TW201835527A - Tube wall thickness measuring apparatus - Google Patents

Abstract

A tube wall thickness measuring apparatus which measures a wall thickness of a tube (52), includes an apparatus main body (3), a sensor (8) installed at the apparatus main body (3) and configured to generate an ultrasonic wave radially outward from a radial center of the tube (52), a pair of expansion/contraction mechanisms (4) installed at the apparatus main body (3) to be expandable and contractible radially outwardly and radially inwardly and provided at regular intervals in a circumferential direction around an axis of the tube (52), a biasing member (5) configured to urge the expansion/contraction mechanism (4) to expand, wheels (6) installed at each of the expansion/contraction mechanisms (4) and configured to guide movement of the apparatus main body (3) in an axis direction (Da) while being in contact with an inner circumferential surface of the tube (52), and a transmission mechanism (7) configured to convert a radial expansion of one (4a) of the expansion/contraction mechanisms into a radial expansion of the other expansion/contraction mechanism (4b).

Description

Tube thickness measuring device

The present invention relates to a tube thickness measuring device.案 This case claims priority from Japanese Patent Application No. 2017-033213 filed on February 24, 2017, and applies its content here.

For example, a boiler for waste incineration must be a regular boiler tube thickness measurement that is useful to detect problems. As a general method for measuring the thickness of a boiler tube, a submerged UT (ultrasonic testing) method or the like is known.

For example, Patent Document 1 describes a technique for measuring the thickness of a boiler tube without cutting the boiler tube. The technique described in Patent Document 1 is a catheter using an ultrasonic probe (sensor) that guides thickness measurement. After the duct is introduced into the header from the inspection hole formed in the header, the leading end thereof is introduced into the boiler tube.

Thereafter, the ultrasonic probe connected to the sensor cable is introduced into the catheter from the inspection hole side, and the ultrasonic probe is advanced. Thereby, after the ultrasonic probe advances along the duct, it is introduced into the boiler tube in a manner guided by the duct.

In addition, Patent Document 2 describes a tube thickness measuring device including three arm portions that can be extended and retracted, and the three arm portions are extended to contact the inner peripheral surface of a boiler tube, thereby enabling ultrasonic detection. The needle is held in the radial center of the boiler tube. Each arm portion is a link mechanism having a driven link extending parallel to the axis direction of the boiler tube, and a pair of driving links supporting the slave link. The outer side of the one drive link in the radial direction and the driven link are connected via a long hole. Thereby, the driven link can move and rotate freely in the axial direction of the boiler tube with respect to one drive link. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 4056679 [Patent Document 2] Japanese Patent Laid-Open No. 2015-169548

[Technical problem to be solved by the invention]

However, in the tube thickness measuring device described in Patent Document 2, each of the three arm portions is driven by different driving sources, so the amount of expansion and contraction of the arm portion may not be constant. In addition, the actuator is used to drive the arm, which makes it difficult to reduce the size. For example, the inner peripheral surface of the boiler tube may have a protrusion caused by welding or fixing, and the wheel may be stuck.

The purpose of the present invention is to provide a tube thickness measuring device, which is capable of centering the sensor by a simpler and smaller mechanism. [Technical solution to solve the problem]

According to a first aspect of the present invention, a tube thickness measuring device for measuring the thickness of a tube is provided. The device includes: a device body; and a sensor, which is mounted on the device body and moves from the center of the radial direction of the tube toward Ultrasonic waves are emitted outward; a pair of telescopic mechanisms are attached to the aforementioned device body, and are mounted to be retractable toward the outer side and the inner side of the radial direction, and are arranged at equal intervals in the circumferential direction centered on the axis of the tube; The component is used to push the telescopic mechanism in an elongated manner; the wheel is installed to each of the telescopic mechanisms and guides the movement of the device body toward the axis of the pipe while contacting the inner peripheral surface of the pipe; And the transmission mechanism converts the radial extension of one of the aforementioned telescopic mechanisms into the radial extension of the other aforementioned telescopic mechanism.

According to this configuration, since the elastic pushing member pushes the telescopic mechanism so as to extend the telescopic mechanism, and the operation of one telescopic mechanism is transmitted to the other telescopic mechanism by the transmission mechanism, thereby eliminating the need to use a drive source such as a motor. A pair of telescopic mechanisms can be simultaneously extended and contracted. This makes it possible to center the sensor with a simpler and smaller mechanism. In addition, the telescopic mechanism is composed of only two parts in the circumferential direction, so that the inner peripheral surface of the tube may have protrusions accompanying welding, and the device can be easily passed through.

In the aforementioned tube thickness measuring device, each of the aforementioned telescopic mechanisms may be a 1-degree-of-freedom parallel link mechanism, and the parallel link mechanism may include a first link and a second link connected to the aforementioned device. The main body is rotatably mounted in parallel with each other; and a parallel link is connected between the front end side of the first link and the front end side of the second link, and moves in the radial direction while maintaining parallel to the axis, and the aforementioned A wheel; the transmission mechanism includes: a first gear that rotates with rotation of the first link of the one telescopic mechanism; and a second gear that is fixed to the second connection of the telescopic mechanism of the other The lever is in mesh with the aforementioned first gear.

According to such a configuration, the telescopic mechanism is a parallel link mechanism of one degree of freedom, and the transmission mechanism is a gear, so that the parallel links can be continuously kept parallel, so that the position or posture of the sensor can be stabilized.

In the tube thickness measuring device, each of the telescopic mechanisms may include: a pair of the parallel link mechanisms, which are parallel to a plane including the axis, and are arranged at equal intervals from the axis. In-plane expansion and contraction to a plane.

According to such a structure, a pair of parallel link mechanisms are arrange | positioned at intervals in the direction orthogonal to the plane in which a parallel link mechanism is arrange | positioned. This can improve the stability of the sensor. [Effect of the invention]

According to the present invention, a pair of telescopic mechanisms can be synchronized and retracted without using a driving source such as a motor. This makes it possible to center the sensor with a simpler and smaller mechanism. In addition, the telescopic mechanism is composed of only two parts in the circumferential direction, so that the inner peripheral surface of the tube may have protrusions accompanying welding, and the device can be easily passed through.

Hereinafter, an embodiment of the tube thickness measuring device 1 of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the tube thickness measuring device 1 of this embodiment is used when measuring the thickness of the boiler tube 52 of the boiler 50. The tube thickness measuring device 1 measures the thickness of the boiler tube 52 using, for example, a sensor such as an ultrasonic probe.

The boiler 50 includes a header 51 and a plurality of boiler tubes 52. The boiler tube 52 is a plurality of rigid-body tubes serving as a flow path of water vapor, and is arranged along the extending direction of the header 51, and one end thereof is connected to the header 51. Each boiler tube 52 communicates with the header 51 and extends in a manner orthogonal to the header 51, respectively.

In the header 51, inspection holes 53 serving as inspection holes are separated from each other in the extending direction of the header 51 and are opened plurally. The inspection hole 53 and the boiler tube 52 are arrange | positioned so that it may become in the positional relationship which skews (Skew) mutually. The inner diameter of the boiler tube 52 is, for example, 68 mm. The ultrasonic probe is introduced into the boiler tube 52 through the inspection hole 53 and the header 51.

Next, the tube thickness measuring device 1 for measuring the tube thickness of the boiler tube 52 to be inspected will be described. The tube thickness measuring device 1 includes: a data collection device 31; a data analysis device 32, which analyzes the data collected by the data collection device 31; a cable winding device 33, which is connected to the data collection device 31; The wire 30 is discharged from the cable take-up device 33; the sensor probe 2 is a sensor installed at the front end of the cable 30; and the conduit 34 is a guide device of the sensor probe 2 .

The data collection device 31 is a device in which the thickness data of the boiler tube 52 measured by the sensor probe 2 is input via the cable 30. That is, the data collection device 31 has a function of collecting the thickness data of the boiler tube 52. The data analysis device 32 is a computer that analyzes the thickness data of the boiler tubes 52 collected by the data collection device 31.

The cable 30 is a long elastic tube made of, for example, metal or vinyl, and can be flexed over its entire length. The outer diameter of the cable 30 is, for example, 12 mm. The radon sensor probe 2 is provided at the front end portion of the cable 30 and measures the thickness data of the boiler tube 52 by emitting an ultrasonic wave. A water supply pipe is connected to the sensor probe 2 together with the cable 30.

The cable winding device 33 is connected to the rear end of the cable 30 and is used to wind the cable 30 inserted into the boiler tube 52.

The duct 34 is a tube that guides the cable 30 and the sensor probe 2 into the boiler tube 52 and is placed in the header 51 before the thickness of the boiler tube 52 is measured. The duct 34 is arranged so as to connect the inspection hole 53 and the boiler tube 52 in a skewed positional relationship with each other.

The catheter 34 is composed of a bellows-shaped elastic tube. As a result, the catheter 34 can be flexibly retracted and flexed. The catheter 34 is capable of maintaining the flexed state as long as there is no external force acting when the catheter 34 is flexed. The duct 34 is inserted into the header 51 from the inspection hole 53, and is bent and extended in the header 51. The front end of the duct 34 is connected to the boiler tube 52.

As shown in FIG. 2 and FIG. 3, the sensor probe 2 of the tube thickness measuring device 1 of the present embodiment includes: a body 3 (device body); a pair of telescopic mechanisms 4, a support body 3; Each of the pusher members 5 is configured to push each of the telescopic mechanisms 4 (extend toward the outside in the radial direction centered on the axis A of the boiler tube 52); the wheels 6 are mounted to each telescopic mechanism 4; the transmission mechanism 7. The radial motion of one telescopic mechanism 4a is converted to the radial motion of the other telescopic mechanism 4b; and the sensor body 8 is mounted on the main body 3.

The main body 3 is a member having a long axial direction Da in the boiler tube 52, and is arranged so that the longitudinal direction of the main body 3 is along the axis of the boiler tube 52. Hereinafter, the axis A of the main body 3 disposed coaxially with the axis A of the boiler tube 52 is referred to as a central axis C. The telescopic mechanism 4 is retractable to the main body 3 toward the outside in the radial direction and the inside in the radial direction with the central axis C as the center. Hereinafter, a plane including the central axis C and a plane along the telescopic direction of the telescopic mechanism 4 is referred to Center plane F (see Fig. 3).

The sensor probe 2 of this embodiment is formed so as to be symmetrical with respect to the center plane F. Each telescopic mechanism 4 in this embodiment is provided with two parallel link mechanisms 15 so as to be symmetrical with respect to the center plane F. The push spring member 5 is a tension coil spring. The pusher member 5 is not limited to a tension coil spring, and may be a configuration using a rubber or a torsion spring, for example.

The sensor body 8 is mounted on one end of the body 3. The sensor body 8 oscillates an ultrasonic wave from the center of the radial direction of the boiler tube 52 toward the inner circumferential surface of the boiler tube 52 outside the radial direction, and receives the reflected wave of the ultrasonic wave. The sensor body 8 is mounted in a state where the central axis C of the body 3 and the axis A of the boiler tube 52 substantially coincide with each other, and is positioned at a center position in the boiler tube 52.

The main body 3 is supported by a pair of telescopic mechanisms 4 so that the central axis C is disposed coaxially with the axis A of the boiler tube 52. Each telescopic mechanism 4 is a link mechanism that telescopes radially outward and radially inward with the central axis C as the center. The respective telescopic mechanisms 4 are arranged at regular intervals in the circumferential direction around the central axis C. In other words, each telescopic mechanism 4 is mounted so that the pitch in the circumferential direction is 180 °.

One telescopic mechanism 4a expands and contracts freely from the main body 3 in one direction orthogonal to the central axis C, and the other telescopic mechanism 4b expands and contracts from the main body 3 toward the other direction orthogonal to the central axis C. freely. The body 3 is centered by the pair of telescopic mechanisms 4 being extended so that the wheels 6 are pressed against the inner peripheral surface of the boiler tube 52.

The main body 3 includes a main body portion 9, a first telescopic restriction portion 11 and a second telescopic restriction portion 12 which restrict the telescopic movement of the telescopic mechanism 4, a first rotary shaft 13, and a second rotary shaft 14. The cymbal body portion 9 is tubular and has a through hole 10 formed coaxially with the central axis C. A cable 30 is inserted into the through hole 10. The main body portion 9 has a flat portion 16 which is a plane parallel to the center plane F. The plane portion 16 is a plane on which the telescopic mechanism 4 is mounted through the rotation shafts 13 and 14.

The first rotation axis 13 is an axis extending in a direction orthogonal to the flat portion 16. The first rotation shaft 13 is formed by a shaft portion of a fastening member such as a bolt. The second rotation axis 14 is an axis extending in a direction orthogonal to the plane portion 16. The second rotation shaft 14 is formed by a shaft portion of a fastening member such as a bolt. The first rotation shaft 13 and the second rotation shaft 14 are separated from each other in the axial direction Da.

The telescopic mechanism 4 is a so-called link mechanism and includes: a first link 17 that is rotatably attached to the first rotation shaft 13; a second link 18 that is rotatably attached to A link of the second rotation shaft 14 and a parallel link 19 are rotatably mounted on the front ends of the ends of the first link 17 and the second link 18 opposite to the rotation axes 13 and 14 Side link. The first link 17 and the second link 18 are attached to the main body 3 so as to be rotatable and parallel to each other.

The first link 17 and the body portion 9 are rotatably connected in a plane parallel to the center plane F through the first rotation shaft 13. Similarly, the second link 18 and the body portion 9 are rotatably connected in a plane parallel to the center plane F through the second rotation shaft 14. The first rotary shaft 13 and the second rotary shaft 14 are pin joints capable of 1 degree of rotation.

The first link 17 and the parallel link 19 are rotatably connected through a joint 20 in a plane parallel to the center plane F. Similarly, the second link 18 and the parallel link 19 are rotatably connected through a joint 20 in a plane parallel to the center plane F. The joint 20 is a pin joint capable of 1 degree of rotation.伸缩 The first link 17, the second link 18, and the parallel link 19 and the telescopic mechanism 4 constitute a parallel link mechanism 15 of one degree of freedom. The length of the first link 17 and the length of the second link 18 are set to keep the parallel link 19 and the central axis C (axis A) continuously parallel.

The wheels 6 are attached to both ends of the parallel link 19. The wheels 6 are attached so as to be able to travel on the inner peripheral surface of the boiler tube 52 in the axial direction Da. The push spring member 5 is attached to connect the central portion of the parallel link 19 and the main body portion 9. The pusher member 5 pushes the parallel link 19 so that the parallel link 19 moves outward in the radial direction. Accordingly, the telescopic mechanism 4 is maintained in an extended state as shown in FIG. 2.

The transmission mechanism 7 is a mechanism that transmits the operation of the first link 17 of the one telescopic mechanism 4 a to the second link 18 of the other telescopic mechanism 4 b. The transmission mechanism 7 includes a first gear 21 that rotates with the rotation of the first link 17 of one telescopic mechanism 4a, and a second gear 22 that is a second link fixed to the other telescopic mechanism 4b. 18 and mesh with the first gear 21. The pitch diameters of the first gear 21 and the second gear 22 are the same. The speed ratio of the first gear 21 and the second gear 22 is 1.

The first gear 21 is a spur gear, and is fixed to the first link 17 of one of the telescopic mechanisms 4 a so that the center of the first gear 21 coincides with the center of the first rotary shaft 13. The center of the pitch circle of the first gear 21 coincides with the center of the first rotation shaft 13. When the first link 17 is rotated around the first rotation shaft 13, the first gear 21 fixed to the first link 17 by the bolt 26 is also rotated around the first rotation shaft 13.

The second gear 22 is a spur gear, and is fixed to the second link 18 of the other telescopic mechanism 4b so that the center of the second gear 22 and the center of the second rotation shaft 14 coincide with each other. The center of the pitch circle of the second gear 22 coincides with the center of the second rotation shaft 14. When the second gear 22 is rotated around the second rotation shaft 14, the second link 18 fixed to the second gear 22 by the bolt 27 is also rotated around the second rotation shaft 14.

The first gear 21 is partially cut away due to space constraints. The first gear 21 and the second gear 22 have the same shape except that a part of the first gear 21 is cut away. That is, the first gear 21 and the second gear 22 have the same pitch circle diameter and tooth profile. (1) The first gear 21 and the second gear 22 of the transmission mechanism 7 mesh with each other in a symmetrical and synchronous manner with one telescopic mechanism 4a and the other telescopic mechanism 4b.

As described above, the sensor probe 2 is formed so as to be symmetrical with respect to the center plane F. Each telescopic mechanism 4 includes a pair of parallel link mechanisms 15 that are parallel to the center plane F and extend and contract in a pair of planes spaced apart from the center plane F at equal intervals.

As shown in FIG. 3, in the pair of parallel link mechanisms 15, the parallel links 19 are shared. In other words, the pair of parallel link mechanisms 15 are connected through the parallel link 19. The wheels 6 are arranged at the ends in the longitudinal direction of the parallel links 19 and are arranged apart from the width direction of the parallel links 19. In other words, the wheels 6 are arranged at the four corners of the parallel links 19 that are rectangular when viewed from the axial direction Da.

The telescopic restriction portions 11 and 12 are portions that restrict the telescopic movement of the telescopic mechanism 4. (1) The first telescopic restriction portion 11 is a first contact surface 23 that restricts rotation of the first link 17 of the telescopic mechanism 4. The first contact surface 23 is formed to restrict the operation of the first link 17 so that the telescopic mechanism 4 does not excessively extend. Specifically, the first telescopic restricting portion 11 is formed to restrict the elongation of the telescopic mechanism 4 in a state where the telescopic mechanism 4 is only slightly extended than the state shown in FIG. 2.

The second telescopic restriction portion 12 has a second contact surface 24 that restricts rotation of the second link 18 of the telescopic mechanism 4. The second contact surface 24 is formed to restrict the operation of the second link 18 so that the telescopic member does not shrink more than the state shown in FIG. 6. The telescopic restriction portions 11 and 12 do not need to be surfaces. For example, bolts that interfere with the links 17 and 18 may be attached to the plane portion 16 of the body portion 9.

Next, the operation of the telescopic mechanism 4 of the sensor probe 2 according to this embodiment will be described. Further, in the diagrams shown in FIGS. 4 and 5, in order to easily understand the function of the transmission mechanism 7, only the operation of the first link 17 of the telescopic mechanism 4 a among the plurality of links 17 and 18 and other The second link 18 of one of the telescopic mechanisms 4b is indicated by a solid line.

In the case where the sensor probe 2 is disposed inside the boiler tube 52 having a large inner diameter, as shown in FIG. 4, the telescopic mechanism 4 is extended by the tension of the pusher member 5. That is, the telescopic mechanism 4 serving as the parallel link mechanism 15 is extended, the parallel link 19 of the telescopic mechanism 4 moves outward in the radial direction, and the first link 17 of one of the telescopic mechanisms 4a rotates clockwise.

As the first link 17 rotates, the first gear 21 of the transmission mechanism 7 fixed to the first link 17 also rotates clockwise R1. As the first gear 21 rotates, the second gear 22 meshing with the first gear 21 rotates counterclockwise R2. As a result, the second link 18 of the other telescopic mechanism 4b rotates counterclockwise R2. That is, the first link 17 rotates in synchronization with the second link 18. Since the other telescopic mechanism 4b is also a parallel link mechanism 15, the parallel link 19 of the other telescopic mechanism 4b also moves radially outward by the rotation of the second link 18.

When the sensor probe 2 is disposed inside the boiler tube 52 having a small inner diameter, as shown in FIG. 5, the telescopic mechanism 4 contracts against the tension of the pusher member 5. That is, the telescopic mechanism 4 as the parallel link mechanism 15 is contracted, the parallel link 19 of the telescopic mechanism 4 is moved inward in the radial direction, and the first link 17 of one of the telescopic mechanisms 4a is rotated counterclockwise R2.

As the first link 17 rotates, the first gear 21 of the transmission mechanism 7 fixed to the first link 17 also rotates counterclockwise R2. As the first gear 21 rotates, the second gear 22 meshing with the first gear 21 rotates clockwise R1. As a result, the second link 18 of the other telescopic mechanism 4b rotates clockwise R1. By the rotation of the second link 18, the parallel link 19 of the other telescopic mechanism 4b also moves radially inward.

As shown in Fig. 6, the boiler tube 52 has a small-diameter portion 52a. The small-diameter portion 52 a is, for example, provided at a connection portion between the header 51 (see FIG. 1) and the boiler tube 52.感 The sensor probe 2 of this embodiment is pulled in by the cable 30 (pulled up toward the upper side of FIG. 6) to contract the telescopic mechanism 4. The sensor probe 2 of this embodiment is contracted by the telescopic mechanism 4 when passing through the small-diameter portion 52a, and is extended after passing through the small-diameter portion 52a.

The reduction ratio of the sensor probe 2 in this embodiment, that is, the ratio of the minimum width W2 (see FIG. 6) to the maximum width W1 (see FIG. 2) is 0.511. Specifically, the maximum width W1 is 70.1 mm, and the minimum width W2 is 35.8 mm.

According to the aforementioned embodiment, since the pusher member 5 pushes the telescopic mechanism 4 so as to extend the telescopic mechanism 4, and the operation of one telescopic mechanism 4 a is transmitted to the other telescopic mechanism 4 b by the transmission mechanism 7. A driving source such as a motor can simultaneously expand and contract a pair of telescopic mechanisms 4. This makes it possible to center the sensor body 8 with a simpler and smaller mechanism. In addition, since the telescopic mechanism 4 is formed only at two locations in the circumferential direction, the inner peripheral surface of the boiler tube 52 may have protrusions accompanying welding, and the sensor probe 2 can be easily passed through.

In addition, by setting the telescopic mechanism 4 to a parallel link mechanism 15 of one degree of freedom and the transmission mechanism 7 to be a gear, the parallel link 19 can be continuously kept parallel, so that the position or posture of the sensor body 8 can be stabilized. .

In addition, the pair of parallel link mechanisms 15 are arranged at intervals in a direction orthogonal to the center plane F, whereby the wheels 6 are arranged in a rectangular shape when viewed from the axial direction Da, so that the stability of the sensor body 8 can be made Promotion.

In addition, since the links 17, 18 constituting each of the telescopic mechanisms 4 are not connected to the parallel link 19 via the long holes, the strength of the parallel link mechanism 15 can be improved.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the scope of the gist of the present invention. In addition, in the foregoing embodiment, although a gear is used as the structure of the transmission mechanism 7, it is not limited to this, and a chain, a sprocket, or a belt can also be used as the transmission mechanism 7. In addition, an intermediate gear may be provided between the first gear 21 and the second gear 22. [Industrial possibilities]

According to the aforementioned tube thickness measuring device, the sensor can be centered by a simpler and smaller mechanism.

1‧‧‧ tube thickness measuring device

2‧‧‧ Sensor Probe

3‧‧‧Body (device body)

4‧‧‧ Telescopic mechanism

5‧‧‧ Pusher

6‧‧‧ Wheel

7‧‧‧ Transmission mechanism

8‧‧‧ sensor body (sensor)

9‧‧‧Body

10‧‧‧through hole

11‧‧‧The first telescopic restriction section

12‧‧‧Second telescopic restriction section

13‧‧‧first rotation axis

14‧‧‧second rotation axis

15‧‧‧ Parallel Link Mechanism

16‧‧‧Plane Department

17‧‧‧ the first link

18‧‧‧ second link

19‧‧‧ Parallel Link

20‧‧‧ connector

21‧‧‧first gear

22‧‧‧Second Gear

23‧‧‧First contact surface

24‧‧‧Second contact surface

30‧‧‧cable

31‧‧‧Data Collection Machine

32‧‧‧Data Analysis Device

33‧‧‧cable winding device

34‧‧‧ Catheter

50‧‧‧ boiler

51‧‧‧ Collector

52‧‧‧boiler tube (pipe)

53‧‧‧ manhole

A‧‧‧ axis

C‧‧‧center axis

F‧‧‧ center plane

[Fig. 1] An overall schematic view of a tube thickness measuring device and a boiler according to an embodiment of the present invention. [Fig. 2] It is a front view of a sensor probe of a tube thickness measuring device according to an embodiment of the present invention, and is a view showing a state where a telescopic mechanism is extended. [Fig. 3] is a plan view of a sensor probe according to an embodiment of the present invention. [Fig. 4] Fig. 4 is a diagram illustrating an operation of a sensor probe according to an embodiment of the present invention, and is a diagram illustrating a state where a telescopic mechanism is extended. [Fig. 5] Fig. 5 is a diagram illustrating an operation of a sensor probe according to an embodiment of the present invention, and is a diagram illustrating a state where a telescopic mechanism is contracted. [FIG. 6] It is a front view of a sensor probe of a tube thickness measuring device according to an embodiment of the present invention, and is a view showing a state where a telescopic mechanism is contracted.

Claims (3)

A tube thickness measuring device for measuring the thickness of a tube, comprising: (i) a device body; (ii) a sensor mounted on the device body and emitting an ultrasonic wave from a radial center of the tube toward a radial outside; The mechanism is attached to the aforementioned device body, and is installed to be retractable toward the outer side and the inner side of the radial direction, and is arranged at equal intervals in the circumferential direction centered on the axis of the tube; ； Push the elastic member to extend the aforementioned telescopic mechanism弹 Wheels are mounted to each of the aforementioned telescopic mechanisms, while contacting the inner peripheral surface of the tube, while guiding the device body to move in the direction of the axis of the tube; and a transmission mechanism that connects one of the foregoing The radial extension of the telescopic mechanism is converted into the radial extension of the other telescopic mechanism. The tube thickness measuring device according to claim 1, wherein: each of the aforementioned telescopic mechanisms is a parallel link mechanism of 1 degree of freedom, and the parallel link mechanism includes: a first link and a second link, The device body is rotatably mounted in parallel with each other; and a parallel link is connected between the front end side of the first link and the front end side of the second link, moves in the radial direction while maintaining parallel to the axis, and is mounted There are the aforementioned wheels; The transmission mechanism includes: a first gear that rotates with rotation of the first link of one of the telescopic mechanisms; and a second gear that is fixed to the first of the telescopic mechanisms of the other The two links are in mesh with the first gear. The tube thickness measuring device according to claim 2, wherein each of the telescopic mechanisms includes a pair of parallel link mechanisms that are parallel to a plane including the axis, and are disposed at equal intervals from the axis. A pair of planes expand and contract in-plane.