JP4825525B2 - Wire rope flaw detector - Google Patents

Description

  The present invention relates to a wire rope flaw detector, and more particularly to a wire rope flaw detector suitable for use in an elevator.

  An example of a conventional wire rope damage detector is described in US Pat. In the damage detector described in this publication, a permanent magnet is used as an exciting means for magnetizing the wire rope so as to facilitate portability and operability. The permanent magnet has a strip shape and is separated from the magnet by a predetermined distance. A probe incorporating a probe coil for detecting leakage magnetic flux is attached to the magnetizer.

  An example of a conventional leakage magnetic flux detection device is described in Patent Document 2. The detection apparatus described in this publication magnetizes an inspection material close to a saturation magnetic flux density by placing a magnet near the non-inspection material in order to detect minute defects inside the inspection material. Three magnetic sensors, which are probe coils, are arranged in the middle of the magnetic poles, and the probe coils at both ends are in phase and the center probe coil is in reverse phase.

  Another example of the wire rope flaw detector is described in Patent Document 3. In the flaw detection apparatus described in this publication, in order to detect the presence or absence of damage for each strand, a plurality of magnetic sensors are arranged along the strand to detect leakage magnetic flux from the permanent magnet. The processing device detects a damage signal for each strand from the output of the magnetic sensor.

Japanese Unexamined Patent Publication No. 7-198684 JP 2002-257789 A JP 2003-50230 A

  In the detection apparatus described in Patent Document 1, it is recognized that it is difficult to accurately estimate the remaining strength of the rope when it is damaged both inside and outside the rope. Therefore, when this detection apparatus is used, another means is required to estimate the rope life with higher accuracy.

  Moreover, in the flaw detection apparatus described in Patent Document 2, flaw detection is certainly performed using the outputs of a plurality of sensors, but since consideration for flaw detection of a plurality of steel wires such as a wire rope is not sufficient. It is difficult to accurately estimate which of the steel wires is damaged. As a result, it is difficult to predict the life of the wire rope with high accuracy.

  In the flaw detection apparatus described in Patent Document 3, damage for each strand can be grasped. However, since there is no consideration for a decrease in output when scratches occur inside a plurality of steel wires constituting the strand, there is a risk of underestimating the scratches generated internally compared to externally generated scratches. is there.

  The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to detect damage to a wire rope with high accuracy regardless of the steel wire breaking position of the wire rope. Another object of the present invention is to estimate the life of a wire rope with high accuracy by detecting the damage of the wire rope with high accuracy.

A feature of the present invention that achieves the above object is that, in a wire rope flaw detector for flawing a wire rope having a strand formed by twisting a plurality of steel wires, a magnetizing means for partially magnetizing the wire rope, A plurality of magnetic detection means for detecting damage of the steel wire constituting the magnetized wire rope, the magnetic detection means being provided in the first and second magnetic detection spaced apart in the axial direction of the wire rope Each of the first and second magnetic detection means groups includes a plurality of magnetic detection means, and the circumferential positions of the first and second magnetic detection means groups are changed in units of groups . Storage means for storing a number of information on the position and orientation of the magnetic detection means and the moving speed of the wire rope; Output of the magnetic detection means; information on the position and orientation of the magnetic detection means stored in the storage means; And has a calculating means for calculating the damage degree of the wire rope on the basis of the moving speed of the-loop.

  In the above feature, the magnetic detection means is a directional magnetic detection means, and is preferably oriented so as to increase the magnetic detection sensitivity from the central axis of the wire rope to the outer diameter side. Among the magnetic detection means constituting the second magnetic detection means group, the first magnetic detection means that has obtained an output having a peak, and the first magnetic detection means adjacent to the first magnetic detection means It is preferable to calculate the position of the damaged portion in the wire rope using the output values of at least two second magnetic detection means that are not positioned on one straight line when included.

  In the above feature, the calculation means includes a first magnetic detection means for obtaining an output having a peak among the magnetic detection means constituting the first and second magnetic detection means groups, and the first magnetic detection means. It is preferable to calculate the position and degree of damage of the damaged portion in the wire rope using the output values of at least three second magnetic detection means that are not located on one straight line when including the means.

  Furthermore, the magnetic detection means which comprises the 1st, 2nd magnetic detection means group is hold | maintained, the jig | tool of the shape divided | segmented into plurality, the fixing means which integrates several jigs, and the integrated jig | tool The wire rope flaw detector main body to which the jig is attached, and the fixing means should release the integration of a plurality of jigs when an overload is applied to the jig from the wire rope. It is preferable to provide a signal transmission means for transmitting the signal of the magnetic detection means at the coupling portion. In addition, it is preferable that the storage unit has a storage unit that stores a wire rope usage history, and the calculation unit preferably identifies a portion where the wire rope is bent frequently from the wire rope usage history stored in the storage unit.

  According to the present invention, the two groups of magnetic sensors are arranged apart from each other in the axial direction of the wire rope, and the circumferential positions (phases) of the two groups of magnetic sensors are changed. Can be identified with high accuracy and high efficiency. Moreover, the degree of damage of each steel wire can be easily grasped. Furthermore, since noise caused by the irregularities of the strands of the wire rope and noise caused by the swinging of the wire rope can be canceled, it is easy to grasp the damage position and the degree of damage.

  Hereinafter, an embodiment of a wire rope flaw detector according to the present invention will be described with reference to the drawings. FIG. 1 schematically shows a wire rope flaw detector 27. The wire rope flaw detector 27 includes a plurality of magnetic sensors 3 a to 3 h arranged around the wire rope 1 and side portions of the wire rope 1, and the magnetic sensors 3 a to 3 h are positioned in the middle of the wire rope 1 in the axial direction. And a magnetizer 2 sandwiched in this manner. The magnetizer 2 is formed in a C shape. The magnetic sensors 3 a to 3 h are connected to the calibrator 4. A calculator 6 is connected to the calibrator 4. Storage devices 5a and 5b are connected to the calibrator 4 and the arithmetic unit 6, respectively. An output unit 7 is also connected to the computing unit 6.

  Here, two magnetizers 2 are set apart by a predetermined distance in the axial direction so as to magnetize the wire rope 1 in the longitudinal direction. Four first magnetic sensors 3a to 3d are arranged at a pitch of 90 degrees in the circumferential direction at a portion where the wire rope 1 is magnetized by the magnetizer 2. The other four second magnetic sensors 3e to 3h are arranged at a pitch of 90 ° apart from the magnetic sensors 3a to 3d in the axial direction. At this time, the phases of the first magnetic sensors 3a to 3d and the second magnetic sensors 3e to 3h are changed by 45 °.

  The operation of the wire rope flaw detector 27 shown in this embodiment configured as described above will be described below. The calibrator 4 corrects the input outputs of the magnetic sensors 3a to 3h based on the calibration values of the magnetic sensors 3a to 3h stored in advance in the storage device 5a connected to the calibrator. The corrected outputs of the magnetic sensors 3 a to 3 h are information on the installation positions of the magnetic sensors 3 a to 3 h stored in advance in the storage device 5 b connected to the calculator 6, the moving speed of the wire rope 1, and the magnetic detection information. It is calculated by the calculator 6 using the threshold value.

  The computing unit 6 calculates the degree of damage to the wire rope 1 such as whether or not the wire rope 1 is damaged. The calculated damage degree of the wire rope 1 is output to the output device 7 and displayed. Here, the degree of damage includes the position and degree of the flaw, the number of broken wires, the residual strength, the damage mode, and the like, and is output according to the inspection item of the target wire rope 1.

The principle of flaw detection by the flaw detector 27 for wire rope shown in FIG. 1 will be described with reference to FIG. FIG. 2A is a cross-sectional view of a portion of the wire rope 1 where the first magnetic sensors 3a to 3d are arranged, and FIG. 2B is a diagram where the second magnetic sensors 3e to 3h are arranged. It is a cross-sectional view of a wire rope 1 portion. The wire rope 1 includes a core wire portion 32 that forms a core wire, and strand portions 33 that are arranged around the core wire portion 32 at approximately equal pitches. In the strand part 33, the six steel wires 31b of the diameter substantially the same as this steel wire 31a are arrange | positioned around the steel wire 31a of the center part. As is clear from the comparison of FIGS. (A) and (b), the first magnetic sensors 3a to 3d group and the second magnetic sensors 3e to 3h group are arranged at 45 ° positions in the circumferential direction. Has been.

  It is assumed that one of the steel wires 31b constituting the upper strand portion 33 is broken. The first magnetic sensors 3 a to 3 d group are attached to the same position in the axial direction of the wire rope 1. Similarly, the second magnetic sensors 3e to 3h are attached to the same cross section at different axial positions from the first magnetic sensors 3a to 3d. Since the outputs of the magnetic sensors 3a to 3h change according to the distance from the breaking position to the magnetic sensors 3a to 3h, when the measurement is performed while moving the wire rope 1, the output of the magnetic sensor 3a or the magnetic sensor 3e close to the breaking portion 8a is obtained. The output of the magnetic sensor 3c or the magnetic sensor 3g located far away becomes small.

3A to 3H show the output results of the magnetic sensors 3a to 3h when the wire rope 1 having the fracture portion 8a is flawed. The numbers (a) to (h) in the figure correspond to the numbers of the magnetic sensors 3a to 3h. The vertical axis is the output magnitude, and the horizontal axis is the time. In FIG. 1, when the wire rope 1 is moved from the near side to the far side, the broken portion 8a first passes through the first magnetic sensors 3a to 3d, and then passes through the second magnetic sensors 3e to 3h. Peak time of the first magnetic sensor 3a~3d group is equal _{t 0,} earlier than the peak time _{t 1} of the second magnetic sensor 3e~3h group.

  Comparing the peak outputs of the magnetic sensors 3a to 3d constituting the first magnetic sensor 3a to 3d group, the output of the magnetic sensor 3a closest to the fracture site 8a is the maximum, and the magnetic sensor farthest from the fracture site 8a. The output of 3c is the minimum. It can be determined that the scratch on the steel wire 31b is in the vicinity of the magnetic sensor 3a. The determination result is output to the output unit 7.

  A procedure for reducing noise generated when the wire rope 1 swings and noise due to the unevenness of the strands 33 of the wire rope 1 will be described below. 4A to 4H show the outputs of the magnetic sensors 3a to 3h when the wire rope 1 is not damaged. When the wire rope 1 is not damaged, the leakage magnetic flux having a constant period from the wire rope 1 is measured according to the unevenness of the strands of the wire rope 1. If the distances from the wire rope 1 to the magnetic sensors 3a to 3h are equal, the peak outputs of the magnetic sensors 3a to 3h are the same for all the magnetic sensors 3a to 3h.

  When the wire rope 1 swings and the distance from the wire rope 1 to each of the magnetic sensors 3a to 3h changes, the peak output value changes according to the distance. When the wire rope approaches the magnetic sensor 3a, the output of the magnetic sensor 3a increases as shown in FIG. 4A, and the output of the magnetic sensor 3c decreases as shown in FIG. 4C. The difference in peak output is also observed in the second magnetic sensors 3e-3h.

When the wire rope 1 approaches the magnetic sensor 3a and the distance from the magnetic sensor 3e to the wire rope 1 becomes equal to the distance from the magnetic sensor 3h to the wire rope 1, the peak output values of the magnetic sensor 3e and the magnetic sensor 3h are equal. Become. From the change in the peak output value, it can be determined that the wire rope 1 has approached the magnetic sensor 3a and has passed through the magnetic sensor 3a. Therefore, the change in the output due to the wire rope 1 passing through the magnetic sensors 3a to 3h is subtracted from the output as a noise component.

Furthermore, since the strand part 33 is arrange | positioned by twisting to the axial direction of the wire rope 1, if the wire rope 1 is moved to an axial direction, the distance to the magnetic sensors 3a-3h will change periodically. That is, from the magnetic sensors 3a to 3h, it appears that the unevenness is formed in the strand portion 33 . Due to the leakage magnetic flux generated due to the unevenness, the output of the magnetic sensors 3a to 3h appears as a wave having the same size and a constant period when the influence of the swing of the wire rope 1 is excluded. Therefore, the influence of the unevenness of the strand portion 33 is eliminated by subtracting the magnitude of the wave with a certain period from the output of each of the magnetic sensors 3a to 3h as a noise component.

The example of an output of each magnetic sensor 3a-3h when the above-mentioned two kinds of noise are removed is a figure shown in Drawing 3 (a)-(h). As apparent from FIG. 3, only the influence of the fractured portion 8a of the steel wire 31b appears in the output waveform. Therefore, according to the present Example, the fracture | rupture site | part of the steel wires 31a and 31b can be evaluated with high precision.

  FIG. 5 shows an example of flaw detection when two different steel wires 31b break. FIG. 5 is a view similar to FIG. 2, and is different from FIG. 2 only in that the fracture portions 8 a and 8 b are formed in the two steel wires 31 b. FIG. 6 shows the outputs of the magnetic sensors 3a to 3h provided on the wire rope 1 broken at two places for each of the magnetic sensors 3a to 3h. FIG. 6 shows an output waveform after removing the above two types of noise.

  If the wire rope 1 is sufficiently magnetized and the breaking form of the steel wire 31b is the same, the amount of leakage magnetic flux from the breaking portion 8b of the steel wire 31b located inside the wire rope 1 and the outside of the wire rope 1 The amount of leakage magnetic flux from the fracture site 8a of the steel wire 31b located is equal. Therefore, the peak output of each magnetic sensor 3a-3h is determined according to the distance from each fractured sensor to each magnetic sensor 3a-3h.

  The output of the magnetic sensor 3a located above is slightly larger than the case where there is only one fracture site 8a shown in FIG. The reason for this is that the leakage magnetic fluxes from the two fracture sites 8a and 8b are superimposed and detected by the magnetic sensor 3a. Similarly, the outputs of the magnetic sensors 3b to 3d are larger than the case where the breaking portion 8a is one. It can be seen from these changes in the outputs of the magnetic sensors 3a to 3h that at least two or more fracture portions 8a and 8b are formed.

  The outputs of the magnetic sensors 3a to 3h are different depending on the positions and the number of the fracture portions 8a and 8b. Then, the position and magnitude | size of fracture | rupture site | part 8a, 8b are identified using the some magnetic sensors 3a-3h. The positions and orientations of the magnetic sensors 3a to 3h are stored in the storage device 5b in advance. In order to identify the coordinates in the three-dimensional space when there is one fracture site 8a or one fracture site 8b, it is necessary to output at least three magnetic sensors that are not on one straight line, and the fracture sites 8a and 8b In order to evaluate the degree of scratches, at least four or more magnetic sensor outputs are required.

  That is, the upper limit of the number of flaws to be detected is determined within a predetermined flaw detection length of the wire rope 1, and the magnetic sensors 3a,... Three times or four times the upper limit value of the flaws to be detected are arranged. Thereby, a flaw can be detected regardless of the position in the wire rope 1, and the amount of damage to the wire rope 1 can be obtained with high accuracy.

In the above embodiment, the number of magnetic sensors 3a to 3h is eight, but in order to improve detection accuracy, the number of magnetic sensors 3a,... Arranged around the wire rope 1 may be increased. FIG. 7 shows an example in which the number of magnetic sensors 3a used for flaw detection is increased. In FIG. 7, a first sensor group 3 i composed of a large number of magnetic sensors is arranged around the same position in the axial direction of the wire rope 1, and a large number of magnetic fields are separated from the first sensor group 3 i in the axial direction. A second sensor group 3j consisting of sensors is arranged. At that time, the circumferential direction phases of the first sensor group 3i and the second sensor group 3j are different.

  If the deviation of the peak time of the output waveform due to the positional deviation of the wire rope 1 in the axial direction is corrected using the moving speed of the wire rope 1, it is equivalent to arranging the magnetic sensors at a high density in one axial direction. The effect is obtained. In order to arrange such magnetic sensor groups 3i and 3j, it is advantageous to use the fixing jig 9a shown in FIG.

  A semicircular groove is formed on the upper surface of the fixing jig 9a. Magnetic sensors 3a are arranged in a double row on the fixing jig 9a or a plate 10a bent in a semicircular shape, and magnetic sensors 3a are arranged in a staggered manner in the front row and the rear row. The magnetic sensor 3a is similarly arranged on an upper fixing jig or an upper bent plate (not shown). Using these lower fixing jig and upper fixing jig, the wire rope is sandwiched.

It is desirable that the magnetic sensors 3a to 3h have directivity and are arranged so as to measure the magnetic flux in the vertical direction from the surface of the wire rope 1. FIG. 9 shows changes in the output of the magnetic sensor 3a depending on the directivity. When the directivity of the magnetic sensor 3a is small, as shown in FIG. 9B, the peak output of the magnetic sensor 3a becomes gentle when the wound wire rope 1 moves. When large directivity, as shown in FIG. 6 (a), the peak output of the magnetic sensor 3a becomes steep, peak time becomes clear. Therefore, peak detection becomes easy.

  A method of arranging the magnetic sensors 3a,... Around the wire rope 1 will be described below with reference to FIGS. In order to increase the sensitivity of the magnetic sensors 3a,..., The magnetic sensors 3a,. In the example of FIG. 10, the magnetic sensors 3a,... Are arranged on the cylindrical groove surfaces of the two-divided jigs 9a, 9b in which the cylindrical grooves are formed. One jig 9 a is fixed to a flaw detector main body (not shown), and the other jig 9 b is made movable with respect to the jig 9 a using a hinge 11. After placing the wire rope 1 on the jig 9a, the wire rope 1 is sandwiched between the jigs 9b. Because the jig 9b is also provided with the magnetic sensors 3a,..., The output of the magnetic sensor 3a is transmitted to the flaw detector main body using the cable 12 which is a signal transmission means provided in the vicinity of the hinge 11.

In the embodiment of FIG. 10, a cable is used as the signal transmission means, but FIG. 11 shows an example in which signals are transmitted by the terminals 13a and 13b. The jig 9a and the jig 9b are formed in a two-divided shape, which is suitable when the jigs 9a and 9b are fixed using the fixing means 14a and 14b. Terminals 13a and 13b are provided on the joint surfaces of the jigs 9a and 9b.

If the wire rope 1 exerts an excessive force on the jig 9a or the jig 9b due to the undulation or swing of the wire rope 1, the fixing means 14a and 14b are released from being fixed. Thereby, the wire rope 1 deviates from the cylindrical groove formed in the jigs 9a and 9b. As such fixing means 14a and 14b, a snap lock or a biting mechanism that maintains fixing by a spring force is used. Similar fixing means 14a, 14b are also provided in the embodiment shown in FIG.

An example in which the wire rope flaw detector 27 is attached to the elevator 30 will be described with reference to FIG. One end of the wire rope 1 is fixed to a fixing portion 17 a provided in the hoistway via a pulley 16 provided on the top of the car 15. The other end of the wire rope 1 is similarly fixed to a fixing portion 17b provided in the hoistway via a pulley 19 of a counterweight 18. A pulley 16 is attached to the upper surface of the car 15, and a sheave 20 that frictionally drives the wire rope 1 is disposed between the pulley 16 and the pulley 19 of the counterweight 18. When the sheave 20 is driven, the car 15 moves up and down in the hoistway. The sheave 20 is connected to the hoisting machine 21, and the control device 22 of the hoisting machine 21 controls the operation of the sheave 20.

  The control device 22 includes a storage device 23 that stores the operation history of the car 15. The storage unit 23 is connected to a determination unit 24 that determines whether or not the wire rope 1 needs to be inspected. The determination unit 24 determines whether or not the inspection is necessary based on the information in the storage unit 23, and outputs the determination result to the output unit 25. A flaw detector fixing unit 26 is attached to the upper surface of the car 15, and a flaw detector 27 is fixed to the fixing unit 26. Thereby, the flaw of the wire rope 1 can be detected during the operation of the elevator 30.

Even if the car 15 moves up and down in the hoistway, the wire rope 1 near the fixing portions 17a and 17b is not bent at all. Therefore, in the wire rope 1 near the fixing portions 17a and 17b, the steel wires 31a and 31b are not broken by bending fatigue. When only the fracture of the steel wires 31a and 31b due to bending fatigue of the wire rope 1 is to be inspected, the portion passing through the sheave 20 and the pulleys 16 and 19 may be measured. For this reason, in the embodiment of FIG. 12, a wire rope flaw detector 27 is installed in the vicinity of the pulley 16 attached to the upper surface of the car 15.

  In the elevator 30, the car 15 does not always operate in the entire section of the hoistway. There are floors where people get on and off, and floors that are rarely used. That is, in the entire length of the wire rope 1, there are a portion where the number of times of bending is large and a portion where the number of bending is small. The determination unit 24 obtains the floor where the car 15 stops most frequently from the operation history of the elevator 30 stored in the storage unit 23. The determination unit 24 obtains the bending position of the wire rope 1 corresponding to the stop position and outputs it to the output unit 25. When the determiner 24 determines that the wire rope 1 needs to be flawed, the output device 25 outputs the position information of the wire rope 1 to be inspected to the flaw detector 27. According to the present embodiment, only the portion that needs to be inspected needs to be measured, and the inspection becomes efficient.

It is a schematic diagram of the wire rope flaw detector according to the present invention. It is a figure explaining the positional relationship of the magnetic sensor and wire rope which the wire rope flaw detector shown in FIG. 1 has. It is an example of an output waveform of the magnetic sensor with which the wire rope flaw detector shown in FIG. 1 is provided. It is another example of an output waveform of a magnetic sensor. It is a figure explaining the other positional relationship of a magnetic sensor and a wire rope. It is a figure explaining the relationship between a magnetic sensor and a wire rope. It is a perspective view which shows the arrangement | positioning state of a magnetic sensor. It is a figure explaining the mounting method of the magnetic sensor which the wire rope flaw detector shown in FIG. 1 has. It is another example of an output waveform of a magnetic sensor. It is a perspective view of the jig | tool used for the wire rope flaw detector shown in FIG. It is a perspective view of the other Example of the jig | tool used for the wire rope flaw detector shown in FIG. It is a block diagram when the wire rope flaw detector shown in FIG. 1 is used for an elevator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wire rope, 3a-3h ... Magnetic sensor, 3i, 3j ... Magnetic sensor group, 8a, 8b ... Broken part of wire rope, 9a, 9b ... Jig, 12 ... Signal transmission cable, 13a, 13b ... Joining terminal, 14a, 14b ... fixing means, 27 ... flaw detector.

Claims (8)

In a wire rope flaw detector for flaw detecting a wire rope having a strand formed by twisting a plurality of steel wires,
Magnetizing means for partially magnetizing the wire rope, and a plurality of magnetic detecting means for detecting damage of the steel wire constituting the wire rope magnetized by the magnetizing means. The first and second magnetic detection means groups are provided apart from each other in the axial direction, and each of the first and second magnetic detection means groups includes a plurality of the magnetic detection means. Changing the circumferential position of the magnetic detection means group of 2 in group units ,
Storage means for storing a number of information on the position and orientation of the magnetic detection means and the moving speed of the wire rope; Output of the magnetic detection means; information on the position and orientation of the magnetic detection means stored in the storage means; A wire rope flaw detector , comprising: a calculating means for calculating a damage degree of the wire rope based on the moving speed of the rope . The magnetic detection means constituting the first and second magnetic detection means groups includes a plurality of magnetic detection means arranged at the same axial position of the wire rope and around the wire rope. Item 4. The wire rope flaw detector according to Item 1.   2. The wire rope according to claim 1, wherein the magnetic detection means is a directional magnetic detection means, and is oriented so as to increase magnetism detection sensitivity from a central axis of the wire rope to an outer diameter side. Flaw detection equipment.   The calculation means includes a first magnetic detection means for obtaining an output having a peak among the magnetic detection means constituting the first and second magnetic detection means groups, and the first magnetic detection means. Calculating the position of the damaged portion in the wire rope using the output values of at least two second magnetic detection means not located on one straight line when including the adjacent first magnetic detection means; The wire rope flaw detector according to claim 1.   The arithmetic means includes a first magnetic detection means and a first magnetic detection means that have an output having a peak among the magnetic detection means constituting the first and second magnetic detection means groups. The position and degree of damage of the damaged portion in the wire rope are calculated using output values of at least three second magnetic detection means that are not positioned on one straight line at the time. Wire rope flaw detector.   Holding the magnetic detection means constituting the first and second magnetic detection means groups, a jig having a plurality of shapes, a fixing means for integrating a plurality of jigs, and the integrated jig 2. The wire rope flaw detector main body to which is attached, and the fixing means releases integration of a plurality of jigs when an overload is applied to the jig from the wire rope. Wire rope flaw detector. The wire rope flaw detector according to claim 6 , wherein a signal transmission means for transmitting a signal of the magnetic detection means is provided at a joint portion of the jig with the wire rope flaw detector main body.   2. The storage device according to claim 1, further comprising a storage unit that stores a wire rope usage history, wherein the calculation unit identifies a portion of the wire rope that is frequently bent from the wire rope usage history stored in the storage unit. The wire rope flaw detector described in 1.

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