JPH07137985A - Wire rope inspection method for rope suspended crane - Google Patents

Abstract

PURPOSE:To make unmanned inspection possible by installing a magnetic detector on a wire rope wound on a fixed sheave for a rope suspended crane nd making a judgement if the wire rope for detect based on the magnetic signals of the wire rope detected when a crane hook is moved up and down. CONSTITUTION:The coil 1, magnetic pole 2, and bracket 4 of an eddy current type detector for generating magnetic flux and detecting its variation in impedance are assembled into a sleeve 3 which is halved from the diameter part and through which a wire rope 13 is passed. Also a variation in condition of magnetic coupling between the wire rope 13 and the detector is detected by the coil 1, and signals through an amplifier 6 are inputted into a HPF7 of 10Hz and a HPF8 of 100Hz. Then signals outputted from filters 7 and 8 are inputted into comparators 9 and 10 and, based on the comparison results with reference judgment values, the detect of the wire rope 13 is identified. When the wire rope 13 is judged faulty, a warning is given by a warning device 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire rope inspection method for a rope suspension crane.

[0002]

2. Description of the Related Art Inspection of a wire rope of a conventional rope-suspended crane has mainly been a visual inspection of a crane driver. However, since this tends to cause individual differences, inspection detection is being started using devices. As an example, Japanese Patent Application Laid-Open No. 2-56397 proposes "a wire rope inspection device for a crane" and describes a method for detecting a wire rope disconnection.

Here, in a crane equipped with a hoisting device for rotating a drum to wind and unwind a wire rope,
An image pickup means and an analysis means for the image signal thereof are provided, and the wear amount of the wire rope, the wire breakage, the corrosion, etc. are detected from the image analysis data.

In this method, however, it takes a lot of man-hours to attach and detach the detector. On the other hand, since expensive equipment is used, it cannot be permanently installed in each crane and fixedly used. Therefore, frequent diagnosis is required. Is difficult to repeat.

[0005]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and the total length of the wire rope can be easily inspected, and the wire rope can be inspected for wire breakage before the wire break or wire breakage. An object of the present invention is to provide a method for inspecting a wire rope of a rope suspension type crane, which is capable of inspecting the wire breakage of the rope and the wear amount at the same time.

[0006]

In order to achieve the above object, the present invention is to attach a magnetic detector to a fixed sheave winding wire portion of a rope suspension type crane and detect when the hook of the crane moves up and down. A wire rope inspection method for a rope-suspended crane is characterized in that the presence or absence of abnormality of the wire rope is determined from the magnetic signal of the wire rope.

In the above method, a low-pass filter and a high-pass filter are connected in parallel to the output of the signal amplifier of the magnetic detector, the wear degree of the wire rope is detected from the output of the low-pass filter, and the wire rope is detected from the output of the high-pass filter. This is to detect a wire break.

[0008]

The present invention has the above-described structure, and the magnetic detector is attached to the fixed sheave portion of the rope suspension type crane through which the entire length of the portion where the wire rope is likely to be deteriorated and broken by the lifting and lowering of the hook passes. Therefore, the total length of the wire rope where there is a possibility of deterioration and disconnection can be checked with this detector by a normal crane lifting scan without a special scanning mechanism. Disconnection and wear can be determined by the difference in the frequency of the detection signal when the wire rope is wound up and down at a constant speed.

If the wire rope is worn,
The distance between the detector and the surface of the wire rope (hereinafter referred to as lift-off) changes, and the magnetic coupling state between the magnetic pole of the detector and the wire rope changes. By comparing, the wear can be reliably detected regardless of the temperature change of this detector and the difference in the material of the wire rope.

[0010]

Embodiments of the present invention will be described with reference to the drawings. Figure 1
Is a diagram showing an embodiment of a detector used in the present invention,
(A) is a front view of the detector, (b) is a plan view of the same,
(C) is the same side view. Reference numeral 1 is a coil of an eddy current type detector for generating a magnetic flux and detecting its impedance change, 2 is a magnetic pole, and 3 is a sleeve. As shown in the side view of (b), the bracket of 4 is 2 from the diameter part.
The wire rope is pierced in half. This makes it easy to install and remove this detector. This has an effect that the detector can be easily attached and detached when carrying one detector around many cranes for inspection. However, if it is a fixed type, it does not necessarily have to be divided into two. Further, the eddy current detector may be a magnetic detector in which a change in the magnetic circuit appears due to disconnection or wear. For example, a leakage flux type detector can also be applied.

FIG. 2 shows a schematic view of the detector used in the present invention attached to the fixed sheave winding wire part of a rope suspension type crane. In FIG. 2, 16 is a club, and 13
Is a wire rope to be inspected, 14 is a fixed sheave, and 17 is a moving sheave. In this figure, the chain is hung under the club so that the detector can be easily attached and removed. As another attachment method, a channel may be provided below the club 16 and the present detector may be fixed by penetrating the wire rope 13 with a bracket. Since the size of this detector is approximately Φ150 × 100 [mm], the detector can be properly attached regardless of the measurement location.

FIG. 3 shows a schematic circuit diagram of the present invention. In FIG. 3, reference numeral 12 is a power supply device. The change in the magnetic coupling state between the wire rope 13 and the magnetic pole of the detector is detected by the coil 1 and the signal detected by the amplifier 6 is amplified. 7 is 1
Reference numeral 8 is a low-pass filter of 0 Hz, and 8 is a high-pass filter of 100 Hz. Both of them are connected in parallel to the output of the amplifier 6, and the signals output from the respective filters are discriminated as the presence or absence of abnormality of the wire rope by passing through the respective comparators 9 and 10. The filtering frequency of the filter is empirically determined from the ascending / descending speed of the wire rope. Here, if it is determined that the wire rope is abnormal, the alarm device 11 issues an alarm.

FIG. 4 is a diagram showing a state of a signal detected by the detector of the present invention. (A) is a signal obtained from a wire rope having a diameter of 20 mm in which wear and disconnection occur, and shows an example of a waveform at the output portion of the amplifier 6. (B) is the waveform of the output portion of the filter 7 with the low frequency portion emphasized, and there is a signal portion whose level is higher than the threshold value. This corresponds to the worn part of the wire rope. It has been confirmed from the results of the implementation so far that wear of 0.01 mm or more can be detected. However, since the wear of the wire rope cannot be judged unless the diameter of the new portion of the wire rope is used as a reference, it is necessary to calibrate the amplification factor and the threshold value before the inspection in accordance with the lift-off of the new portion. (C) is a waveform of the output part of the filter 8 in which the high frequency part is emphasized, and a part of the signal shows a sharp peak,
The threshold is exceeded. This indicates a break in the wire of the wire rope.

[0014]

According to the present invention, the total length of the wire rope of the rope suspension crane can be automatically detected and the detection accuracy is high. Therefore, if it is installed permanently, a complete unmanned inspection can be performed. Further, the detector used in the present invention is easy and quick to install and remove from the crane, and can be quickly carried around for inspection by many cranes. Further, according to the present invention, not only the breakage of the strands but also the wear state of the strands in the preliminary stage can be inspected. Therefore, it is possible to perform a rational inspection such as changing the inspection frequency according to the degree of wear.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a detector used in the present invention.

FIG. 2 is a schematic view in which a detector used in the present invention is attached to a fixed sheave winding wire portion.

FIG. 3 is a schematic circuit diagram of the present invention.

FIG. 4 is a diagram showing a state of a signal detected by the detector of the present invention.

[Explanation of symbols]

 1 coil 2 magnetic pole 3 sleeve 4 mounting bracket 5 signal cable 6 amplifier 7 low pass filter 8 high pass filter 9, 10 comparator 11 alarm device 12 power supply device 13 wire rope 14 fixed sheave 15 channel 16 club 17 moving sheave

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Tokudome 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Izumi Terada 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Inside the Steel Pipe Corporation (72) Inventor Shinji Kobayashi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Steel Pipe Corporation

Claims (2)

[Claims] 1. A magnetic detector is attached to a fixed sheave winding wire part of a rope-suspended crane, and whether or not there is an abnormality in the wire rope is detected from a magnetic signal of the wire rope detected when the hook of the crane moves up and down. A method of inspecting a wire rope for a rope suspension crane, which is characterized by making a judgment. 2. A low-pass filter and a high-pass filter are connected in parallel to the output of the signal amplifier of the magnetic detector, and the degree of wear of the wire rope is detected from the output of the low-pass filter,
The wire rope inspection method according to claim 1, wherein a wire break in the wire rope is detected from the output of the high-pass filter.