JP2000146632A - Structure for cable type sensor for sensing slope breakdown - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make freely executable a construction work without any restraint of the place of construction by providing a cable type sensor for transmitting the tension of a fixed point moving according to a breakdown through each conductor in the cable, and transmitting the tension to the fixed point, which does not move, by 100% when the cable type sensor is extended according to the generation of a crack of the ground. SOLUTION: The conductor of a twisting line whose extensibility is known is inserted into a semi-circular groove. The diameter of the semi-circle is made larger than the diameter of the conductor. A lubricating oil is injected into the groove so that abrasion resistance with a rod when the twisting line is extended can be decreased. A paper tape is wound around the expandable rod so that the conductor can be prevented from dropping from the groove. The rod is made of vinyl chloride, NBR, rubber, and spandex or the like. The position of the cut part can be estimated by transmitting a pulse by a pulse reflection method, and measuring a time until the pulse is reflected from the cut part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a sensor structure for avoiding danger by detecting ground cracks observed on a slope failure or the like and continuously sensing the movement of the ground. The function of the sensor utilizes the difference in the elongation rate of each conductor inside. This sensor is not intended for measurement. The cable is laid on a slope where collapse is expected as shown in FIG. 1 while avoiding obstacles and fixing cables to the ground at appropriate intervals. An electric current is constantly applied to each conductor, and the time when the ground moves and the conductor is cut is regarded as a signal.

[Prior Art] There has been no sensor using the difference between the elongation percentages of conductors, so that direct technical comparison is not possible.

[0003] When a multi-core cable without twist is manufactured by a conventional manufacturing method, hemp, cotton, or the like is inserted as an intervening material, and the whole is trimmed with a paper tape or the like, and then coated. It is very difficult to make a cable in which the conductor is set parallel to the longitudinal axis direction and the cut surface is round, and it is generally required to twist the wire in order to make it round. Even if the conductor is set parallel to the longitudinal axis direction, the conductor is pressed with paper tape, and the coating material applies external pressure to the conductor, so the frictional resistance is reduced by the conductor and inclusions such as hemp and cotton. It is very difficult to pull out the conductor in the longitudinal direction, which occurs between the paper tape.

[0004] Although optical fiber cables are provided with slotted slot rods, the purpose is different. Although the cut surfaces are very similar, the grooves are spirally formed on the surface in a twisted manner by the same manufacturing method as that of the electric wire. Since the purpose of the slot rod is to prevent microfibers from being applied to the fiber by the external pressure, the slot rod is not required to have elasticity and is hard.

[0005] This cable-type sensor has a structure in which the tension at a fixed point moving due to a crack in the ground is transmitted through each conductor in the cable, and the tension is transmitted 100% to the fixed point that does not move. is necessary.

[Means for Solving the Problems] As shown in FIG. 2, a plurality of grooves parallel to the longitudinal axis direction of a cylindrical rod having a telescopic characteristic and provided inside a cable are formed on the surface, and each groove is formed. Insert the conductor into. Create a state in which the conductor is housed inside the cavity. The shape, size, and number of grooves on the rod vary depending on the purpose of use.

[Operation] With the above structure, the external pressure generated by the paper tape and the cable covering material is applied to the rod, and the tension can be transmitted without applying the external pressure to the conductor in the cavity.

[Embodiment of the Invention] FIG.
This will be described with reference to FIG. A stranded conductor having a known elongation is inserted into a semicircular groove as shown in FIG. The semicircular diameter is larger than the diameter of the conductor. Lubricating oil is injected into the groove to reduce the frictional resistance between the stranded wire and the rod when it is extended.
The telescoping rod is wrapped with paper tape to prevent the conductor from coming off the groove. The rod is made of vinyl chloride, NBR, rubber, spandex and the like. The position of the cut point can be estimated by sending a pulse by the pulse reflection method and measuring the time until the light is reflected from the cut point.

[Effects of the Invention] The present invention has the configuration as described above, and has the following effects.

When a cable-type sensor is laid and it is stretched due to the occurrence of a ground crack there, the tension at the fixed point moving due to collapse is transmitted through each conductor in the cable, and the tension at the fixed point that does not move is 100%. Because of the transmitted structure, the frictional force due to external pressure can be ignored,
It is possible to set a fixed distance according to installation conditions such as a detour. That is, there is no restriction on the construction site, and construction can be performed freely.

In the case where single wires having different elongation rates are collected and laid, there is a sufficient danger that the tension during work will be applied to the single wires and the wire will be stretched. Absent. But this kind of cable made it possible.

Further, the fact that the cutting is stopped halfway means that the collapse is temporarily stopped. Such a situation cannot be grasped by a single-wire device, but a desired motion state can be understood by a cable having a plurality of conductors having different elongation rates.

Further, the moving distance of the ground at the place where the fixed interval distance is known can be roughly estimated.

For example, when a cable having three types of conductors having elongation percentages of 1%, 10% and 20% is laid at a distance of 10 m between fixed points, the conductor cracks to widths of 0.1 m, 1 m and 2 m. Expires when spreads. When the distance between the fixings is increased, the signal detection time interval is increased, and the width of the ground crack changes greatly and is sensed later. If the distance between the fixed positions is short, on the contrary, the change sensing interval is short, and even a small change in width can be recognized. In other words, two cables having different fixed distances can be laid in parallel to increase the accuracy of change sensitivity.

[Brief description of the drawings]

FIG. 1 Sensor installation state

FIG. 2 is a cross-sectional view and a longitudinal sectional view of a central single-core conductor of an outer three-core conductor.

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Claims (1)

[Claims] 1. A plurality of parallel grooves are formed on the surface of a cylindrical rod having elasticity inside a cable, the conductors having different elongation rates being inserted into the grooves. A cable that is placed at the center of the cable, the surface of the rod is helically wrapped with tape or the like, pressed down, and the rod is directly covered with a covering material that has elasticity. It also includes a cable having a structure in which a conductor and a tension member are embedded near the center of the rod. The shape, size and number of the grooves vary depending on the purpose of use.