JPS59135404A - Open-type optical fiber cable - Google Patents

Abstract

PURPOSE:To lead out easily optical fibers by winding relatively a cable body, where optical fibers are stored in grooves provided in the lengthwise direction on the outside circumferential face of a linear spacer, and a linear body loosely. CONSTITUTION:Optical fibers 13 are stored in grooves in the lengthwise direction of a linear spacer 12 which are provided on the outside circumferential face of the linear spacer 12 incorporating a tension member 11 and have a circular section, and a linear body 14 is wound around the outside of the linear spacer 12 loosely. Optical fibers are not provided with a housing, and they are held with the linear body 14 merely from the outside of optical fibers 13 to prevent them from slipping off. Consequently, long-sized optical fibers 13 are pulled out easily from spaces of winding intervals when the cable is connected in an optional position, and thus, the connecting work is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an open optical fiber cable from which an optical fiber can be easily drawn out from any location.

Optical fiber cables with excellent transmission characteristics have recently been used as transmission lines in communication systems in place of copper conductor cables. In a general communication system, as shown in Fig. 1, a connection part 2 is provided at an arbitrary point on a transmission line 1 to branch off, and a connection B
Terminals 5 can be added via OX 3 or connection terminal 4. When the transmission line 1 is a copper conductor cable, several α is sufficient for the total working length at the connection part 2, but on the other hand, when an optical fiber cable is used as the transmission line 1, the length of the optical fiber is The working extra length is required to be approximately several tens of cIrL to 1 m. However, conventional original fiber cables have a structure in which multiple optical fibers, tension members, etc. are inserted into a jacket tube, and in order to take out such a long extra length of optical fiber from the middle of the cable, it is necessary to remove the jacket tube. It was necessary to carry out complicated work such as cutting and removing the liver over a long distance.

An object of the present invention is to provide an open-type optical fiber cable in which the original fiber can be easily pulled out by exposing the original fiber on the surface of the cable. The fiber is characterized by being formed by relatively coarsely winding a wire body and a cable body in which the original fiber is housed in a longitudinal groove cut in the fiber.

Hereinafter, the open optical fiber cable of the present invention will be explained in detail based on examples.

The first embodiment of the present invention is shown in FIG. 2, and the second embodiment is shown in FIG.
Each is shown in the figure. In the embodiments shown in both figures, longitudinal grooves are carved on the outer peripheral surface of the linear spacer 12 that houses the tension member 11 on the top, bottom, left and right sides of the figure, and a total of four light beams are inserted into each of the grooves. The fiber 13 is housed to form a cable body. As shown in the drawings, the linear spacer 12 may be made of plastic molded on a tensile member such as the tension member 11, or may be entirely made of metal. The groove formed in the linear spacer 12 has a substantially circular cross-sectional shape, and has a shape that allows the optical fiber 13 to be accommodated and easily removed. As the original fiber 13, in addition to the one without the protective layer shown in the drawings, it is also possible to use fibers with a protective layer such as optical fiber cores and optical fiber cords.

Furthermore, in the first embodiment shown in FIG. 2, the linear body 14 is loosely wound around such a cable body, while in the second embodiment shown in FIG. ni coarse (
It is wrapped. In this way, the cable body and the linear body 14
Since the optical fiber 13 is wound relatively roughly, the optical fiber 13 is prevented from falling off the linear spacer 12.

As the linear body 14, a flexible body having appropriate hardness and flexibility can be used, such as a plastic tape, a plastic string, a metal wire, or a coated material thereof. It should be noted that if the linear body 14, the linear spacer 12, the original fiber 13, etc. are made of materials with excellent environmental resistance, it will be suitable for outdoor use.

Next, a third embodiment is shown in FIG. In the embodiment shown in the figure, the optical fiber 13 is wound not linearly in the longitudinal direction but spirally. That is, four grooves are spirally carved along the longitudinal direction on the outer peripheral surface of the linear spacer 12, and the latent pressure optical fibers 13 are accommodated in each groove.

The linear body 14 is loosely wound around such a cable body and the support wire 15. The winding direction of the linear body 140 and the helical direction of the original fiber 13 are opposite to each other, so that they do not cross each other. Note that optical fiber cables with external support wires 15 are classified as self-supporting type.
It is possible to install it alone.

The open type optical fiber cable of the present invention having the above configuration does not have an outer jacket, and merely presses the optical fiber 13 from the outside with the linear body 14 to prevent it from falling off, and the optical fiber 13 is exposed on the surface. are doing. Therefore, when connecting the open optical fiber cable of the present invention at an arbitrary location, the long original fiber can be easily pulled out with a gap in the winding interval, and the connection work is simplified.

Furthermore, since the grooves carved in the linear spacer 12 are open spaces, moisture from rain is removed by natural fall, and even if it remains and freezes, the compressive force due to the volumetric expansion of the ice is transferred to the optical fiber. In addition to ((), it has the advantage of good transmission characteristics even when frozen at low temperatures.

Furthermore, since the cable has an asymmetrical cross-sectional structure, the wind pressure load is small and snow does not easily adhere to it, so unnecessary tension is not applied and there is little risk of wire breakage.

Next, a method of manufacturing the first open type optical fiber cable mentioned above will be explained with reference to FIG. In this method, the process of inserting the optical fiber 13 into the linear spacer 12 and the process of winding the linear body 14 around the cable body are performed in the same process. That is, the linear spacers 12 are continuously fed from the supply device 16 to the insertion device 17 . The optical fiber 13 is inserted into the linear smoother 12 in the insertion device 17 , and the cable body is then sent to the winding device 18 . The cable is wound around the cable body in the winding device 18, and then passed through the cab stan 19 and wound up in the winding device 20. Note that the manufacturing method is not limited to such a manufacturing method, and manufacturing may be performed by extrusion molding the linear spacer 12 and spirally winding a plastic string as the linear body 14 around the outer periphery thereof.

If this happens, stress may remain inside the plastic string.
The open optical fiber cable of the present invention has the advantage that it does not vary even if the string is cut at an arbitrary point because it is maintained in a spiral shape. Since the optical fiber is exposed on the surface, it is easy to pull out the original fiber in a long length (this makes the connection work easy).

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of the communication system, Figs. 2 to 5 relate to the open optical fiber cable of the present invention, Fig. 2 is a perspective view of the first embodiment, and Fig. 3 is the second embodiment. Example perspective view, 4th
The figure is a perspective view of the third embodiment, and FIG. 5 is a schematic configuration diagram of the manufacturing apparatus. 11 in the drawing is a tension member. 12 is a linear spacer, 13 is an optical fiber, 14 is a linear body, 15 is a support wire, 16 is a supply device, 17 is an insertion device, 18 is a winding device, and 19 is a capstan. 20 is a winding device. Patent Applicant Sumitomo Electric Industries, Ltd. Nippon Telegraph and Telephone Public Corporation Agent Patent Attorney Shibe Mitsuishi (and 1 other person) Figure 1 Co Figure 2

Claims (1)

[Claims] An open-type optical fiber cable characterized by being formed by winding a linear body and a cable body in which an optical fiber is housed in a longitudinal groove carved on the outer circumferential surface of a linear spacer. .