JPH1138149A - Structure of composite multicore electric wire type sensor with cores having different coefficients of elongation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of composite multicore electric wire type sensor which can detect the progress of a landslide and cracks in the ground by utilizing such a fact that the cores of a composite multicore electric wire containing cores having different coefficients of elongation and laid along a slope are cut with time lags when the distance between fixing points becomes longer due to a crack in the ground when the structure is used for a landslide detecting system sensor which is installed to the slope for detecting landslide. SOLUTION: The cores of a composite multicore electric wire type sensor are formed by spirally winding electric wires around elastic bodies, the outside diameters of which are reduced as the elastic bodies elongate, at calculated intervals. In addition, the cores are mixed with cores, which exert peculiar elongating characteristics when the cores are worked. Therefore, the coefficients of the cores can be set freely as compared with a core composed of twisted electric wires or a single electric wire. In addition, such an electric wire that has a coefficient of elongation which is remarkably larger than that of a copper wire, etc., can be manufactured. Since thin electric wires can be used, moreover, the cores can be cut even by a small tension. Therefore, a cable, which is lighter and more flexible than the conventional cable using electric wires only can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications]

[0002] The present invention relates to a composite multi-core electric wire having a core wire formed by spirally winding electric wires at calculated intervals in order to detect a continuous dynamic phenomenon of ground cracks.

[Prior art]

At present, there is no composite multi-core electric wire type sensor having the above-mentioned concept with a high degree of flexibility and a function having no restriction on an installation place. Therefore, the performance cannot be compared.

[Problems to be solved by the invention]

[0004] An object of the present invention is to utilize the time difference between cutting of a core wire when a composite multi-core wire having a difference in elongation rate of each core wire is pulled to manufacture a sensor for sensing the continuity of the phenomenon. However, although it is desired to use an electric wire currently produced, there are physically the following problems.

At present, soft copper wire for electric use (purity: 99) is mainly made of copper, which is the most widely used and used in large quantities and is stable in price.
(98%), in the test method according to the JIS standard, when the marked line distance of the sample is 250 mm, even if it is sufficiently tempered, it is about 40% with a single wire diameter of 2 mm. When this is used as a final product wire, the wire is stretched by applying tension to the wire during processing, the molecular structure of copper changes, and the elongation rate of the wire is lost.

In addition, although the reference line distance is specified as 250 mm, the fixed distance at both ends is required to be 400 mm for measurement. Since the distance between fixed points is practically uncertain, it is necessary that the elongation rate is not affected by the distance between fixed points.

Further, the elongation is calculated to be proportional to the cross-sectional area, but in reality, it is not in a state of being uniformly expanded as compared with rubber or the like. Even if the growth is limited, maintaining a stable growth rate is not a quality control item in the current production system and management technology. Even if it is controlled, it is said that it is the limit to control it within about 5% of the target elongation at each stage of processing. Single wire diameter 2mm
However, when measured by the JIS standard measurement method, it is impossible to expect an elongation rate of 40% or more in the final processed product.

As described above, there is a drawback in a method that depends on an inherent elongation characteristic generated when an electric wire such as a copper electric wire is processed for the purpose of freely setting the elongation rate of the core wire.

[Means for Solving the Problems]

In order to use the sensor for detecting a dynamic phenomenon by utilizing the time difference of cutting when each core wire is expanded, it is necessary to freely set the elongation rate of the core wire according to the purpose. Therefore, in order to make it freely set, the core wire is made by winding an electric wire with a known elongation rate in a spiral shape at the calculated interval on the outside of the elastic body whose outer diameter is reduced as it is stretched. To solve the problem.

[Action]

The basic relationship between each element constituting the structure as described above is shown in Equation 1. When the elastic body whose outer diameter shrinks uniformly as it expands uniformly expands, the wires wound spirally at the calculated intervals will have the same ratio of windings in parallel, as shown in FIG. The interval spreads.

[0011]

(Equation 1)

The diameter of the elastic body becomes thinner with elongation. Depending on the setting of the conditions, when the balance between the distance of the helical curve inherent in the elastic body and the length of the spirally wound winding is lost, Cut off. As shown in FIG. 2, D1> D2 temporarily due to the relationship between the spirally wound electric wire and the winding interval, and passes through a region where a small space is formed between the electric wire and the elastic body (the hatched portion in FIG. 3), and D1 <D2. The wire is cut because the length of the electric wire does not become the length required by the elastic body. FIG. 3 (graph) shows a relationship between a change in diameter, a change in unit length of the spiral, and a distance between the spirals when an electric wire is spirally wound around the elastic body at an interval of 4 mm. Under the conditions of FIG. 3, the point at which the elongation rate becomes 2.2 times is the cutting point.

As reference data of the cutting point, the spiral spacing, and the elongation, FIG. 4 (graph) shows the elongation when the spiral winding interval, 3 mm, 4 mm, 5 mm, and 6 mm length are set on an elastic body having a diameter of 3 mm. The relation of the movement of the cutting point is shown.

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiment will be described with reference to FIG. 1 using a mixed-type composite multifilamentary wire having 7 cores as an example. An electric wire having a known elongation percentage is calculated for an elastic body such as rubber or spandex. Three types of core wires spirally wound at intervals are used.

Further, existing electric wires are used for the four types of core wires having a low elongation. At the center, an existing electric wire with the smallest elongation is placed as a core wire. For example, it is possible to manufacture a 7-core mixed-type composite multi-core wire having the following elongation percentages. Elongation: 1%, 5%, 15%, 25%, 60%, 120
%, 210%

【The invention's effect】

Since the present invention has the configuration as described above, the following effects can be obtained. (B) Compared to twisted core wire or solid wire,
The elongation can be set freely, regardless of the thickness of the wire. (B) It is possible to manufacture electric wires having a much higher elongation than using the inherent elongation of copper electric wires. (C) Since a thin wire can be used, the wire can be cut even with a small tension. Therefore, a lighter and more flexible cable can be produced as compared with the case where only the conventional electric wire is used. (D) The type of electric wire to be used can be reduced as compared with the method using the inherent elongation of the electric wire.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mixed-type composite 7-core wire with a copper core wire.

FIG. 2 is a diagram showing an electric wire wound around an elastic body and an enlarged winding interval due to stretching.

FIG. 3 is a graph showing a relationship between a change in elongation of the elastic body, a change in diameter of the elastic body, and a change in unit length of a spiral.

FIG. 4 shows a distance between spirals of 3 mm and 4 m on an elastic body having a diameter of 3 mm.
Graph showing the relationship between the change in the unit length of the spiral of 5 mm, 5 mm and 6 mm and the cutting point (elongation percentage) Distance between spirals Cutting point (elongation percentage) 3 mm: 3.1 4 mm: 2.25 mm: At 1.66 mm: 1.3

[Explanation of symbols]

R1: diameter of elastic body when wire is wound L1: unit length of elastic body when wire is wound R2: diameter of elastic body when stretched L2: length of elastic body when stretched D1: The length of the wire when the wire is spirally wound to the unit length. D2: The length of the spiral curve when the elastic body is extended. D: The length of the spiral curve locus. L: The length of the elastic body. Unit length π: Pi R: Diameter of elastic body

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01B 7/32 H01B 7/32 Z H01H 13/52 H01H 13/52 D

Claims (1)

[Claims] 1. A composite multi-core electric wire having a core wire formed by winding an electric wire spirally at a calculated interval on the outside of an elastic body whose outer diameter is reduced as it is extended. Also, a mixed-type composite multi-core wire with a core wire having an inherent elongation characteristic formed when the wire is processed.