prism shape (corner separation step).

Further, as shown in FIG. 5C, the corner portion 113β of the columnar portion 113-2 that has undergone the first corner portion separating step is
A notch 114β having substantially the same depth as the wire insertion groove 112 is formed in the vicinity so as to separate the same corner 113α into a triangular prism shape (corner separation step).

Then, as shown in FIG. 5D, the corners 113α and 113β separated from the columnar part 113-3 into a columnar shape through two corners separating steps are crushed by a worker with a hammer or the like. Then, the fragments are discharged from the recess forming area 111 (corner removing step).

After the chamfering of the columnar section 113 is completed, the columnar section 113-3 is cut by using the cutting device 11 having the above-mentioned configuration. That is, FIGS. 1 to 3 and 6 (a)
As shown in FIG. 5, the cutting device 111 is moved on the rail 104 by the starter vehicle, and the arm 2 is moved within a predetermined work area.
2 and the columnar portion 113-3 are positioned so as to face each other. Then, the clamp fitting 31 is used for the wheel 14 and the rail 10.
The cutting device 11 is fixed on the rail 104 by being interposed between the cutting device 11 and the rail 4. In this state, the arm 22
Guide pulley 25 on the pulley support portion 22α in
And the base of the columnar portion 113-3 are located in substantially the same horizontal plane.

The cutting device 11 operates the hydraulic unit 18 in advance to move the drive pulley 21 to the guide rail 10.
It is placed at the end of 4. Cutting wire 2 in this state
The cutting portion 27α of No. 7 is inserted into the wire insertion groove 112 and wound around the outer periphery of the base of the columnar portion 113-3 (wire winding step).

Then, as described above, the cutting wire 2
By rotating the drive pulley 21 to the front side of the carriage 12 while rotating the columnar portion 7, the columnar portion 113-3
Is cut horizontally at its base. In addition, during this cutting work, to prevent the generation of heat and dust,
In order to allow the smooth movement of the cutting wire 27, water is injected into the cutting portion 27α by a water injection device (not shown).

Here, the cutting device 11 has wire saw mechanisms 15A, 1 at symmetrical positions on both sides of the carriage 12.
The cut portion 27α of 5B is arranged. Therefore, the above-mentioned cutting of the columnar portion 113-3 is performed by cutting the columnar portion 113-3 in the recess forming area 111 located on the opposite side through the drainage groove 102.
The same is also performed in (columnar portion cutting step).

As shown in FIG. 6B, the columnar section 113-3 separated from the track 101 through the columnar section cutting step.
Is removed from the recess forming area 111 by a worker using a crane or the like. Therefore, the ballast 10
A concave portion 105 is formed on the upper surface of 1 corresponding to the sleeper trace (columnar portion removing step).

After the cutting of the pair of columnar parts 113-3 through the discharge groove 102 is completed as described above, the cutting device 11 moves forward on the rail 104 to move to the next recess forming area 111. And the recess forming area 1 in the same manner as described above.
The columnar portion 113-3 in 11 is cut. As described above, the cutting operation of the columnar portion 113-3 is repeated in the predetermined work area, so that the recess 105 is formed on the upper surface of the roadbed 101 so as to correspond to all traces of the sleepers.

Then, as shown in FIG. 6B, a vibration isolator 106 having a box shape is housed and arranged in each recess 105,
As shown in FIG. 8, a new PC sleeper 103B is placed and fixed on the vibration isolator 106. Then, by removing the jack or the like and fixing the rail 104 on the PC sleeper 103B, the application construction of the vibration-proof sleeper system to the existing railway track is completed.

The present embodiment having the above-mentioned structure has the following effects. (1) When applying the anti-vibration sleeper system to an existing railroad track, that is, when forming the recess 105 in the roadbed 101, it is not necessary to completely destroy the roadbed 101. Therefore, the applicable construction can be efficiently performed, which leads to reduction of construction time, reduction of personnel, and reduction of construction cost.

(2) The cutting device 11 having the wire saw mechanism 15 is used to cut the columnar portion 113. Therefore, the cut surface of the columnar portion 113, that is, the bottom surface 105α of the recess 105 can be a flat surface, and the post-treatment of the bottom surface 105α is not necessary. Therefore, the formation time of each recess 105 can be shortened, which in turn leads to a reduction in construction time and a reduction in the number of workers.

(3) The cutting work of the columnar portion 113 using the wire saw mechanism 15 has lower noise, vibration, dust generation, etc., as compared with the case where the columnar portion 113 is crushed by using a bar, a breaker or the like. Can be suppressed. Therefore, the working environment of the worker is improved, and the labor of the worker is reduced. Further, it is possible to reduce the damage to the surrounding roadbed 101 due to the vibration.

(4) The columnar section 113 is separated from the track 101 without breaking its shape (in a block). Therefore, the post-cut columnar portion 113 can be easily removed from the inside of the recess forming area 111, and can be easily discharged to the outside of the construction area.

(5) By the chamfering process, the columnar portion 113
The corners 113α and 113β on the side on which the cutting wire 27 is wound in -1, 113-2 are chamfered. Therefore, the bending radius of the cutting wire 27 in the vicinity of the same corner can be increased, and the orbiting operation of the cutting wire 27 can be smoothly performed. Therefore, it is possible to prevent the cutting wire 27 from slipping on the drive pulley 21 due to the cutting wire 27 being caught at the corners 113α and 113β. As a result, the columnar portion 113 can be cut efficiently.

(6) In the chamfering step, the corner separating step is repeated a plurality of times (twice). Therefore, the bending radius of the cutting wire 27 near the same corner can be further increased, and the orbiting operation of the cutting wire 27 becomes smoother.

(7) The cutting device 11 includes the cutting wires 2
The cutting portions 27α of No. 7 are arranged at symmetrical positions on both sides of the carriage 12. Therefore, in the application work of the vibration-proof sleeper system, cutting of the columnar portion 113 located on the opposite side through the drainage groove 102 can be performed substantially at the same working position. Therefore, the cutting efficiency of the columnar portion 113 is improved, which leads to shortening of the construction time.

(8) Wire saw mechanism 15A, 15B
Are independent mechanisms. Therefore, each cutting wire 2
The operations of 7, the adjustment of the cutting tension and the like can be independently performed, and the work efficiency and the cutting accuracy are improved.

(9) The drive pulley 21 is arranged on the carriage 12 and is linearly moved back and forth on the carriage 12.
Therefore, a predetermined tension can be applied to the cutting wire 27 without moving the entire cutting device 11.

The following embodiments can be carried out without departing from the spirit of the present invention. (1) Use the above-mentioned recess forming method in the construction to apply the anti-vibration sleeper system to the railway on the ground.

(2) Use this recess forming method to cut rock from a rock to a rectangular parallelepiped shape in a cut-out site of marble or the like. (3) In the chamfering step, the corner separating step is performed only once. Or repeat 3 times or more. That is, shift to the corner removing step in the state of FIG. Alternatively, from the state of FIG. 5C, a cut is further made near the corner of the columnar portion 113-3, and the corners of the columnar portion 113-1 are separated into a total of three or more columns, and the process is moved to the corner removal step. To do.

(4) To provide an electric motor, a hydraulic motor, etc. for rotating the wheels on the carriage so that the cutting device can be self-propelled. (5) The cutting wire 27 is made of only steel wire,
Cutting the object to be cut while supplying a slurry containing abrasive grains to the cutting portion 27α of the cutting wire 27.

(6) Only one wire saw mechanism 15 is provided, and the cutting wire 27 is guided by a pulley or the like, and the cutting portion 27α is located at a symmetrical position on both sides of the carriage 12.
To deploy.

(7) Three or more wire saw mechanisms 15 are provided so that three or more columnar parts 113 can be cut at substantially the same working position. It is convenient to provide an even number of wire saw mechanisms 15 in the application work of the vibration-proof sleeper system as described above.

(8) The tension adjusting means 16 to 19 are eliminated, the drive pulley 21 is fixed directly on the frame 13, and the entire cutting device 11 is moved along the rail 104, so that the cutting wire 27 is fixed. It should be configured to apply the tension of.

(9) The present invention should be embodied in the construction of replacing sleepers only. In this way, when replacing with another type of sleeper, it is possible to cut the same sleeper so that the new sleeper matches the sleeper.

The technical idea that can be understood from the above embodiment will be described. (1) The wire saw mechanism 15 includes a drive pulley 21 and
The drive means 20 for rotationally driving the drive pulley 21, the endless cutting wire 27 wound between the drive pulley 21 and the cutting target 113, and the drive pulley 2
Tension adjusting means 1 for adjusting the cutting tension of the cutting wire 27 by linearly reciprocating 1 on the carriage 12.
The cutting device according to claim 5, comprising 6 to 19.

In this way, a predetermined tension can be applied to the cutting wire 27 without moving the entire cutting device 11. (2) The cutting device according to (1), in which guide mechanisms 23 to 25 that guide the cutting wire 27 wound around the drive pulley 21 to the side of the carriage 12 are provided on the carriage 12.

In this way, the arrangement position of the drive pulley 21 is not regulated.

[0061]

According to the invention of claim 1 having the above-mentioned structure, it is possible to efficiently form the recess.

According to the second to fourth aspects of the invention, the smooth cutting operation of the cutting wire is allowed, and the cutting work is efficiently performed. According to the invention of claim 5, it is possible to cut the objects to be cut, which are respectively arranged on both sides of the carriage, at the same work position substantially at the same time, and the cutting work can be efficiently performed.

According to the invention of claim 6, the operation of each cutting wire, the adjustment of the cutting tension and the like can be independently performed, which leads to the improvement of the working efficiency and the cutting accuracy.

[Brief description of drawings]

FIG. 1 is a plan view of a cutting device.

FIG. 2 is a side view of the cutting device.

FIG. 3 is a front view of the cutting device.

FIG. 4 is a perspective view illustrating a wire saw mechanism.

5A is a wire insertion groove drilling step, FIG. 5B is a first corner separation step, FIG. 5C is a second corner separation step, and FIG.
The perspective view which shows each corner removal process.

6A and 6B are perspective views respectively showing a columnar portion cutting step, a columnar portion removing step, and a step of inserting and arranging a vibration isolator into the recess.

FIG. 7 (a) is a perspective view showing an existing railway track, and FIG. 7 (b).
The perspective view explaining application construction of the conventional anti-vibration sleeper system.

FIG. 8 is a perspective view showing a railway track to which a vibration-proof sleeper system is applied.

[Explanation of symbols]

20 ... Drive unit as drive means, 27 ... Cutting wire, 101 ... Roadbed as construction, 105 ... Recess, 1
11 ... Recessed area, 112 ... Wire insertion groove, 113 ...
Column.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshihiro Kodama, Sekigahara-machi, Fuwa-gun, Gifu 2067 Address, Sekigahara, Sekigahara Manufacturing Co., Ltd. Address: Sekigahara Manufacturing Co., Ltd.

Claims (6)

[Claims] 1. A wire insertion groove boring step of boring a wire insertion groove along an outer peripheral line of a recess forming area in a structure, and forming a columnar part in the recess forming area; A wire winding step of inserting and arranging in a groove and winding it around a columnar section, a columnar section cutting step of cutting the columnar section by running the cutting wire by a driving means, and a concave section of the columnar section separated from the construct. A method for forming a concave portion, which comprises a columnar portion removing step of removing from a formation area. 2. The columnar portion has a corner portion on its outer circumference, and a chamfering step of chamfering the same corner portion is provided between the wire insertion groove drilling step and the wire winding step.
The method for forming recesses according to [4]. 3. The chamfering step includes a corner separating step of making a notch in the vicinity of a corner of a columnar portion in a recess forming area to separate the same corner into a columnar shape, and a corner separated from the columnar section. The method for forming a recess according to claim 2, further comprising a step of removing a corner from the inside of the recess forming area. 4. The recess forming method according to claim 3, wherein in the chamfering step, at least the corner separating step is repeated a plurality of times. 5. A cutting device provided with a wire saw mechanism, which is arranged on a support base, and cuts a cutting wire wound around a cutting object with a cutting portion to cut the cutting wire. A cutting device in which the cutting parts are arranged symmetrically on both sides of the support base. 6. The cutting device according to claim 5, wherein the wire saw mechanism for arranging the cutting portion on one side of the support base and the wire saw mechanism for arranging the cutting portion on the other side are independent mechanisms.