JPS5831121Y2 - Non-metallic fiber optic cable - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a non-metallic optical fiber cable used in optical communications and the like.

One of the necessary characteristics of optical fiber cables used in optical communications is non-inductive properties, and especially in the case of this type of cable installed alongside power lines, it is impossible to lack the above characteristics.
For this reason, so-called non-metallic types that do not use any metal have already been provided.

Such optical fiber cables use optical fibers with a plastic coating layer as core wires, and a multilayered plastic sheath is formed around the outer periphery of many core wires to avoid the use of metal. In the case of this type of cable in which a space is interposed between the core wire and the inner sheath that directly encloses the core wire for the purpose of preventing the occurrence of distortion, the following problems have occurred.

In other words, during cable processing in which the above-mentioned core wires having a coating layer are bundled and the outer periphery of the core wires is wrapped with an inner sheath, an outer sheath, etc., mutual friction occurs between the plastic coating layer and the inner sheath, causing the core wires to When the coating layer is charged, the core wire may come into close contact with the inner surface of the sheath within the inner sheath having a space, or the core wire may be undesirably bent.
This caused an increase in optical transmission loss.

Further, if the above-mentioned charged state is extremely high, the shock of the tentacles will be large and will have an unfavorable effect on the workers.

For this reason, it is conceivable to install an antistatic device in the processing equipment for this type of cable, but this would increase the equipment cost by the amount required to prevent static electricity, and it may not be possible to prevent static electricity that occurs after the cable is made. become.

In view of the above-mentioned problems, the present invention is designed to prevent harmful charging from occurring even when there is a space between the core wire and the layer that protects it. This is explained by:

FIG. 1 is a cross-sectional view showing the first embodiment of the present invention, in which 1 is a core wire made of an optical fiber, and 2 is a core wire 1.
A covering layer made of semiconductive plastic formed around the outer periphery of the

Reference numeral 3 denotes a tubular protective layer for enclosing the plurality of core wires 1, and this tubular protective layer 3 is also made of semi-conducting plastic. Encapsulated.

Reference numeral 5 denotes an outer sheath that directly covers the outer periphery of the tubular protective layer 3, and this outer sheath 5 is mainly made of insulating plastic, and in some cases may be made of semiconductive plastic.

In addition, to explain the plastic that can be used as the coating layer 2 and the tubular protective layer 3, it is preferable that the plastic has a specific electrical resistance value of 101 to 106 Ωcm, and has semiconductivity due to its structural factors. The base polymer used is rubber, plastic, and conductive carbon black.

Next, the second embodiment of the present invention will be explained with reference to FIG.
In this embodiment, a core wire 1 covered with a tubular protective layer 3 is bundled by a twisting means or the like, and its outer periphery is wrapped with a plastic tape 6, and an outer sheath 3 is further formed around the outer periphery. Also in this embodiment, the plastic properties regarding the covering layer 2 and the tubular protective layer 3 are the same as in the first embodiment.

In the first and second embodiments, only one of the covering layer 2 and the tubular protective layer 3 may be made semiconductive.

The present invention, which can be implemented more concretely as described above, is a non-metallic optical fiber cable in which a core wire 1 made of an optical fiber is housed in an outer sheath 3, which has a coating layer 2 around the outer periphery of the core wire and a space 4. Since one or both of the tubular protective layers 3 encasing the core wire 1 are made of semiconductive plastic, the coating layer 2 of the core wire 1 and the tubular protective layer 3 can be easily removed during cable processing or other operations. Even if they rub against each other, a charging phenomenon that causes harmful bending of the core wire 1 does not occur, and therefore, in this type of non-metallic cable, the optical transmission loss increases due to charging, There is no electric shock when the tentacles are touched, and therefore both performance and ease of handling have been improved.

Moreover, even though the semiconductive layer has electrical conductivity, it has a considerably higher electrical resistance than a metal conductor, and therefore the problem of inductive interference does not occur at all, which is inherent in non-metallic optical fiber cables. Does not impair inductivity.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing various embodiments of the cable of the present invention. 1... Cord wire, 2... Coating layer, 3...
... Tubular protective layer, 4 ... Space, 5 ...
・External sheath.

Claims (1)

[Scope of utility model registration request] In a non-metallic optical fiber cable in which a core wire consisting of an optical fiber is housed in an outer sheath, the core wire has a coating layer around its outer periphery and a space is left around the core wire. A non-metallic optical fiber cable on which a tubular protective layer is formed, and either or both of the coating layer and the tubular protective layer are made of semiconductive plastic.