JPS6136961Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in optical fiber cables used for communications.

When constructing a non-gas maintenance type communication cable based on optical fiber, a jelly-like mixture layer is formed within the cross section of the cable, making it waterproof. Granted.

Although the above-mentioned admixture layer is effective in ensuring waterproofness, it has a poor function of protecting the optical fiber as a core wire, and it is difficult to completely remove the admixture layer when connecting the cable, and it is difficult to use the adhesive afterwards. The adhesion effect is also reduced.

On the other hand, some products are provided with a cushion layer that can protect the optical fiber instead of the above-mentioned mixture layer.
Although this cushion layer has the protective function of the optical fiber against external forces, it cannot be expected to have waterproof properties, and therefore, this type of cushion layer is particularly unsuitable for installation under water.

In light of the above, it would be desirable to have a material that is highly waterproof, cushiony, and has good peeling properties, but as a practical matter, the development of this material is quite difficult.

In view of the above-mentioned problems, the present invention is an improvement of this type of cable so that all of the optical fiber protection effects, waterproofness, peeling properties, etc. can be satisfactorily obtained. This is explained by:

In FIG. 1, 1 is a central member, 2 is a core layer made of optical fiber 3, 4 is a protective layer, 5 is an admixture layer,
6 and 7 are covering layers.

The central member 1 mentioned above is made of a tensile strength material called a tension member or other inclusion.

The optical fiber 3 is made of an optical waveguide material made of glass or plastic, and the outer periphery of the optical waveguide material is coated with a primary coat of plastic, a secondary buffering coat of silicone rubber, etc., and a strong tertiary coat of nylon, polyethylene, etc. Of these, the secondary coat may be omitted.

A plurality of optical fibers 3, 3, 3, . . . are arranged around the central member 1, thereby forming the aforementioned core wire layer 2.

The protective layer 4 is made of a polymeric material with so-called cushioning properties, such as rubber (silicon rubber) or plastic elastomer, and is formed to cover the outer periphery of the core wire layer 2 .

The jelly-like mixture layer 5 is made of known polybutene-based or other petroleum-based materials.
is formed on the outer periphery of the core layer 2.

Furthermore, a coating layer 6 made of a plastic tape or the like is provided on the outer periphery of the mixture layer 5, and a plastic coating layer 7 as an outer cover is provided on the outer periphery of the coating layer 6.

In the present invention according to the embodiments described above, there is a central member 1 in the center, multilayer (or single layer may be sufficient) covering layers 6 and 7 at the outermost part, and a plurality of light beams around the central member 1. There is a cord layer 2 made of fibers 3, 3, 3, .

Next, a manufacturing example of the cable according to the present invention will be described as a second example.
To explain with a diagram, at the left end of the figure, a central member 1 is fed from the central supply bobbin A, and a plurality of optical fibers 3, 3, . The central member 1 and the optical fibers 3, 3... are twisted together and applied to the next coating device B, so that the protective layer 4 is coated on the outer periphery of the optical fibers 3, 3... At the same time, the excess amount is removed by a die C and cured in a drying device D at the next stage.

The semi-finished product here has a circular cross section, and a jelly-like mixture is applied to its outer periphery by the next coating device E to form a mixture layer 5.

Thereafter, a tape F sent from a feeder (not shown) is pressed and wound around the outer periphery of this mixture layer 5 by a core wrap means, thereby forming a coating layer 6. The coating layer 7 is extruded using a multi-stage plastic extruder G.

The cable shown in FIG. 1 is manufactured in this way, and if the outer periphery of this cable requires further coating, an appropriate coating process H as shown at the right end of FIG. 2 is carried out.

As explained above, the optical fiber cable according to the present invention includes a plurality of optical fibers 3, 3, 3...
There is a cushioning protective layer 4 on the outer periphery of the cord layer 2, and a jelly-like mixture layer 5 is provided on the outer periphery. 4 to each optical fiber 3,
3, 3... can be protected and their mechanical properties can be improved, and the admixture layer 5 on the outer periphery can also ensure waterproofness.

Further, since the mixture layer 5, which has a poor protective effect when used alone, is laminated on the outer periphery of the protective layer 4, it cooperates with the protective layer 4 to protect the core wire layer 2. directly covers the conductor layer 2, so that the admixture layer 5 does not penetrate into the conductor layer 2 side, and furthermore, by peeling off the protective layer 4 when connecting the cable, the admixture layer 5 is also removed at once. ,
In addition, since it can be completely removed, the peeling properties are improved, and the cable connectivity (workability, adhesive strength) is also improved because no admixture remains.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the cable of the present invention, and FIG. 2 is a schematic explanatory view showing one manufacturing example of the same cable. DESCRIPTION OF SYMBOLS 1... Central member, 2... Core wire layer, 3... Optical fiber, 4... Protective layer, 5... Admixture layer, 6, 7...
...covering layer.

Claims (1)

[Scope of utility model registration request] The above-mentioned optical fiber cable has a central member in the center, a single-layer or multiple-layer coating layer on the outermost layer, and a core layer made of a plurality of optical fibers around the central member. An optical fiber is provided between the core layer and the coating layer, with a protective layer made of a cushioning polymer material covering the outer periphery of the core layer, and a jelly-like mixture layer covering the outer periphery of the protective layer. cable.