JP2011007641A - Torsion angle detection method and device of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torsion detection method and torsion detection device for accurately measuring torsion direction and torsion angle of a long member having different-shaped cross section in an in-line manner.SOLUTION: This torsion detection method is used for detecting the torsion angle and torsion direction of the long member having a different-shaped cross section. The torsion detection method includes a measuring process of measuring each projection wire diameter of the long member from at least two or more positions separated at a predetermined angle along a circumferential direction at an optional position of at least one axial direction and measuring each projection wire diameter. The torsion detection method further includes an indexing process of comparing an actually measured value of each projection wire diameter measured in the measuring process with a correlation of a cross-sectional model calculated from the projection wire diameter from each of at least two or more positions separated at the predetermined angle along the circumferential direction in the cross-sectional model having the same cross-sectional shape as the cross-sectional shape of the long member to be measured, and determining the actually measured torsion angle and torsion direction of the long member.

Description

  The present invention relates to a torsion angle detection method and a torsion angle detection device for a long member that is used in a spring, a ring, a rail, or the like and has an irregular cross section.

  For example, the oil spring tempered wire (OT wire) for valve springs is designed to have a cross-sectional shape other than a perfect circle for the purpose of reducing stress dispersion and spring height, in addition to those having a true circular cross-sectional shape. There is an irregular cross section line (MA line). The MA wire may be twisted during the oil temper treatment (OT treatment). Here, torsion means that when the cross section of the wire rod at a predetermined position is compared with the cross section of the wire rod at another position different from this position, the cross section at another position is inclined with respect to the cross section at the predetermined position. State. When the twist angle is large, or when the degree of twist differs depending on the location of the wire (when the variation is large), the quality of the molded product is greatly affected, for example, the dimensional accuracy of the subsequent molded product varies. For this reason, with the aim of improving the quality of molded products and improving the yield rate, there is an increasing demand for reduction in torsional variation and control of the torsion direction, and accurately measure the torsion angle and torsion direction of the wire in advance. Need to manage.

  Thus, an apparatus for detecting the twist angle of the MA wire has been proposed (Patent Document 1). The apparatus described in Patent Document 1 fixes one end of an MA wire, places the other end of the MA wire on a support base having a V-shaped groove, and displays the end surface. Then, by detecting the inclination of the one end with respect to the end face, it is possible to detect how much the other end of the MA wire is inclined with respect to the one end. In this case, the two ends of the MA line are cut, for example, by 2 m, and the twist angles are detected to detect how much twist is generated at both ends of the MA line.

  There is also a method for monitoring the torsional variation of the entire length in-line. In this method, the MA line is projected from a certain direction, and a change in the projected line diameter is detected. That is, the MA line has a major axis (maximum diameter) and a minor axis (minimum diameter), and when the MA line is inclined, the projected line diameter changes. By detecting the presence or absence of a change in the projected wire diameter, the presence or absence of torsional variation is monitored.

JP-A-1-223306

  However, in the apparatus described in Patent Document 1, it is not possible to measure parts other than both ends only by measuring the torsion angles of both ends of the MA line, and grasp the variation in torsion over the entire length of the MA line. Can not do it. Further, in the method of Patent Document 1, an error is induced by a gap generated between the other end of the MA wire and the V-shaped groove of the support base, the reliability is inferior, and the conditions such as the wire diameter change. As a result, the measurement accuracy changes. For this reason, the thing of patent document 1 has the problem that precision management is not enough.

  In addition, in the method of projecting the MA line from a certain direction and detecting the change in the projected line diameter, it is impossible to actually measure the angle and direction of the twist that are most necessary in in-line monitoring as numerical values. However, it is only monitoring. For this reason, it is difficult to adjust the setup work at the time of manufacture, and the management standard at the time of monitoring is made opaque.

  Thus, a technique for accurately measuring both the twist direction and the twist angle over the entire length of the wire has not been established.

  In view of the above problems, the present invention provides a torsion detection method and a torsion detection apparatus capable of measuring the torsion direction and torsion angle of a long member having an irregular cross section with high accuracy in-line.

  The torsion detection method of the present invention is a torsion detection method for detecting a torsion angle and a torsion direction of a long member having an irregular cross-sectional shape, and is obtained from at least two positions separated by a predetermined angle along the circumferential direction. Measure the projected line diameter of each member at at least one arbitrary position in the axial direction and measure each projected line diameter, and measure the actual value of each projected line diameter measured in the measuring process. In the cross-sectional model having the same cross-sectional shape as that of the target long member, the cross-sectional model calculated from the projected wire diameters from at least two positions separated by a predetermined angle along the circumferential direction. Compared with the correlation, it includes an indexing step for determining the twist angle and twist direction of the actually measured long member. Here, the irregular cross-sectional shape has a shape other than a perfect circle, has a long diameter and a short diameter, and may have an elliptical shape, an oval shape, a triangular shape, a polygonal shape, or a random shape. . The projected line diameter refers to a line diameter (a width dimension from a tangent line of the long member in a certain direction to a tangent line parallel thereto) when the long member is parallel-projected from a certain direction.

  According to the torsion detection method of the present invention, in the cross-sectional model having the same cross-sectional shape as that of the long member to be measured, the projected line diameter changes when the long member relatively rotates (twists). To do. This change is measured from a direction separated by a predetermined angle along the circumferential direction while maintaining the predetermined angle, and a correlation between the projection line diameters from different directions is obtained in advance. Then, each of the elongated members having the same cross-sectional shape as the cross-sectional model is measured by measuring each projection line diameter from a position separated by a predetermined angle along the circumferential direction at at least one arbitrary position in the axial direction. The displacement of the projected line diameter is measured, and the displacement of each measured value is compared with the correlation. Thereby, the torsion angle and torsion direction of the elongate member which has an irregular cross section can be calculated | required by a specific numerical value.

  The first projection line diameter, which is a line diameter obtained by parallel projection of the long member from a first direction orthogonal to the axial direction of the long member, is relative to the position of the long member relative to the projection direction along the circumferential direction. A wire diameter obtained by parallel projection of the long member from a second direction perpendicular to the axial direction of the long member and forming a constant angle with the first direction. The second projection line diameter is obtained over the entire circumference in the circumferential direction while relatively displacing the position of the long member relative to the projection direction along the circumferential direction, and the first projection line diameter at the circumferential position of the long member is obtained. And the corresponding relationship with the second projected wire diameter at the position corresponding to this can be obtained over the entire circumference, and this corresponding relationship can be used as the correlation in the cross-sectional model of the long member.

  The predetermined angle may be an angle at which the correlation forms a closed loop when the correlation of the cross-sectional model of the long member is obtained.

  The indexing step detects the torsion angle of the long member by detecting the moving distance and moving direction on the closed loop in the relationship between the measured first projection line diameter and second projection line diameter. Can determine the twist direction.

  The respective projected wire diameters can be continuously measured with respect to the entire length or a specific range of the long member. Thereby, a twist angle and a twist direction can be calculated | required about the full length of a long member, or a specific range.

  The long member may be a wire for spring forming. As a result, it is possible to determine whether or not the variation in torsion with respect to the reference (standard) in the spring wire is acceptable.

  The torsion detection device according to the present invention is a torsion detection device for detecting a torsion angle and a torsion direction of a long member having an irregular cross-sectional shape, and each projection of the long member from a position separated by a predetermined angle along the circumferential direction. A first wire diameter measuring means and a second wire diameter measuring means for measuring a wire diameter at an arbitrary position in the axial direction and measuring a displacement of each projected wire diameter; and each projection measured in the measuring step. In the cross-sectional model having the same cross-sectional shape as the cross-sectional shape of the long member to be measured, the displacement of the measured value of the wire diameter is measured from each of at least two positions separated by a predetermined angle along the circumferential direction. Indexing means for obtaining the measured twist angle and twist direction of the long member in comparison with the correlation calculated from the projected wire diameter, and the twist angle and twist in the direction perpendicular to the axial direction of the long member Direction It is possible to detect the.

  The torsion detection method of the present invention can determine the torsion angle and torsion direction of a long member having an irregular cross section with specific numerical values. Can be measured.

  Since the correspondence between the first projection line diameter at the circumferential position of the long member and the second projection line diameter at the position corresponding thereto can be obtained over the entire circumference, each projection shifted by a predetermined angle. The correlation of the wire diameter can be accurately obtained. Thereby, the twist angle and twist direction of a long member can be calculated | required with higher precision.

  When the predetermined angle is an angle such that the correlation forms a closed loop when determining the correlation of the cross-sectional model of the long member, the twist angle and the twist direction can be reliably determined.

  By detecting the moving distance and moving direction on the closed loop, the torsion angle and torsion direction of the long member can be calculated, and the torsion angle and torsion direction can be quantified, and the torsion angle and torsion direction can be accurately expressed. And can be measured.

  When the respective projected wire diameters are continuously measured with respect to the full length or a specific range of the long member, the twist angle and the twist direction can be obtained over the full length of the long member, and the variation of the twist is grasped. be able to. Thereby, the twist of a specific location can be detected and the twist of a long member can be detected with high precision.

  When the elongated member is a wire for spring forming, it is possible to determine whether or not torsional variation with respect to a standard (standard) is acceptable in spring forming, and suppress variation in spring height when spring forming is performed. And a high-quality spring can be manufactured stably.

  The torsion detection device of the present invention can determine the torsion angle and the torsion direction of a long member having an irregular cross section with specific numerical values, and therefore can measure the torsion angle and torsion direction with high accuracy. .

It is a front view of the twist measuring device of the present invention. It is a side view of the twist measuring device of the present invention. It is a front view of the measurement part of the twist measuring apparatus of this invention. It is the figure and graph which show the change of the projection wire diameter of the twist measuring method of this invention, (a) is a 1st projection wire diameter, (b) is a 2nd projection wire diameter. It is the graph which synthesize | combined the 1st projection line diameter of the twist measuring method of this invention, the 1st projection line diameter, and the 2nd projection line diameter which makes 45 degrees. It is a graph which shows the correlation with the 2nd projection line diameter which makes 45 degrees with the 1st projection line diameter and the 1st projection line diameter of the twist measuring method of this invention. It is the graph which synthesize | combined the 1st projection line diameter of the twist measuring method of this invention, the 1st projection line diameter, and the 2nd projection line diameter which makes 90 degrees. It is a graph which shows the correlation with the 2nd projection line diameter which makes 90 degrees with the 1st projection line diameter and the 1st projection line diameter of the twist measuring method of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  The torsion detection method of the present invention is to detect the torsion angle and torsion direction of a member having a long and irregular cross-sectional shape used for, for example, a spring, ring, rail or the like. The irregular cross-sectional shape has a shape other than a perfect circle and has a long diameter and a short diameter, and may have an elliptical shape, an oval shape, a triangular shape, a polygonal shape, or a random shape.

  As shown in FIGS. 1 and 2, the torsion detection apparatus according to the present invention includes a frame 1, a measurement unit 2 that measures a projected wire diameter of a long member L that is a measurement object, and a long measurement unit 2. A pair of linear guides 3a and 3b that travel along the axial direction of the length member L, an air chuck portion 4 that fixes the long member L with an air chuck, a servo motor 5 that rotates the long member L, and illustration are omitted. Indexing means. Here, the projected wire diameter refers to a wire diameter (a width dimension from a tangent line of a long member in a certain direction to a tangent line parallel to the long member L) obtained by parallel projection of the long member L from a certain direction.

  As shown in FIG. 3, the measuring unit 2 includes a stage 10, first wire diameter measuring means 11, and second wire diameter measuring means 12. The stage 10 is a flat plate having a rectangular outer periphery, and is provided with one slit 17. A circular hole 18 that is continuously provided from the slit 17 is provided at a substantially central portion of the stage 10. The long member L is inserted into the hole 18.

  The first wire diameter measuring means 11 is composed of a pair of a projector 13 and a light receiver 14. The projector 13 is disposed at one corner of the stage 10 and emits, for example, LED light. A light receiver 14 is disposed at a corner on the diagonal line with this, and the light emitted from the projector 13 is transmitted. Receive light. Thereby, a part of the light emitted from the projector 13 is blocked by the long member L, and the projected line diameter which is the blocked wire diameter can be measured. The second wire diameter measuring means 12 is composed of a pair of light projectors 15 and light receivers 16. The light projectors 15 are disposed at one corner of the stage 10, and the light receivers are disposed at the corners on the diagonal line of the light projectors 15. 16 is disposed. The angle formed by the first wire diameter measuring means 11 and the second wire diameter measuring means 12 is 45 °. That is, the angle formed by the straight line connecting the projector 13 and the light receiver 14 and the straight line connecting the projector 15 and the light receiver 16 is 45 °. As a result, the first wire diameter measuring means 11 and the second wire diameter measuring means 12 are long from a position shifted by a predetermined angle (45 ° in this embodiment) along the circumferential direction with respect to the long member L. Each projected line diameter of the scale member L can be measured.

  The indexing means is constituted by a personal computer, for example, and the displacement of the measured values of the respective projected wire diameters measured by the first wire diameter measuring means 11 and the second wire diameter measuring means 12 is expressed by the long member L. The measured twist angle and twist direction of the long member are obtained by comparing with the correlation calculated from the respective projection wire diameters shifted by a predetermined angle in the circumferential direction in the cross-sectional model. The cross-sectional model refers to one having the same cross-sectional shape as the cross-sectional shape of the long member to be measured.

  A twist detection method according to the present invention will be described. In this embodiment, as the long member L, a spring material (oil tempered wire) having an oval deformed cross-sectional shape and having a major axis of about 4.5 mm and a minor axis of about 3.7 mm is used.

  First, this long member is set in the twist detection device of the present invention. Specifically, at least one end portion of the long member L only needs to be fixed, and one end portion of the long member L which is a cross-sectional model is fixed to the air chuck portion 4. The other end is in a free state that is not fixed in the present embodiment, but may be fixed. Here, the cross-sectional model refers to one having the same cross-sectional shape as the cross-sectional shape of the long member to be measured. In this embodiment, the long member L to be measured is used as it is as a cross-sectional model. In this case, the long member L is inserted into the hole 18 of the stage 10 of the measurement unit 2. Further, the direction of the long member L fixed to the air chuck portion 4 is the direction shown in A of FIG. 4A, and the twist angle at this time is 0 °. Thereafter, by driving the servo motor 5, the long member is rotated once, and the position of the long member L with respect to the projection direction of the first wire diameter measuring means 11 and the second wire diameter measuring means 12 is along the circumferential direction. Displace relatively.

  Thereby, the first projection line which is the length of the shadow (wire diameter) obtained by parallel projection of the long member L from the first direction orthogonal to the axial direction of the long member L by the first wire diameter measuring means 11. The change in diameter is obtained over the entire circumference of the long member L in the circumferential direction. In this case, the change in the first projected wire diameter changes periodically as shown in FIG.

  In addition, the second wire diameter measuring means 12 performs parallel projection of the long member L from a second direction orthogonal to the axial direction of the long member L (that is, a position shifted by 45 ° in the circumferential direction from the first direction). A change in the second projected wire diameter, which is the length of the shadow (wire diameter), is obtained over the entire circumference of the long member L in the circumferential direction. In this case, the change in the second projected wire diameter changes periodically as shown in FIG.

  FIG. 5 shows a graph obtained by combining the change in the first projection line diameter and the change in the second projection line diameter. In this way, the first wire diameter measuring means 11 and the second wire diameter measuring means 12 that are displaced along the circumferential direction respectively determine the projected wire diameters, so that the two directions can be obtained at the same rotation angle of the long member L. Thus, the projection line diameter can be measured with a predetermined angle (45 ° in the present embodiment), and two data of the first projection line diameter and the second projection line diameter are always obtained. Then, a correspondence relationship between the first projection wire diameter and the second projection wire diameter is obtained over the entire circumference, and this correspondence relationship corresponds to the first projection wire diameter in the cross-sectional model of the long member L and this. It is set as a correlation with the 2nd projection line diameter in the position to perform. That is, as shown in FIG. 6, a correlation is made by plotting the values of the respective projection line diameters on the coordinates with the first projection line diameter as the horizontal axis and the second projection line diameter as the vertical axis. When the angle formed by the first wire diameter measuring means 11 and the second wire diameter measuring means 12 is 45 °, the correlation forms a closed loop.

  In the long member L having an oval deformed cross-sectional shape, the closed loop of the correlation is made one turn (A → B → C → D → A) when the long member L makes a half turn (180 °). Thus, as the long member L makes one rotation (360 °), the closed loop of the correlation becomes two rounds (A → B → C → D → E → F → G → H → A). Thus, according to the rotation of the long member L, the relationship between the first projection line diameter and the second projection line diameter moves on the closed loop. That is, by detecting the moving distance and moving direction on the closed loop in the relationship between the measured first and second projected wire diameters, the twist angle and twist direction of the long member are determined. be able to.

  Next, the measuring part 2 is scanned along the long member L from one end (chuck part) of the long member L to the other end. Accordingly, the projected line diameters of the first projected line diameter and the second projected line diameter are continuously measured with respect to the entire length of the long member at one arbitrary position in the axial direction. Measure the displacement of the projected wire diameter.

  Then, the indexing unit compares the measured displacement of each projected line diameter with the correlation in the cross-sectional model of the long member L, and obtains the measured twist angle and twist direction of the long member L. . Specifically, at one end portion of the long member L, the twist angle is 0 °, and in this case, the position of A in FIG. 6 is shown. For example, when the measured displacement between the first projection line diameter and the second projection line diameter moves clockwise from A and reaches C, the long member L is 90 in the positive direction. ° You can see that it is twisted. It can also be seen that when C reaches C again in the counterclockwise direction via B, A and D, it is twisted 180 ° in the negative direction. Thus, the twist angle of the long member L can be obtained by determining the start position and end position of the correlation from the measured displacement between the first projection line diameter and the second projection line diameter. Further, by detecting whether the correlation is clockwise or counterclockwise, the twist direction can be determined.

  By the way, when the angle formed by the first wire diameter measuring means 11 and the second wire diameter measuring means 12 is 90 °, the respective projected wire diameters of the long member L from the position shifted by 90 ° along the circumferential direction. It can also be measured.

  In this case, a graph in which the change in the first projected line diameter measured by the first wire diameter measuring unit 11 and the change in the second projected line diameter measured by the second wire diameter measuring unit 12 are combined, As shown in FIG. And the correlation which calculated | required the correspondence of the 1st projection line diameter and the 2nd projection line diameter over the perimeter is shown in FIG. When the first wire diameter measuring means 11 and the second wire diameter measuring means 12 are 90 °, the correlation draws one arc and does not form a closed loop. Thus, when the deformed cross-sectional shape is an oval, the first wire diameter measuring means 11 and the second wire diameter measuring means 12 are 0 °, 90 °, 180 °, 270 ° and the first The displacement of the projected line diameter and the displacement of the second projected line diameter cancel each other, and no closed loop is formed.

  In this case, when the twist angle is 0 °, the correspondence between the first projection line diameter and the second projection line diameter is the position A in FIG. And after reaching C, it moves from C to E. Thus, since this arc is reciprocated, the twist direction cannot be detected. Accordingly, it is desirable that the correlation is an angle that forms a closed loop.

  In the present invention, since the torsion angle and the torsion direction of the long member L having an irregular cross section can be obtained with specific numerical values, the torsion angle and the torsion direction of the long member L can be measured with high accuracy in-line. can do.

  Since the correspondence relationship between the first projection line diameter at the circumferential position of the long member L and the second projection line diameter at the position corresponding thereto can be obtained over the entire circumference, each shifted by a predetermined angle. It is possible to accurately obtain the correlation between the projected line diameters. Thereby, the twist angle and the twist direction of the long member L can be obtained with higher accuracy.

  When the predetermined angle is an angle at which the correlation forms a closed loop when determining the correlation of the cross-sectional model of the long member L, the twist angle and the twist direction can be reliably determined.

  By detecting the moving distance and moving direction on the closed loop, the torsion angle and torsion direction of the long member L can be calculated, and the torsion angle and torsion direction can be quantified, and the torsion angle and torsion can be accurately calculated. Direction.

  When the respective projected wire diameters are continuously measured with respect to the entire length or a specific range of the long member L, the twist angle and the twist direction can be obtained over the entire length of the long member L, and the variation of the twist is grasped. can do. Thereby, the twist of a specific location can be detected and the twist of the elongate member L can be detected with high precision.

  When the long member L is a wire for spring forming, it is possible to determine whether or not torsional variations with respect to a reference (standard) are acceptable in spring forming, and suppress spring height variations when spring forming is performed. And a high-quality spring can be manufactured stably.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the modified cross-sectional shape is not limited to an oval shape, an oval shape, Various shapes other than a true circle such as a triangle, a polygon, and a parallelogram can be used. Further, the angle formed between the first wire diameter measuring means and the second wire diameter measuring means can be various angles as long as the correlation is an angle that forms a closed loop. The long member L is not limited to a spring wire, but may be used for a ring, a rail, or the like. In short, the long member L can be applied to all long members that are twisted. As the first wire diameter measuring means and the second wire diameter measuring means, those that project light are used, but other means (for example, various measuring means such as a contact type) can be used as long as they can measure the projected wire diameter. ) To obtain the projected line diameter. Also, when obtaining the correlation, a measuring means other than projecting light may be used. Moreover, in the said embodiment, although the two-dimensional correlation of the elongate member L was calculated | required from two positions spaced apart along the circumferential direction, it is long from three positions spaced apart along the circumferential direction. The three-dimensional correlation of the member L can be obtained. Even if the correlation is two-dimensional, the actual measurement of the long member L can be measured from three or more positions. In this case, the twist angle and twist direction of the long member L can be obtained with high accuracy. In the above-described embodiment, the correlation is created using the long member L to be measured as a cross-sectional model. However, a cross-sectional model having the same cross section as that of the long member L is drawn by a computer, and the correlation is generated from the cross-sectional model drawn on the computer. You may create a relationship.

11 First wire diameter measuring means 12 Second wire diameter measuring means L Long member

Claims (7)

In a torsion detection method for detecting a torsion angle and a torsion direction of a long member having an irregular cross-sectional shape,
Measurement in which each projection line diameter is measured by measuring each projection line diameter of the long member from at least two or more positions separated by a predetermined angle along the circumferential direction at at least one axial position. Process,
In the cross-sectional model having the same cross-sectional shape as that of the long member to be measured, at least two of the measured values of the projected line diameters measured in the measurement step are separated by a predetermined angle along the circumferential direction. A torsion characterized by comprising an indexing step for determining the torsion angle and torsion direction of the long member measured in comparison with the correlation of the cross-sectional model calculated from the projected wire diameter from each of the above positions Detection method. The first projection line diameter, which is a line diameter obtained by parallel projection of the long member from a first direction orthogonal to the axial direction of the cross-sectional model of the long member, and the position of the long member with respect to the projection direction in the circumferential direction Along the entire circumferential direction while relatively displacing along the
A second projected wire diameter which is a wire diameter obtained by parallel projecting the elongated member from a second direction perpendicular to the axial direction of the cross-sectional model of the elongated member and forming a constant angle with the first direction; Finding the position of the long member relative to the projection direction over the entire circumference in the circumferential direction while relatively displacing along the circumferential direction,
A correspondence relationship between the first projection line diameter at the circumferential position of the cross-sectional model of the long member and the second projection line diameter at a position corresponding to the first projection line diameter is obtained over the entire circumference, and this correspondence relationship is obtained as the long member. The twist detection method according to claim 1, wherein the correlation in the cross-sectional model is the correlation.   3. The torsion detection method according to claim 1, wherein the predetermined angle is an angle at which the correlation forms a closed loop when the correlation of the cross-sectional model of the long member is obtained. .   The indexing step detects the moving distance on the closed loop and the moving direction of the correlation between the measured first projection line diameter and the second projection line diameter, thereby detecting the twist angle of the long member and The twist angle detection method according to claim 3, wherein the twist direction is determined.   The twist angle detection method according to any one of claims 1 to 4, wherein the respective projected wire diameters are continuously measured with respect to an entire length or a specific range of the long member.   The twist angle detection method according to any one of claims 1 to 5, wherein the elongated member is a wire for spring forming. In a torsion detection device for detecting a torsion angle and a torsion direction of a long member having an irregular cross-sectional shape,
A first wire diameter that measures the respective projected wire diameters of the elongated member from positions separated by a predetermined angle along the circumferential direction at at least one axial position, and measures the displacement of each projected wire diameter Measuring means and second wire diameter measuring means;
The displacement of the actual measurement value of each projected line diameter measured in the measurement step is at least spaced apart by a predetermined angle along the circumferential direction in a cross-sectional model having the same cross-sectional shape as the cross-sectional shape of the long member to be measured. Compared with the correlation calculated from the respective projected wire diameters from two or more positions, the indexing means for obtaining the measured twist angle and twist direction of the elongated member,
A twist detection device that detects a twist angle and a twist direction in a direction orthogonal to the axial direction of the long member.

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