JPH03233413A - Method for optical fiber connecting part with reinforcing material - Google Patents

Abstract

PURPOSE:To coat heat shrinkable tube without twisting nor loosening a connecting part by coating the connecting part with the reinforcing material while part of a tensile force in screening is left continuously as a linear holding tensile force. CONSTITUTION:Chucking in the screening is held as it is and at the same time, part of the tensile force in the screening is left continuously as the linear holding tensile force, while the connecting part is coated with the reinforcing material 3. Consequently, the reinforced part is not twisted internally and the connection is drawn with the linear holding tensile force and never slacks.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for coating a reinforcing material on an optical fiber core connection portion.

[Problem N that the prior art and invention are trying to solve] Generally,
When connecting a pair of coated optical fibers, first, the protective coating layer is peeled off only at the tips of the coated optical fibers, and the precoat is also removed. (In other words, the optical fiber strand at the tip is exposed.) Thereafter, the tip surface of each optical fiber strand that has been mirror-cut at a predetermined length from the end of the protective coating layer is heated, and the tip surfaces are brought into contact with each other. The fibers are brought into contact with each other and fused and spliced by pressing only a minute dimension, and then a reinforcing material made of an unshrinkable heat-shrinkable tube is covered over the entire length of the exposed fiber wire and the protective coating layer in the vicinity thereof.

However, in the above-mentioned splicing operation, after the fiber wires are fusion spliced and before being covered with a heat shrink tube, it is checked whether the mechanical strength of the spliced portion is sufficiently satisfied, for example.
After applying a tensile load of 150 g to 250 g, it was confirmed (screening test) that it would not break, and then
It covers the heat shrink tube and guarantees the reliability of the connection.

However, in the past, the mechanism of this screening test was
It was incorporated into the connecting device. Therefore, after conducting a screening test, the fiber connection part was removed from the connection device and set in a heater for heating the heat-shrinkable tube, and the tube was heated and shrunk. , twisting occurred at the connection, and the tube was covered with the twisting.

Therefore, even though it has been confirmed in the above-mentioned screening test that if a tensile force is applied to the connection due to changes in ambient temperature etc. after connection, the wire will not break due to that tension,
Since tension is applied at the connection part in a sprung state, it will break with a load smaller than the screening load.

For this purpose, after removing the fiber connection part from the connection device and setting it in a heat shrink tube heating heater, a screening test is performed, and if it breaks, it is returned to the connection device and connected again, and if it is not broken, A method has been proposed in which the screening load is removed and then the heat-shrinkable tube is heat-shrinked. However, when the load is removed, the fiber core slips at the cha/7 joint, causing the fiber to loosen. Therefore, the heat-shrinkable tube is coated while the tube is sagging, and the fiber core wire is undesirably housed in the tube after being coated in a bent, twisted, or loose state.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method of coating a reinforcing material on an optical fiber connection portion, which can cover a heat-shrinkable tube without twisting or loosening the connection portion.

[Means to solve the problem]

In order to achieve the above-mentioned object, the method of coating a reinforcing material on an optical fiber cable connection part according to the present invention maintains the chucking at the time of screening as it is, and at the same time, retains part of the tensile force at the time of screening as it is. This is to cover the reinforcing material while continuously maintaining the tension in a straight line.

[For production]

When covering the reinforcing material, the fiber core retains the chucking during screening, so
There is no built-in twisting in the reinforcing part, and the connecting part is pulled with tension to keep it straight, so it will not loosen.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, this invention will be explained based on drawing which shows an Example.

FIG. 1 shows a reinforcing material coating device used in the reinforcing material coating method according to the present invention. and a tension generating mechanism 6 that applies tension to the fiber connection portion 5, and the pair of optical fiber cores 7, 7 connected in the previous step shown in FIG. 2
The connecting portion 5 is covered with the heat-shrinkable tube 3.

Here, the pre-process shown in FIG. 3 means, as shown in FIG. 3 (1), that the protective coating layer is peeled off from only the tips of the pair of optical fiber cores 7 and 7, and the precoat is also removed. Fiber wire 9
．． 9 is exposed and mirror-cut at a predetermined length from the end of the protective coating layer. Note that a heat-shrinkable tube 3 is fitted onto one optical fiber 7 in advance, and a hot-melt adhesive tube (not shown) is fitted onto the other optical fiber 7 in advance. . Thereafter, the tip of the fiber is heated by the heating device 8, and the tip surfaces of the optical fibers 9, 9 are brought into contact with each other as shown in FIG. (Connect as shown in [[[].

And the above (not shown) that was loosely fitted on the outside.
A tube of hot-melt adhesive and an unshrinkable heat-shrinkable tube 3 are fitted over the exposed fiber wire 9.9 as an inner layer and an outer layer. At this time, a reinforcing additive such as a stainless steel wire or a glass rod is further inserted between the inner layer hot melt adhesive tube and the outer layer heat shrink tube 3 (not shown).

Thus, one chuck member 1 is fixed, and the other chuck member 2 is movable along the axial direction of the optical fiber core 7.7. Further, as shown in FIG. 4, the heater 4 has a storage heating chamber 10 that stores the heat shrinkable tube 3 loosely fitted onto the connecting portion 5, and is provided with a heating element 11 such as a nichrome wire. There is. Note that the hot-melt adhesive tube (as an inner layer) inserted into the heat-shrinkable tube 3 and the reinforcing additive are not shown in FIG. 4 either.

Next, as shown in FIG.
#2 swinging arm 13 which swings around the center and whose base end 13a is pivotally attached to the chuck member 2; and a first resilient member consisting of a tension coil spring etc. which is pivoted to the tip 13b of the swinging arm 13. 14, and the tip 14 of the first resilient member 14.
b is pivotally connected to the rotating disk 15, and the base end 16a is the fulcrum 12.
and a second resilient member 16 made of a tension coil spring or the like connected to the arm 13 between the chuck member 2 and the chuck member 2, and a tip 16b of the second resilient member 16 is connected to the fixing portion 17. Further, a first switch L consisting of a limit switch is disposed near the rotating disk 15, and a first switch L is provided near the rotating disk 15.
A second switch L2 consisting of a mint switch is installed near the
is installed.

Therefore, if the disk 15 rotates in the direction of the arrow from the state shown in FIG.
b is pulled toward the disk 15, and when the tip 14b of the first resilient member 14 is in the opposite position with respect to the disk axis from the state shown in FIG.
The chuck member 2 is pulled to the maximum in the direction of the arrow. In this state, for example, approximately 2
A screening tension of 0.00 g is set to be applied. Note that, in the state shown in FIG. 1, no tensile force is applied to the connecting portion 5.

Next, a method of covering the heat-shrinkable tube 3 using the reinforcing material covering apparatus configured as described above will be explained.

That is, the connected pair of optical fiber core wires 7, 7 are each chucked by the chuck member 1.2, and the switch L,
The rotary disk 15 is rotated to a position where it is in an on state and then stopped. In other words, the state shown in FIG. 1 is established. Then, as shown in the time chart of Fig. 2 (1), the rotating disk 1
5 stops its rotation (rotates approximately 415 times) after a predetermined time (that is, T3 seconds). At this time, at 1/2 rotation, a screening tension (approximately 200 g) is applied to the connection part 5 as described above, and a screening test is performed, and at 415 rotations, a part of the tensile force at the time of screening continues as it is in a straight line. It remains as a holding tension and does not form slack in the connecting portion 5.

In this case, if the connection part 5 is not disconnected, the heating element 11 is energized for a predetermined time (
That is, the heat shrinkable tube 3 (outer layer) and the true melt adhesive tube (inner layer) are heated (for 12 seconds), and the tube 3 is heat-shrinked and the adhesive tube is melted to reduce the total length of the fiber wires 9 and 9. The reinforcing additives, such as stainless steel wires and glass rods, are coated over the protective coating layer in the vicinity, and are surrounded by the melted adhesive, covering the entire length of the fiber element 19.9 and the ends of the protective coating layer. It is tightened as one piece with a heat-shrinkable tube 3. Note that during heating, an LED (not shown) lights up to notify the worker that the heating is in progress. Thereafter, the motor of the rotating disk 15 rotates until the switch L is turned on, and the rotating disk 15 rotates in the direction of the arrow for T3 seconds and then stops. In other words,
The rotating disk 15 rotates 115 times.

Furthermore, when the connecting portion 5 is disconnected, the chuck member 2 moves in the direction of arrow A, and as shown in the time chart of FIG. 2 (II), the switch L2 is turned on and the rotating disk 15 The motor rotates, and the rotating disk 15 rotates in the direction of the arrow until the switch L1 is turned on, and then stops. In other words, the rotating disk 15 rotates once. In this case, a disconnection indicating sound (for a predetermined period of time, for example, 2 seconds) is generated from a buzzer (not shown), the heating element II is not energized, and the heat shrink tube 3 does not heat shrink.

Therefore, when covering the exposed optical fiber strands 9, 9 with the heat shrink tube 3, the chucking at the time of screening is maintained as is, and at the same time, part of the tensile force at the time of screening is absorbed. Since the connecting portion 5 is maintained intermittently as a direct holding tension, the connecting portion 5 will neither twist nor loosen. In addition, the straight line holding tension is F
′ and the screening tension is F, then F′ is
The content of F is 5% to 50%, preferably 20% to 30%.

In the example, F'/F = 50/200 (xl
OO) = 25%.

Next, FIG. 5 shows a modification of the coating device, in which the switch L2 is provided between the first resilient member 14 and the fulcrum 12, and similarly, the motor 19 drives the switch L2. Fifth
As shown in Figure (It), the crank 18 is driven and this crank 18 pulls the first resilient member 14 toward the crank 18 side. In this case, if the connection part 5 does not break, the chuck member 2 will hardly move, but if it breaks, the chuck member 2 will move in the direction of arrow A, and the switch L2
is turned on, and the heating element 11 is not energized. Also, the fifth
As shown in the figure (I [[), when the crank 18 rotates about 3/4 and stops, and there is no breakage in the connection part 5, the heating element 11 is energized, the heat shrink tube 3 is heat-shrinked, and the light is emitted. The fiber strand 9.9 is coated. That is, in this case as well, heat shrinkage is carried out while the chucking during screening is maintained as is, and at the same time, a portion of the tensile force during screening continues to remain as a linear holding tension.

It should be noted that the present invention can of course be modified in addition to the embodiments described above. For example, in the case where the optical fiber is a tape-shaped multicore optical fiber, the reinforcing additive described above may have a substantially half-moon cross section. Using a glass rod, attach its flat surface to the tape-shaped multicore optical fiber core wire, heat-shrink the heat-shrinkable tube in the same way, and melt the hot-melt adhesive tube at the same time. After that, they are bonded and integrated by cooling and solidifying.

In addition, at the tape-type multicore optical fiber core wire connection part, two reinforcing plates such as an elongated rectangular glass plate and a ceramoto vine plate, which have a hot melt adhesive on the joint surface, are used. It is also possible to cover and reinforce the connecting portion by sandwiching it in a sandwich shape and pressurizing and heating it (that is, in the present invention, it is possible not to use a heat shrink tube).

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

When heat-shrinking the heat-shrinkable tube 3 or heating and pressurizing it with two reinforcing plates in the form of a side witch to cover the reinforcing material, the fiber connecting portion 5 should not be twisted or loose. The reliability of the connecting portion 5 can be fully guaranteed, and the connected optical fiber core 7
．． 7 has stable quality and excellent durability.

[Brief explanation of drawings]

Fig. 1 is a simplified diagram of the reinforcing material coating device used in the reinforcing material coating method according to the present invention, Fig. 2 is a time chart diagram, Fig. 3 is a diagram of the optical fiber connection process, and Fig. 4 is a cross section of the heater. figure,
FIG. 5 is a simplified diagram of a modification of the coating device. 3...Heat shrink tube.

Claims (1)

[Claims] 1. An optical fiber core connection characterized by maintaining the chucking during screening as it is and at the same time, coating a reinforcing material while allowing a part of the tensile force during screening to remain as straight line holding tension. Method of covering reinforcement material on parts.