JPH04198902A - Method for holding excess length shape of coated optical fiber - Google Patents

Abstract

PURPOSE:To keep the shape of a coated optical fiber in an appropriate one while keeping the necessary bend radius with the use of a shape holding tube to easily hold the shape of the coated optical fiber by fitting the shape holding tube in the excess length part of the coated optical fiber. CONSTITUTION:The shape holding tube 11 which holds the given shape is fitted to the excess length part of the coated optical fiber 1, and the shape holding tube 11 is also fitted to the excess length part of the coated optical fiber 1 of another optical cable 7. The shape holding tube 11 is bent in a loop shape while keeping the allowable bend radius for the coated optical fibers 1 and 7 in the excess length parts of the coated optical fibers 1 and 7. Thus, the shapes of the coated optical fibers 1 and 7 are kept appropriate, and the shape of the coated optical fiber is easily held.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for maintaining the shape of the extra length of a coated optical fiber, which maintains the extra length of the coated optical fiber in a desired shape.

[Prior Art] When optical fibers are connected in a closure or the like, an extra length is provided in the optical fibers for later connection changes. The excess length of the optical fiber core 1 is removed by cutting several turns while observing the allowable bending radius.
As shown in the figure, the ringed shape is held by the molded sheet 2, but the ringed shape is held by the tray 3 as shown in Fig. 5, or by a storage plate with hooks 4 as shown in Fig. 6. 5 to maintain the looped shape and also protect the optical fiber core 1.

[Problems to be Solved by the Invention] However, when the optical fiber core 1 is looped, since the optical fiber core 1 has a repulsive force, the looped portion bounces and the loop shape is distorted. (There was a problem that the looping workability was poor. Also, the looped optical fiber core 1 was attached to the forming sheet 2.tray 3.hook 4.
Since the rounded shape is maintained by the attached storage plate 5, there is a problem in that a large storage space must be provided inside the closure or the like.

An object of the present invention is to maintain the shape of the excess length of the optical fiber by easily maintaining the shape of the excess length of the coated optical fiber, and also by minimizing the increase in the accommodation space. The purpose is to provide a method.

[Means for Solving the Problems 2] To explain in detail the present invention for achieving the above object, the method for maintaining the shape of an optical core/core wire according to the present invention provides a shape that maintains a given shape. The present invention is characterized in that by fitting a holding tube into the extra length of the optical fiber/<4- wire and bending the shape holding tube into a desired shape, the extra length of the optical fiber core is maintained in that shape.

[Function] When such a shape-retaining tube is fitted into the extra length of the optical fiber, the shape of the optical fiber is maintained in the appropriate shape given to the shape-retaining tube while maintaining the required bending radius. I can do it. Therefore, the shape of the optical fiber can be easily maintained.

Furthermore, since the shape-retaining tube itself also serves as a protector for the optical fiber core, the storage space can be reduced compared to when a tray or the like is used.

=Example] Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

1 and 2 show a first embodiment of the present invention in which the present invention is applied to the extra length of the optical fiber core 1 inside the closure 6. FIG. The end of the optical cable 7 is connected from the end of the cable sheath 8 to the cable core 9 and the tension member 1.
0 is derived sequentially. An optical fiber core 1 to be connected is taken out from the cable core 9 with an extra length.

A shape-retaining tube 11 that maintains a given shape is fitted into the extra length of the optical fiber core 1. The shape-retaining tube 11 is made of, for example, thin metal, polyethylene, metal foil laminated plastic, or the like, and is formed as a hollow tube having an inner diameter larger than the outer diameter of the optical fiber core 1 . The shape-retaining tube 11 is also fitted to the extra length of the optical fiber/core wire 1 of the other optical cable 7. The distal ends of the mutual optical fibers are connected to each other at a core connection section 12, and the outer periphery thereof is covered with a connection section cover 13. The extra length of each optical fiber core 1 is obtained by bending each shape-retaining tube 11 into a loop shape while observing the allowable bending radius of the optical fiber core 1. is held in The end of the shape-retaining tube 11 on the cable core 9 side is secured to the cable core 9 by a tube retaining member 14. In FIG. This shows an example in which the invention is applied. Each optical fiber core 1 is led out from the end of the optical cable 7 with a required extra length, and a shape-retaining tube 11 is fitted into each of these optical fiber cores 1. A connector 15 is provided at the tip of each optical fiber core 1.
or installed respectively. In order to prevent the connectors 15 from overlapping at the same position and causing an increase in the outer diameter, the positions of the connectors 15 are shifted in the longitudinal direction. It is held in its shape by rounding. The optical fiber core 1 with the shape-retaining tube 11 and the connector 15 are housed in a protection tube 16. The base of the protective tube 16 is fluid-tightly retained by the sheath retaining portion 17. Further, a pulling eye 18 is attached to the tip of the protective tube 16.

In such an optical cable terminal with a connector, the shape of the excess length of the optical fiber core 1 is maintained by the shape-retaining tube 11, so it does not take up much space compared to the case where a tray or the like is used, and the protective tube 16 It is possible to suppress the increase in the outer diameter of.

[Effects of the Invention] As explained above, in the method for maintaining the shape of an optical fiber with extra length according to the present invention, since the shape-retaining tube is fitted into the extra length of the optical fiber, the shape-retaining tube has the required shape. The shape of the coated optical fiber can be maintained in an appropriate shape by observing the bending radius. Therefore, the shape of the optical fiber can be easily maintained. Also,
Since the shape-retaining tube itself also serves as a protector for the optical fiber, the storage space can be reduced compared to when a tray or the like is used.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a first embodiment in which the present invention is applied to the extra length of the optical fiber in the closure, and FIG. 2 is a side view showing the state of the optical fiber in FIG. 1 before connection. 3 is a longitudinal sectional view of a second embodiment in which the present invention is applied to the extra length of the optical fiber in the terminal portion of the optical cable with a connector, and FIGS. 4 to 6 are longitudinal cross-sectional views of the conventional optical fiber. FIG. 7 is a perspective view showing three examples of shape retention states in the extra length portion. 1... Optical fiber core wire, 6... Closure, 7...
- Optical cable, 8... Cable sheath, 9... Cable core, 10... Tension member, 11... Shape retaining tube, 12... Core wire connection portion, 15... Connector, 16...・Protective tube. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A shape-retaining tube that maintains a given shape is fitted into the extra length of the coated optical fiber, and the shape-retaining tube is bent into a desired shape to maintain the extra length of the coated optical fiber in that shape. A method for retaining the extra length shape of an optical fiber core.