JPS60218012A - Detecting method of abnormal surface of steel-tape armored cable - Google Patents

Abstract

PURPOSE:To detect abnormality of a cable surface continuously by irradiating the outer periphery part of a cable which run lengthwise with light in its tangential direction, converting projections and recesses of the surface into an electric signal and obtaining reference data, and deciding on deviation in the time interval of the electrical signal on the basis of the reference data. CONSTITUTION:Projections and recesses are formed regularly on the surface of the steel-tape armored cable C at pitch P. The light emitting element 10 and photodetecting element 12 of an optical size measuring instrument 10 are arranged at the outer periphery part of the cable C which is run at a linear speed while crossling a light beam L nearly parallel to the outer peripheral tangential direction of the cable C, and variation in external diameter is detected in the form of variation in the quantity of arrival light and converted into an analog electric signal, which is transmitted to an A/D converter 14 through an amplifier 13; and its digitized signal is sent to a central procesing unit CPU15 and time intervals of level variation are measured to set a reference value.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for detecting an abnormal surface of a copper band armored cable.

[Prior Art] Generally, copper 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 copper band armored cable, in which reference numeral 1 indicates a lead-sheathed core, numeral 2 indicates a polyethylene jacket, numeral 3 indicates an exterior seat, and numeral 4 indicates 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 the copper band armored cable to determine whether it is good or bad. However, in this case, since there are irregularities due to the copper band wrapping, it is necessary to simply compare the deviation level. There were problems such as the conventional method of detecting unevenness deviation levels when the surface is smooth 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 continuously and reliably perform automatic detection. be.

"Structure of the Invention" The present invention allows a cable to run in its length direction and crosses the outer circumference of the cable with light rays that are substantially parallel to the tangential direction of the cable to convert surface irregularities into electrical signals. The time interval in which the level of the electrical signal repeats periodically multiple times is set as reference data, and by determining the deviation in the time interval due to irregular changes in the level of the electrical signal with respect to this reference data, abnormal phenomena can be detected. It is characterized by carrying out detection.

"Example" An example of the method according to the present invention will be described below in Figures 2 to 4.
This will be explained based on the diagram.

FIG. 2 schematically shows a copper band armored cable C, in which regular irregularities with a pitch P as a periodicity are formed on its outer surface. Such a cable C is run at a linear speed V, and the maximum diameter of its uneven portion is Dg*Jl.
When the small diameter is Ds, these uneven parts are relative to the stationary point,
Minimum diameter Ds, transitional portion A where the diameter increases, maximum diameter D"'g
This shows a phenomenon in which the transient portion B in which the s diameter decreases is regularly repeated at a time interval of P/V.

FIG. 3 shows an example of the configuration of an electric circuit for detecting such a phenomenon.
A light-emitting element 11 and a light-receiving element 12 are arranged on the outer circumference of the cable C so that light rays substantially parallel to the tangential direction thereof intersect, and a change in the outer diameter is detected as a change in the amount of arriving light. , converts this into an analog electrical signal change, transmits it to the A/D converter 14 via the amplifier 13, and sends this digitized output signal to the central processing unit (CP).
U) 15 and performs the following processing.

As shown in FIG. 4, a signal whose level changes is sent to the central processing side 15, and by utilizing the fact that the rising portion or the falling portion (the transient portions A and B) are periodically repeated,
The time interval Ts is measured, and this time interval Ts is set as a reference value. The reference value is set by calculating the average value of a plurality of time intervals in the central processing unit 15 and setting the value, or by giving a command from the setting device 16 in advance to set the value.

On the other hand, as shown by X and Y in FIG. 4, when a phenomenon in which the data level fluctuates occurs, the time intervals Tx and Ty between the rising and falling portions differ from the reference value Ts.

Therefore, the central processing unit 15 determines the difference in time interval,
By comparing the ratios, etc., it is possible to easily determine that there is an abnormality in the surface condition of the cable C. 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 abnormal signal is sent to activate an alarm device 1 or a recorder.

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 when the time interval between the rising edge and the next rising edge corresponds to the pitch P, 1'1i
It is also possible to use other repeating portion time intervals such as Tp. In the example in FIG. 3, the light emitting element 11 and the light receiving cable 12 are shown as a pair, but they can be used as a plurality of pairs to digitally detect a change in the outer diameter depending on the presence or absence of arriving light.
1 can be replaced with a method such as swinging.

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

(a) Even if the surface of a copper band armored cable or the like periodically has surface irregularities, the surface abnormality can be reliably detected.

(b) Since irregular portions are detected by utilizing the regular repetition of the pitch of the surface irregularities, 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, resulting in a simple structure.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing an example of the structure of a copper band armored cable, Figure 2
Figures 4 to 4 are for explaining one embodiment of the present invention. Figure 2 is an explanatory diagram of the uneven shape, Figure 3 is a wiring diagram of an example of the configuration of an electric circuit, and Figure 4 is a data level change. FIG. c. Copper band armored cable, 10. ,,,,,,
Optical dimension measuring instrument, 14. ,,． 0. A/D converter, 1
5. , , , central processing unit, io, 0. ．． 0. Setting device. Figure 1 Figure 2

Claims (1)

[Claims] As the cable runs along its length, light rays that are almost parallel to the tangential direction cross the outer circumference of the cable, converting the unevenness of the surface into an electrical signal, and the level of the electrical signal is periodically repeated multiple times. A method for detecting an abnormal surface of a copper-band armored cable, characterized by setting a time interval as reference data, and determining a deviation in the time interval due to irregular changes in the level of an electrical signal with respect to the reference data. .