Method and apparatus for evaluating damage to magnetic linear body
AssigneeTokyo Rope Manufacturing Co., Ltd.
InventorsHiroaki ITOI, Sadanori SHIIKI, Masamichi SUGAHARA, Toshiyuki MORIYA
Life of this patent
Estimating the term…
Abstract
A magnetic detector includes permanent magnets that magnetize a wire rope W in the longitudinal direction, and a search coil that detects a change in the cross sectional area of the wire rope W magnetized by the permanent magnets. The magnetic detector is provided so as to surround a part of the wire rope W. Prior to inspection, the magnetic detector is moved back and forth at least three times across an inspection range of the wire rope W. After the magnetic detector is moved back and forth, the change in the cross sectional area, that is, damage to the wire rope W is inspected by using signals outputted from the search coil.
Claims7
A damage detection method of a wire rope using a portable damage detection device which is provided so as to surround a part of the wire rope in the longitudinal direction over the entire circumference, the portable damage detection device including a magnetizing device that magnetizes the wire rope in the longitudinal direction, and a search coil that detects a change in the cross sectional area of the wire rope in an inspection range magnetized by the magnetizing device, the damage detection method comprising:
- moving the damage detection device back and forth on the wire rope the predetermined number of times across the inspection range of predetermined length of the wire rope;
- and
- after the damage detection device is moved back and forth the predetermined number of times, recording signals outputted from the search coil.
A signal processor comprising:
- a voltage signal receiving device that receives an input of voltage signals corresponding to the change in the cross sectional area of a wire rope, the voltage signals outputted from a search coil of a portable damage detection device which is provided so as to surround a part of the wire rope in the longitudinal direction over the entire circumference, the portable damage detection device including a magnetizing device that magnetizes the wire rope in the longitudinal direction, and the search coil that detects a change in the cross sectional area of the wire rope in an inspection range magnetized by the magnetizing device;
- a converting device that converts the voltage signals received by the voltage signal receiving device into magnetic flux signals;
- a smoothing device that smooths the magnetic flux signals converted by the converting device and calculates smoothed magnetic flux signals;
- and
- a subtracting device that subtracts the smoothed magnetic flux signals from the magnetic flux signals.
A signal processing method comprising:
- receiving, by a voltage signal receiving device, an input of voltage signals corresponding to the change in the cross sectional area of a wire rope, the voltage signals outputted from a search coil of a portable damage detection device which is provided so as to surround a part of the wire rope in the longitudinal direction over the entire circumference, the portable damage detection device including a magnetizing device that magnetizes the wire rope in the longitudinal direction, and the search coil that detects a change in the cross sectional area of the wire rope in an inspection range magnetized by the magnetizing device;
- converting the received voltage signals into magnetic flux signals by a converting device;
- calculating smoothed magnetic flux signals by smoothing the converted magnetic flux signals by a smoothing device;
- and
- subtracting the smoothed magnetic flux signals from the magnetic flux signals by a subtracting device.
A portable damage detection device including a moving mechanism, comprising:
- a portable damage detection device including a magnetizing device which has a columnar internal space through which a wire rope passes, the internal space having a diameter larger than a diameter of the wire rope, the magnetizing device that magnetizes the wire rope in the longitudinal direction, the magnetizing device being arranged in an annular shape, and a search coil that detects a change in the cross sectional area of the wire rope in an inspection range magnetized by the magnetizing device, the search coil being arranged in an annular shape;
- and
- a moving mechanism including rotatable support rollers respectively attached to both end portions of the portable damage detection device at equal angle intervals, the support rollers that support the wire rope from four directions around the wire rope at both the end portions, wherein
- the respective support rollers in both the end portions of the portable damage detection device are attached in such a manner that the cross sectional center of the wire rope matches with the cross sectional center of the internal space.
Dependencies are inferred from the claim text.