JPS6050505A - Optical fiber cable - Google Patents

Abstract

PURPOSE:Not to make a supporting line large-sized, and also to make it inexpensive by twisting a cable body part against a supporting part through a plastic connecting part, and also reversing periodically the twisting direction. CONSTITUTION:A supporting part 1 is constituted by performing a plastic covering to a high tensile strength body 6 constituted of a fiber reinforcing plastic, etc. A cable body part 2 has a high tensile strength body 5 of a fiber reinforcing plastic, etc. in the center, an optical fiber 7 is contained in a groove of a plastic spacer 8, and a plastic covering 9 is performed. The optical fiber 7 is wound spirally along the groove of the plastic spacer 8. The cable body part 2 is connected to the supporting part 1 by a plastic connecting part 3, twisted against the supporting part 1, and also the twisting direction is reversed periodically. In this way, an elongation of the cable body part can be reduced, comparing with an elongation of a supporting line, therefore, the supporting line size can be reduced, and also it can be made inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND AND OBJECTS OF THE INVENTION The present invention relates to self-supporting optical fiber cables.

Conventionally, as this type of optical fiber cable, cables called a lashing type, a wrapping type, and a gourd type are known.

The lashing type uses, for example, a galvanized steel stranded wire as a support wire, attaches the cable body including the optical fiber in parallel thereto, and integrates the wire by spirally winding the bind wire.

Wrapping is a method in which the cable is wrapped around a support wire at a constant width.

The gourd type is one in which the support wire and the cable body including the optical fiber are integrally connected with the same plastic coating.

In such a structure, even if the support wire bears tension, the cable main body follows the elongation of the support wire. Therefore, during installation, it is necessary to assume the elongation of the optical fiber under severe conditions, and to install the entire cable 81 so that this elongation value is less than the permissible limit of the ship.

This restriction is stricter in the case of optical fiber cables than in the case of metal communication couples, and when the outer diameter and weight of the cable body are equal, the size of the support wire is larger in the case of optical fiber cables. It will become.

In particular, in order to ensure that optical fiber cables are non-metallic and non-inductive, which are the characteristics of optical fiber cables, if the support wire were made of fiber-reinforced plastic, it would be extremely large and extremely expensive.

In view of this situation, it is an object of the present invention to provide an inexpensive self-supporting optical fiber cable without increasing the size of the support wire.

[Summary of the Invention] The present invention connects a support portion including a support wire and a couple body portion including an optical fiber by a plastic connection portion, and furthermore, the cable body portion is twisted relative to the support portion and periodically twisted. By reversing the direction of rotation, the elongation of the support wire does not directly affect the cable main body and is relaxed.

[Example] The configuration of the present invention will be specifically explained with reference to the drawings showing one example.

FIG. 1 shows an embodiment of the present invention (it is an explanatory diagram), and FIG. 2 is a sectional view of the same embodiment.

A high tensile strength member 6 made of fiber-reinforced plastic or the like is coated with plastic and constitutes the support portion 1 .

The cable main body M2 has a high tensile strength member 5 such as fiber-reinforced PlusDeck at its center, accommodates an optical fiber 7 in a vortex of a PlusDek spacer 8, and is coated with a plastic coating 9.

Optical) 7j The fiber 7 is wound in a B-spiral shape along the vortex of the Plusdex spacer 8.

The cable body f152 is connected to the support part 1 by a plastic connection part 3, is twisted relative to the support part 1, and the twisting direction is periodically reversed. 4 indicates a reversal section.

The plastic connecting part 3 has a certain height (approximately 2 joints) and is made of a relatively soft material such as foam.

FIG. 3 is a diagram for comparing the effects of the present invention with the conventional technology.

As an example of a conventional structure, the cable main body is wound around the support part f=j
The integrated one is taken up and shown as A in Figure 3,
The case of the embodiment of the present invention is designated as B.

According to this, in the past, the elongation of the cable main body was about 1/2 of the elongation of the support wire, but in the embodiment of the present invention, it was reduced to about 1/6 of the elongation of the support wire. I understand that.

This is the #1 structure of the present invention, since the support part and the cable main body are not in direct contact with each other, but are connected via the plastic connection part 3, when tension is applied to the support wire, the plastic cable This is due to the fact that the connecting part can fall down and rotate slightly at the reversing part 4 to escape.

The greater the height and the softer the plastic connection, the greater this effect will be.

Moreover, materials other than fiber-reinforced plastic, such as galvanized steel wire, etc., can also be used as the high tensile strength member.

[Effects of the Invention J As explained above, the optical fiber cable of the present invention has the following remarkable effects.

(1) Since the elongation of the cable main body can be significantly reduced compared to the elongation of the support wire, the size of the support wire relative to the allowable strain of the optical fiber can be reduced compared to conventional methods, and the entire optical fiber cable can be made smaller and smaller. It will be cheaper.

(2) If the overall size of the optical fiber cable is the same as the conventional one, the elongation of the cable main body can be significantly reduced, so the safety factor of the optical fiber is large and the reliability is high.

[Brief explanation of the drawing]

1 and 2 are an explanatory diagram and a sectional view showing an embodiment of the present invention, and FIG. 3 is a diagram for explaining the present invention in detail. 1: Support part, 2: Cable main body part, 3 Niblastic connection part, 4: Inversion part, 5, 6: High tensile strength body, 7: Optical fiber, 8 Niblastic spacer, 9 Niblastic coating.

Claims (4)

[Claims] (1) It has a support section in which the lX tensile strength member is covered with a plastic protective coating, and a cable body section that includes an optical fiber and is covered with a plastic protective coating, and the cable body section is connected via a plastic connection section. An optical fiber cable, characterized in that the cable is twisted relative to the support part, and the direction of the twist is periodically reversed. (2) The optical fiber cable according to item 1, wherein the high tensile strength body is a fiber-reinforced plastic wire. (3) The optical fiber according to item 1, wherein the cable main body has an optical fiber spirally wound around a non-metallic high tensile strength body and is coated with a protective coating. fiber cable. (4) The optical fiber cable according to item 1, wherein the support portion, the plastic connection portion, and the cable main body portion do not contain any metal material.