A device for measuring the amount of curvature of structural steel, a method for measuring the amount of curvature of structural steel, a method for straightening structural steel, and a method for manufacturing structural steel.

Abstract

To provide a shape steel bending amount measuring device, a shape steel bending amount measuring method, a shape steel correction method, and a shape steel manufacturing method with which it is possible to measure a bending amount irrespective of a type of shape steel.SOLUTION: A shape steel bending amount measuring device according to the present invention comprises: a distance measuring unit having five or more distance sensors as one set that are provided on a same coordinate plane orthogonal to a longitudinal direction, with at least two each arranged at left and right in a width direction of a shape steel and at least one located upward of the shape steel; a measurement position calculation unit for calculating a plurality of measurement position coordinates on a surface in a cross sectional shape of the shape steel from information on distance from each distance sensor to the surface of the shape steel and information regarding a position of each distance sensor; a feature point calculation unit for calculating a plurality of feature point coordinates in the cross sectional shape of the shape steel using the plurality of measurement position coordinates; and a bending amount calculation unit for calculating the position coordinate of a center of gravity position in the cross sectional shape of the shape steel by using the plurality of feature point coordinates and compare the position coordinates of the center of gravity position at three or more points in the longitudinal direction so as to calculate a bending amount of the shape steel.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This invention relates to a device for measuring the amount of curvature of structural steel, a method for measuring the amount of curvature of structural steel, a method for straightening structural steel, and a method for manufacturing structural steel. [Background technology]

[0002] Structural steel refers to steel materials with various distinctive shapes, such as H-beams and unequal-sided angle steel, and some products are long, exceeding 20 meters in length. Because they are long, straightness is considered important when they are shipped as products. For example, in the case of H-beams, JIS regulations allow a deviation of up to 1 mm in the width direction for every 1 meter in the longitudinal direction (0.1% of the length ratio). Structural steel manufactured by hot rolling will bend, so it is important to quantitatively measure the amount of bending in order to correct the bending to within the acceptable range. Conventionally, the following methods have been known for measuring the amount of bending in the longitudinal direction of long objects.

[0003] Patent Document 1 discloses a method for determining the curvature of an H-shaped steel beam in a stationary state. In the method disclosed in Patent Document 1, a distance sensor that can travel along the longitudinal direction of the stationary H-shaped steel beam is installed, and distance information is continuously measured by moving the distance sensor in the longitudinal direction, and the curvature of the H-shaped steel beam is measured based on the measured distance information.

[0004] Patent Document 2 discloses a method for measuring the shape of an H-beam while it is running on a rolling line. In the method disclosed in Patent Document 2, a pair of distance sensors are used in the vertical direction of the H-beam, and a pair of distance sensors are used in the horizontal direction to continuously measure the shape of the H-beam in the width direction and Z direction along the longitudinal direction, and the amount of bending and warping of the H-beam is calculated.

[0005] Patent Document 3 discloses a method for measuring the shape of an H-beam while it is running on a rolling line. In the method disclosed in Patent Document 3, a total of seven distance sensors are used to take measurements: three pairs of distance sensors from one side in the width direction of the H-beam, and one distance sensor from the Z direction. The longitudinal shape of the H-beam is then measured based on the obtained distance information. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2013-228325 [Patent Document 2] Japanese Patent Publication No. 2006-234540 [Patent Document 3] Japanese Patent Publication No. 2018-159561 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the method disclosed in Patent Document 1 is limited to measurements taken when the structural steel is stationary and cannot be performed on a conveyor line. Furthermore, it requires a mechanism to travel several tens of meters in length to match the length of the structural steel, which results in high costs.

[0008] The method disclosed in Patent Document 2 allows for measurement on the conveyor line, but it has the drawback of being susceptible to the effects of the structural steel being tilted or vibrating during transport. It has been confirmed that the structural steel vibrates upward by several centimeters on the conveyor line.

[0009] The method disclosed in Patent Document 3 is a technique that can measure the amount of bending while reducing the effects of slanting and vibration of H-shaped steel during transport, compared to the method disclosed in Patent Document 2. However, the method disclosed in Patent Document 3 is limited to H-shaped steel only, and cannot measure the amount of bending of other types of steel, such as unequal-sided angle steel, which has a right-angled triangular cross-section.

[0010] As shown in Figure 1(a), the unequal-sided angle steel 100, which has a long side portion 100a and a short side portion 100b, is placed on the shaped steel conveying device 60 and conveyed in an asymmetrical V-shape during the manufacturing process. In the method disclosed in Patent Document 3, for example, as shown in Figure 1(a), a laser beam 22 emitted from a distance sensor 21 positioned in the width direction perpendicular to the conveying direction of the unequal-sided angle steel 100 strikes the outer surface of the long side portion 100a, which is the outer surface of the long side portion 100a, of the unequal-sided angle steel 100 at an oblique angle. In Figure 1(a), the unequal-sided angle steel 100 is not bouncing upward due to vibrations during conveying, and the irradiation position of the laser beam 22 on the outer surface of the long side 101a is at point P11, which is approximately in the center of the outer surface of the long side 101a. On the other hand, as shown in Figure 1(b), if the unequal-sided angle steel 100 bounces upward due to vibration during transport, the irradiation position of the laser beam 22 on the long side outer surface 101a from the distance sensor 21 will be at point P12, which is closer to the distance sensor 21 in the width direction than point P11 shown in Figure 1(a). Therefore, if there is a displacement shift in the width direction at the irradiation position (measurement position) on the long side outer surface 101A, it will be measured by the measurement sensor, resulting in an incorrect amount of bending being measured.

[0011] Furthermore, in the method disclosed in Patent Document 3, the distance sensor is installed above the H-beam so that the laser beam emitted from the distance sensor strikes the upper surface of the web of the H-beam, taking into account the effects of vibration during the transportation of the H-beam. However, the laser beam from the distance sensor installed above the H-beam also incidents on the unequal-sided angle steel at an oblique angle. Therefore, it is impossible to distinguish whether the displacement of the upper surface of the web of the H-beam measured by the laser beam is due to the vibration of the unequal-sided angle steel or to the movement of the unequal-sided angle steel in the width direction. Consequently, when measuring the amount of curvature of unequal-sided angle steel using the method disclosed in Patent Document 3, it is impossible to determine whether the measured amount of curvature is due to the curvature itself or to the effects of vibration, and the method disclosed in Patent Document 3 can only be applied to H-beams.

[0012] The present invention has been made in view of the above problems, and its purpose is to provide a structural steel bending amount measuring device that can measure the amount of bending of structural steel regardless of the type of structural steel, a method for measuring the amount of bending of structural steel, a method for straightening structural steel, and a method for manufacturing structural steel. [Means for solving the problem]

[0013] In order to solve the aforementioned problems and achieve the objective, (1) The steel section bending amount measuring device according to the present invention is a bending amount measuring device for measuring the amount of bending in the longitudinal direction of a steel section, and comprises: a distance measuring unit which has five or more distance sensors arranged as a set on the same coordinate plane perpendicular to the longitudinal direction, with at least two on each side in the width direction perpendicular to the longitudinal direction of the steel section and at least one above the steel section; a measurement position calculation unit which calculates a plurality of measurement position coordinates on the surface of the cross-sectional shape of the steel section from distance information from each distance sensor to the surface of the steel section measured by the distance measuring unit and information on the position of each distance sensor; a feature point calculation unit which calculates a plurality of feature point coordinates in the cross-sectional shape of the steel section using the plurality of measurement position coordinates calculated by the measurement position calculation unit; and a bending amount calculation unit which calculates the position coordinate of the center of gravity in the cross-sectional shape of the steel section using the plurality of feature point coordinates calculated by the feature point calculation unit, and calculates the amount of bending of the steel section by comparing the position coordinate of the center of gravity at three or more locations in the longitudinal direction.

[0014] (2) The steel bend amount measuring device according to the present invention, in the invention of (1) above, wherein the steel is an unequal-sided angle steel and is placed in an asymmetrical V-shape, and the distance measuring unit includes a first distance sensor positioned on the short side in the width direction so as to irradiate laser light toward the surface of the short side of the unequal-sided angle steel, and a second distance sensor positioned on the short side in the width direction below the first distance sensor so as to irradiate laser light toward a position below the irradiation position of the laser light of the first distance sensor on the surface of the short side, and The device includes: a third distance sensor positioned on the long side in the width direction so as to irradiate laser light toward the surface of the long side of the unequal-sided angle steel; a fourth distance sensor positioned on the long side in the width direction and below the third distance sensor so as to irradiate laser light toward a position below the irradiation position of the laser light of the third distance sensor on the surface of the long side; and a fifth distance sensor positioned above the long side so as to irradiate laser light toward a position above the irradiation position of the laser light of the third distance sensor on the surface of the long side.

[0015] (3) The steel bend amount measuring device according to the present invention is characterized in that, in the invention of (1) or (2) above, three distance measuring units are arranged at predetermined intervals in the longitudinal direction.

[0016] (4) The method for measuring the amount of curvature of a structural steel according to the present invention is a method for measuring the amount of curvature of a structural steel in the longitudinal direction, comprising: a distance measurement step of measuring the distance from each distance sensor to the surface of the structural steel by a distance measuring unit provided on the same coordinate plane perpendicular to the longitudinal direction, with five or more distance sensors arranged as a set on the same coordinate plane perpendicular to the longitudinal direction, with at least two arranged on each side in the width direction perpendicular to the longitudinal direction of the structural steel and at least one arranged above the structural steel; distance information measured by each distance sensor in the distance measurement step and related to the position of each distance sensor The system includes: a measurement position coordinate calculation step that calculates multiple measurement position coordinates on the surface of the cross-sectional shape of the steel section from the information obtained; a feature point coordinate calculation step that calculates multiple feature point coordinates in the cross-sectional shape of the steel section using the multiple measurement position coordinates calculated in the measurement position coordinate calculation step; and a bending amount calculation step that calculates the position coordinate of the centroid in the cross-sectional shape of the steel section using the multiple feature point coordinates calculated in the feature point coordinate calculation step, and calculates the bending amount of the steel section by comparing the position coordinates of the centroid at three or more locations in the longitudinal direction.

[0017] (5) The method for measuring the amount of curvature of a structural steel according to the present invention is as described in (4) above, wherein the structural steel is an unequal-sided angle steel and is placed in an asymmetrical V-shape, and in the measurement position coordinate calculation step, the position coordinates of the first distance measurement position on the surface of the short side portion are calculated by a first distance sensor located on the short side portion of the unequal-sided angle steel in the width direction, and the position coordinates of the second distance measurement position on the surface of the short side portion are calculated by a second distance sensor located on the short side portion in the width direction and below the first distance sensor, and the position coordinates of the second distance measurement position on the surface of the short side portion are calculated The system calculates the position coordinates, calculates the position coordinates of the third distance measurement position on the surface of the long side of the unequal-sided angle steel, calculates the position coordinates of the fourth distance measurement position on the surface of the long side of the long side of the steel, calculates the position coordinates of the fourth distance measurement position on the surface of the long side of the steel, which is below the third distance measurement position, using a fourth distance sensor located on the long side of the steel in the width direction and below the third distance sensor, and calculates the position coordinates of the fifth distance measurement position on the surface of the long side of the steel, which is above the third distance measurement position, using a fifth distance sensor located above the long side of the steel.

[0018] (6) The method for measuring the bending amount of the section steel according to the present invention is, in the invention of (5) above, in the characteristic point coordinate calculation step, a first straight line passing through the first distance measurement position and the second distance measurement position, and a second straight line passing through the third distance measurement position, the fourth distance measurement position, and the fifth distance measurement position are calculated, and the position coordinates of a first characteristic point, which is the intersection point of the first straight line and the second straight line, are calculated. The position coordinates of a second characteristic point at a position below the first characteristic point by the length of the short side portion on the first straight line are calculated, and the position coordinates of a third characteristic point at a position below the first characteristic point by the length of the long side portion on the second straight line are calculated.

[0019] (7) The method for measuring the bending amount of the section steel according to the present invention is, in the invention of (6) above, in the bending amount calculation step, on a coordinate plane orthogonal to the longitudinal direction, for a triangle having the first characteristic point, the second characteristic point, and the third characteristic point as vertices, the average of the position coordinates of the first characteristic point, the second characteristic point, and the third characteristic point is taken, and the position coordinates of the centroid position of the triangle are calculated as the position coordinates of the centroid position in the cross-sectional shape of the section steel.

[0020] (8) The method for correcting the section steel according to the present invention uses the method for measuring the bending amount of the section steel of any one of the inventions of (4) to (7) above to correct the section steel.

[0021] (9) The method for manufacturing the section steel according to the present invention includes a step of correcting the section steel using the method for correcting the section steel of the invention of (8) above.

Effect of the Invention

[0022] The section steel bending amount measuring device, the method for measuring the bending amount of the section steel, the method for correcting the section steel, and the method for manufacturing the section steel according to the present invention have the effect of being able to measure the bending amount regardless of the type of the section steel.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a diagram for explaining the vibration influence of an unequal-leg angle steel. [Figure 2] Figure 2 shows an unequal-sided angle steel being transported by a structural steel conveying device. [Figure 3] Figure 3 is a cross-sectional view showing the schematic configuration of an unequal-sided angle steel according to the embodiment. [Figure 4] Figure 4 is a block diagram showing the schematic configuration of a structural steel bending amount measuring device according to an embodiment. [Figure 5] Figure 5 shows a configuration in which three distance measuring units are arranged in the conveying direction of an unequal-sided angle steel in a structural steel bending amount measuring device according to the embodiment. [Figure 6] Figure 6 shows the position of the distance sensor relative to the unequal-sided angle steel on the structural steel conveying device. [Figure 7] Figure 7 is a flowchart showing an example of the control for calculating the amount of curvature in the structural steel curvature measuring device according to the embodiment. [Figure 8] Figure 8 shows the calculation method for the cross-sectional shape of an unequal-sided angle steel by the calculation unit. [Figure 9] Figure 9 shows a method for calculating the amount of curvature from the characteristic points and centroid position of the cross-sectional shape of an unequal-sided angle steel. [Figure 10] Figure 10 shows the position of the distance sensor relative to the H-shaped steel on the steel shaping conveying device. [Figure 11] Figure 11 shows the method by which the calculation unit calculates the cross-sectional shape of an H-shaped steel beam. [Modes for carrying out the invention]

[0024] The following describes embodiments of the steel section bending amount measuring device, steel section bending amount measuring method, steel section straightening method, and steel section manufacturing method according to the present invention. However, the present invention is not limited to these embodiments.

[0025] Figure 2 shows an unequal-sided angle steel 100 being transported by a structural steel transport device 60. Figure 3 is a cross-sectional view showing the schematic configuration of the unequal-sided angle steel 100 according to this embodiment.

[0026] As shown in Figure 2, in this embodiment, the unequal-sided angle steel 100, which is the structural steel material to be measured for bending, is placed on the structural steel conveying device 60 in an asymmetrical V-shape. The structural steel conveying device 60 is a device for conveying structural steel such as the unequal-sided angle steel 100 along its longitudinal direction. The structural steel conveying device 60 is provided with a plurality of conveying rollers arranged along the conveying direction, and the unequal-sided angle steel is supported from below by the plurality of conveying rollers, enabling the unequal-sided angle steel 100 to be conveyed in the longitudinal direction. The unequal-sided angle steel 100 has a long side portion (web portion) 100a and a short side portion (flange portion) 100b. Also, as shown in Figure 3, the length L1 of the long side portion 100a is longer than the length L2 of the short side portion 100b. The unequal-sided angle steel 100 can be either an unequal-sided, equal-thickness angle steel in which the thickness of the long side 100a and the thickness of the short side 100b are equal, or an unequal-sided, unequal-thickness angle steel in which the thickness of the long side 100a and the thickness of the short side 100b are different.

[0027] Figure 4 is a block diagram showing the schematic configuration of the structural steel bending amount measuring device 1 according to this embodiment.

[0028] As shown in Figure 4, the structural steel bending amount measuring device 1 according to this embodiment includes a distance measuring unit 2, an operating condition acquisition unit 3, a calculation unit 4, and a display unit 5, etc.

[0029] The distance measuring unit 2 includes a first distance sensor 21a, a second distance sensor 21b, a third distance sensor 21c, a fourth distance sensor 21d, and a fifth distance sensor 21e as a sensor set. In the following description, unless otherwise specified, the first distance sensor 21a, the second distance sensor 21b, the third distance sensor 21c, the fourth distance sensor 21d, and the fifth distance sensor 21e will simply be referred to as distance sensor 21. Furthermore, this embodiment describes the case where a laser distance meter is used for distance sensor 21, but this is not the only case.

[0030] The operating condition acquisition unit 3 acquires information regarding operating conditions, including product specification information of the structural steel to be measured and information regarding the position of each distance sensor 21 of the distance measurement unit 2. The information regarding the position of the distance sensor 21 is, for example, the position coordinate on a two-dimensional coordinate plane perpendicular to the conveying direction of the structural steel. In this embodiment, when the conveying direction of the structural steel is the x-axis direction, the width direction of the structural steel perpendicular to this z-axis direction is defined as the y-axis direction, and the height direction of the structural steel perpendicular to the x-axis and y-axis directions is defined as the z-axis direction. The information regarding the position of the distance sensor 21 is then acquired by obtaining the position coordinate on a two-dimensional coordinate plane having a y-axis and a z-axis at a predetermined position coordinate on the x-axis.

[0031] The calculation unit 4 includes a measurement position calculation unit 41, a feature point calculation unit 42, a curvature amount calculation unit 43, a profile calculation unit 44, and a storage unit 45.

[0032] The measurement position calculation unit 41 determines, for each of the five distance sensors 21a to 21e, the irradiation position of the laser beam from the distance sensor 21 on the surface of the unequal-sided angle steel 100 and the distance between the distance sensor 21 and the distance sensor 21, based on the data output from each of the five distance sensors 21a to 21e. Then, the measurement position calculation unit 41 calculates the measurement position coordinates on the surface of the cross-sectional shape of the unequal-sided angle steel 100 on a two-dimensional coordinate plane for each of the five distance sensors 21a to 21e, based on the determined distances and information regarding the position of the distance sensors 21.

[0033] The feature point calculation unit 42 calculates the position coordinates of multiple feature points in the cross-sectional shape of the unequal-sided angle steel 100 using the measurement position coordinates calculated by the distance sensors 21a to 21e, which are calculated by the measurement position calculation unit 41, in the cross-sectional profile calculated by the profile calculation unit 44.

[0034] The curvature calculation unit 43 calculates the curvature of the unequal-sided angle steel 100 using the position coordinates of multiple feature points in the cross-sectional shape of the unequal-sided angle steel 100, which are calculated by the feature point calculation unit 42.

[0035] The profile calculation unit 44 calculates a cross-sectional profile representing the surface shape (cross-sectional shape) of the cross section perpendicular to the transport direction of the transported structural steel, based on the information of multiple measurement positions calculated by the measurement position calculation unit 41. For example, the profile calculation unit 44 acquires the coordinates of each measurement position from the five distance sensors 21a to 21e calculated by the measurement position calculation unit 41 as five two-dimensional profiles. Then, the profile calculation unit 44 combines the five two-dimensional profiles for the same cross section of the unequal-sided angle steel 100 and calculates a single cross-sectional profile as information of the surface shape for the same cross section (on the same two-dimensional coordinate plane) of the unequal-sided angle steel 100.

[0036] The memory unit 45 stores various information used to calculate the amount of curvature of the unequal-sided angle steel 100, such as distance information measured by the distance measurement unit 2 and operating condition information acquired by the operating condition acquisition unit 3.

[0037] The display unit 5 displays the amount of curvature of the unequal-sided angle steel 100, calculated by the calculation unit 4, on the display.

[0038] Figure 5 shows a configuration in the structural steel bending amount measuring device 1 according to the embodiment, in which three distance measuring units 2 are arranged in the transport direction of the unequal-sided angle steel. In this embodiment, as shown in Figure 5, when the unequal-sided angle steel 100 is transported by the structural steel transport device 60, the transport direction of the unequal-sided angle steel 100 is defined as the x-axis, the width direction of the unequal-sided angle steel 100 is defined as the y-axis, and the height direction of the unequal-sided angle steel 100 is defined as the z-axis.

[0039] As shown in Figure 5, the distance measuring unit 2 is equipped with a first distance sensor 21a, a second distance sensor 21b, a third distance sensor 21c, and a fourth distance sensor 21d so as to be able to measure distances at two locations, one above and one below, on both the left and right sides in the width direction of the unequal-sided angle steel 100. In addition, the shaped steel bending amount measuring device 1 according to this embodiment is equipped with a fifth distance sensor 21e above the unequal-sided angle steel 100.

[0040] Laser beams 22a, 22b, 22c, and 22d are emitted from the first distance sensor 21a, the second distance sensor 21b, the third distance sensor 21c, and the fourth distance sensor 21d, respectively, along the width direction of the unequal-sided angle steel 100. Laser beam 22e is emitted from the fifth distance sensor 21e along the height direction of the unequal-sided angle steel 100.

[0041] The first distance sensor 21a is positioned on the short side 100b side in the width direction of the unequal side angle steel 100 so as to irradiate laser light 22a toward the short side outer surface 101b, which is the outer surface of the short side portion 100b of the unequal side angle steel 100. The second distance sensor 21b is positioned on the short side 100b side in the width direction of the unequal side angle steel 100, below the first distance sensor 21a, so as to irradiate laser light 22b toward a position below the irradiation position of the laser light 22a on the short side outer surface 101b. The third distance sensor 21c is positioned on the long side 100a side in the width direction of the unequal side angle steel 100 so as to irradiate laser light 22c toward the long side outer surface 101a, which is the outer surface of the long side portion 100a of the unequal side angle steel 100. The fourth distance sensor 21d is positioned below the third distance sensor 21c on the long side portion 100a side in the width direction of the unequal side angle steel 100, so as to irradiate the laser beam 22d toward a position below the irradiation position of the laser beam 22c on the long side outer surface 101a. The fifth distance sensor 21e is positioned above the long side portion 100a in the height direction of the unequal side angle steel 100, so as to irradiate the laser beam 22e toward a position above the irradiation position of the laser beam 22c on the long side outer surface 101a.

[0042] While the distance measuring unit 2 can satisfy the requirement for calculating the curvature of the unequal-sided angle steel 100 by equipping it with a minimum of five distance sensors 21 as a set, the number of distance sensors 21 in a set provided by the distance measuring unit 2 is not limited to five. In other words, the distance measuring unit 2 can be equipped with five or more distance sensors 21 as a set by arranging at least two distance sensors 21 on each side in the width direction of the unequal-sided angle steel 100 and at least one distance sensor 21 above the unequal-sided angle steel 100.

[0043] Furthermore, in order to accurately calculate the amount of curvature of the unequal-sided angle steel 100, it is preferable that the optical axes of all distance sensors 21 provided in the distance measurement unit 2 are on the same plane. Therefore, the more distance sensors 21 are provided in the distance measurement unit 2, the more complicated the work of arranging the distance sensors 21 so that the optical axes of all distance sensors 21 provided in the distance measurement unit 2 are on the same plane tends to become. Also, for maintenance purposes, all distance sensors 21 provided in the distance measurement unit 2 will need to be replaced every few years. When replacing the distance sensors 21 in this way, the factory line will have to be stopped, so it is desirable to minimize the time required to replace the distance sensors 21 as much as possible. Therefore, in order to shorten the time required to replace the distance sensors 21, it is preferable that the number of distance sensors 21 in a set provided in the distance measurement unit 2 be as small as possible. Also, the more distance sensors 21 in a set provided in the distance measurement unit 2, the higher the cost. For these reasons, it is preferable that the distance measurement unit 2 is equipped with five distance sensors 21 as a set.

[0044] Furthermore, in the structural steel bending amount measuring device 1 according to the embodiment, as shown in Figure 5, three distance measuring units 2 are installed at regular intervals in the longitudinal direction (conveying direction) of the unequal-sided angle steel 100. However, the number of distance measuring units 2 installed in the longitudinal direction of the unequal-sided angle steel 100 is not limited to three.

[0045] For example, when calculating the amount of curvature of an unequal-sided angle steel 100 with a length of 10 [m] by measuring it at 1 [m] intervals in the longitudinal direction, one set of distance measuring units 2 will be placed at 1 [m] intervals in the longitudinal direction of the unequal-sided angle steel 100, resulting in a total of 11 sets of distance measuring units 2. Alternatively, for example, if the amount of movement in the width direction and the amount of rotation along the z axis of the unequal-sided angle steel 100 on the structural steel conveying device 60 are significantly small, only one set of distance measuring units 2 can be used, and measurements can be taken with the distance measuring unit 2 every 1 [m] of conveying the unequal-sided angle steel 100. Then, by summing the measurement data after conveying is complete, the amount of curvature of the unequal-sided angle steel 100 can be calculated using one set of distance measuring units 2. Furthermore, for example, when calculating the amount of curvature statically without transporting the unequal-sided angle steel 100, or when the transport speed of the unequal-sided angle steel 100 is slow and the effects of vibration and Z-axis rotation are minimal, the amount of curvature of the unequal-sided angle steel 100 may be measured by arranging only one set of distance measuring units 2. In that case, for example, the distance measuring unit 2 is scanned in the longitudinal direction of the unequal-sided angle steel 100 and measurements are taken every 1 [m].

[0046] Figure 6 shows the position of the distance sensor 21 relative to the unequal-sided angle steel 100 on the structural steel conveying device 60.

[0047] As shown in Figure 6, the first distance sensor 21a, the second distance sensor 21b, the third distance sensor 21c, the fourth distance sensor 21d, and the fifth distance sensor 21e, and the distance measurement positions P1, P2, P3, P4, and P5 of each distance sensor 21, lie on the same yz coordinate plane. The distance measurement positions P1, P2, P3, P4, and P5 are the irradiation positions of the laser beams 22a to 22e emitted from the distance sensors 21a to 21e onto the surface of the cross-sectional shape of the unequal-sided angle steel 100. There are no particular restrictions on the inclination of the laser beams 22a to 22e emitted from the distance sensors 21a to 21e on the yz coordinate plane. On the other hand, for computational purposes, it is preferable that the laser beams 22a to 22d of the first distance sensors 21a to the fourth distance sensors 21d are parallel to the y axis, and the laser beam 22e of the fifth distance sensor 21e is parallel to the z axis.

[0048] In this embodiment, the position coordinates of the nth distance sensor on the yz coordinate plane are (yn, Zn). The laser beams 22a to 22e from the distance sensors 21a to 21e only need to strike somewhere on the outer surface (long side outer surface 101a and short side outer surface 101b) of the unequal-sided angle steel 100 to be measured.

[0049] Therefore, the first distance sensor 21a and the second distance sensor 21b do not need to have the same position coordinates (y1=y2) in the y-axis direction (width direction). Also, the third distance sensor 21c and the fourth distance sensor 21d do not need to have the same position coordinates (y3=y4) in the y-axis direction (width direction). Furthermore, the first distance sensor 21a and the third distance sensor 21c do not need to have the same position coordinates (z1=z3) in the z-axis direction (height direction). Also, the second distance sensor 21b and the fourth distance sensor 21d do not need to have the same position coordinates (z2=z4) in the z-axis direction (height direction).

[0050] On the other hand, for computational purposes, it is preferable that the first distance sensor 21a and the second distance sensor 21b have the same position coordinates (y1=y2) in the y-axis direction (width direction). Similarly, it is preferable that the third distance sensor 21c and the fourth distance sensor 21d have the same position coordinates (y3=y4) in the y-axis direction (width direction). Similarly, it is preferable that the first distance sensor 21a and the third distance sensor 21c have the same position coordinates (z1=z3) in the z-axis direction (height direction). Similarly, it is preferable that the second distance sensor 21b and the fourth distance sensor 21d have the same position coordinates (z2=z4) in the z-axis direction (height direction).

[0051] Furthermore, the positions of the first distance sensor 21a, the second distance sensor 21b, the third distance sensor 21c, the fourth distance sensor 21d, and the fifth distance sensor 21e in the z-axis direction (height direction) must be greater than the maximum upward vibration amount of the unequal-sided angle steel 100. For example, the position of the fifth distance sensor 21e in the z-axis direction (height direction) must be greater than or equal to the distance at which it does not come into contact with the unequal-sided angle steel 100. Note that there are no particular restrictions on the position of the fifth distance sensor 21e in the y-axis direction (width direction), as long as the laser beam 22e strikes somewhere on the outer surface of the unequal-sided angle steel 100 being measured. Furthermore, the positions of the first distance sensor 21a, the second distance sensor 21b, the third distance sensor 21c, and the fourth distance sensor 21d in the y-axis direction (width direction) must be positions that do not come into contact with the unequal-sided angle steel 100 being measured.

[0052] Furthermore, when multiple sets of distance measuring units 2 are arranged along the longitudinal direction of the unequal-sided angle steel 100, the positional relationship of each distance sensor 21 in each distance measuring unit 2 only needs to be known by the relative position coordinates of each distance sensor 21 on the yz coordinate plane. On the other hand, for calculation purposes, it is preferable that the y coordinate and z coordinate are the same. For example, if the position coordinate of the first distance sensor 21a of the distance measuring unit 2 installed at a position where the position coordinate in the x-axis direction (conveying direction) is x=10 is (10,20,30), then it is preferable that the position coordinate of the first distance sensor 21a of the distance measuring unit 2 installed at a position where the position coordinate in the x-axis direction (conveying direction) is x=20 is (20,20,30). Furthermore, if the position coordinates of the fifth distance sensor 21e of the distance measuring unit 2 installed at a position where the x-axis direction (conveying direction) position coordinate is x=10 are (10,30,60), then it is preferable that the position coordinates of the fifth distance sensor 21e of the distance measuring unit 2 installed at a position where the x-axis direction (conveying direction) position coordinate is x=20 are (20,30,60).

[0053] Figure 7 is a flowchart showing an example of the control for calculating the amount of curvature in the structural steel curvature measuring device 1 according to the embodiment.

[0054] The bending amount calculation flow shown in Figure 7 starts when the unequal-sided angle steel 100, which is the target of bending amount measurement, is transported by the shape steel transport device 60, and, for example, the distance value measured by the distance measurement unit 2 exceeds a threshold, and the calculation unit 4 determines that a shape steel exists. In addition, in the bending amount selection flow shown in Figure 7, it is assumed that information regarding the position of the distance sensor 21 has been acquired in advance by the operating condition acquisition means as an operating condition.

[0055] First, the structural steel bending amount measuring device 1 measures the distance from each distance sensor 21 to the unequal-sided angle steel 100 using each distance sensor 21 of the distance measuring unit 2 (Step S1: Distance measurement process). Next, the structural steel bending amount measuring device 1 calculates the measurement position coordinates of the unequal-sided angle steel 100 using the measurement position calculation unit 41, based on the distance to the unequal-sided angle steel 100 measured by each distance sensor 21 and the position coordinates of each distance sensor 21 (Step S2: Measurement position coordinate calculation process). Next, the structural steel bending amount measuring device 1 acquires operating conditions such as product specification information of the unequal-sided angle steel 100 using the operating condition acquisition unit 3 (Step S3: Operating condition acquisition process). Next, the structural steel bending amount measuring device 1 calculates the characteristic point coordinates in the cross-sectional shape of the unequal-sided angle steel 100 from the calculated measurement position coordinates using the product specification information of the unequal-sided angle steel 100, with the characteristic point calculation unit 42 (Step S4: Feature point coordinate calculation step). Next, the structural steel bending amount measuring device 1 calculates the bending amount of the unequal-sided angle steel 100 from the calculated multiple characteristic point coordinates using the bending amount calculation unit 43 (Step S5: Bending amount calculation step). Next, the structural steel bending amount measuring device 1 outputs the calculated bending amount result to the display unit 5 (Step S6: Display step). After that, the structural steel bending amount measuring device 1 terminates the control of the series of bending amount calculations.

[0056] Next, the details of the method for calculating the amount of curvature of the unequal-sided angle steel 100 according to the embodiment will be described. In the method for calculating the amount of curvature of the unequal-sided angle steel 100 according to the embodiment, the cross-sectional shape of the unequal-sided angle steel 100 is calculated by multiple sets of distance measuring units 2, and the coordinates of multiple feature points in the calculated cross-sectional shape are calculated. Then, in the method for calculating the amount of curvature of the unequal-sided angle steel 100 according to the embodiment, the amount of curvature of the unequal-sided angle steel 100 is calculated by comparing the widthwise position of the centroid position obtained from the multiple feature point coordinates for each cross-sectional shape calculated by the multiple sets of distance measuring units 2.

[0057] Figure 8 shows the method for calculating the cross-sectional shape of the unequal-sided angle steel 100 by the calculation unit 4. In the method for calculating the cross-sectional shape of the unequal-sided angle steel 100 explained using Figure 8, the cross-sectional profile in the yz coordinate plane is calculated by the profile calculation unit 44.

[0058] First, in the measurement position coordinate calculation process, the calculation unit 4 calculates the position coordinates of distance measurement positions P1 to P5 on the surface of the cross-sectional shape of the unequal-sided angle steel 100, using measurement information from distance sensors 21a to 21e, as shown in Figure 8(a). Then, using the position coordinates of distance measurement positions P1 to P5, the calculation unit 4 calculates the cross-sectional profile of the unequal-sided angle steel 100 in the yz coordinate plane as information about the surface shape of the unequal-sided angle steel 100 on the same coordinate plane.

[0059] Next, in the feature point coordinate calculation step, the calculation unit 4 calculates a first straight line 71 passing through the first distance measurement position P1 and the second distance measurement position P2, and a second straight line 72 passing through the third distance measurement position P3, the fourth distance measurement position P4, and the fifth distance measurement position P5, as shown in Figure 8(b). Then, the calculation unit 4 calculates the position coordinates of the feature point O, which is the intersection point of the calculated first straight line 71 and the second straight line 72, as the first feature point.

[0060] Here, the product specifications of the unequal-sided angle steel 100 (such as the length L1 of the long side portion 100a and the length L2 of the short side portion 100b, as well as which side in the y-axis direction (width direction) is the long side portion 100a) is known in advance from the operating condition information acquired by the operating condition acquisition unit 3.

[0061] Therefore, as shown in Figure 8(c), the calculation unit 4 calculates the position coordinates of the second feature point, feature point A, which is located on the first straight line 71 at a distance L2 from feature point O along the length of the short side portion 100b. The calculation unit 4 also calculates the position coordinates of the third feature point, feature point B, which is located on the second straight line 72 at a distance L1 from feature point O along the length of the long side portion 100a. The position coordinates of feature points O, A, and B calculated in this way are the feature point coordinates on the surface of the cross-sectional shape of the unequal-sided angle steel 100.

[0062] Next, in the bending amount calculation process, the calculation unit 4 determines the centroid position G of the triangle △OAB whose vertices are feature point O, feature point A, and feature point B, as shown in Figure 8(d). △ The position coordinates are calculated using the position coordinates of feature point O, feature point A, and feature point B on the yz coordinate plane. Then, the calculation unit 4 calculates the centroid position G △ The amount of curvature of the unequal-sided angle steel 100 is calculated using the position coordinates in the width direction (y-axis direction).

[0063] Figure 9 shows a method for calculating the amount of curvature from the characteristic points and centroid position of the cross-sectional shape of the unequal-sided angle steel 100. Note that this explanation describes the case where three sets of three distance measuring units 2 are used for the unequal-sided angle steel 100, but the method is not limited to this.

[0064] As shown in Figure 9(a), for each of the three sets of distance measuring units 2 arranged at predetermined intervals in the transport direction (x-axis direction) of the unequal-sided angle steel 100, the calculation unit 4 calculates the characteristic points A and B and the centroid position G based on the cross-sectional shape calculation method described above. △ The calculation unit 4 calculates the position coordinates of the feature points A1, B1 and the centroid position G1 for the distance measurement unit 2 located at the furthest downstream side in the transport direction (x-axis direction). △Calculate the position coordinates. Further, the calculation unit 4 calculates the position coordinates of the feature points A2, B2 and the centroid position G2 for the distance measurement unit 2 arranged in the middle in the transport direction (x-axis direction). △ Calculate the position coordinates. Further, the calculation unit 4 calculates the position coordinates of the feature points A3, B3 and the centroid position G3 for the distance measurement unit 2 arranged on the most upstream side in the transport direction (x-axis direction). △ Calculate the position coordinates.

[0065] Next, the calculation unit 4 plots the feature points A, B and the centroid position G of each of the three sets of distance measurement units 2 on the same xy coordinate plane as shown in FIG. 9(b). Next, the calculation unit 4 determines the centroid position G1 of the distance measurement unit 2 arranged on the most downstream side in the transport direction (x-axis direction). △ And the centroid position G3 of the distance measurement unit 2 arranged on the most upstream side in the transport direction (x-axis direction). △ Calculate a straight line 73 passing through. Then, the calculation unit 4 calculates the distances from the straight line 73 to each centroid position G1 △ , G2 △ , G2 △ , G3 △ in the y-axis direction, and uses each of the calculated distances as the amount of bending at the measurement points in each longitudinal direction.

[0066] In the method for measuring the amount of bending of the unequal-leg angle steel 100 according to the embodiment, the amount of bending at each measurement point in the longitudinal direction of the unequal-leg angle steel 100 is calculated using the xy coordinates of the centroid positions G1 △ , G2 △ , G3 △ . Thereby, in the method for measuring the amount of bending of the unequal-leg angle steel 100 according to the embodiment, the amount of bending of the unequal-leg angle steel 100 can be calculated while suppressing the influence of the vibration and z-axis rotation during the conveyance of the unequal-leg angle steel 100.

[0067] Next, the case where the shape steel to be measured for the amount of bending by the shape steel bending amount measuring device 1 according to the embodiment is an H-shaped steel will be described. Note that, since the method for measuring the amount of bending of the H-shaped steel by the shape steel bending amount measuring device 1 according to the embodiment is substantially the same as the method for measuring the amount of bending of the unequal-leg angle steel 100, the description will be omitted as appropriate.

[0068] Figure 10 shows the position of the distance sensor 21 relative to the H-shaped steel beam 200 on the structural steel beam conveying device 60.

[0069] The structural steel bend amount measuring device 1 according to this embodiment is equipped with a first distance sensor 21a, a second distance sensor 21b, a third distance sensor 21c, and a fourth distance sensor 21d so as to be able to measure distances at two locations, one above and one below, on both the left and right sides in the width direction of the H-shaped steel 200. In addition, the structural steel bend amount measuring device 1 according to this embodiment is equipped with a fifth distance sensor 21e above the H-shaped steel 200.

[0070] Laser beams 22a, 22b, 22c, and 22d are emitted from the first distance sensor 21a, the second distance sensor 21b, the third distance sensor 21c, and the fourth distance sensor 21d, respectively, along the width direction (y-axis direction) of the H-shaped steel beam 200. Laser beam 22e is emitted from the fifth distance sensor 21e along the height direction (z-axis direction) of the H-shaped steel beam 200.

[0071] The first distance sensor 21a is positioned on the flange portion 200b side in the width direction of the H-shaped steel 200 so as to irradiate laser light 22a toward the flange outer surface 201b, which is the outer surface of the flange portion 200b of the H-shaped steel 200. The second distance sensor 21b is positioned on the flange portion 200b side in the width direction of the H-shaped steel 200 and below the first distance sensor 21a so as to irradiate laser light 22b toward a position below the irradiation position of laser light 22a on the flange outer surface 201b. The third distance sensor 21c is positioned on the flange portion 200c side in the width direction of the H-shaped steel 200 so as to irradiate laser light 22c toward the flange outer surface 201c, which is the outer surface of the flange portion 200c of the H-shaped steel 200. The fourth distance sensor 21d is positioned below the third distance sensor 21c on the flange portion 200c side in the width direction of the H-beam 200, so as to irradiate the laser beam 22d toward a position below the irradiation position of the laser beam 22c on the flange outer surface 201c. The fifth distance sensor 21e is positioned above the web portion 200a in the height direction of the H-beam 200 so as to irradiate the laser beam 22e toward the web outer surface 201a, which is the outer surface of the web portion 200a.

[0072] As shown in Figure 10, the distance sensors 21a to 21e and the distance measurement positions P1, P2, P3, P4, and P5 on the surface of the cross-sectional shape of the H-shaped steel 200 measured by the distance sensors 21a to 21e lie on the same yz coordinate plane.

[0073] Figure 11 shows the method by which the calculation unit 4 calculates the cross-sectional shape of the H-shaped steel beam 200.

[0074] First, in the measurement position coordinate calculation process, the calculation unit 4 calculates the position coordinates of distance measurement positions P1 to P5 on the surface of the cross-sectional shape of the H-beam 200 using measurement information from distance sensors 21a to 21e, as shown in Figure 11(a). Then, using the position coordinates of distance measurement positions P1 to P5, the calculation unit 4 calculates the cross-sectional profile of the H-beam 200 in the yz coordinate plane as information about the surface shape of the H-beam 200 on the same coordinate plane.

[0075] Next, in the feature point coordinate calculation process, the calculation unit 4 calculates a first straight line 81 passing through the first distance measurement position P1 and the second distance measurement position P2, and a second straight line 82 passing through the third distance measurement position P3 and the fourth distance measurement position P4, as shown in Figure 11(b). Furthermore, the calculation unit 4 finds a line segment 83 that passes through the fifth distance measurement position P5 and has the shortest distance between the first straight line 81 and the second straight line 82. Then, the calculation unit 4 calculates the position coordinate of feature point C, which is the intersection point of the first straight line 81 and the line segment 83. In addition, the calculation unit 4 calculates the position coordinate of feature point D, which is the intersection point of the second straight line 82 and the line segment 83.

[0076] Here, the product specifications of the H-beam 200 (such as the lengths of the left and right flanges 200b and 200c of the H-beam 200, and the widths of the outer surfaces of the flanges 201b and 201c) are already known from the operating conditions information acquired by the operating conditions acquisition unit 3.

[0077] Therefore, when the length of the flange portion 200b is L, the calculation unit 4 calculates the position coordinates of feature point H, which is located L / 2 above feature point C on the first straight line 81, as shown in Figure 11(c). The calculation unit 4 also calculates the position coordinates of feature point I, which is located L / 2 below feature point C on the first straight line 81. Furthermore, when the length of the flange portion 200c is L, the calculation unit 4 calculates the position coordinates of feature point J, which is located L / 2 above feature point D on the second straight line 82, as shown in Figure 11(c). Furthermore, the calculation unit 4 calculates the position coordinates of feature point K, which is located L / 2 below feature point D on the second straight line 82. The position coordinates of the feature points H, I, J, and K calculated in this way are the feature point coordinates in the cross-sectional shape of the H-shaped steel 200.

[0078] Next, as shown in Figure 11(d), the calculation unit 4 uses the position coordinates of feature points H, I, J, and K on the yz coordinate plane to determine the centroid position G of the H-shaped steel beam 200. H Calculate the position coordinates.

[0079] Then, the calculation unit 4 calculates the centroid position G corresponding to each of the multiple sets of distance measuring units 2, similar to the method for calculating the amount of curvature of the unequal-sided angle steel 100 explained using Figure 9. H The amount of curvature of the H-beam 200 is calculated using the position coordinates in the width direction (y-axis direction).

[0080] As described above, the structural steel bending amount measuring device 1 according to the embodiment can measure the bending amount of structural steel using the same device regardless of the type of structural steel, such as unequal-sided angle steel 100 or H-shaped steel 200. Therefore, the structural steel bending amount measuring device 1 according to the embodiment can shorten the time required for measuring the bending amount generated for straightening the bending of structural steel and setting up the bending straightening machine, and can also suppress the time required for straightening again.

[0081] Furthermore, the amount of curvature of a structural steel calculated by the structural steel curvature measurement method according to the embodiment can be used, for example, in a structural steel straightening method for straightening structural steel after rolling or heat treatment. This allows the curvature of the structural steel to be appropriately straightened by the structural steel straightening method. In addition, by including a step of straightening structural steel using this structural steel straightening method in the structural steel manufacturing method, structural steel can be manufactured with high precision. [Explanation of symbols]

[0082] 1. Steel Bevel Measurement Device 2. Distance measurement unit 3. Department for Acquiring Operating Conditions 4 Arithmetic section 5 Display section 21a First distance sensor 21b Second distance sensor 21c Third distance sensor 21d 4th distance sensor 21e Fifth distance sensor 60-shaped steel conveying device 100 Unequal-sided angle steel 100a Long side 100b Short side 101a Outer surface of the longer side 101b Short side outer surface 200 H section steel 200a Web Department 200b, 200c flange section 201a Web exterior 201b, 201c Flange outer surface

Claims

1. A bending amount measuring device for measuring the amount of bending in the longitudinal direction of a structural steel, A distance measuring unit comprising five or more distance sensors arranged as a set on the same coordinate plane perpendicular to the longitudinal direction, with at least two sensors positioned on each side in the width direction perpendicular to the longitudinal direction of the steel section, and at least one sensor positioned above the steel section; A measurement position calculation unit calculates a plurality of measurement position coordinates on the surface of the cross-sectional shape of the steel, based on distance information from each distance sensor measured by the distance measurement unit to the surface of the steel section and information regarding the position of each distance sensor. A feature point calculation unit calculates multiple feature point coordinates in the cross-sectional shape of the steel section using the multiple measurement position coordinates calculated by the measurement position calculation unit, A bending amount calculation unit calculates the position coordinates of the centroid in the cross-sectional shape of the steel section using the multiple feature point coordinates calculated by the feature point calculation unit, and calculates the bending amount of the steel section by comparing the position coordinates of the centroid at three or more locations in the longitudinal direction. A device for measuring the amount of bending of structural steel.

2. Whether three or more of the distance measuring units are arranged at predetermined intervals in the longitudinal direction, The structural steel is transported along the longitudinal direction by an external structural steel transport device, and its distance is measured at predetermined intervals by the distance measuring unit, The distance measuring unit scans in the longitudinal direction and measures the structural steel at predetermined intervals, A structural steel bending amount measuring device according to claim 1, having any of the above.

3. The aforementioned steel section is an unequal-sided angle steel, and is placed in an asymmetrical, angled shape. The distance measuring unit is A first distance sensor is positioned on the short side in the width direction so as to irradiate laser light toward the surface of the short side of the unequal-sided angle steel, A second distance sensor is positioned on the short side in the width direction and below the first distance sensor, so as to irradiate laser light toward a position below the irradiation position of the laser light of the first distance sensor on the surface of the short side, A third distance sensor is positioned on the longer side in the width direction so as to irradiate laser light toward the surface of the longer side of the unequal-sided angle steel, A fourth distance sensor is positioned on the long side in the width direction and below the third distance sensor, so as to irradiate laser light toward a position below the irradiation position of the laser light of the third distance sensor on the surface of the long side, A fifth distance sensor is positioned above the long side portion so as to irradiate laser light toward a position above the irradiation position of the laser light of the third distance sensor on the surface of the long side portion, A steel bend amount measuring device according to claim 1 or 2, having the following:

4. A method for measuring the amount of curvature of a structural steel in the longitudinal direction, A distance measurement step is to measure the distance from each distance sensor to the surface of the steel section by a distance measuring unit that has five or more distance sensors arranged as a set on the same coordinate plane perpendicular to the longitudinal direction, with at least two sensors arranged on each side in the width direction perpendicular to the longitudinal direction of the steel section and at least one sensor arranged above the steel section, A measurement position coordinate calculation step calculates multiple measurement position coordinates on the surface of the cross-sectional shape of the steel, based on the distance information measured by each distance sensor in the distance measurement step and information regarding the position of each distance sensor. A feature point coordinate calculation step, which uses the multiple measurement position coordinates calculated in the measurement position coordinate calculation step to calculate multiple feature point coordinates in the cross-sectional shape of the steel section, A bending amount calculation step is performed which involves using the multiple feature point coordinates calculated in the feature point coordinate calculation step to calculate the position coordinate of the centroid in the cross-sectional shape of the structural steel, and comparing the position coordinates of the centroid at three or more locations in the longitudinal direction to calculate the bending amount of the structural steel, A method for measuring the amount of curvature of structural steel.

5. Whether three or more of the distance measuring units are arranged at predetermined intervals in the longitudinal direction, The structural steel is transported along the longitudinal direction by an external structural steel transport device, and the distance is measured at predetermined intervals by the distance measuring unit, The distance measuring unit is scanned in the longitudinal direction, and the structural steel is measured by the distance measuring unit at predetermined intervals, A method for measuring the amount of curvature of a structural steel according to claim 4, comprising any of the above.

6. The aforementioned steel section is an unequal-sided angle steel, and is placed in an asymmetrical, angled shape. In the above measurement position coordinate calculation step, The position coordinates of the first distance measurement position on the surface of the short side portion are calculated by the first distance sensor, which is positioned on the short side portion of the unequal-sided angle steel in the width direction. The position coordinates of the second distance measurement position, which is located below the first distance measurement position on the surface of the short side, are calculated by the second distance sensor, which is located on the short side in the width direction and below the first distance sensor. The position coordinates of the third distance measurement position on the surface of the long side portion are calculated by the third distance sensor, which is positioned on the long side portion of the unequal-sided angle steel in the width direction. The position coordinates of the fourth distance measurement position, which is located below the third distance measurement position on the surface of the long side, are calculated by the fourth distance sensor, which is located on the long side in the width direction and below the third distance sensor. A fifth distance sensor positioned above the long side calculates the position coordinates of the fifth distance measurement position, which is above the third distance measurement position on the surface of the long side. The method for measuring the amount of curvature of a structural steel according to claim 4.

7. In the feature point coordinate calculation step, A first straight line passing through the first distance measurement position and the second distance measurement position is calculated, and a second straight line passing through the third distance measurement position, the fourth distance measurement position and the fifth distance measurement position is calculated, and the position coordinates of the first feature point which is the intersection of the first straight line and the second straight line are calculated. The position coordinates of the second feature point located on the first straight line, at a position below the first feature point by the length of the short side, are calculated. The position coordinates of the third feature point located on the second straight line, at a position below the first feature point by the length of the long side, are calculated. The method for measuring the amount of curvature of a structural steel according to claim 6.

8. In the process of calculating the amount of curvature, On a coordinate plane perpendicular to the longitudinal direction, for a triangle whose vertices are the first feature point, the second feature point, and the third feature point, the average of the position coordinates of the first feature point, the second feature point, and the third feature point is taken to calculate the position coordinate of the centroid of the triangle as the position coordinate of the centroid of the cross-sectional shape of the steel section. The method for measuring the amount of curvature of a structural steel according to claim 7.

9. A method for straightening a structural steel, comprising straightening the structural steel using the method for measuring the amount of curvature of the structural steel described in any one of claims 4 to 8.

10. A method for manufacturing structural steel, comprising the step of straightening structural steel using the method for straightening structural steel described in claim 9.

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