JPH0380244B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for detecting abnormal surfaces of steel strip armored cables.

"Prior Art" Generally, steel band armored cables, iron wire steel band armored cables, etc. are used as underground cables and submarine cables.

Figure 1 shows an example of the structure of a steel band armored cable. In the figure, 1 is a lead-sheathed core, 2 is a polyethylene jacket, 3 is an exterior seat, and 4 is a steel strip. 5 is an outer coating. Since such a cable is made by winding the steel strip 4 in a spiral manner, the surface has some irregularities even when the outer coating 5 is applied.

For this reason, it is necessary to visually inspect the surface condition during the manufacturing process of steel strip armored cables to determine pass/fail, but in this case, since there are irregularities due to the steel strip wrapping, it is necessary to simply compare the deviation level. There have been problems in that the conventional method of detecting the unevenness deviation level for a smooth surface cannot be applied.

"Object of the Invention" The present invention has been made in view of the above circumstances, and aims to effectively solve the problems of the prior art and to carry out automatic detection continuously and reliably. be.

"Structure of the Invention" The present invention provides a method for running a cable in which a steel strip is spirally wound at the same pitch on the outer peripheral surface in the length direction thereof, and in a tangential direction substantially orthogonal to the length direction to the outer peripheral part of the cable. In this system, a parallel beam of light is emitted from the cable, and the light is received by a photoelectric conversion element and converted into an electrical signal according to the unevenness of the cable surface. By measuring the interval multiple times, the average value is set as reference data, and the time interval of the electric signal due to the unevenness of the cable surface is compared with the time interval of the reference data to determine whether the time interval is shorter. An abnormal surface of the cable is detected by determining whether the cable is bent or not.

“Example” An example of the method according to the present invention will be described below with reference to FIGS. 2 to 4.

Figure 2 shows an outline of the steel strip armored cable C. By winding the steel strip in a spiral shape with the same pitch P, the outer surface of the cable C is formed with regularly repeating irregularities. ing. While such a cable C is run at a linear speed V,
If the maximum diameter of the uneven portion is Dg and the minimum diameter is Ds, these uneven portions have the minimum diameter Ds,
This shows a phenomenon in which a transient portion A in which the diameter increases, a maximum diameter Dg, and a transition portion B in which the diameter decreases are repeated regularly at time intervals of P/V.

FIG. 3 shows an example of the configuration of an electric circuit for detecting such phenomena and the like.
The light emitting element 11 and the light receiving element 1 are
2 are arranged on the outer circumference of the cable C so that the light ray L that is almost parallel to the tangential direction intersects the cable C, and the change in the outer diameter is detected as a change in the amount of arriving light, and this is detected as an analog electrical signal. The signal is converted into a signal and transmitted to the A/D converter 14 via the amplifier 13, and the digitized output signal is sent to the central processing unit (CPU) 15, where the following processing is performed.

As shown in FIG. 4, a signal whose level changes is sent to the central processing unit 15, and the time interval is Ts is measured and this time interval Ts is set as a reference value. This reference value is set by calculating the average value of a plurality of time intervals in the central processing unit 15 and setting the calculated value.

On the other hand, when a phenomenon in which the data level fluctuates occurs as shown by X and Y in Fig.
A difference is generated with respect to Ts, and the time interval Tx, Ty becomes shorter than the reference value Ts.

Therefore, by comparing the time interval difference, ratio, etc. by the central processing unit 15, the cable C
It is possible to easily determine that there is an abnormality in the surface condition of the surface. Furthermore, when performing these determinations, it is desirable to set tolerance ranges for the height and length of the unevenness.

Further, when an abnormal surface is detected by the central processing unit 15, an alarm device 17, a recorder, etc. is activated by an abnormal signal.

In the above embodiment, the time interval between the rising edge and the falling edge of the data level was used as the reference, but the time interval between other repeating portions, such as the time Tp corresponding to the pitch P between the rising edge and the next rising edge, may be used as the reference. You can also use it as In the example in FIG. 3, the light emitting element 11 and the light receiving element 12 are shown as a pair, but they can be used as multiple pairs to digitally detect changes in the outer diameter depending on the presence or absence of arriving light, or to swing the light emitting element 11. It can be replaced by the method

"Effects of the Invention" As explained above, according to the present invention, the following effects can be achieved.

(a) Even if there are periodic surface irregularities such as on a steel strip armored cable, the surface abnormality can be reliably detected.

(b) Since irregular portions are detected by utilizing the regularly repeated pitches of the surface unevenness, automatic detection of the cable surface can be carried out continuously.

(c) By using an optical sensor, the cable surface can be kept in a non-contact state and the structure can be simplified.

(d) Since the average value of multiple time intervals is set as the reference data, if a phenomenon that fluctuates the data level occurs, the time interval based on surface irregularities will differ from the average value. , it is possible to easily determine that there is an abnormality in the surface condition of the cable, and even if the cable take-up speed changes somewhat, the abnormal surface of the cable can be reliably detected.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an example of the structure of a steel band armored cable, Figs. The figure is a wiring diagram of an example of the configuration of an electric circuit, and FIG. 4 is a curve diagram of data level changes. C... Steel strip armored cable, 10... Optical dimension measuring device, 14... A/D converter, 15... Central processing unit, 16... Setting device.

Claims (1)

[Scope of Claims] 1. A cable having a steel strip wound spirally at the same pitch on the outer circumferential surface is run in its length direction, and parallel to the outer circumference of the cable from a tangential direction substantially perpendicular to the length direction. In a device that irradiates a light beam, receives the light with a photoelectric conversion element, and converts it into an electrical signal corresponding to the unevenness of the cable surface, the time interval of the level change of the electrical signal at the repeated unevenness part due to the steel strip winding is determined in advance. By measuring multiple times, the average value is set as reference data, and the time interval of the electric signal due to the unevenness of the cable surface is compared with the time interval of the reference data to determine whether the time interval has become shorter. A method for detecting an abnormal surface of a steel strip armored cable, the method comprising determining whether or not the cable is present.