JPH08327864A - Terminal part of spacer type optical fiber cable - Google Patents

Abstract

PURPOSE: To provide a terminal part of a spacer type optical fiber cable with which execution of the work to change terminal connection is possible without carrying out the work to clean the inside of, for example, a connecting box by preventing the leaking out of jelly in the terminal part of the optical fiber cable. CONSTITUTION: A spacer 2 and optical fiber l are projected from the terminal part of a protective layer 4 in the terminal part of the spacer type optical fiber cable. A terminal covering tube 5 is put on the projecting part of the optical fiber l and is housed into a groove 3. The (b) side of the terminal covering tube 5 is put into a reduced diameter state. Further, a waterproof sealing layer 6 is disposed extending over the outer periphery of the terminal part of the protective later 4 and the outer periphery of the projecting part of the spacer 2 in which the terminal covering tube 5 is housed. Then, the leaking out of the jelly 7 in the groove 3 to the outside of the cable is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal portion of a spacer type optical fiber cable.

[0002]

2. Description of the Related Art A spacer type optical fiber cable is an example of an optical fiber cable capable of safely protecting an optical fiber from moisture and external force. The terminal portion is shown in FIG. 6 and will be described below.

A spacer 2 made of a metal wire material such as aluminum is provided with a groove 3 spirally in the longitudinal direction, and the optical fiber 1 is inserted in the groove 3 via a jelly 7 (mixture for waterproofing). It is stored. The jelly 7 is made of a resin having a water repellent property in order to prevent moisture from coming to the optical fiber 1. In addition, a material having a high viscosity is used to prevent the jelly 7 from leaking out of the cable. Has been. A protective layer 4 is provided on the outer circumference of the spacer 2 over the entire length in the longitudinal direction to protect the inside of the cable from external force. Here, the protective layer 4 is composed of, for example, a plastic tape press winding or a sheath layer of cross-linked polyethylene or the like, which is sequentially provided on the outer periphery of the spacer 2.

After the spacer type optical fiber cable is laid, the protective layer 4 is removed from the end of the cable for a predetermined length,
The optical fiber 1 is exposed together with the spacer 2 and used, for example, by connecting the end of the optical fiber 1 to the end of another optical fiber or optical device in a connection box.

[0005]

However, although the jelly 7 is made of a highly viscous material, the jelly 7 moves in the groove 3 of the spacer 2 after the above-mentioned terminal connection. In some cases, the terminal portion of the protective layer 4 leaked into the inside of the junction box or the like.

Therefore, after that, the connection box is opened to switch the connection target of the spacer type optical fiber cable from another optical fiber cable terminal or optical device terminal which has been connected until then to another terminal (hereinafter, When simply performing the terminal connection changing work), it was necessary to first perform a troublesome cleaning work of wiping the jelly 7 inside the connection box.

[0007]

It is an object of the present invention to prevent the jelly from leaking out at the end portion of an optical fiber cable, so that the terminal connection can be replaced without cleaning the inside of the connection box. It is to provide a terminal portion of an optical fiber cable.

[0008]

In the terminal portion of the spacer type optical fiber cable according to claim 1 of the present invention, an optical fiber is accommodated through a jelly in the groove of a spacer having a spiral groove in the longitudinal direction, A protective layer is formed on the outer periphery of the spacer, and a spacer projection part in which the spacer projects from the end part of the protection layer, and an optical fiber projection part in which the optical fiber projects from the end part of the protection layer. The optical fiber projecting portion is inserted into the terminal coating tube, and one end portion of the terminal coating tube which is the protective layer end portion side is accommodated in the groove of the spacer projecting portion in a fitted state. A waterproof seal layer is provided across the outer periphery of the end portion of the protective layer and the outer periphery of the spacer protrusion in which the terminal coating pipe is housed in a fitted state, The other end of the cladding tube, characterized in that it is covered by the contracted state to the optical fiber protrusion periphery.

In the terminal portion of the spacer type optical fiber cable according to the second aspect of the present invention, the optical fiber is accommodated through the jelly in the groove of the spacer having the spiral groove in the longitudinal direction, and the outer periphery of the spacer is protected. Layers are formed,
And a spacer projecting part in which the spacer projects from the end part of the protective layer, and an optical fiber projecting part in which the optical fiber projects from the end part of the protective layer, wherein the optical fiber projecting part is a terminal. One end portion of the end coating pipe, which is the end portion side of the protective layer, is inserted into the cladding tube and is accommodated in the groove of the spacer protrusion in a fitted state, and the tip portion of the one end side is inside the protective layer. And the other end side of the terminal coating tube is covered with the outer circumference of the optical fiber projecting portion in a reduced diameter state.

[0010]

According to the first aspect of the present invention, the optical fiber projecting portion is inserted through the terminal coating tube, and the one end portion of the terminal coating tube is accommodated in the groove of the spacer projecting portion in a fitted state. There is. In addition, a waterproof sealing layer is provided so as to extend over the outer periphery of the end portion of the protective layer and the outer periphery of the spacer protruding portion in which the terminal covering pipe is housed in a fitted state. Therefore, the jelly filled along the length of the cable is
It travels in the groove of the spacer without leaking out to the outside of the cable, enters the inside of the waterproof seal layer from the end portion of the protective layer, and further enters the inside of the terminal covering tube. Here, the other end side of the terminal covering tube is covered with the outer circumference of the optical fiber projecting portion in a reduced diameter state. Therefore, the gap between the inner wall of the terminal covering tube and the optical fiber is narrowed, and the jelly itself forms a surface tension field, so that the jelly can be prevented from leaking outside from the end of the terminal covering tube.

According to the second aspect of the present invention, the one end portion of the terminal coating tube, through which the optical fiber projecting portion is inserted, is housed in the groove of the spacer projecting portion in a fitted state, and the one end side tip portion of the terminal coating tube. Are contained within the protective layer.

Therefore, the jelly inside the cable travels in the groove of the spacer without leaking out to the outside of the cable and enters the inside of the terminal covering tube from the end portion of the protective layer. Here, as in the case of the invention according to claim 1 of the present application, since the other end side of the terminal covering tube is covered with the outer periphery of the optical fiber projecting portion in a reduced diameter state, jelly leaks from the end of the terminal covering tube to the outside. You can prevent it.

As described above, according to the end portion of the spacer type optical fiber cable according to the first and second aspects of the present invention, the jelly is prevented from leaking out while the tip end portion of the optical fiber protruding portion is exposed. be able to.

In the present invention, that the one end side of the pipe is in a reduced diameter state means that the inner diameter of the one end side is smaller than the inner diameter of the other end side. Further, it is desirable that the inner diameter of the terminal-coated tube in the reduced diameter state is such that the optical fiber contained therein is not pressed.

In the present invention, the number of the grooves formed in the spacer may be any number, but it is preferable that the cross-sectional shape is an arc shape so that the terminal covering pipe can be easily fitted therein.

Further, the optical fiber according to the present invention is housed in the groove of the spacer in the form of an optical fiber element wire obtained by applying only a primary coating to the optical fiber or an optical fiber core wire further provided with a coating. It is possible to accommodate not only one optical fiber but also a plurality of optical fibers in one groove.

Further, the spiral groove in the present invention includes not only the spiral groove having a constant spiral direction but also the spiral groove having the spiral direction reversed at a predetermined interval.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings. (Embodiment 1) FIG. 1 shows a terminal portion of a spacer type optical fiber cable of this embodiment. 2 shows a cross-sectional view taken along the line AA ′ in FIG. 1, and FIG. 3 shows a cross-sectional view taken along the line BB ′.

As shown in FIG. 1, a spacer 2 made of aluminum wire is provided with a groove 3 spirally formed in the longitudinal direction, and the optical fiber 1 is accommodated in the groove 3 via a jelly 7. ing.

On the outer periphery of the spacer 2, a plastic tape is wound and a protective layer 4 made of a polyethylene sheath layer provided on the pressed winding is formed over the entire length in the cable longitudinal direction.

The following processing was performed on the terminal portion of the spacer type optical fiber cable thus manufactured. First, the protective layer 4 is peeled off for a predetermined length to form the protruding portion of the spacer 2 and the protruding portion of the optical fiber 1. Then, as shown in FIG. 1, the projecting portion of the optical fiber 1 is inserted from the tip into a terminal coating tube 5 made of heat-shrinkable resin, and one end portion of the terminal coating tube 5 indicated by a is fitted into the groove 3. Store in the state. Further, the other end side of the terminal covering tube 5 shown by b was reduced in diameter by local heating. Here, examples of the heat-shrinkable resin used for the terminal covering tube 5 include fluorine resin and cross-linked polyethylene.

In order to prevent one end portion of the terminal covering tube 5 from falling out of the groove 3 and preventing the jelly 7 from leaking out of the cable, the outer periphery of the end portion (the portion indicated by c) of the protective layer 4 is protected. And a spacer 2 protruding portion (portion indicated by d) in which the terminal covering pipe 5 is housed in a fitted state, straddling the outer periphery of the spacer 2 and being made up of a waterproof tape such as a pressure-bonding tape. The seal layer 6 was formed. Here, as shown in FIGS. 2 and 3, the inside of the cable is a spacer 2,
It is sealed by the terminal covering tube 5 and the protective layer 4.
Therefore, the jelly 7 does not leak outside the cable.

The optical fiber 1 is provided on the b side of the terminal coating tube 5.
Since the outer circumference of the protruding part of the
Even if the jelly 7 intrudes into the terminal covering tube 5 from the inside, the jelly 7 does not leak to the outside of the cable.

In the present embodiment, the spacer 2 is made of an aluminum wire, but it may be made of another material or a combination of a plurality of members made of different materials. Specifically, the outer periphery of the high-strength wire is extruded and coated with a plastic resin, and the groove 3 is formed in the plastic part.
May be formed.

Further, another layer such as a flame-retardant resin layer for protection against fire or a metal pipe line may be provided on the outer periphery of the protective layer 4 and the waterproof sealing layer.

Further, the embodiment of the terminal coating tube 5 is not limited to the above-mentioned one. For example, the terminal coating tube 5 having one end formed in a reduced diameter state from the beginning is used, and the terminal coating tube 5 is formed from the side with the wide inner diameter of the tube. It may be overlaid on the protrusion 1. Further, the shape of the terminal covering pipe 5 is not limited to that shown in FIG. 1, and for example, as shown in FIG. 7, cylindrical pipe lines may be stacked in multiple stages.

(Embodiment 2) FIG. 4 shows another embodiment of the present invention, which will be described below. As shown in FIG. 4, the spacer 2
A groove 3 spirally formed in the longitudinal direction is provided in the same manner as in the first embodiment. Further, the optical fiber 1 is housed in the groove 3 and is filled with the jelly 7,
A protective layer 4 is formed on the outer periphery of the spacer 2 over the entire length in the cable longitudinal direction.

In the cable end portion, the optical fiber 1 is previously inserted into the terminal coating tube 5, and thereafter, as shown in FIG. 5, one end side of the terminal coating tube 5 (the portion indicated by e).
The tip of the is inserted into the protective layer 4. In addition, the diameter of the end covered tube 5 indicated by f is reduced as in the first embodiment. In the spacer type optical fiber cable thus manufactured, the jelly 7 does not leak out from the inside of the cable as in the first embodiment.

[0029]

According to the present invention, it is possible to prevent the jelly from leaking from the end portion of the spacer type optical fiber cable. Therefore, it is possible to perform the terminal connection changing work of the spacer type optical fiber cable without performing the cleaning work inside the connection box and the like.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a terminal portion of a spacer type optical fiber cable showing an embodiment of the present invention.

FIG. 2 is a transverse cross-sectional view of the end portion of the spacer type optical fiber cable taken along the line AA ′ in FIG.

FIG. 3 is a cross-sectional view of a terminal portion of the spacer type optical fiber cable taken along the line BB ′ of FIG.

FIG. 4 is a partially cutaway side view of a terminal portion of a spacer type optical fiber cable showing another embodiment of the present invention.

5 is a transverse cross-sectional view of the end portion of the spacer type optical fiber cable taken along the line CC 'of FIG.

FIG. 6 is a partially cutaway side view showing an example of a terminal portion of a conventional spacer type optical fiber cable.

FIG. 7 is a vertical cross-sectional view showing an example of a terminal covering tube.

[Explanation of symbols]

 1 Optical Fiber 2 Spacer 3 Groove 4 Protective Layer 5 Terminal Covering Tube 6 Waterproof Seal Layer 7 Jerry

Claims (2)

[Claims] 1. An optical fiber is accommodated in the groove of a spacer having a spiral groove in the longitudinal direction via a jelly, a protective layer is formed on the outer periphery of the spacer, and an end portion of the protective layer is formed. Is a terminal portion of a spacer type optical fiber cable having a spacer protruding portion from which the spacer protrudes, and an optical fiber protruding portion in which the optical fiber protrudes from an end portion of the protective layer, wherein the optical fiber protruding portion is a terminal. One end portion of the terminal coating pipe, which is the end portion side of the protective layer, is inserted into the groove and is housed in the groove of the spacer protrusion in a fitted state. A waterproof sealing layer is provided over the outer periphery of the spacer protruding portion in which the pipe is housed in a fitted state, and the other end side of the terminal covering pipe has the optical fiber protrusion. A terminal portion of a spacer type optical fiber cable, characterized in that the outer periphery of the portion is covered in a reduced diameter state. 2. An optical fiber is accommodated in the groove of a spacer having a spiral groove in the longitudinal direction via a jelly, a protective layer is formed on the outer periphery of the spacer, and an end portion of the protective layer is formed. Is a terminal portion of a spacer-type optical fiber cable having a spacer protruding portion from which the spacer protrudes, and an optical fiber protruding portion in which the optical fiber protrudes from an end portion of the protective layer, wherein the optical fiber protruding portion is a terminal. One end portion which is inserted into the cladding tube and is the protective layer end portion side of the terminal cladding tube is accommodated in the groove of the spacer protrusion in a fitted state, and the one end side tip portion is inside the protective layer. The spacer type optical fiber cable, wherein the other end side of the terminal covering tube is covered with the outer periphery of the optical fiber protruding portion in a reduced diameter state.