JPS61275708A - Spacer for optical cable - Google Patents

Abstract

PURPOSE:To provide a strength characteristic against external force approximately equal to the strength characteristic of a metallic spacer by providing a layer consisting of a material having the smaller compressive modulus than the compressive modulus of a member forming spiral grooves for contg. an optical fiber formed on the outside circumference to the lower layer of said spiral grooves. CONSTITUTION:This spacer is formed by using an 'Aramid(R)' fiber reinforced plastic as a central tensile material 1, extrusion-molding a layer 2 of HDPE having the spiral grooves on the outside circumference and uniting these members by an adhesive agent while forming a thin aluminum tape 3 on the outside thereof in conformity with the grooves. The PE layer 2 generates the effect as a cushion and absorbs impact force when the impact is exerted to an optical cable, as said layer has the compression modulus smaller than the compressive modulus of the aluminum 3 forming the grooves. The grooves contg. the optical fibers is formed of the aluminum and therefore the effect as a shell is generated as against a side pressure by which the strength characteristic against the external force approximately equal to the strength characteristic of the metallic spacer is obtd. and flexibility approximately equiv. to the flexibility of a plastic spacer is provided.

Description

[Detailed Description of the Invention] [Summary of the Invention] An optical cable spacer having a longitudinal spiral groove on the outer periphery, the spacer having a layer of a material softer than the material of the member forming the spiral groove below the spiral groove. By this,
It has strength characteristics against external forces comparable to those of metal spacers, and flexibility comparable to plastic spacers.

[Industrial application field]

The present invention relates to a spacer C for an optical cable and a spacer for an optical cable.

[Conventional technology]

Optical cables are used in many fields because they enable high-capacity communication with low loss.

However, optical fiber core wires or optical fiber bare wires (hereinafter referred to as optical fibers) that constitute optical cables have the disadvantage that they are less susceptible to external forces such as impact, crushing, and tension than metal communication wires. Various optical cable structures have been developed to support this. In particular, when installing an optical cable, in places where there is a risk of receiving large external forces even after installation, such as the above-mentioned external forces such as impact, crushing, and tension, the groove C of the original cable spacer, which has a spiral groove in the length direction of the outer circumference C: A spacer type cable that accommodates an optical fiber is used (for example, Japanese Patent Publication No. 59-38563).

For optical cable spacers, the materials used for the parts (hereinafter referred to as "members") are selected depending on the environment in which the optical cable is used and the magnitude of external force to which it is likely to be subjected. Where large external forces are expected, metal spacers such as aluminum are used, and where large external forces are not expected, plastic spacers such as polyethylene are used.

[Problem that the invention seeks to solve]

Conventional metal spacers have excellent characteristics against external forces, but are inferior to plastic spacers (2) in terms of flexibility and weight reduction of cables.On the other hand, plastic spacers have excellent characteristics in terms of flexibility and weight reduction of cables. So, what about metal spacers?C, but it has the disadvantage that it is inferior to metal spacers in terms of external forces. It is characterized by having a lower layer made of a material that is softer than the material of the member forming the groove.

[For production]

According to the present invention C2, an optical cable spacer can be obtained which has strength characteristics against external forces comparable to those of metal spacers and flexibility comparable to plastic spacers. It will be explained below from Drawing 1.

〔Example〕

FIG. 1 shows a cross-sectional structure of an embodiment of the optical cable spacer of the present invention. 1 has center tensile strength, for example, outer diameter 1,
2rmmφ aramid fiber reinforced plastic, 2 is a layer of material softer than the material of the member forming the groove, for example, a layer of high density polyethylene with an outer diameter of 4.5mmφ, 3 is aluminum, for example 0.2am thick, forming the groove. It is. The optical cable spacer of this example is made by extruding a high-density polyethylene layer having a spiral groove on the outer periphery C using aramid fiber-reinforced plastic as the central tensile strength material, and then aligning aluminum tape with the groove in the high-density polyethylene layer. While molding, the high-density polyethylene layer and aluminum groove were integrated using adhesive C2.

Having a layer of a material softer than the material of the member forming the groove under the groove of the spacer of the present invention has excellent characteristics against external forces.

This is because when an impact is applied to the optical cable I:@, the lower layer of the spacer groove is made of a softer material than the material forming the groove, which creates a cushioning effect and absorbs the impact force. be. In addition, in terms of lateral pressure, the groove that accommodates the optical fiber is made of a harder material than a spacer where all the members forming the entire spacer except the center tensile strength material are made of polyethylene, etc., so the shell This effect results in that the optical cable subenamer of the present invention has superior properties.

Furthermore, the optical cable spanner of the present invention is suitable for storing optical fibers.C: Even if the material is made of a material that is difficult to form into a sufficient groove shape, the groove for storing the optical fiber can be formed easily if the shape is formed to a certain extent. It has the advantage that it can be molded from a member made of another material to accommodate the optical fiber (an optical cable space having a groove shape of 20 minutes) can be molded.

In order to form the optical fiber spanner of the present invention, which has excellent impact force (2) characteristics and flexibility, it is necessary to use a groove-forming member, each groove, as shown in Figure 1:2. If the configuration is such that each groove is separated into two, each groove can move freely, and both the characteristics and flexibility for the swing crab (-T
We will get separated.

Comparison of the characteristics under impact Isg of the optical cable spanner of the present invention shown in Fig. 1, the cross-sectional structure of which is shown in Figs. Figure 5 1; shown. 51 and 52 in Fig. 2 α and b indicate the groove, and 6 in Fig. 2 6 indicates the central tensile strength member. For each of the original cable space f, aluminum spacer, and polyethylene spacer in the comparative example, the outer periphery of the nylon-coated optical fiber core wire of 0.9 m 7 Q.Cable samples were made by sheathing them with polyethylene with a thickness of 5 mm.
These are the results of dropping each load of a cylinder of nφ five times and measuring the amount of change in transmission loss of each chimple each time each load was dropped.

In Fig. 3 6 =, ■ is the original cable space f of the present invention.
k Characteristics of the cable used, ■ and I are the second
Figures α and b show the characteristics of cables using aluminum spacers and polyethylene spacers, the cross-sectional structures of which are shown.

As can be seen from Fig. 3, the optical cable using the optical cable spacer of the present invention does not break the optical fiber core wire even if a load of 5 bonds is dropped five times, but the optical cable using the aluminum spacer and polyethylene spacer does not break. Hikari Group reported that the optical fiber core wire broke when the load of 5 bonds was dropped.This result shows that the original cable spanner of the present invention has excellent characteristics against impact force. There is.

In addition, flexibility (two samples each having a length of 5Q am of optical cable using the original cable spanner of the present invention and an aluminum spacer and a polyethylene base fabricated for comparison in FIG. 6) were used; One end of the optical cable of the present invention was fixed, and a weight of IKF was hung on the other end C, and the displacement of the end on which the weight was suspended was investigated after 1 minute had elapsed since the weight was hung.As a result, the optical cable of the present invention For optical fiber cables using aluminum spacers and optical cables using polyethylene spacers, a displacement of more than 5 cyx was observed in which the end where the weight was hung fell from the initial position, whereas the original cable using aluminum spacers No displacement due to the feeling of falling was observed at the end where the weight was suspended.

As is clear from the above measurement and observation results of impact drop characteristics and flexibility, the original cable substrate of the present invention has characteristics against external forces comparable to those of metal spacers, and has the same flexibility as plastic spacers. It has flexibility.

〔Effect of the invention〕

As described above, the spacer for optical cables according to the present invention has strength characteristics comparable to those of metal spacers and flexibility comparable to plastic spacers, and is highly effective when applied to optical cables. 0

[Brief explanation of drawings]

FIG. 1 is a cross-sectional structural diagram of the optical cable spacer of the present invention, FIG.
It is an optical cable impact drop characteristic using the optical cable spacer of each optical cable spacer of (b). 1...Central tensile strength material, 2...High density polyethylene layer, 3...Groove forming aluminum! , 31.32...groove,
4... Aluminum spacer, 5... Polyethylene spacer, 6... Center tensile strength material

Claims (1)

[Scope of Claims] An optical cable spacer having a longitudinal spiral groove on the outer periphery, characterized in that a layer of a material softer than the material of the member forming the spiral groove is provided below the spiral groove. .