JPS6039843Y2 - Protection structure for optical fiber introduction section - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a protection structure for the introduction part of an optical fiber.

2. Description of the Related Art Conventionally, in optical communication repeaters and the like, when an optical fiber from a stuff cable is directly introduced into equipment via an optical connector, a structure as shown in FIG. 1 is used.

One end of a stub cable 3 is inserted into a dam fitting 2 attached to a housing 1, and an optical fiber 4 coming out of the stub cable 3 is led to a device 5 without being exposed and connected by an optical connector 6. .

Note that resin 7 is injected into the dam fitting 2 to maintain airtightness within the housing.

This type of optical fiber introduction structure is advantageous in terms of optical fiber transmission characteristics, reliability, cost, and simplification of assembly work, but on the other hand, optical fibers are thin and weak, so they are prone to breakage when handling optical connectors. Furthermore, there are drawbacks such as the need for a wire alignment jig or the like when fixing the optical fiber by injecting resin into the dam fitting 2.

The present invention was devised to improve this drawback.

Therefore, in the optical fiber introduction part protection structure of the present invention, a protective tube is fitted over the optical fiber introduced into the housing from the stub cable inserted from one side of the tom fitting attached to the housing, and then glued. The protective tube is fixed to the clasp by applying a compound and caulking, and the dam fitting is removably provided with a fixing plate having a screw hole for fixing the clasp and a hole for resin injection, and the fixing The present invention is characterized in that the clasp of the protective tube is fixed to the plate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 shows a sectional view of the embodiment.

In the figure, 2 is a dam fitting, 3 is a stub cable with one end inserted into the dam fitting, and 4 is its optical fiber.

This optical fiber 4 is inserted into a protective tube 8 and connected to an optical connector 6 at the tip.

A fastener 9 is attached to the other end of the protective tube 8, and is fixed to a fixing plate 10 with a screw at its tip.

Further, the fixing plate 10 is fixed to the dam fitting 2 by a ring screw 11.

In this embodiment, the protective tube 8 has a three-layer structure consisting of an inner tube 12, a braided Kevlar 13, and an outer sheath 14, as shown in FIGS. Remove a part of the braided Kevlar 13, cover the knurling part 15 of the fastener, apply adhesive, and then fit the ferrule 16 on top of it.The part corresponding to the knurled part 15 is caulked to form a protective tube. 8 and the fastener 9 are strongly connected.

Further, as shown in FIG. 5, the fixing plate 10 is provided with a plurality of screw holes 19 for fixing the fasteners 9 to a disk 18 having a hole 17 for resin injection in the center, and reaching the outer periphery from the screw holes. A notch 20 is provided.

This notch 20 is provided to allow the optical fiber to pass through so that the fastener can be fixed to the fixing plate even after the optical fiber is inserted into the protective tube.

Note that 21 is a notch for preventing rotation that engages with a pin provided on the dam fitting 2.

In this embodiment thus constructed, the optical fibers can be sufficiently protected and, at the same time, the optical fibers can be easily aligned without requiring a alignment jig when fixing the optical fibers with resin, resulting in good assemblability.

As explained above, the protective structure of the optical fiber introduction part of the present invention uses a protective tube and a fixing plate for fixing the protective tube, thereby preventing bending, twisting, and pulling of the optical fiber during construction and maintenance of the optical fiber cable. The reliability of handling is increased by reducing compression forces and other forces.

Further, when fixing the optical fibers by injecting resin into the dam metal fittings, a wire alignment jig is not required, and the wire alignment can be easily performed, resulting in good assembly efficiency.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an example of a conventional protection structure for an optical fiber introduction part, Fig. 2 is a sectional view of a protection structure for an optical fiber introduction part according to an embodiment of the present invention, and Fig. 3 is a cross-sectional view of a protection structure for an optical fiber introduction part. 4 is a sectional view of the fastener, FIG. 4 is a sectional view taken along the line IV--IV of FIG. 3, and FIG. 5 is a plan view of the fixing plate. 1... Housing, 2... Dam fittings, 3...
...Stub cable, 4...Optical fiber,
6... Optical connector, 7... Resin, 8.
・・・Protective tube, 9 ・・・ Fastener, 10
...Fixing plate, 11...Ring screw, 1
9...Fixing screw hole, 20...Notch.

Claims (1)

[Scope of utility model registration request] A protective tube is fitted onto the optical fiber introduced into the housing from the stub cable inserted from one side of the tom fitting attached to the housing, and the protective tube is fixed to the clasp by applying adhesive and caulking. Then, a fixing plate having a screw hole for fixing the fastener and a hole for resin injection is removably provided on the metal fitting, and the fastener of the protective tube is fixed to this fixing plate. Features a protective structure for the optical fiber introduction section.