JPH0933775A - Manufacture of optical fiber cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a cable which has a coated optical fiber tape put in an SZ spiral groove and has a small in transmission loss. SOLUTION: A grooved spacer 11 with the SZ spiral groove 15 is made to travel, and a guide pipe 23 is rotated reciprocally around the grooved spacer 11 halfway during the travel to follow up the groove 15 while its exit end is put in the groove 15. The guide pipe 23 is held so that the tape surface of the coated optical fiber tape 17 exiting from the exit end always face the groove bottom of the SZ spiral groove 15. Then the coated optical fiber tape 17 after entering the groove 15 changes its direction through the inversion part of the groove 15, so that the cable which has small curvature strain can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical fiber cable in which a tape-shaped optical fiber core wire is housed in an SZ spiral groove of a grooved spacer.

[0002]

2. Description of the Related Art An optical fiber cable in which an SZ spiral groove is formed on the outer periphery and an optical fiber core wire is housed in the groove is used for connection and terminal processing.
There is an advantage that it is easy to take out the optical fiber from the groove. This type of cable uses a tape-shaped optical fiber core as the optical fiber core.Conventionally, multiple tape-shaped optical fiber cores are stacked in the depth direction of the groove and stored in the groove. (Japanese Unexamined Patent Publication No. 2-83)
No. 507) and a device laminated in the width direction of the groove and housed in the groove (Japanese Patent Application Laid-Open No. 4-55803) are known.

[0003]

A tape-shaped optical fiber core is formed by arranging a plurality of optical fibers in parallel on the same plane and applying a common coating to form a tape. For this reason, each optical fiber bends uniformly in the direction of bending the tape surface, and almost no increase in transmission loss occurs,
When bending in the direction of bending the tape side edge (edgewise bending) in the tape surface, distortion occurs in the compression direction in the optical fiber on the inner side of the bend, and the optical fiber on the outer side of the bend in the tape. Causes strain in the tensile direction, causing a large increase in transmission loss.

In the conventional optical fiber cable, a plurality of tape-shaped optical fiber core wires are housed in the SZ spiral groove of the grooved spacer in a state of being laminated in a certain direction with respect to the direction of the groove. A portion in which each tape-shaped optical fiber core is always bent in the direction of bending the side edge of the tape is generated. For example, in a cable in which a plurality of tape-shaped optical fiber core wires are laminated in the depth direction of the groove, each tape-shaped optical fiber core wire is mainly at the tape side at the reversal part of the SZ spiral groove (the part where the spiral direction is reversed). Subject to bending in a direction that bends the edges. Also, in a cable in which a plurality of tape-shaped optical fiber cores are laminated in the width direction of the groove, the tape is mainly formed in the middle part between the inversion parts of the SZ spiral groove (between one inversion part and the next inversion part). It is bent in the direction that bends the side edge.

As described above, the optical fiber cable of the type in which the grooved spacer having the SZ spiral groove is used and the tape-shaped optical fiber is accommodated in the groove is inevitably impossible with the tape-shaped optical fiber. Bending stress is applied,
In addition to the increase in transmission loss of the optical fiber, there is also a problem in terms of long-term reliability, and it has been said that practical use is difficult.

As a result of intensive studies, it has been found that in this type of optical fiber cable, the tape-shaped optical fiber core may be housed in the SZ spiral groove in the following state. That is, the tape surface faces the groove bottom at the central portion between the reversal portions of the SZ spiral groove (the central portion between one reversal portion of the groove and the next reversal portion) and the tape surface at the reversal portion of the SZ spiral groove. When it is assumed that the tape is stored in the groove while facing the groove bottom, the tape is stored so that the side edge of the tape located inside the bend of the groove of the reversing portion faces the groove bottom. In this way, the tape-shaped optical fiber core wire is not subjected to excessive bending stress, and the increase in transmission loss of the optical fiber can be reduced.

An object of the present invention is to provide a method for easily manufacturing such an optical fiber cable.

[0008]

According to the method of manufacturing an optical fiber cable of the present invention, a grooved spacer having an SZ spiral groove is made to run in the longitudinal direction, and in the middle of its running path,
A guide pipe for guiding the tape-shaped optical fiber core wire from the inlet end to the outlet end in a state in which the orientation of the tape surface is constrained is provided, and the guide pipe has the outlet end entering the SZ spiral groove,
In addition, with the tape surface of the tape-shaped optical fiber core emerging from the exit end held so as to always face the groove bottom of the SZ spiral groove, this guide pipe is oriented in the direction of the SZ spiral groove that changes with the travel of the grooved spacer. Follow it and rotate it back and forth around the grooved spacer to exit the guide pipe and SZ
It is characterized in that the tape-shaped optical fiber core wire which has entered the spiral groove can freely change its direction in the SZ spiral groove.

In this method, the tape-shaped optical fiber core wire is released from the restraint of the guide pipe by leaving the outlet of the guide pipe and entering the SZ spiral groove with the tape surface facing the groove bottom. At the central portion between the reversal portions of the groove, the state in which the tape surface is directed toward the groove bottom is the direction in which the tape surface is curved, so that the state can be easily maintained without difficulty. However, in the state where the tape surface is directed to the groove bottom at the reversal portion of the groove, it is a twisted state when viewed from the state of the central portion between the reversal portions of the groove,
The tape-shaped optical fiber core wire changes its direction in the groove in the direction of returning the twist by its elastic restoring force. As a result, at the reversal portion of the SZ spiral groove, the side edge of the tape located inside the bend of the reversal portion faces the groove bottom, assuming that the tape surface is stored in the groove with the tape surface facing the groove bottom. It becomes a state. This state is a state in which an excessive bending stress is not applied to the tape-shaped optical fiber core wire, and thus a transmission loss increase is small.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. 1 to 4 show an embodiment of a method for manufacturing an optical fiber cable according to the present invention.
In the figure, 11 is a grooved spacer having a tension member 13 at the center and an SZ spiral groove 15 on the outer periphery,
Reference numeral 17 denotes a tape-shaped optical fiber core wire housed in the SZ spiral groove 15. The SZ spiral groove 15 is a groove in which the spiral direction is periodically inverted as shown in FIG. In FIG. 7, 19 is the inverted portion of the groove 15 in the spiral direction, and 21 is the groove 1
5 between the reversal parts (center part between one reversal part 19 and the next reversal part 19 of the groove 15), P is the reversal pitch of the groove 15 (from one reversal part 19 to the next reversal part 19) Is the center axis distance of the grooved spacer).

Grooved spacer 1 in FIGS. 1 and 2.
Reference numeral 1 denotes four SZ spiral grooves 15 as described above formed at equal intervals in the circumferential direction. SZ spiral groove 1
In order to store the tape-shaped optical fiber core wire 17 in 5, the guide pipe 23 is used in the present invention.

The guide pipe 23 is a metal pipe having a rectangular cross section as shown in FIGS. 3 and 4, and the laminated body of the tape-shaped optical fiber core wires 17 does not lose the laminated state from the inlet end to the outlet end (tape surface). It is dimensioned so that it can pass through (with the orientation constrained). The inlet end of the guide pipe 23 is widened like a trumpet.

The guide pipe 23 shown in FIGS. 3 and 4 guides a laminate of three tape-shaped optical fiber core wires 17, and for example, the tape-shaped optical fiber core wire 23 is used.
5 has a cross-sectional shape as shown in FIG. 5 when it is laminated, and when the tape-shaped optical fiber core wire 23 has 4 laminated layers, it has a cross-sectional shape as shown in FIG. In any case, the guide pipe 23 guides the tape-shaped optical fiber core wire 23 from the inlet end to the outlet end while maintaining the laminated state.

The inner dimensions of the guide pipe 23 are set as follows, where H is the height, D is the width, W is the width of the tape-shaped optical fiber core wire 17, T is the thickness, and N is the number of laminated layers. It

[0015]

## EQU1 ## H, D <{W ² + (NT) ² } ^1/2

[0016]

[Equation 2] H> NT

[0017]

[Equation 3] D> W

The guide pipe 23 is supported by an annular rotary support 25 as shown in FIGS. The rotary support 25 is rotatably supported by a fixed support 29 via a bearing 27. The rotary support 25 is a grooved spacer 1
The grooved spacer 11 and the central axis line are arranged in the middle of the travel route 1.

A rectangular hole 31 into which the guide pipe 23 is inserted is formed obliquely in the rotary support 25. This hole 31
When the guide pipe 23 is inserted until the trumpet-like portion at the inlet end is caught, the outlet end of the guide pipe 23 comes into the SZ spiral groove 15. An eye plate 33 is attached to the end surface of the rotary support 25 on the inlet side. This eye plate 3
Reference numeral 3 serves to prevent the guide pipe 23 from coming out of the rotary support 25.

The guide pipe 23 is supported by the rotary support 25 such that the tape surface of the tape-shaped optical fiber core wire 17 that emerges from the outlet end thereof always faces the groove bottom of the SZ spiral groove 15 (see FIG. 2). ).

With the above configuration, the grooved spacer 11
When running in the longitudinal direction, the exit end is SZ spiral groove 15
Since the guide pipe 23 located inside follows the direction of the groove 15, the guide pipe 23 and the rotary support 25 that supports the guide pipe 23 follow the direction of the groove 15 and reciprocally rotate. The tape-shaped optical fiber core wire 17 that has passed through the guide pipe 23 exits the guide pipe 23 and is housed in the SZ spiral groove 15.

When the tape-shaped optical fiber core wire 17 exits the guide pipe 23, the tape surface always faces the groove bottom.
This state is shown in FIG. 8A to 8M are sectional views taken along lines aa to mm of FIG. 7, respectively. That is, when the SZ spiral groove 15 of the grooved spacer 11 passes through the exit position of the guide pipe 23, the tape-shaped optical fiber core wires 17 enter the SZ spiral groove 15 in the states as shown in a to m of FIG. come. In order to identify the direction of the tape-shaped optical fiber core wire 17, one side is marked with a circle.

Here, for example, in the state of "a", the tape-shaped optical fiber core wire 17 is only bent in the direction of bending the tape surface, and is hardly twisted. But b,
Twisting is gradually added as it goes to c and d.
Next, in e and f, the twist is restored, and in g, the same state as a is returned. Next, h, i, and j are twisted to the opposite side, k and l return the twist, and m is the same as a.

In this way, the tape-shaped optical fiber core wire 17 is constrained in direction by the guide pipe 23, and the SZ spiral groove 15 is formed.
Since it is twisted when it is dropped in, when it is released from the constraint by the guide pipe 23, it rotates in the groove 15 in the direction to untwist. As a result, the orientation of the tape-shaped optical fiber core wire 17 in the groove 15 is as shown in FIG.

That is, the tape-shaped optical fiber core wire 17 is
The tape surface faces the groove bottom at the central portion (a, g, m) between the inverted portions of the SZ spiral groove 15, and the tape surface remains oriented at the groove bottom at the inverted portion (d, j) of the SZ spiral groove 15. Assuming that the tape is housed in the groove 15, the side edge of the tape located inside the bend of the groove 15 of the reversing portion faces the groove bottom. In this state, since the tape-shaped optical fiber core wire 17 is mainly bent in the direction in which the tape surface is curved even at the inverted portion of the SZ spiral groove 15, bending strain can be sufficiently reduced.

Although FIG. 8 and FIG. 9 show the case where the number of the tape-shaped optical fiber core wires is one, the same applies when the number of the tape-shaped optical fiber core wires is two or more.

FIG. 10 shows an example of the optical fiber cable manufactured as described above. (A) is SZ spiral groove 1
5 is a cross-sectional view at the central portion between the reversal portions (g-g line in FIG. 7), (B) is a cross-sectional view at one reversal portion (d-d line in FIG. 7) of the SZ spiral groove 15, and (C) is SZ spiral groove 15
FIG. 9 is a cross-sectional view of the other inversion part (j-j line in FIG. 7). 1 of the three laminated tape-shaped optical fiber cores 17
In order to identify the one sheet and the direction thereof, the two marks on the outer side of the two tape-shaped optical fiber core wires 17 are marked with a circle and a cross.

In (A), the tape-shaped optical fiber core wire 17 has the tape surface facing the groove bottom, (B) has one side edge facing the groove bottom, and (C) has the other side edge. It faces the bottom of the groove. Reference numeral 11 is a grooved spacer, 13 is a tension member, 35 is a press winding, and 37 is a sheath. The cross-sectional dimension of the SZ spiral groove 15 is set to a size in which the laminated body of the tape-shaped optical fiber core wires 17 can change its direction.

An example of the dimensions of the manufactured cable and the guide pipe used for manufacturing is as follows. Tape-shaped optical fiber core: thickness 0.4 mm, width 1.1
mm, 4 cores, 3 laminated layers Grooved spacer: Outer diameter 10.8 mm, Groove width 2.0 m
m, groove depth 1.7 mm, reversal pitch 250 mm, reversal angle 290 ° Guide pipe: inner surface longitudinal dimension 1.4 mm, inner surface lateral dimension 1.3 mm, wall thickness 0.1 mm

[0030]

As described above, according to the present invention, the tape-shaped optical fiber core wire is directed to the SZ spiral groove of the grooved spacer, and the tape surface is directed to the groove bottom in the central portion between the inverted portions of the SZ spiral groove. As described above, in the reversal part of the SZ spiral groove, when it is assumed that the tape surface is stored in the groove with the tape surface facing the groove bottom, the side edge of the tape located inside the bend of the reversal part faces the groove bottom. Moreover, the housed optical fiber cable can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of a method for manufacturing an optical fiber cable according to the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a vertical cross-sectional view of the guide pipe used in FIG.

4 is a cross-sectional view taken along the line BB of FIG.

FIG. 5 is a cross-sectional view showing another example of the guide pipe used in the present invention.

FIG. 6 is a cross-sectional view showing still another example of the guide pipe used in the present invention.

FIG. 7 is an explanatory view of a grooved spacer used in the present invention.

8A to 8M are cross-sectional views taken along the line aa to the line mm in FIG. 7, showing the states at the moment when the tape-shaped optical fiber core wire comes out of the guide pipe and enters the SZ spiral groove.

9A to 9M are cross-sectional views taken along lines aa to mm in FIG. 7, showing a state where the tape-shaped optical fiber core wire is housed in the SZ spiral groove.

FIG. 10 shows an example of an optical fiber cable manufactured by the manufacturing method of the present invention, (A) is a cross-sectional view in the central portion between the reversal portions of the SZ spiral groove, and (B) and (C) are reversal of the SZ spiral groove. FIG.

[Explanation of symbols]

 11: Spacer with groove 13: Tension member 15: SZ spiral groove 17: Tape-shaped optical fiber core wire 23: Guide pipe 25: Rotating support 27: Bearing 29: Fixed support 31: Rectangular hole 33: Eye plate

Claims (1)

[Claims] 1. A grooved spacer having an SZ spiral groove is run in the longitudinal direction, and a tape-shaped optical fiber core wire is guided from the entrance end to the exit end in the state where the tape surface is constrained in the middle of the running path. A guide pipe is provided, and the guide pipe is held so that the outlet end enters the SZ spiral groove and the tape surface of the tape-shaped optical fiber core that exits from the outlet end always faces the groove bottom of the SZ spiral groove. , The tape-shaped optical fiber core that follows this guide pipe in the direction of the SZ spiral groove that changes depending on the running of the grooved spacer, reciprocally rotates around the grooved spacer, and exits the guide pipe and enters the SZ spiral groove. A method for manufacturing an optical fiber cable, characterized in that the wire can be turned freely within the SZ spiral groove.