JPH10319285A - Sheath for optical fiber cable, method for manufacturing sheath for optical fiber cable, method for inserting optical fiber wire into sheath for optical fiber cable - Google Patents

Abstract

[PROBLEMS] To easily insert an optical fiber core wire into an optical fiber cable sheath. SOLUTION: An optical fiber cable sheath 1 comprises an inner sheath 2 and an outer sheath 3, and a wire 5 is inserted into an inner space 4 of the inner sheath 2. Then, in order to insert the optical fiber into the sheath 1, a wire 5 is attached to one end of the optical fiber, and the wire 5 is pulled out of the sheath 1 to obtain an optical fiber cable in which the optical fiber is inserted into the sheath 1. Can be

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sheath for protecting an optical fiber cable used for optical communication and the like.
The present invention relates to a method for manufacturing the sheath and a method for inserting an optical fiber into the sheath.

[0002]

2. Description of the Related Art Optical fiber cables are widely used as equipment constituting a communication network for optical communication. For optical fibers, primary coating (primary coating) with a plastic such as urethane, epoxy, or silicone is applied to the periphery of an elongated fiber strand with a cladding placed around a core formed by drawing, and nylon and polyethylene , And a secondary coating such as polycarbonate is applied to form an optical fiber core wire. And
One or a plurality of optical fiber core wires are bundled, inserted into a sheath which is an exterior covering member, formed as an optical fiber cable, and laid.

[0003] The sheath for accommodating the optical fiber core wire has an influence from the surroundings due to the cable laying, and furthermore,
In order to protect the fiber core wire housed inside from bending or tension due to cable laying, a tubular metal material is used as a tensile strength member, and the surrounding area is made of urethane,
It is formed by coating with a plastic material such as polyurethane or polyethylene. Then, an optical fiber cable is formed by manually inserting an optical fiber core wire into the space in the sheath.

As a method of automatically inserting an optical fiber core wire into a sheath, there is also known a method in which an optical fiber core wire is blown together with air from one end of a sheath and blown out from the other end.

[0005]

An optical fiber cable used for optical communication or the like generally requires a cable having a length of several tens to several hundreds of meters.
However, it is extremely difficult and time-consuming to manually insert the optical fiber core from one end of the manufactured sheath, which causes problems such as breakage of the optical fiber core along the way. Also,
Even in the method of inserting the optical fiber core wire with air,
When the length of the sheath is long, an obstacle such as the optical fiber core wire being caught in the middle is likely to occur.

In particular, to insert an optical fiber core wire in a state where a sheath having a length ranging from several tens of meters to several hundreds of meters is linearly extended, that much space is required.
It is not realistic and would be inserted into a sheath that is manufactured and wound on a drum or the like. However, inserting an optical fiber core into a non-linear sheath is a very difficult task, which increases manufacturing costs and contributes to an expensive optical fiber cable.

[0007]

In order to solve the above-mentioned problems in the prior art, according to the present invention, a wire for introducing an optical fiber into the sheath is previously inserted into the sheath for the optical fiber cable.

As the sheath, for example, a sheath composed of an inner sheath formed by spirally winding a band-shaped metal covering member and an outer sheath made of resin provided outside the inner sheath can be considered. Further, the inner sheath and the outer sheath are not limited to a single layer, and may be a multilayer. Also,
The sheath is a flexible tube, but has a problem that it is weak against tension. Therefore, by inserting a Kepler cable as a wire in the sheath in advance, the sheath itself can be pulled during routing (wiring).

In the method for manufacturing a sheath for an optical fiber cable according to the present invention, the inner sheath is formed by continuously winding a strip-shaped metal covering member in a spiral shape. The wire is supplied synchronously from one end side of the inner sheath into the cylindrical space of the inner sheath, and thereafter, the outer sheath is formed outside of the inner sheath by extrusion or the like.

According to the above-described optical fiber cable sheath, a wire for guiding the optical fiber is inserted in advance in the space of the manufactured optical fiber cable sheath. Can be inserted into the sheath.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a cross-sectional view of a sheath for an optical fiber cable according to the present invention,
FIG. 2 is a cross-sectional view showing a state in which the optical fiber is being inserted through the sheath, and FIG. 3 is a cross-sectional view showing a state in which the optical fiber is inserted through the sheath.

An optical fiber cable sheath 1 comprises an inner sheath 2 and an outer sheath 3, and a wire 5 is inserted into an inner space 4 of the inner sheath 2. The inner sheath 2 is formed by continuously winding a strip-shaped metal in a spiral shape.
Is formed by, for example, extruding a resin such as urethane, polyurethane, or polyethylene to the outside of the inner sheath 2, and the wire 5 is a metal wire (wire) or a resin wire such as a Kepler cable.

In order to insert the optical fiber into the sheath 1, as shown in FIG. 2, the wire 5 is connected to one end of the optical fiber 6, and the wire 5 is pulled out of the sheath 1. Then
As shown in FIG. 3, an optical fiber cable having the optical fiber 6 inserted in the sheath 1 is obtained.

FIGS. 4A to 4C are views showing an example of a manufacturing process of the inner sheath. In the present invention, the wires 5 are simultaneously inserted into the inner sheath 2 in the process of manufacturing the inner sheath 2. I do.

That is, first, as shown in FIG. 4A, the wire 5 is inserted into a cylindrical body 8 which is rotated by rollers 7, 7, and the tip of the wire 5 is bonded to the band-shaped metal 2a. Next, as shown in FIG. 4B, the bobbin of the strip-shaped metal 2a is rotated by rotating the cylinder 8 so that the strip-shaped metal 2a is obliquely wound around the outer peripheral surface of the cylinder 8 so that a part thereof overlaps. 2b is moved along the cylinder 8 to near the base end. When the band-shaped metal 2a is wound on substantially the entire surface of the cylindrical body 8 in this manner, the cylindrical body 8 is rotated in the opposite direction and the bobbin 2 is rotated.
b is moved along the cylinder 8 to the original position. Then, as shown in FIG. 4C, the inner sheath 2 formed by spirally winding the band-shaped metal 2a from the cylindrical body 8 comes off. Then, when the inner sheath 2 comes off from the cylindrical body 8,
Since the wire 5 is bound to the tip of the inner sheath 2, the inner sheath 2 is manufactured in a state where the wire 5 is inserted through the inner sheath 2.

Thereafter, the inner sheath 2 is covered with the outer sheath 3 by an extruder or the like to obtain the optical fiber cable sheath shown in FIG.

FIGS. 5A and 5B show another means for supplying a wire to the inner space of the inner sheath.
Without using the drum of the wire 5, as shown in these figures, one end of the wire 5 is connected to the tip of the cylindrical body 8,
In this state, the tubular body 8 is rotated in the same manner as described above to wind the band-shaped metal 2a around the outer peripheral surface of the tubular body 8, and then the tubular body 8 is reversed to obtain the spirally wound band-shaped metal 2a. A wire 5 is inserted inside the spirally wound strip-shaped metal 2a.

[0018]

As is apparent from the above, according to the sheath for an optical fiber cable according to the present invention, since the wire is previously inserted into the sheath, the optical fiber core wire can be easily inserted into the long sheath. The optical fiber cable can be provided at low cost. In addition, by inserting a Kepler cable, for example, as a wire into the sheath, the sheath itself can be pulled during routing (wiring).

According to the method for manufacturing a sheath for an optical fiber cable according to the present invention, the sheath for an optical fiber cable having the above-described structure can be easily manufactured by existing manufacturing equipment, and the above-described present invention can be easily realized. I do.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sheath for an optical fiber cable according to the present invention.

FIG. 2 is a sectional view showing a state in which an optical fiber is being inserted into a sheath.

FIG. 3 is a sectional view showing a state where an optical fiber is inserted into a sheath.

4 (a) to 4 (c) are views showing a manufacturing process of an inner sheath.

FIGS. 5 (a) and (b) show other means for supplying wire to the inner space of the inner sheath.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... sheath, 2 ... inner sheath, 2a ... strip metal, 3 ... outer sheath, 4 ... space of inner sheath, 5 ... wire, 6 ... optical fiber, 8 ... cylinder.

Claims (5)

[Claims] 1. An optical fiber cable sheath in which a space for accommodating an optical fiber is continuously formed therein, wherein a wire for introducing an optical fiber is inserted into the space. Fiber optic cable sheath. 2. The sheath for an optical fiber cable according to claim 1, wherein the sheath is an inner sheath formed by spirally winding a band-shaped metal covering member, and a resin outer sheath provided outside the inner sheath. A sheath for an optical fiber cable, comprising a sheath. 3. The sheath for an optical fiber cable according to claim 1, wherein said wire is a Kepler cable. 4. An inner sheath is formed by continuously winding a strip-shaped metal covering member in a spiral shape, and when forming the inner sheath, a wire is inserted into the space of the inner sheath from one end side of the inner sheath. Wherein the outer sheath is formed outside of the inner sheath, and then the outer sheath is formed outside the inner sheath. 5. An optical fiber is connected to a wire exposed from one end of an optical fiber cable sheath in which a wire has been inserted in advance, and the optical fiber is inserted into the sheath by pulling out the wire exposed from the other end of the sheath. A method of inserting an optical fiber into a sheath for an optical fiber cable.