JPH0360091B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a terminating structure for an optical fiber cable.

Conventionally, the method of terminating a spacer type optical fiber cable has been to splice a fiber cord with an optical connector and protect that part with a protection box. This construction method involves installing a protection box and splicing the fiber cord with optical connector and the cable fiber at the construction site, and at the factory, installing the optical connector and the optical fiber cord and performing several steps. I was trying to assemble it after going through the process.

Industrially, this configuration needs to be improved in terms of cost and transmission loss in the system. For example, a building may need space to install a protection box that protects the spliced part between a fiber cord with an optical connector and a cable fiber, and the space required inside a terminal board to house the cable may be large. It becomes necessary to provide a Also, from the point of view of transmission loss,
This results in adding the splice loss of the cable fiber and the cable cord with optical connector to the required line loss value.

The present invention was developed in view of the above circumstances, and provides an optical fiber cable termination structure that can safely protect the optical fiber of a terminal, downsize and simplify the terminal processing structure, and reduce transmission loss. It is intended for this purpose.

[Summary of the invention]

In the optical fiber cable termination structure of the present invention, the grooved spacer, the cable tension member, and the cable sheath at the terminal part of the spacer-type optical fiber cable are each stepped and peeled to predetermined dimensions. The optical fibers of the optical fiber cable are exposed for a length necessary for termination, and a fixing block having a plurality of through holes is provided in front of the end of the optical fiber cable, and the fixing block has a plurality of through holes. A protective sleeve consisting of an inner sleeve portion into which the optical fiber is inserted and an outer sleeve portion is inserted and fixed into each of the through holes of the fixing block, and the inner sleeve portion is inserted into the grooved sleeve. The outer sleeve portion of the protective sleeve is pulled out from the fixing block, and an optical connector is attached to the tip of the optical fiber within the outer sleeve portion. The gist is that a molded sleeve covers the fixed block and the cable sheath end portion.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the optical fiber cable termination structure of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a perspective view illustrating the structure of the terminal processing, FIG. 2 is a front view showing a part of the terminal processing section of FIG. 1 in cross section, and FIG. 3 is a front view of the completed terminal processing of FIG. 1. In the figure, numeral 1 is a fixing block having a plurality of through holes, and numerals 2 and 3 are an outer sleeve portion and an inner sleeve portion, respectively, which constitute a protective sleeve.
4 is a cable tension member, 5 is a grooved spacer, 6 is a cable sheath, 7 is a ground terminal, 8 is a ground wire, 9 is a molded sleeve (case), and 10 is an optical connector.

In the case of termination processing, first, the terminal end of the spacer type optical fiber cable is peeled into predetermined dimensions in the order of the cable tension member 4, the grooved spacer 5, and the cable sheath 6. At this time, the length of optical fiber required for termination is removed from the cable. Next, as shown in FIG. 4, which shows the structure of the protective sleeve, the inner sleeve part 3 of the protective sleeve is
A length required for termination is prepared, and one end of the cable is peeled to a length that can be inserted into the lower side of the cable sheath 6 along the groove of the grooved spacer 5 of the cable.
The protective sleeve, which has been peeled in stages and is formed hollow, is inserted into each through hole of the fixing block 1 from the inner sleeve portion 3 side as shown in FIG. At that time, an adhesive is applied to the through hole of the fixing block 1 and the fixing block 1 is fixed with adhesive. In addition, as shown in FIG. 4, in the protective sleeve, the inner sleeve part 3 is made thin in order to be inserted into the groove of the grooved spacer 5, and the outer sleeve part 2 is drawn out from the fixed block 1. The purpose is to protect optical fibers that are exposed to
It is slightly thicker than the internal sleeve part 3.

Next, apply adhesive to the tip of the cable tension member 4 of the cable, and attach it to the fixing block 1.
While gently inserting the optical fiber cable into the protective sleeve fixed to the inner sleeve part 3 side, the fixing block 1 is moved to the cable terminal side and the optical fiber is drawn into the protective sleeve. At this time, the internal sleeve portion 3 is pushed into the inner peripheral side of the cable sheath 6 along the groove of the grooved spacer 5. As a result, the fixing block 1 reaches the cable tension member 4, and the cable tension member 4 is fixed in the hole of the fixing block 1. still,
If the cable sheath 6 is a lap sheath, it is necessary to consider the grounding of the metal body. In that case, a grounding terminal 7 can be attached to the cable sheath 6 and pulled out externally using a grounding wire 8.

The terminated cable end is covered with a molded sleeve 9 over the cable sheath 6 and fixing block 1 for overall protection. FIG. 1 shows a state in which this molded sleeve 9 is covered,
FIG. 3 shows the state in which the optical connector 10 is attached to the tip of the optical fiber inside the jacket sleeve 2 and the terminal processing is completed.

In this way, in the optical fiber cable termination structure of this embodiment, the cable tension member is fixed to the fixing block provided in front of the terminal part of the spacer type optical fiber cable, and the cable tension member is fixed to the through hole of this fixing block. A protective sleeve consisting of an inner sleeve part and an outer sleeve part into which the optical fiber is inserted is inserted and fixed until the inner sleeve is accommodated in the groove of the grooved spacer, and then the optical fiber is attached to the tip of the optical fiber inside the outer sleeve part. By attaching the optical connector and covering the fixing block and cable sheath with a molded sleeve, the size of the terminal processing part can be made smaller than before, and the splice part can be reduced in size by two.
Since fewer parts can be used, transmission loss can be reduced, and the overall price can be reduced by a few percent considering parts, materials, and man-hours.
The structure can be simplified.

In addition, cover the end of the optical cable with a cylindrical sleeve that is sealed on one end, wrap the optical fiber within this sleeve with sufficient extra length around the cable tension member, and pull out the optical fiber through the hole in the end plate of the sleeve. The heat-shrinkable tube and the jacket tube are coated to form an optical cord, and this optical cord is fixed to the outer wall of the sleeve with a ring and a nut.
No. 49511) is known, but in the terminal part of such an optical cable, the optical fiber is wrapped around a tension member, and the optical fiber pulled out from the sleeve is covered with a jacket and fixed to the outer wall of the sleeve. When the optical fiber protrudes into the sleeve due to expansion and contraction of the cable, the wrapped optical fiber is subjected to excessive bending, which not only increases transmission loss but also may break in the worst case. However, in the present invention, the optical fiber is protected by a protective sleeve from within the groove at the end of the spacer, and an optical connector is attached to the optical fiber at the tip of the jacket sleeve, so the protrusion of the optical fiber is reduced to Since the optical fiber is relaxed to the side and protrudes as described above, there is no fear of bending or damage to the optical fiber.

〔Effect of the invention〕

As explained above, the optical fiber cable termination structure of the present invention has the effect of safely protecting the optical fiber of the terminal, simplifying and downsizing the terminal treatment structure, and reducing transmission loss. It is.

[Brief explanation of drawings]

Fig. 1 is a perspective view for explaining the configuration of the optical fiber cable termination structure of the present invention, Fig. 2 is a front view showing a part of Fig. 1 in cross section, and Fig. 3 is the terminal processing of Fig. 1. FIG. 4 is an explanatory diagram of the protective sleeve shown in FIG. 2. 1: Fixed block, 2: Outer sleeve part, 3:
Internal sleeve part, 4: cable tension member, 5: grooved spacer, 6: cable sheath,
9: Molded sleeve, 10: Optical connector.

Claims (1)

[Claims] 1. In a termination structure in which an optical connector is attached to the end of a spacer-type optical fiber cable, a cable tension member, a grooved spacer, and a cable sheath at the end of the optical fiber cable each have a predetermined position. The optical fiber cable is peeled in steps, and the optical fiber of the optical fiber cable is exposed for a length necessary for termination, and a fixing block having a plurality of through holes is provided in front of the end of the optical fiber cable, The cable tension member is fitted and fixed into the fixing block, and a protective sleeve consisting of an inner sleeve portion through which the optical fiber is inserted and an outer sleeve portion is inserted and fixed into each of the through holes of the fixing block. An inner sleeve portion is housed in the groove of the grooved spacer, and the outer sleeve portion of the protective sleeve is pulled out from the fixing block and is attached to the tip of the optical fiber within the outer sleeve portion. 1. A terminating structure for an optical fiber cable, wherein an optical connector is attached, and a molded sleeve covers the fixing block and the end portion of the cable sheath.