JPS636845B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] The allowable bending radius of the cable is minimized by providing a cable with a tension member whose both ends are fixed to a connector and a wire rod which is telescopically engaged with the connector. , designed to facilitate cable installation.

[Industrial application field]

The present invention relates to an optical fiber cable having connectors connected to both ends of the cable, and more particularly to an optical fiber cable provided with a tension member and wire for protecting the optical fiber.

Optical fiber cables used as signal lines input to and output from electronic devices cannot be laid straight due to the conditions under which the electronic devices are arranged, and may require bending.

Therefore, such optical fiber cables are generally equipped with protective members to prevent damage to the optical fibers even if the cables are bent and laid in a specified manner. When a fiber cable is provided with a protective member, the permissible bending radius is increased by the protective member, resulting in less flexibility during installation.

Therefore, even if such a protective member is provided, it is desired that the allowable bending radius of the optical fiber cable be as small as possible.

[Conventional technology]

Conventionally, the configuration was as shown in the conventional explanatory diagram of FIG. 4. A is a plan view, and b is a sectional view.

As shown in a, the cable 11 is made up of a plurality of optical fibers 1, a protection member 12 made of a metal material such as a piano wire stretched along each optical fiber 1, and an outer skin of a cable sheath 2. A connector 10 is provided at each end of the cable 11, and each optical fiber 1 is connected to a connector of the connector 10.

In addition, the pipe 13 in which the optical fiber 1 is installed and the protection member 12 are arranged alternately as shown in b, so that the protection member 12 protects the optical fiber 1 from external forces such as lateral pressure. It is formed like this.

Further, the terminal portion of the protective member 12 is fixed to the connector 10 and is designed to receive the tensile force applied to the cable 11 so that no tension is applied to the optical fiber 1.

[Problem that the invention seeks to solve]

However, in such a configuration, for example, as shown in the installation explanatory diagram of FIG.
When the cable 11 is laid on the cable 1, expansion and contraction occurs at the inner and outer peripheries at each of the bent portions A, B, and C. Therefore, in the case of the solid line, the expansion and contraction in parts A and B cancel each other out, making it possible to install the cable, but in the case of the dotted line, the expansion and contraction in parts A and C is doubled, making installation impossible. .

Furthermore, since the protective member 12 is made of a metal material, the elongation rate of the material is small. Therefore, when the cable width is 2 mm, the relationship between the elongation rate E and the allowable bending radius R is as shown in the graph in Figure 6. When the elongation rate E is 0.3%, R is approximately 667 mm, which is a huge amount. This will require a radius.

Therefore, there was a problem in that a large space was required for laying the cable 11.

[Means for solving problems]

FIG. 1 is a plan view of the principle of the present invention.

As shown in FIG. 1, an optical fiber cable includes a cable 3 formed by embedding an optical fiber 1 in a cable sheath 2, and connectors 4 connected to both ends of the cable 3, the connector 4
a tension member 5 fixed at both ends to the connector 4; and a flexible pipe 7 fixed at both ends to the connector 4.
and a wire rod 6, which is formed such that both ends or one end thereof are free ends, and is loosely engaged with the inner wall of the pipe 7, are formed so as to be attached to the optical fiber 1 and stretched.

With this configuration, the above-mentioned problems are solved.

[Effect]

That is, a tension member whose both ends are fixed to the connector and protects against force in the tensile direction, and a wire whose both ends or one end are elastically locked to the connector and protects against lateral pressure are stretched over the cable. As a result, the allowable bending radius of the cable, which was limited by the elongation rate, is relaxed by the free expansion and contraction of the wire.

Therefore, the permissible bending radius of the cable can be made smaller than before, saving space for cable installation and providing flexibility in the installation work.

〔Example〕

The present invention will be explained in detail below with reference to FIGS. 2 and 3. Fig. 2 is an explanatory diagram showing an embodiment according to the present invention, in which a is a plan view, b is a cross-sectional view, c is an explanatory diagram at the time of bending, and a, b, and c in Fig. 3 are explanatory diagrams of joining wire rods. be. The same reference numerals indicate the same objects throughout the figures.

As shown in FIG. 2a, the cable 3 includes a flexible pipe 7 made of a synthetic resin material, etc., and a tube 8 in which the optical fiber 1 is installed, and the cable 3 is made of a flexible pipe 7 made of a synthetic resin material, etc., which is installed inside so that the wire rod 6 made of a metal material is loosely connected. and a tension member 5 made of a metal material are arranged and covered with a cable sheath 2 made of a PVC resin material, and the terminals of the pipe 7 and the tension member 5 are fixed to the member of the connector 4. Thus, the connector 4 is connected to both ends of the cable 3.

The tension member 5 and the pipe 7 can be easily joined to the connector 4 using an insert or the like when molding the connector 4.

With this configuration, the wire rod 6 can freely move along the inner wall of the pipe 7 when the cable 3 is bent.

Moreover, such movement of the wire rod 6 is more effective if lubricant 9 is injected to reduce the friction between the wire rod 6 and the inner circumferential surface of the pipe 7, as shown in b.

When the cable 11 configured in this way is bent, as shown in c, the tip 6A of the wire 6 on the outer circumference is recessed from the normal position, and the tip 6B of the wire 6 on the inner circumference is bent, with the tension member 5 as the neutral plane. On the contrary, it stands out. Therefore, it is possible to bend the wire 6 without affecting its elongation rate E, and the allowable bending radius R can be reduced.

In this case, the tension member 5 protects the tension applied to the cable 3, and the wire 6 protects the lateral pressure applied to the cable 3, so the connection with the connector 4 is shown in Figure 3. It can be done as shown in

In the case of a, both ends of the tension member 5 are provided with hollow parts D at both ends of each wire rod 6 stretched inside the fixed pipe 7, as shown in part C, so that the tension member 5 can be expanded and contracted. In the case of b, one end of the first wire 6 is fixed like the part C like the tension member 5, and the other part is made to be expandable and contractible by the hollow part D, and c In the case of , one end of the two wire rods 6 is alternately fixed like part C, and the other fixed end is made to be expandable and contractible by the hollow part D. In either case, the above-mentioned The same effect can be obtained.

In the embodiment, the case where two sets of wire rods 6 are stretched has been explained, but the tension member 5 and wire rod 6 can be similarly stretched even in combinations other than the two sets. , equivalent effects can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, when installing a cable having an optical fiber, the wire stretched as a protective member is formed so as not to affect the bending of the cable, so that the permissible bending radius is can be made as small as possible.

Therefore, the installation work becomes easy, flexibility is obtained in the arrangement of electronic equipment, and the installation space can be reduced, which has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the principle of the present invention, and FIG. 2 is an explanatory diagram showing an embodiment of the present invention, where a is a plan view and b is a plan view.
is a cross-sectional view, c is an explanatory diagram at the time of refraction, a,
b and c are explanatory diagrams for joining wire rods, Fig. 4 is an explanatory diagram of the conventional method, a is a plan view, b is a sectional view, Fig. 5 is an explanatory diagram for installation, and Fig. 6 is an elongation rate E and allowable bending radius R. Shows the relationship graph. In the figure, 1 is an optical fiber, 2 is a cable sheath, 3 is a cable, 4 is a connector, 5 is a tension member, 6 is a wire, and 7 is a pipe.

Claims (1)

[Scope of Claims] 1. An optical fiber cable comprising: a cable 3 formed by embedding an optical fiber 1 in a cable sheath 2; and connectors 4 connected to both ends of the cable 3; a tension member 5 fixed at both ends to the connector 4; a flexible pipe 7 fixed at both ends to the connector 4; An optical fiber cable characterized in that a wire rod 6 is attached to the optical fiber 1 and stretched.