Rectangular tube inspection device

Abstract

To provide a rectangular tube inspection device that facilitates positioning work on rectangular tubes. [Solution] A square tube inspection device 1 for inspecting the inner surface of a square tube SP while pulling a housing 10 having an inspection means 20, comprising a biasing mechanism 30 that biases a roller 31 that contacts the inner surface of the square tube SP, and a position adjustment mechanism 40 that has a rolling element 41 that contacts the inner surface of the square tube SP and adjusts the position of the housing 10 on the square tube SP, wherein the housing 10 has four surfaces, the biasing mechanism 30 is arranged on two adjacent orthogonal surfaces of the housing 10, and the position adjustment mechanism 40 is arranged on the other two adjacent orthogonal surfaces of the housing 10.

Description

Technical Field

[0001] The present invention relates to a square tube inspection device for inspecting the inner surface of a square tube.

Background Art

[0002] Conventionally, a transport container for storing a nuclear fuel assembly and used for transportation is known. This transport container includes a plurality of loment parts formed in a long square tube shape (see FIG. 7). Since this loment part stores a nuclear fuel assembly, it is necessary to inspect the state of the inner surface (appearance) before and after use.

[0003] On the other hand, in order to inspect the inner surface of a tube, for example, inner surface inspection devices as disclosed in Patent Documents 1 and 2 are known. These inner surface inspection devices include centering means and are capable of aligning the central axis of a circular tube with the central axis of the inner surface inspection device. In addition, these inner surface inspection devices also include self-propelling means on the premise of use in a horizontal (lying) posture of a circular tube in order to move inside the tube.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, although the inner surface inspection devices disclosed in Patent Documents 1 and 2 include centering means, they are for circular tubes (cylindrical tubes). Even if they are directly applied to a square tube (square cylindrical tube) in which the distance from the central (centroid) axis is not constant, the positioning accuracy is poor, and the traveling performance and inspection workability are not good.

[0006] Therefore, the present invention has been made in view of the above problems, and aims to provide a rectangular tube inspection device that facilitates positioning work on rectangular tubes. [Means for solving the problem]

[0007] (1) One aspect of the present invention is a rectangular tube inspection device for inspecting the inner surface of a rectangular tube while pulling a housing having an inspection means, comprising: a biasing mechanism for biasing a roller that contacts the inner surface of the rectangular tube; and a position adjustment mechanism having a rolling element that contacts the inner surface of the rectangular tube and adjusting the position of the housing on the rectangular tube, wherein the housing has four surfaces, the biasing mechanism is arranged on two adjacent orthogonal surfaces of the housing, and the position adjustment mechanism is arranged on two other adjacent orthogonal surfaces of the housing. (2) In the embodiment of (1) above, a plurality of the biasing mechanism and the position adjustment mechanism may be provided in a direction along the axis of the square tube. (3) In the embodiment of (1) or (2) above, the position adjustment mechanism may be capable of changing the amount of protrusion of the rolling element relative to the inner surface of the rectangular tube. (4) In any one embodiment of (1) to (3) above, the housing may have a length such that it protrudes from the end face of the square tube at the position in which the housing penetrates the end face of the square tube the furthest. (5) In any one embodiment of (1) to (4) above, the roller and the rolling element may be in contact with the corner or side of the rectangular tube. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a rectangular tube inspection device that facilitates positioning work on rectangular tubes. [Brief explanation of the drawing]

[0009] [Figure 1A] This is a cross-sectional view taken by cutting a rectangular tube in a plane along its axis, showing the inspection process using the rectangular tube inspection device according to an embodiment of the present invention. [Figure 1B]This is an enlarged plan view, seen from the lower end of a rectangular tube, showing the inspection process using the rectangular tube inspection device according to an embodiment of the present invention. [Figure 2A] This is a side view showing the biasing mechanism. [Figure 2B] This is a front view showing the biasing mechanism. [Figure 3A] This is a side view showing the position adjustment mechanism. [Figure 3B] This is a front view showing the position adjustment mechanism. [Figure 4] This is a cross-sectional view taken by cutting a rectangular tube in a plane along its axis, showing the inspection process using the rectangular tube inspection device according to the second embodiment of the present invention. [Figure 5] This is a cross-sectional view taken by cutting a rectangular tube in a plane along its axis, showing the inspection process using the rectangular tube inspection device according to the third embodiment of the present invention. [Figure 6] This is an enlarged plan view, seen from the lower end of a rectangular tube, showing the inspection process using the rectangular tube inspection device according to the fourth embodiment of the present invention. [Figure 7] This is a partial cross-sectional view showing the logistics section of a transport container. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below with reference to the drawings. In the embodiments described herein, the same reference numerals are used for the same components throughout the text.

[0011] Figure 1 shows the inspection process using the rectangular pipe inspection device 1 according to an embodiment of the present invention. Figure 1A is a cross-sectional view of the rectangular pipe SP cut along a plane parallel to axis Z, and Figure 1B is an enlarged plan view of the rectangular pipe SP viewed from the lower end. As shown in Figures 1A and 1B, the rectangular tube inspection device 1 comprises a housing 10 which is the main body, and an inspection means 20 for inspecting the inner surface of the rectangular tube SP. The housing 10 of the rectangular tube inspection device 1 is connected to a towing rope 100 of a towing device (not shown), and the device is supported by towing so that it is suspended from above the rectangular tube SP.

[0012] The traction device is provided with a winding mechanism capable of controlling the traction speed (winding and unwinding speed) of a metal traction rope 100, and may be, for example, a crane, a winch, etc. The traction rope 100 should be long enough to be longer than the total length of the square tube SP to be inspected, and a length of at least about 10m to 20m is sufficient.

[0013] The square tube SP is the lug part (see Fig. 7) of a transport container for storing a fuel assembly made of nuclear fuel. Depending on the type of fuel, for example, it has a square cross-section with a length of about 4m to 5m and an inner dimension of about 15cm×15cm to 30cm×30cm. However, the square tube SP inspected by the square tube inspection device 1 is not limited to the above uses and dimensions. The axis Z is an axis passing through the cross-section center (centroid) of the square tube SP.

[0014] The inspection means 20 can communicate the inspected data, either wired or wirelessly, or store it in a removable storage medium and send (transfer) it to an external observation device 25. The inspection means 20 is appropriately selected according to the inspection content, for example, means for imaging and observing the appearance and surface condition, means for inspecting by emitting and incident ultrasonic waves and radiation, means for inspecting by changes in eddy currents, etc. The inspection means 20 of this embodiment is, for example, an imaging means such as a CCD camera, which images the inner surface of the square tube SP, generates imaging data in the form of still images or moving images, and is used for appearance inspection.

[0015] Also, the square tube inspection device 1 may be provided with a plurality of types of inspection means 20 described above in the housing 10, and may be provided with lighting as needed. The lighting may be provided on the inspection means 20.

[0016] The observation device 25 to which the data is sent may be a personal computer provided with, for example, a display unit such as a monitor, a storage unit such as an SSD or HDD, an input / output unit (or USB input / output unit) capable of connecting various devices, a communication unit, an arithmetic unit capable of processing data, etc.

[0017] As shown in Fig. 1A, the housing 10 is formed in a stepped shape with a head part 11 for fixedly holding the inspection means 20 and a tail part 12 connected to the traction rope 100.

[0018] The head portion 11 is made of a metal such as stainless steel or aluminum alloy, and has a rectangular prism or rectangular tube shape with a rectangular cross-section (square in this embodiment), and has four flat surfaces on its outer surface. The head portion 11 may also be a cylinder or tube with four chamfered edges, as long as it has four planes where adjacent planes are orthogonal to each other. The axis passing through the center of the cross-section (central center) of the housing 10 is positioned to coincide with the axis Z of the rectangular tube SP, and may therefore be called axis Z.

[0019] The head portion 11 has an L-shaped bracket 111 at its tip. The inspection means 20 is inserted, for example, into a through hole formed in the tip of the bracket 111, which has a half-split, and is detachably fixed by narrowing the slit with a set screw.

[0020] On the other hand, although the tail portion 12 is a cylindrical shape made of metal in this embodiment, it may also be, for example, a rectangular tube shape. The hollow structure of the tail portion 12 allows power cables, signal / communication cables, etc. of the inspection means 20 to pass through.

[0021] Furthermore, although the tail portion 12 is slightly smaller than the outer diameter of the head portion 11, its length in the direction along the axis Z may be equal to the length of the head portion 11, or it may be about two to three times longer.

[0022] Furthermore, the tail section 12 has a suspension device 121 such as an eye bolt on its end face, and the towing rope 100 is connected to this suspension device 121 via a suspension device (not shown) such as a shackle.

[0023] Next, the biasing mechanism 30 will be described. Figure 2 shows the biasing mechanism 30, with Figure 2A being a side view and Figure 2B being a front view.

[0024] As shown in Figures 2A and 2B (see also Figure 1B), the biasing mechanism 30 includes a roller 31 that contacts the inner surface of the square tube SP, a biasing arm 32 that holds the roller 31, and a biasing means 33 that biases the biasing arm 32.

[0025] The roller 31 is formed in a disc shape and is rotatably supported on a support shaft via bearings. The roller 31 may also have a cylindrical metal surface, such as stainless steel or aluminum alloy, covered with rubber, elastomer, or hard resin.

[0026] The biasing arm 32 has one end formed in a U-shape to fix both ends of the support shaft of the roller 31 (see Figure 2B). The other end of the biasing arm 32 is rotatably connected via a pivot to a post 13 that protrudes from the surface of the housing 10 (see Figure 2A). The length of the biasing arm 32 should be set appropriately according to the inner dimensions of the square tube SP.

[0027] The biasing means 33 is provided between the biasing arm 32 and the post 13 and biases the biasing arm 32 in a direction away from the housing 10. The biasing means 33 may be, for example, a metal torsion spring, a compression coil spring, or an elastic body such as rubber, and is not limited to these as long as it generates a biasing force.

[0028] The biasing means 33 in this embodiment is a metal torsion spring with an arm angle of 90° to 180° where the two arms intersect. Therefore, at the pivot point between the biasing arm 32 and the post 13, one arm of the torsion spring is fixed to the biasing arm 32, and the other arm is fixed to the post 13. The biasing force of the biasing means 33 should be appropriately set according to the inner dimensions of the square tube SP.

[0029] The biasing mechanism 30 described above is arranged in pairs on two adjacent, orthogonal surfaces of the housing 10 (see Figure 1B).

[0030] Next, the position adjustment mechanism 40 will be explained. Figure 3 shows the position adjustment mechanism 40, with Figure 3A being a side view and Figure 3B being a front view.

[0031] As shown in Figures 3A and 3B (see also Figure 1B), the position adjustment mechanism 40 includes a rolling element 41 that contacts the inner surface of the rectangular tube SP, a stem 42 that holds the rolling element 41, and an adjustment dial 43 that allows the stem 42 to move in and out.

[0032] The rolling element 41 is formed in a cylindrical shape and is rotatably supported on the support shaft via bearings. The rolling element 41 is preferably wider than the width of the roller 31 and has a larger diameter than the diameter of the roller 31 in order to increase the contact area (line) with the inner surface of the rectangular tube SP and improve posture stability. The cylindrical surface of the rolling element 41 may also be covered with rubber, elastomer, hard resin, or the like.

[0033] The stem 42 is formed in an overall U-shape to fix both ends of the pivot shaft of the rolling element 41 (see Figure 3B). Specifically, the stem 42 has a pair of plate-shaped support parts 421, 421 that fix the pivot shaft of the rolling element 41, and a block-shaped main body part 422 that connects these pair of support parts 421, 421.

[0034] The adjustment dial 43 is located between the biasing arm 32 and the boss 14, and adjusts the position of the stem 42 so that it can move in and out in a direction away from the housing 10. Specifically, the adjustment dial 43 is formed in the shape of a disc, and a screw shaft 433 is provided in the center, with a male screw threaded on one end and a reverse male screw threaded on the other end. The adjustment dial 43 has a knurled pattern engraved on its cylindrical surface.

[0035] Here, the main body 422 of the stem 42 has a female thread that engages with the screw shaft 433 of the adjustment dial 43, and the boss 14 of the housing 10 has a reverse female thread that engages with the screw shaft 433 of the adjustment dial 43. The length of the screw shaft 433 should be set appropriately according to the inner dimensions of the square tube SP.

[0036] Furthermore, the housing 10 is formed so that a pair of guide columns 15, 15 protrude from the surface at positions flanking the boss 14 (see Figure 3B). These guide columns 15, 15 are inserted through guide holes formed in the main body portion 442 of the stem 42, and are designed to guide the forward and backward movement of the stem 42.

[0037] With this position adjustment mechanism 40, when the adjustment dial 43 is rotated counterclockwise, one male thread on the screw shaft 433 of the adjustment dial 43 and the female thread on the stem 42 are retracted, and the other reverse male thread and the reverse female thread on the boss 14 are retracted, increasing the distance between the boss 14 (or adjustment dial 43) and the stem 42, and allowing the rolling elements 41 to protrude from the inner surface of the square tube SP. Conversely, when the adjustment dial 43 is rotated clockwise, one male thread on the screw shaft 433 of the adjustment dial 43 and the female thread on the stem 42 are advanced, and the other reverse male thread and the reverse female thread on the boss 14 are advanced, decreasing the distance between the boss 14 (or adjustment dial 43) and the stem 42, and allowing the rolling elements 41 to retract from the inner surface of the square tube SP.

[0038] In other words, the amount of protrusion of the roller 41 relative to the inner surface of the square tube SP can be changed and adjusted simply by rotating the adjustment dial 43. A lock nut may also be added to prevent the screw shaft 433 from loosening.

[0039] The position adjustment mechanism 40 described above is arranged in pairs on two adjacent, orthogonal surfaces of the housing 10, on the other (remaining) surfaces where the pair of biasing mechanisms 30 are not located (see Figure 1B).

[0040] Therefore, these biasing mechanisms 30 and position adjustment mechanisms 40 are arranged on all four sides of the housing 10 such that the straight line connecting one pair of biasing mechanisms 30 and position adjustment mechanisms 40 is perpendicular to the straight line connecting the other pair of biasing mechanisms 30 and position adjustment mechanisms 40. As a result, the two posts 13 and the two bosses 14 are provided on all four sides of the housing 10 at equal angles (90 degrees) around the axis Z, as shown in Figure 1B.

[0041] With this configuration, by rotating the adjustment dial 43 of the position adjustment mechanism 40, the amount of protrusion of the rolling element 41 relative to the inner edge PL of the square tube SP is adjusted, and the roller 31, which is pressed against the inner edge PL of the square tube SP by the biasing force of the biasing means 33 of the biasing mechanism 30, allows the central axis of the housing 10 to align with the axis Z of the square tube SP, thereby enabling the square tube inspection device 1 to be positioned, or centered. However, it is not necessary for them to perfectly coincide, and a positional misalignment that does not hinder the traction movement of the housing 10 is acceptable.

[0042] Then, as the traction device rewinds the traction rope 100, the square tube inspection device 1 descends along the axis Z of the square tube SP by its own weight. Conversely, as the traction device winds up the traction rope 100, the square tube inspection device 1 can be raised along the axis Z of the square tube SP. Note that the inspection of the inner surface of the square tube SP by the inspection means 20 may be performed during the rising or descending phase, and the rising and descending may be repeated multiple times.

[0043] Finally, the second to fourth embodiments of the present invention will be described.

[0044] Figure 4 is a cross-sectional view taken by cutting a rectangular tube SP along the axis Z of the rectangular tube SP in an inspection using the rectangular tube inspection device 201 of the second embodiment according to the present invention. The square tube inspection device 201 of the second embodiment differs from the square tube inspection device 1 of the first embodiment in that, as shown in Figure 4, it is equipped with multiple biasing mechanisms 30 and position adjustment mechanisms 40 in the direction along the axis Z of the square tube SP.

[0045] Here, the biasing mechanism 30 and position adjustment mechanism 40 of the head section 211 and the biasing mechanism 30 and position adjustment mechanism 40 of the second head section 213 have the same structure. Furthermore, the biasing mechanisms 30 of the head section 211 and the second head section 213 are provided on the same two sides of the housing 210, and the position adjustment mechanisms 40 of the head section 211 and the second head section 213 are also provided on the remaining two sides of the housing 210.

[0046] A tail section 212 is positioned between the head section 211 and the second head section 213, and a second tail section 214, connected to the towing rope 100, is positioned at the other end of the second head section 213.

[0047] In the second embodiment of the rectangular tube inspection device 201, the housing 210 can be centered by a total of four biasing mechanisms 30 and a total of four position adjustment mechanisms 40.

[0048] Figure 5 is a cross-sectional view taken by cutting a rectangular tube SP along the axis Z of the rectangular tube SP in an inspection using the rectangular tube inspection device 301 of the third embodiment according to the present invention. The rectangular tube inspection device 301 of the third embodiment differs in that the length of the housing 310 in the direction along axis Z is sufficiently longer than the length of the housing 210 in the direction along axis Z of the rectangular tube inspection device 201 of the second embodiment.

[0049] Specifically, as shown in Figure 5, the housing 310 has a length such that, at the position where the head portion 311 of the housing 310 is most deeply inserted from the end face of the square tube SP, it protrudes from the end face of the square tube SP. In other words, the length L of the housing 310 from the position where the position adjustment mechanism 40 of the second head portion 313 is provided to the end face of the second tail portion 314 is greater than the distance Y from the position where the position adjustment mechanism 40 of the second head portion 313 contacts the inner surface of the square tube SP to the end face of the square tube SP at the position where the housing 310 is most deeply inserted from the end face of the square tube SP.

[0050] A tail section 312 is positioned between the head section 311 and the second head section 313, and a second tail section 314, connected to the towing rope 100, is positioned at the other end of the second head section 313.

[0051] In this third embodiment of the rectangular pipe inspection device 301, the amount of the towing rope 100 extended can be shortened by the length of the housing 310 (second tail portion 314). Furthermore, in the rectangular pipe inspection device 301, the housing 310 (second tail portion 314) can always be exposed to the outside of the rectangular pipe SP, regardless of the position in which the housing 310 enters the rectangular pipe SP.

[0052] Figure 6 is an enlarged plan view, seen from the lower end side, of the inspection being performed using the rectangular pipe inspection device 401 of the fourth embodiment according to the present invention. The square tube inspection device 401 of the fourth embodiment differs significantly from the square tube inspection devices 1,201,301 of the first to third embodiments, in that the roller 431 and the rolling element 441 contact the corner PC of the square tube SP, as shown in Figure 6.

[0053] The roller 431 of the biasing mechanism 430 in the fourth embodiment has a width slightly narrower than the roller 31 of the first embodiment, and a larger diameter. Also, the rolling element 441 of the position adjustment mechanism 440 in the fourth embodiment does not have a large width like in the first embodiment, but has a narrow width similar to the roller 431, and a larger diameter. The other structures are basically the same as the biasing mechanism 30 and position adjustment mechanism 40 of the first embodiment.

[0054] In this fourth embodiment of the rectangular tube inspection device 401, by rotating the adjustment dial 43 of the position adjustment mechanism 440, the amount of protrusion of the rolling element 441 relative to the inner corner PC of the rectangular tube SP is adjusted, and the roller 431, which is pressed against the inner corner PC of the rectangular tube SP by the biasing force of the biasing means 33 of the biasing mechanism 430, allows the central axis of the housing 10 to align with the axis Z of the rectangular tube SP, thereby similarly enabling the positioning, or centering, of the rectangular tube inspection device 401. Note that the narrower the width, the deeper the roller 431 and rolling element 441 will contact the corner PC of the rectangular tube SP.

[0055] As described above, the first embodiment of the rectangular tube inspection device 1 according to the present invention is a rectangular tube inspection device 1 that inspects the inner surface of a rectangular tube SP while pulling a housing 10 having an inspection means 20, and comprises a biasing mechanism 30 that biases a roller 31 that contacts the inner surface of the rectangular tube SP, and a position adjustment mechanism 40 that has a rolling element 41 that contacts the inner surface of the rectangular tube SP and adjusts the position of the housing 10 on the rectangular tube SP, wherein the housing 10 has four surfaces, the biasing mechanism 30 is arranged on two adjacent and orthogonal surfaces of the housing 10, and the position adjustment mechanism 40 is arranged on the other two adjacent and orthogonal surfaces of the housing 10.

[0056] As a result, the rollers 31 and rolling elements 41 come into contact at four orthogonal points on the inner surface of the rectangular tube SP, making it easier to position the housing 10 relative to the rectangular tube SP. Furthermore, since the orientation of the housing 10 can be stabilized inside the rectangular tube SP, the rectangular tube inspection device 1 can be moved (descended) inside the vertically positioned rectangular tube SP by its own weight while being pulled by the traction rope 100.

[0057] Furthermore, while the internal inspection devices described in Patent Documents 1 and 2 were self-propelled and therefore large and complex in structure, the square tube inspection device 1 of this embodiment is compact and can be towed by a towing rope 100. Therefore, even at work sites such as nuclear power plants where the available equipment and devices are somewhat limited, internal inspection of square tubes SP using the square tube inspection device 1 becomes possible as long as there is a crane or winch capable of winding up the towing rope 100.

[0058] The rectangular tube inspection devices 201 and 301 of the second and third embodiments are equipped with multiple biasing mechanisms 30 and position adjustment mechanisms 40 in a direction along the axis Z of the rectangular tube SP. This allows biasing by rollers 31 and positioning by rolling elements 41 to be performed at multiple locations separated along the axis Z of the rectangular tube SP. As a result, it is possible to prevent the housings 210 and 310 from tilting or twisting inside the rectangular tube SP, and to stabilize the posture of the housings 210 and 310.

[0059] The position adjustment mechanism 40 in this embodiment can change the amount of protrusion of the rolling elements 41 relative to the inner surface of the rectangular tube SP. This allows the amount of protrusion of the rolling elements 41 to be adjusted according to the inner dimensions, even when multiple rectangular tube SPs have different inner dimensions, enabling the housing 10 to be positioned within the rectangular tube SP. Furthermore, even when the cross-sectional shape of the rectangular tube SP is not square but rectangular, the housing 10 can still be positioned within the rectangular tube SP.

[0060] In the third embodiment, the housing 310 has a length such that it protrudes from the end face of the square pipe SP at the position where it penetrates furthest from the end face of the square pipe SP. This allows the amount of the tow rope 100 to be extended to be shortened by the length of the housing 310, thereby reducing the effect of the tow rope 100's sway and preventing the housing 310 from tilting. Furthermore, regardless of the position in which the housing 310 penetrates the square pipe SP, the housing 310 (specifically its second tail portion 314) is always exposed to the outside of the square pipe SP. Therefore, by installing a guide means on the outside to guide the housing 310 (the second tail portion 314), the housing 310 can be prevented from tilting.

[0061] In the first to third embodiments, the rollers 31 and rolling elements 41 contact the side PL of the rectangular tube SP, while in the fourth embodiment, the rollers 431 and rolling elements 441 contact the corner PC of the rectangular tube SP. By bringing the rollers 31 and rolling elements 41 into contact with the four side PLs of the rectangular tube SP, or by bringing the rollers 431 and rolling elements 441 into contact with the four corner PCs of the rectangular tube SP, the housings 10, 210, 310, and 410 can be positioned within the rectangular tube SP, and their orientation can be stabilized.

[0062] Although preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims.

[0063] (modified version) In the above embodiment, the housing 10 had a separate structure in which the head portion 11 and the tail portion 12 were integrated. However, the head portion 11 and the tail portion 12 may be a single integrated structure with the same cross-sectional shape. For example, the housing 10 may be formed from an aluminum frame with a rectangular outer shape and grooves, formed by extrusion molding. In this case, the biasing mechanism 30 and the position adjustment mechanism can be attached using the grooves of the aluminum frame, making it easy to align them in the axial Z direction. [Explanation of Symbols]

[0064] 1. Rectangular tube inspection device 10 Housing, 11 Head section, 111 Bracket, 12 Tail section, 121 Suspension device, 13 Post, 14 Boss, 15 Guide column 20 Inspection methods, 25 Observation devices 30 biasing mechanism, 31 roller, 32 biasing arm, 33 biasing means 40 Position adjustment mechanism, 41 Roller, 42 Stem, 421 Support part, 422 Main body, 43 Adjustment dial, 433 Screw shaft 100 Towing ropes 201 Rectangular tube inspection device, 210 Housing, 211 Head section, 212 Tail section, 213 Second head section, 214 Second tail section 301 Rectangular tube inspection device, 310 Housing, 311 Head section, 312 Tail section, 313 Second head section, 314 Second tail section 401 Rectangular tube inspection device, 431 Roller, 441 Roller SP square tube, PC corner, PL side

Claims

1. A rectangular tube inspection device that inspects the inner surface of a rectangular tube while towing a housing equipped with an inspection means, A biasing mechanism that biases a roller that contacts the inner surface of a rectangular tube, It comprises a rolling element that contacts the inner surface of the rectangular tube, and a position adjustment mechanism that adjusts the position of the housing on the rectangular tube, The housing has four sides, The biasing mechanism is arranged on two adjacent, orthogonal surfaces of the housing, The position adjustment mechanism is arranged on two other adjacent, orthogonal surfaces of the housing. A rectangular tube inspection device characterized by the following features.

2. Multiple biasing mechanisms and position adjustment mechanisms are provided in a direction along the axis of the rectangular tube. The rectangular tube inspection device according to claim 1.

3. The position adjustment mechanism is capable of changing the amount the rolling element protrudes from the inner surface of the rectangular tube. The rectangular tube inspection device according to claim 1 or 2.

4. The housing has a length such that it protrudes from the end face of the rectangular tube at the position where the housing penetrates furthest from the end face of the rectangular tube. The rectangular tube inspection device according to claim 1 or 2.

5. The roller and the rolling element contact the corner or edge of the rectangular tube. The rectangular tube inspection device according to claim 1 or 2.

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