JPH10133076A - Spiral spacer for carrying optical fiber - Google Patents

Abstract

(57) [Summary] [Problem] To prevent the occurrence of scratches and deformation during alignment winding. A helical spacer for holding an optical fiber includes a tensile strength line 1 disposed at the center in a cross-sectional direction, and a tensile strength line 1.
Spacer body 2 made of synthetic resin integrally molded on the outer periphery of
And The spacer main body 2 is provided with a plurality of spiral concave grooves 2a on the outer peripheral side along the longitudinal direction.
One end of each of the spiral grooves 2a is open outward. Each spiral groove 2a is separated by a plurality of ribs 2b provided at predetermined intervals along the circumferential direction. An arc portion (R portion) 2c having a radius of 0.2 mm or more is provided at each of the two corners on the distal end side of each rib 2b that separates the spiral groove 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacer for holding an optical fiber, and more particularly to a technique for eliminating the inconvenience in winding such a spacer.

[0002]

2. Description of the Related Art An optical fiber-carrying spacer is a component used when assembling a large number of optical fibers into an optical fiber cable. A spacer body made of synthetic resin integrally formed on the outer periphery of the tensile strength wire, and the spacer body is provided with a plurality of spiral concave grooves for accommodating an optical fiber.

For the spacer body made of synthetic resin, a thermoplastic resin, for example, a polyethylene resin is used from the viewpoint of economy and moldability, and this resin is extruded in a molten state around the tensile strength wire to extrude the resin. Sometimes a spiral groove is formed.

[0004] The spacer manufactured by extrusion molding is long, and in consideration of the subsequent handling, it is usually wound around a bopin or the like, and when manufacturing an optical fiber cable, the wound spacer is usually used. Will be drawn.

[0005] At the time of such winding and drawing, the outer layer portion forming the groove is relatively soft polyethylene resin, so that it is easily damaged. Therefore, conventionally, in order to solve such a problem, for example, as disclosed in Japanese Patent Application Laid-Open No. 1-1457, so-called aligned winding, in which spacers are wound in a state of being in close contact with each other, has been performed. Was.

However, such a conventional aligned winding has the following technical problems.

[0007]

That is, when the spacer having the structure described above is aligned and wound in a close state,
Since a plurality of spiral grooves are formed in the spacer main body, meshing of the concave grooves easily occurs between adjacent spacers. For example, meshing between the spacer wound one round before is performed during winding. Occurs, the spacer that is being wound up rides on the spacer that has already been wound up, runs backward, or has a scratch on the meshed portion.

[0008] Further, when the meshing occurs, there is a problem that, depending on the type of product, the rib that separates the concave groove falls down and the groove shape is deformed.

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and an object of the present invention is to prevent engagement during alignment winding, and to provide an optical fiber carrier capable of easily performing alignment winding. It is to provide a spacer.

[0010]

In order to achieve the above object, the present invention comprises a tensile strength line disposed at the center and a spacer body made of synthetic resin integrally formed on the outer periphery of the tensile strength line. An optical fiber supporting spacer provided with a plurality of spiral grooves for accommodating an optical fiber in the spacer main body, wherein an arc portion of 0.2 mm or more is formed at a tip corner of a rib separating the spiral grooves. Alternatively, a chamfer was provided. According to this configuration, since the arc portion or the chamfered portion of 0.2 mm or more is provided at the tip corner of the rib separating the spiral groove, the corner of the rib does not become an acute angle, and as a result, When the spacers are aligned and wound closely, the spacers do not mesh with each other. In the present invention, the division value of the minimum rib tip width of the rib and the maximum groove outer width of the spiral groove is A, the outer diameter of the spacer body is D, and the twist of the spiral groove is When the pitch is P, tan ^-1 (Dπ / P)
It is preferable that the advancing angle with respect to the longitudinal direction of the spiral groove obtained in the above is B, and the arc portion or the chamfered portion is provided on a spacer having an integrated value of A and B of 10 or less. The reason is that, in the spacer having an integrated value of A and B of 10 or less, the rib easily enters the groove, and the spiral state of the spiral concave groove becomes closer to a straight line, so that it becomes easier to mesh with the aligned winding. Therefore, it is necessary to provide an arc portion or a chamfer portion of 0.2 mm or more at the tip corner of the rib separating the spiral groove.

[0011]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG.
1 shows an embodiment of a spiral spacer for supporting an optical fiber according to the present invention.

The helical spacer for holding an optical fiber shown in FIG. 1 includes a tensile strength line 1 arranged at the center in the cross-sectional direction and a synthetic resin spacer body 2 integrally formed on the outer periphery of the tensile strength line 1. Have.

In this embodiment, the tensile strength line 1 is Φ2 mm.
A × 7 stranded steel wire is employed. In addition, tensile strength line 1
Is not limited to this twisted steel wire, and may be, for example, a single steel wire or a FRP wire.

The spacer body 2 is made of, for example, a low-density or high-density polyethylene resin. In this embodiment, thirteen spiral grooves 2a are formed on the outer peripheral side along the longitudinal direction. It is provided over the entire length.

Each of the spiral grooves 2a is open at one end to the outside, and is a spiral that circulates in one direction or a spiral that reverses the direction of rotation at a predetermined angle. It has a pitch P.

When an optical fiber cable is manufactured, the optical fiber core wires are stored in a multi-stage shape in each spiral groove 2a, and are carried by spacers.

Each spiral groove 2a has a width w and a depth d separated by thirteen ribs 2b provided at predetermined intervals along the circumferential direction. The basic configuration of such an optical fiber supporting spacer is as follows.
Although this type is the same as a conventional spiral spacer for supporting an optical fiber, the spacer of this embodiment has a remarkable feature in the points described below.

That is, at both corners on the tip side of the rib 2b separating the spiral groove 2a, arc portions (R portions) 2c each having a radius of 0.2 mm or more are provided.

According to the spacer for supporting an optical fiber constructed as described above, the corners of the ribs 2b do not become acute, as will be apparent from the concrete examples and comparative examples described later. When aligned and wound in close contact, the spacers do not engage with each other.

Further, in the present invention, as will be apparent from specific examples and comparative examples described later, the minimum rib tip width W _min of the rib 2b and the maximum outer groove width W W of the spiral groove 2a are determined. _When the division value with _max is A, the outer diameter of the spacer body 2 is D, and the twist pitch of the spiral groove 2a is P, t
Let B be the advancing angle of the spiral groove 2a with respect to the longitudinal direction determined by an ^-1 (Dπ / P), and the integrated value of A and B be 10
It is desirable to provide the following spacers with the arc portions 2c.

The reason is that, in the spacer having an integrated value of A and B of 10 or less, the rib 2b easily enters the concave groove 2a, and the spiral state of the spiral concave groove 2a becomes close to a straight line, so that the winding of the aligned winding is not performed. This is because the meshing becomes easier in some cases, and therefore, it is necessary to provide a circular arc portion 2c having a radius of 0.2 mm or more at both ends of the rib 2b separating the spiral groove 2a. Specific Examples and Comparative Examples As shown in the table below, the outer diameter of the spacer body 2 is D, the twist pitch of the spiral groove 2a is P, the minimum rib tip width W _{min of the} rib 2b, and the spiral groove 2a. Eight types of helical spacers for supporting an optical fiber having the maximum outer groove width _Wmax of the above were prototyped.

In this case, in the manufacturing method by the usual extrusion molding of the helical spacer, the radii are formed at the corners at both ends of each rib 2b due to shrinkage of the resin without special processing of the die nozzle for extruding the resin. A round portion of about 0.1 mm is formed.

Therefore, in this trial production, the die nozzle is rounded, and the radius of each rib 2b is set to about 0.
A round portion of about 15 mm (comparative example) and a round portion of about 0.3 mm (example) were formed.

The evaluation of the difficulty of meshing in the prototype spacer is made in the direction in which meshing is likely to occur (for example, the spiral groove 2a).
In the case of Z twisting in which the winding direction is one direction, winding is performed from right to left toward the winding bobbin), and the aligned traverse guide is wound in the winding direction in the winding direction. The displacement amount of the traverse guide at the time when the meshing starts to occur when the displacement occurs in the reverse direction is measured, and the displacement amount is indicated by the number of products.

That is, this evaluation method of the difficulty of meshing indicates that the larger the numerical value, the harder the meshing is generated.

The following table shows that the minimum rib tip width W _{min of the} rib 2b and the spiral groove 2a
In the case where the value obtained by dividing the maximum groove outer width _Wmax by A and the advancing angle B is 10 or more (spacers 6 to 8 in the table), meshing is basically difficult to occur.

Even if a radius having a radius of 0.2 mm or more is provided for the spacer having such an integrated value, the degree of difficulty in meshing is not significantly improved, and the expected effect is obtained. That is not possible.

On the other hand, the division value of the minimum rib tip width W _{min of} the rib 2b and the maximum groove outer width W _max of the spiral groove 2a is A,
When the integrated value with the inclination angle B is 10 or less (spacer 1 in the table)
5) are basically easy to mesh with each other, but if the radius 2c having a radius of 0.2 mm or more is provided in each rib 2b, the degree of difficulty in meshing is greatly improved.

The upper limit of the radius of the radius portion 2c formed at the corner of each rib 2b becomes too large if it is too large.
Since the number of stored optical fiber cores to be housed therein may decrease or fall off, it may be set within a range where such an obstacle does not occur.

Further, in the above-described embodiment, the case where the circular arc portions (R portions) 2c are formed at both corners of the tip of each rib 2b is exemplified.
The same operation and effect can be obtained even with a chamfer of mm or more.

[0031]

【table】

As described above in detail, according to the helical spacer for supporting an optical fiber according to the present invention, meshing during alignment winding is prevented, and undesired scratches and deformation of the product are avoided. , Can be easily aligned and wound.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a spiral spacer for supporting an optical fiber according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tensile strength line 2 Spacer main body 2a Spiral concave groove 2b Rib 2c Arc part (R part)

Claims (2)

[Claims] 1. A plurality of helical recesses comprising a tensile strength line disposed at the center and a spacer body made of synthetic resin integrally formed on the outer periphery of the tensile strength line, and accommodating an optical fiber in the spacer body. In the optical fiber supporting spacer provided with the groove, 0.2 mm is set at the tip corner of the rib separating the spiral groove.
An optical fiber supporting spacer provided with the arc portion or the chamfered portion. 2. A value obtained by dividing a minimum rib tip width of the ribs and a maximum groove outer width of the spiral groove by A, an outer diameter of the spacer body by D, and a diameter of the spiral groove by When the twist pitch is P, the traveling angle with respect to the longitudinal direction of the spiral groove determined by tan ^-1 (Dπ / P) is B, and A
The spacer for holding an optical fiber according to claim 1, wherein the arc portion or the chamfered portion is provided on a spacer having an integrated value of B and B of 10 or less.