JPS5974510A - Optical cable - Google Patents

Abstract

PURPOSE:To gather plural optical fiber units in one process by constituting a device so that optical fiber units stored in plural spaces in a housing are twisted for a central tensile strength material by 100%. CONSTITUTION:Optical fiber units 18 are stored in plural spaces 14 formed in a housing 16 around a central tensile strength material 12. The tensile strength material 12 is inserted through a center nipple 26 of a fixed plate 24 of an extruder 20, and fiber units 18 are inserted through fiber nipples 28, and a nipple case 22 is revolved in a prescribed speed. In this case, since nipples 28 meshed with gears 30 and 32 revolve around the axis of the center nipple 26 and on their axes, optical fiber units 18 are twisted 100% for the tensile strength material 12 in one process. Consequently, even if an optical cable 10 is bent, strong compressive force and tensile force are not applied localy because units 18 are slipped in spaces 14 in directions of axial lines.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in multi-core optical cables.

Conventional multi-fiber optical cables consist of a plurality of optical fiber units in which a plurality of optical fiber cores are either twisted or untwisted in a protection pipe, or a plurality of optical fiber tapes are stacked and housed in a tensile strength body. It is formed by gathering around.

However, this conventional optical cable requires two steps: storing a plurality of optical fiber cores or optical fiber tapes in a retaining pipe and twisting them together, making the manufacturing process complicated and expensive. There are nine drawbacks.

The purpose of the invention is to provide an optical cable that can assemble a plurality of optical fiber units in one process. Examples of the invention will be described with reference to the drawings in Figs. 1 and 2. 1 shows an optical cable 10 according to the present invention, and this optical cable includes an outer sheath 1 provided around a central tensile strength member 12 by extrusion sheathing or the like, and in which a plurality of voids 14 are formed.
6, and one or more optical fiber units 18 housed in each cavity of the jacket. As shown in FIG. 2, the plurality of voids 14 are formed in a spiral shape, but they may also be formed in an S-Z twist shape.

The plurality of optical fiber units 18 are one in the embodiment of FIG.
It is in the form of a book or several troughs of optical fibers, and these optical fibers are not twisted with each other as shown in Figure 3 (A).
) As shown in (B), the optical cable 1 is stored with 100 twists on the tensile strength member 12.
The relative position of the optical fiber unit 18 is constant at different cross-sectional positions of 0, and the optical fiber unit 18 closest to the central strength member 12 in one cross-section is the furthest position in the other cross-section rotated by 180 degrees in the air gap. Further, the actual length of each optical fiber unit 18 is uniform and the helical diameter is also the same. Therefore, even if the optical cable 10 is bent, the optical fiber unit 18
Because it slides in the axial direction within the cavity 14, large compressive or tensile forces are not applied locally.In addition, in order to improve the sliding of the optical fiber unit 18 within the cavity 14, the cavity 1
4 may contain lubricant.

This optical cable 10 can be manufactured in one step using an extruder having a rotary nipple assembly as shown in FIGS. 9 and 10. A central nipple through which the tensile strength member 12 passes is attached to the center of the fiber, and a plurality of optical fiber units 18 are rotatably supported by a fixed plate 24 at intervals around this central nipple, and each through which a plurality of optical fiber units 18 pass. A fiber nipple row is provided. A gear is fixed to the rear end of the fiber nipple 28, and this gear meshes with a gear 32 fixed to the center nipple part.During operation of the extruder, the nipple case n is rotated at a predetermined rotational speed. Therefore, the fiber nipple row revolves around the axis of the center nipple, and therefore the gear 30 meshing with the gear 32 rotates the fiber nipple row in the opposite direction about the axis. The ratio of the gear addition ratio 32 is set so that the gear (supply) rotates once for each rotation of the twist case 2, so for each fiber nipple, the optical fiber unit 18 therein is twisted 100% with respect to the tensile strength body 12. give. In this way, a plurality of voids 14 are formed in the jacket 16 that covers the tensile strength member 12, and the optical fiber unit 18 is twisted 100% within the voids 14.
In addition, when the cross-sectional gap is circular, it is not necessary to use a gear to rotate the fiber nipple. Figure 4 shows another embodiment of the invention, and in this embodiment, the optical As shown in FIG. 5, the fiber unit 18 has a plurality of optical fiber strands 18A arranged side by side to form a coating 18.
This is an optical fiber tape coated with B, and the optical fiber tapes of Nire et al. are laminated and housed in the gap 14 while giving the same 100% twist. A large optical cable can also be manufactured in one step using the rotary nipple assembly shown in FIGS. 9 and 10.

6 is substantially the same as the embodiment shown in FIG. 6, but differs from the embodiment shown in FIG. 6 in that the air gap 14 has a rectangular rather than circular cross section.

Further, in FIGS. 7 and 8, a mark 16a consisting of a V-groove is provided on the outer surface of the jacket 16 in order to facilitate branching and extraction of each fiber unit 18 of the optical cable 10. Marks 16& in FIG. 7 are provided corresponding to each gap 14, and marks 16a in FIG. 8 are provided corresponding to the middle of adjacent gaps 14. Therefore, the seventh
In the case shown in the figure, the optical fiber unit 18 can be taken out by making a cut from mark 16a to q FJ14 and cutting the outer sheath 16, and in the case of Fig. The optical fiber unit 18 can be separated into a fan shape and taken out together with the outer sheath by making a cut in the tensile strength member 1 in the case of FIG.
Since a partition plate 12a is provided corresponding to each mark 16a from 2 to 2 to partition the adjacent gaps 14, separation can be easily performed by making a cut along this partition plate.

When forming the outer sheath 16 by extrusion, the void 14 may be formed by a nipple, but the void may also be formed by forming the outer sheath 16 with a heat insulating tape in advance and extruding the outer sheath 16 from thereon. According to the above, a plurality of spiral or S-Z twisted voids are formed in the outer sheath formed around the central tensile strength member, and one or more optical fiber units are housed in the voids. It is easy to manufacture because the extrusion of the outer sheath and the storage of the optical fiber unit can be done in one step.In particular, the optical fiber unit does not need to be twisted, so it can be obtained economically. .

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the optical cable according to the invention, Figure 2 is a longitudinal cross-sectional view of the jacket, and Figures 3 (A) and (B) are explanatory diagrams showing the relative positional relationship between the tensile strength member and the optical fiber unit. , 4th
FIG. 6 is an enlarged cross-sectional view of an optical fiber tape, and FIGS. 6 to 8 are cross-sectional views of still another embodiment of the present invention. Figures 9 and 10
The figures are a perspective view and a partial longitudinal sectional view of a rotary nipple assembly used to manufacture the optical cable of the invention. 10----1~optical cable, 12----1 central tensile strength member, 12a----1 partition plate, 14----1 gap, 1
6------ Outer cover, 16 a------ Mark, 18-
---One optical fiber unit. Patent Applicant Representative Patent Attorney Kiku Denkan - ″″ No. (1)
tB Figure 4 Figure 5 Figure 7 Figure 5 Figure e

Claims (6)

[Claims] (1) A plurality of spiral or S-Z twisted voids are formed in the outer sheath provided around the central tensile strength member, and one or more optical fiber units are housed in each of the plurality of voids. An optical cable characterized by: (2) The plurality of optical fiber units in each gap are optical fiber core wires that are parallel to each other and are twisted 100% with respect to the central tensile strength member. Optical cable listed. (3) The plurality of optical fiber units in each gap are optical fiber tapes that are mutually stacked and twisted by 100 twists with respect to the central tensile strength member. optical cable. (4) The optical cable according to any one of claims 1 to 3, wherein marks are provided on the outer surface of the front sheath in correspondence with the plurality of gaps. (5) The optical cable according to any one of claims 1 to 3, wherein a mark is provided on the outer surface of the jacket in a manner corresponding to the middle of adjacent gaps. (6) The optical cable 0 according to any one of claims 1 to 3, which includes a partition plate that is integrally provided with the central tensile strength member and partitions between adjacent gaps.