JPS60263908A - Wiring method of flat type optical cable - Google Patents

Abstract

PURPOSE:To easily obtain an optional radius of curvature without applying unreasonable force to optical fiber cores by twisting an inflection part of the flat type optical cable where a coating member is removed by 180 deg. and bending it according to a wiring angle. CONSTITUTION:The coating of the inflection part of the flat type optical cable 1 is peeled and removed to expose optical fiber cores 2 and 3, and one flat type optical cable 1' is twisted by 180 deg. to the other flat type optical cable 1, so that the cores 2 and 3 are twisted without being applied with any unreasonable force. The flexure of the inside optical fiber 3 which is caused in the flexing direction inevitably when the fiber is flexed cancels the extension of the outside optical fiber 2, and the radius R of bending is decreased freely, so the optical fiber is laid easily even where a small radium of bending is required such as a corner of walls in a room. Then, the flexed part is covered with a protection cover 8 and thus protected against external force.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for laying flat optical cables, and is particularly suitable for laying indoor wiring, for example, under tile carpets as data lines connecting OA equipment in an office. The present invention relates to a method of laying a flat optical cable in which a plurality of optical fibers are arranged and accommodated in a covering member, which eliminates the need for construction work such as piping, is easy to maintain, and has an excellent appearance.

BACKGROUND OF THE INVENTION Two examples of the structural concept of a flat optical cable are shown in FIGS. 2a and 2b, respectively. This is an example of a flat optical cable 1 including two optical fiber cores 6, where 4 is a covering member and 5 is a tension member accommodated in the flat optical group 1 as necessary to give strength to the flat optical cable 1.

Flat optical cables have excellent features in terms of maintenance management and aesthetics when installing indoor wiring, as mentioned above.
In complex indoor cable installation locations, especially when installing cables at curved parts of indoor corners, flat optical cables 1 The following methods are usually used to install cables at bends.

(1) As shown in FIG. 6, the flat optical cable 1 is fixed and laid by applying an external force to the same shape and bending it at a possible angle.

(2) As shown in FIG. 4, the flat optical cable is cut at the bent part, set at the required angle, and then fixedly installed in a separately prepared connection connector formed at the required angle.

Note that the tension member 5 accommodated in order to increase the strength of the flat optical fiber is used as necessary, and is not directly related to the present invention, so it will not be described in the following. If the tension member 5 is accommodated, cut it at the bent part.

Problems to be Solved by the Invention In the conventional method (1) in which a normal flat optical cable is laid at a bend, since the flat optical cable has a flat cross-sectional shape, it does not bend in the width direction shown in Fig. 3. However, the bending radius R determined by the dimensions and rigidity of the flat optical cable is specified, and if the cable is bent beyond the bending radius R, there is a problem in that excessive force is applied to the optical fiber and optical transmission loss increases.

In addition, in the conventional method (2), it is necessary to prepare many types of connectors 7 designed and manufactured at arbitrary angles as shown in FIG. Processing of cut end face of core wire.

There are problems in that the number of steps such as mounting on the connecting connector increases, making on-site work complicated, and connection loss occurs due to mounting on the connecting connector.

In order to solve the problems of the prior art, the present invention provides an optical fiber core wire in which the covering member of the bent portion of a flat optical cable is peeled and removed, and the covering member is then removed. 180° bending part
This is a laying method characterized in that by twisting and bending according to the laying angle, an arbitrary bending diameter can be easily obtained without applying excessive external force to the original cored fiber.

Embodiment FIG. 1 is a diagram illustrating the state of a bent portion in an embodiment of a flat optical cable having two core optical fibers according to the present invention. 1 is a flat optical cable, 1' is a flat optical cable twisted by 180 degrees with respect to flat optical cable 1, and 2''? and 5 indicate twisted optical fiber cores, respectively. The coating of the bent portion of the flat optical cable is peeled off to expose the optical fibers 2 and 3, and the other flat optical cable itself is 18
By twisting 0° to make the flat optical cable 1',
The optical fiber core wires 2 and 6 are twisted without being subjected to excessive external force, and when bending, the deflection of the inner optical fiber 6 that inevitably occurs in the bending direction and the extension of the outer optical fiber 2 are offset, The bending radius R can be made as small as desired, and it can be easily installed in areas that require a small bending radius, such as corners near indoor walls.

Further, as shown in FIG. 5, after giving the flat optical cables 1 and 1' an arbitrary bending diameter and fixing them,
It is also an effective aspect of the present invention to cover the bent portion of the flat optical cable with a protective cover 8 to ensure the strength of the bent portion of the flat optical cable against external forces.

In addition, as shown in FIG. 6, the present invention also allows the flat optical cable to be installed by peeling off the covering member at the bent portion of the flat optical cable and then fixing it to the required bending diameter. The optical fiber core 6 is bent, causing an increase in optical transmission loss, and in addition, tensile force is applied to the outer optical fiber core 2, resulting in lack of stability, and there is a limit to the bending diameter. It was confirmed that the limit of this bending diameter was approximately 53 mm.

However, in a bent portion with a large bending diameter, it is of course possible to lay the flat optical cable by simply bending the flat optical cable itself without twisting the flat optical cable through 180° at the bent portion. It is.

Next, specific examples will be shown. Ordinary flat optical cable (second
For the example shown in Figure α), the bending radius R is 5Qmm.

Examples for the case of 1Qmm are shown in the following table. According to the present invention, a flat optical cable can be easily laid without increasing loss.

Effects of the Invention As described above, according to the flat optical fiber installation method of the present invention, the flat optical fiber can be easily installed without applying unnecessary bending force to the optical fiber core wire and without increasing optical transmission loss. Laying at bent portions can be done stably and easily. Further, there is no need for processes such as cutting the optical fiber core wire, processing the cut end face, preparing and connecting various types of connectors, and the bending portion can be processed in a short time, which is a great effect.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the state of the bent portion according to the present invention, and FIG.
Figures α and b are examples of flat optical cables, Figures 6 and 4 are diagrams illustrating the bent portions of conventional flat optical fibers, respectively.
5 and 6 are views showing respective embodiments of the bending portion according to the present invention. 1.1'... Flat optical cable, 2, 6... Twisted optical fiber core wire, 4... Covering member, 5... Tension member, 6... Optical fiber core wire, 7... Connection connector, 8...bending portion protection cover Patent applicant: Sumitomo Electric Industries, Ltd. Representative Patent Attorney Hisashi Tamamushi 5 Part 1 Figure 3 Figure 4 Figure 2

Claims (1)

[Claims] In a method for laying a flat optical cable in which a plurality of optical fibers are arranged in a covering member, when the flat optical cable is bent and laid, the covering member at the bent portion of the flat optical cable is peeled off and removed, and then the vaginal covering member is installed. A method for laying a flat optical cable, which comprises twisting the bent portion of the flat optical cable by 180 degrees and bending the cable according to the laying angle.