JPS6235046Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high tensile strength optical cable comprising an optical fiber core coated with a thermosetting resin containing reinforcing fibers.

This type of optical cable can be twisted without the need for tension members because the tensile properties of each core wire are extremely high. However, although the tensile properties of the individual optical fibers in this optical cable are good, when the optical fibers are twisted together, the elongation of each optical fiber is small, so the optical fibers in the center are less elongated than the optical fibers on the outside. It was found that the load burden due to tension was large, and as a result, an excessive tensile force was applied to the central optical fiber core, which could cause the wire to break.

An object of the present invention is to provide a high tensile strength optical cable in which the central optical fiber core is prevented from breaking.

An embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a high tensile strength optical cable 10 according to the present invention, and this optical cable 10 is made by twisting a plurality of optical fiber core wires 12A, 12B. A plastic jacket 14 is applied thereon.

Each optical fiber core 12A, 12B has a primary coating on the optical fiber 16, as shown in FIG.
8. A thermosetting resin coating 28 containing reinforcing fibers 26 such as glass fibers is applied on the coated optical fiber 24 formed by applying the buffer layer 20. The diameter of the central optical fiber core 12A is set larger than the diameter of the outer optical fiber core 12B. Since the cross-sectional areas of the coated optical fibers 24 of each optical fiber core wire 12A, 12B are equal, the difference in diameter can be obtained by varying the thickness of the thermosetting resin coating 28 containing the outermost reinforcing fibers 26. . In this way, the central optical fiber core 1
It is possible to make the tensile load per cross-sectional area determined by the Young's modulus and Poisson's ratio of the material of the coating 28 almost equal to that of the optical fiber core 2A and the optical fiber core 12B outside thereof, and The load burden will not become excessive.

In addition, in the above embodiment, the outer optical fiber core wire 12
B is one layer, but in the case of multiple layers, it is preferable that the diameter of each optical fiber in the inner layer is larger than the diameter of the optical fiber in the outer layer.

In a specific example of the present invention, ten optical fiber core wires coated with an unsaturated polyester resin containing glass fibers are twisted on the outside of each coated optical fiber 24 as shown in FIG. The terpolymer was applied and a polyethylene jacket was applied on the outside. In this case, the outer diameter of the central optical fiber was 2 mm, the outer diameter of the outer optical fiber was 1 mm, and the thickness of the polyethylene jacket was 0.5 mm.

According to the present invention, as described above, even if a tensile force is applied to the optical cable, the load per unit cross-sectional area of the central optical fiber becomes close to that of the outer optical fiber, so that the central optical fiber An excessive load is not applied to the fiber core wire, and the tensile strength can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a high tensile strength optical cable according to the present invention, and FIG. 2 is an enlarged cross-sectional view of each optical fiber core. DESCRIPTION OF SYMBOLS 10... High tensile strength optical cable, 12A... Center optical fiber core wire, 12B... Outer optical fiber core wire, 24... Optical fiber, 26... Reinforcement fiber, 28... Thermosetting resin coating.

Claims (1)

[Scope of utility model registration request] In a high-tensile optical cable made by twisting a plurality of optical fibers each coated with a fiber-reinforced thermosetting resin on the outside, the diameter of the central optical fiber is equal to that of the outer optical fiber. 1. A high-tensile optical cable, which is larger than the diameter of the optical fiber, and has a resin coating thickness of the optical fiber core in the center part that is larger than that of the outer optical fiber core wire.