JPH03107804A - Construction and method for storing extra length of optical fiber - Google Patents

Abstract

PURPOSE: To continuously and limitedly operate a cable by guiding the cable so as to reduce its movement as much as possible inside a drawer when pulling out the drawer. CONSTITUTION: An optical cable 2 is fixed to a drawer 7 and when the drawer 7 is pulled out, the optical cable 2 can be moved just for a distance (a). A 1st fixing member 1 for the optical cable 2 is provided near a rear wall 3 of rack of the drawer 7, and a hollow pipe member 4 for inserting the optical cable 2 with low friction and a 2nd fixing member 5 for the optical cable 2 are provided near a rear wall 9 of the drawer. Then, when the drawer 7 is pushed in, the optical cable 2 is allowed to form the loop of a length b>2a between the hollow pipe member 4 and the 2nd fixing member 5. Besides, the 2nd fixing member 5 is provided for fixing the position and direction of the optical cable 2 inside a 1st space. Thus, the optical fiber automatically moves to the rear side of the drawer just for the desired length from the single loop without receiving the operation of force.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical cable surplus length storage structure and an optical cable surplus length storage method as described in the preamble of claim 1.

[Prior art, problems to be solved by the invention, and means for solving the problems] In optical waveguide cable terminal technology and optoelectronic connection technology, glass fiber cable terminal plug-in units that can be combined into modules and standard A connection cassette is being used. In the field of electronic engineering, 19-inch frame frames and plug-in units adapted to them are commonly used.

In the known fiberglass cable terminals, the individual cables or cable bundles are embedded in strands, allowing some freedom of movement and allowing extra length in the rack or frame when the plug-in unit is pulled out. The plug-in unit with the cable fixed can be pulled out.

As long as the rack is configured to receive an electronics plug-in unit or a plug-in unit for optoelectronic connection technology and there is sufficient free space for cable movement in the vicinity of the rear wall, the optical waveguide will not be damaged when pulling out the plug-in unit. It is possible to prevent this from happening. However, as the density of plug-in units increases, the individual cables interfere with each other, and when one or more plug-in units are pulled out, the cables bend and fall below the minimum (hazardous) radius of curvature of the cables, causing the risk of cable breakage. occurs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a structure that determines the movement of the cable so that the cable moves continuously and in a limited manner when pulling out the drawer. This object is achieved by the features described in the characterizing part of claim 1 of the invention. Further advantageous embodiments of the invention are set out in the dependent claims. The storage method of the invention is set out in claim 6.

[Operation and Effects of the Invention] The main technical idea of the present invention is to guide the cable so that it does not have to move as much as possible within the drawer when pulling out the drawer. Inside the drawer, the cables are grouped and guided so that when the drawer is pulled forward, it automatically moves from a single loop to the rear of the drawer by the desired length, without any force acting on it. Must be.

Since winding the optical cable on a spool requires excessive force to unwind it from the spool, the present invention utilizes a loop established by burying the optical cable in a small room. The loop is arranged so that as long as possible a straight section exists in this narrow chamber of the drawer after the hollow tube such as the bushing. In this way, the reaction force (frictional force, etc.) applied to the optical cable on the hollow tube member during the pull-out process is only small, and the drawer is not completely pulled out due to the locking part, thereby preventing damage to the optical fiber. The optical cable can be drawn into the standard connection cassette when the drawer is pulled out to its stop, so that it is always accessible for connection operations.

[Example] The present invention will be described in detail below based on the drawings.

FIG. 1 shows how the cables comprising the individual optical cable bundles are inserted into a connecting rack or frame and fixed, for example, to a rear wall 3. FIG.

Optical cables 2, either individually or in bundles, extend upwards through the rear wall 3 and branch off towards the drawer 7 at a suitable plane.

For simplicity, only one stage with a drawer 7 is shown.

FIG. 2 shows in detail how the optical cable 2 is passed from the first fixing member 1 through the bush (hollow tube material) 4 and inserted into the drawer 7, and first a loop is formed therein. In the case of a plurality of optical cables 2, they are bundled together in a drawer using a tube or a cable binder (not shown), so that they always run parallel to each other. The optical cable 2 is fixed with a second fixing member 5. This second fixing member 5 preferably consists of a tube clip, but rather than clamping the optical cable 2 directly, it applies force to the cable via the plastic tube (so that the general direction of the cable is also fixed, but with some changes in direction). ) so that it is possible.

FIG. 3 shows how the loop is accommodated in the first space 6, and the rear wall 9, side wall (partition) 8 and front wall 12 of this first space can be seen. The drawer 7 is guided by a guide rail 13. The guide rail 13 and the drawer 7 are designed for 19 inches, for example.

Cable 2 forms a loop of length b. The drawer 7 has a storage stroke of a distance la. The condition for preventing the optical fiber from breaking during extraction is b=2a. The situation when the drawer is pulled out is shown in FIGS. 2 and 3. Although the loop becomes smaller as it is pulled out, the radius of curvature of the loop remains largely unchanged and is sufficiently large, so there is no risk of breakage and the optical loss is negligible.

FIG. 4 shows the cable 2 arranged in the drawer 7 in a perspective view. The cable 2 (partially exposed) is led from the first space 6 into a relatively wider second space, where it also forms a loop 11 and is then connected to the connection cassette 1° with a member 14. Ru. The cable 2 is looped as usual in the connection cassette lo and can be pulled out and connected. The connection cassette can be easily removed when the drawer 7 is pulled out. This may be necessary when a cable that has been brought in must be reconnected. That is, additional cables can be inserted into the connection cassette or removed from it and inserted into another drawer.

As can be seen from Fig. 4, the frame shown in Fig. 5 has
A drawer 7 with a connection cassette lo is housed therein.

The rack can be connected to flexible optical cables or installed in a fixed position without connectors, which must be removed when relocating the entire rack. Further, the drawer frame assembled into the rack cannot be removed. This lick would still have to be fitted with a connector, but this is not advantageous due to cost or increased attenuation.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the entire connection rack, Figure 2 is a cross-sectional view of the 19-inch drawer, Figure 3 is a diagram showing the drawer shown in Figure 2 in a pulled out state, and Figure 4 is a perspective view of the drawer. FIG. 5 is a diagram of a frame with one out. In the figure, 1 is the first fixing member, 2 is the optical cable, 3 is the rear wall of the rack, 4 is the hollow tube, 5 is the second fixing member, and 6 is the first
, 7 is a drawer, and 9 is a rear wall of the drawer.

Claims (1)

[Claims] 1. A rack or a frame, into which an optical cable is inserted, and a drawer that can be pulled out, the optical cable or a group of optical cables is fixed to the drawer, and when the drawer is pulled out. In the optical cable surplus length storage structure configured to allow the optical cable to move by a certain distance a, the first optical cable fixing member is provided near the rear wall of the rack of the drawer, and the optical cable is lowered near the drawer rear wall. A hollow tube material to be passed through by friction and a second fixing member for the optical cable are provided, and when the drawer is pushed in, the optical cable forms a loop with a length b>2a between the hollow tube material and the second fixing member. However, when the loop is pulled out, the optical cable becomes limited in size because it can be pulled out through the hollow tube, and the loop is located in a first space defined within the drawer, and is located in a first space near the rear wall of the drawer. A second fixing member is provided to determine the position and orientation of the optical cable within the first space, and the height and horizontal axis of the hollow tube are provided in accordance with the first fixing member of the rack rear wall. Optical cable extra length storage structure. 2. The structure of claim 1, wherein each of said first and second securing members is made of conventional cable coupling. 3. The structure according to claim 1 or 2, further comprising a partition wall for partitioning the first space within the drawer. 4. The fixing member is disposed at a predetermined distance from the rear wall of the rack and the rear wall of the drawer, and the optical cable reaches each rear wall with a sufficiently large radius of curvature and is guided there in the vertical direction. A structure according to any one of claims 1 to 3, characterized in that it obtains. 5. The connection cassette is arranged in a relatively wide second space partitioned by the partition wall, with a third space remaining between the rear wall of the connection cassette and the partition wall, into which a spare cable can be inserted. The structure according to any one of claims 1 to 4, characterized in that: 6. In the optical cable surplus storage structure of claim 1, after the optical cable is fixed near the rear wall of the rack, the optical cable is inserted into the first space of the drawer through the hollow tube material, and the optical cable is moved in a short arc toward the rear wall of the drawer. and there the cable runs horizontally with other fixing elements, but at the rear wall of the drawer a part of the optical cable runs parallel to the rear wall of the drawer without falling below a dangerous radius for the transmission of light. The optical cable is bent and fixed so as to be curved so as to be fixed, the optical cable is pulled forward behind the bulkhead, and the excess length is stored in the second space, and a connection cassette for receiving the cable length necessary for connection is provided in the drawer. How to store extra optical cable length.