JPS6070409A - Laying method of optical fiber cable - Google Patents

Abstract

PURPOSE:To obtain a laying method of an optical fiber cable without producing excess optical fiber cores by housing preliminarily only the min. required number of the optical fiber cores into a duct and increasing successively wiring according to an increase in demand by leading the cores into the gap of the duct at each time of such increase. CONSTITUTION:A duct 3 in which only the min. required number of optical fiber cores 1 at the point of laying are housed and which is supported to a messenger wire according to need is laid. When the demand in the area to be laid increases thereafter, the required number of the cores are successively led into the gap 4 of the duct at every time of such increase. The leading-in is accomplished by a method of housing preliminarily several pieces of dummy wires for leading in the cores 1 into the duct 3 in the stage of manufacturing the duct 3 or a method of housing preliminarily only one dummy wire therein, attaching another dummy wire in one bundle with the core 1 to be desired to be led-in in the stage of leading in freshly the core 1 and connecting the same to the existing dummy wire in the cut 3 then leading-in said wire. The optical fiber cores are housed into the existing duct according to the demand at every time in the above-mentioned way, by which the costly cores are effectively used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method of laying an optical fiber cable.

[Prior art]

Conventionally, when laying an optical fiber cable, the future demand trends in the installation area are investigated in advance, a demand forecast is made based on the survey results, and the number of optical fiber cores to be accommodated in the cable is determined based on the forecast. Determine. As a result, there are cases where the optical fiber cores are in short supply, contrary to expectations, but in general, the number of cores is increased in consideration of safety, resulting in surplus cores. This is true not only for optical fiber cables but also for copper cables, but there is a decisive difference between optical fiber cables and copper cables. The reason is that copper cables can be recovered and recycled, but optical fiber cables cannot be recycled. Moreover, optical fiber cables are expensive. For the above reasons, there is a problem of reducing the number of surplus optical fibers as described above.

[Purpose of the invention]

In view of the above-mentioned problems, an object of the present invention is to provide a method for laying an optical fiber cable that does not generate excess optical fiber core wires.

[Structure of the invention]

In order to achieve the above object, the method for laying an optical fiber cable of the present invention involves storing only the minimum necessary number of optical fiber cores in advance in a duct capable of accommodating a large number of optical fiber cores, and then laying the optical fiber cables. The present invention is characterized in that a number of optical fiber cores corresponding to an increase in demand are drawn into the gap of the duct and wired each time.

[Embodiments of the invention]

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

FIG. 1 is a cross-sectional view of one embodiment of a duct used in the present invention. In the optical fiber cable installation method of the present invention, as shown in FIG. 1, only the minimum required number of optical fiber cores 1 are stored in advance at the time of installation, and they are supported by the messenger wire as necessary. Install component 5. As time passes and the demand increases in the installation area, the required number is drawn into the gap end of the duct each time. There are several ways to draw in the duct 11, but when manufacturing the duct 11, several dummy wires for drawing in the optical fiber core 1 may be stored in the duct 5, or alternatively, Store only one dummy wire in advance, and when pulling in a new optical fiber core 1, bundle another dummy wire together with the optical fiber core 1 you want to pull in, and attach it to the existing wire in the duct 3. Another method is to connect it to a dummy wire. With this method, there will always be one lead-in dummy wire inside the duct 3. Since there is only one, it does not get in the way.

1□- As another method, as shown in FIGS. 2 and 5, a continuous slit 5 in the longitudinal direction may be provided in the duct 3 so that the optical fiber core 1 can be accommodated from the outside. Also the fourth
As shown in the figure, in order to remove raindrops etc. that enter through the slit 5,
A through hole 6 for draining water in the longitudinal direction at the bottom of the duct l-3.
It is convenient to provide. Even if the through holes 6 are arranged at regular intervals,
It may be at irregular intervals. Note that the slit 5 is located at the upper part of the duct tl, for example, in FIG.
It is preferable to locate the optical fiber near the neck 7 because more of the optical fiber core 1 can be stored therein. Here, it is preferable to fix the slits 5 with the fixing means 8 at regular or irregular intervals as shown in FIG. 4, since there is no possibility that the slits 5 will open. Further, since the optical fiber core wire 1 will be drawn in later, the inner diameter of the duct 3 must be determined after careful consideration at the time the duct 5 is installed.

In this way, by storing the required number of optical fibers in the existing duct each time according to demand, there will always be no surplus optical fibers, and therefore,
This results in effective use of expensive optical fiber cores.

〔Effect of the invention〕

As described above, according to the method for laying an optical fiber cable of the present invention, there is no need to have surplus optical fiber core wires, so that the optical fiber core wires can be used without waste.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an embodiment of a duct used in the present invention;
FIG. 2 is a cross-sectional view of another embodiment of the duct used in the present invention, FIG. It is a diagram. 1...Optical fiber core wire 2...Metsusenji t"-wire U...Duct 4...Gap part
5...Slit 6...Through hole 7...
... Neck 8 ... Fixing means Fig. 1 Fig. 3 Fig. 2 Fig. 4 b

Claims (3)

[Claims] (1) In a duct that can accommodate a large number of optical fiber cores,
Only the minimum required number of optical fiber cores are stored and laid in advance, and then the number of optical fiber cores corresponding to the increase in demand is drawn into the gap of the duct and wired each time. Features: Optical fiber cable installation method. (2) The method for laying an optical fiber cable according to claim 1, wherein the duct is supported by a Messenger wire that is a tensile strength member. (3) The duct has a continuous slit in the longitudinal direction, and a number of optical fiber cores according to the demand is accommodated from the outside through the slit. 2. Installation method of optical fiber cable as described in section. ('I) The duct has a continuous slit in the longitudinal direction,
Claim 1, characterized in that the bottom part has through-holes for draining water provided at regular or irregular intervals, and a number of optical fiber cores according to the demand can be accommodated from the outside through the slits. The method for laying an optical fiber cable according to item 1 or 2.