JPS6030728Y2 - fiber optic unit cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a unit cable serving as a unit wire when constructing an optical fiber cable.

Conventionally, this type of cable has multiple optical fibers coated with thermoplastic plastic by extrusion molding, so this coating layer undergoes heat shrinkage during extrusion molding.
As a result, the internal optical fibers are undulated and bent, resulting in increased transmission loss.

In addition, to improve the above-mentioned drawbacks, an optical fiber unit has been developed in which a glass fiber cloth or the like having a thermal expansion coefficient similar to that of the multiple optical fibers is wrapped around the outer periphery of the optical fibers, and the cloth is impregnated with a resin. Cables have also been proposed.

However, such unit cables involve wrapping glass fiber cloth around the outer periphery of multiple optical fibers and then impregnating them with resin, so a resin impregnation process must be included during the cable manufacturing process, which slows down the manufacturing process. Not only is it troublesome, but it also takes time to impregnate and harden the resin, making it difficult to increase production efficiency and resulting in high costs.

In view of these points, the present invention improves the transmission characteristics by forming a tape from thermoplastic resin containing an appropriate tension member and wrapping the optical fiber with this tape. To provide an optical fiber unit cable which can sufficiently protect the fibers and which is easy to manufacture.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In the present invention, as shown in FIGS. 1 and 2, fiber reinforcement is a composite of a fiber reinforcement material 1 such as a low-elongation doubled yarn, twisted yarn, or woven fabric configured in the form of a tape, and a thermoplastic resin 2. Use plastic tape 3.

A in FIG. 1 shows a case in which yarns, which are doubled or twisted yarns, are aligned and embedded in a thermoplastic synthetic resin 2, and the opening in the same figure shows a case in which a woven fabric is used.

The cross-sectional form of the fiber-reinforced plastic tape 3 is as shown in FIG. In some cases, an outer layer 2' made of the same resin 2 is formed on only one side of the fiber reinforcing material 1.

Here, the fiber reinforcing material 1 must have high tensile strength against an elongation of around 0.5%, which is the elongation at the time of cutting the optical fiber, not damage the optical fiber, and have no effect on the transmission characteristics of the optical fiber. It is desirable to use glass fiber, carbon fiber, aromatic polyamide fiber, etc. as the material, taking into consideration the various points of not giving any

FIG. 3 shows an embodiment of the unit cable of the present invention using the fiber-reinforced plastic tape 3 as described above.

This unit cable consists of multiple optical fibers 4, 4',
... is covered with fiber-reinforced plastic tape 3. The tape 3 is rolled in the longitudinal direction, the side edges 6, 6' are overlapped, and the overlapped parts are heat-sealed. This is pipe 5.

As described above, the present invention utilizes fiber-reinforced plastic tape 3 with fiber-reinforced material 1 of low elongation to connect optical fibers 4 and 4.
Since the tape is wrapped with a fiber-reinforced plastic tape, there is no problem such as distortion due to heat shrinkage as in the case of extrusion molding. Since the fiber reinforcement material used in the tape has a low elongation, the tape has high tensile strength.
Optical fibers can be protected from tension.

Furthermore, since the tape uses thermoplastic resin rather than thermosetting resin, it has appropriate flexibility and can be used to construct a highly flexible unit cable.

Furthermore, the pipe 5 that envelops the optical fiber can be formed by simply rolling a fiber-reinforced plastic tape and heat-sealing the overlapping parts on both sides of the tape, so it is possible to wrap the glass fiber around the optical fiber and impregnate it with resin. It is not only extremely easy to manufacture, but also can be produced at a high speed.
An inexpensive optical fiber unit cable can be obtained.

[Brief explanation of the drawing]

Portions 49 in FIG. 1 are partial plan views showing different examples of fiber-reinforced plastic tapes used in the unit cable of the present invention, Ports 49 in FIG. The figure is a cross-sectional view showing an embodiment of the optical fiber unit cable of the present invention. 1... Fiber reinforcement material, 2... Thermoplastic resin, 3... Fiber reinforced plastic tape, 4,
4'...Optical fiber, 5...Pipe.

Claims (1)

[Scope of utility model registration request] A fiber-reinforced plastic tape made of a composite of a low-elongation fiber reinforcement material and a thermoplastic resin is molded into a pipe shape, and a plurality of optical fibers are wrapped around the fiber-reinforced plastic tape. A fused optical fiber unit cable.