JPH0439046B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an optical fiber splicing part reinforcing device that strengthens an optical fiber by heating a heat-shrinkable tube placed over the spliced part after fusion splicing the optical fiber.

[Conventional technology]

When fusion splicing optical fibers, the protective coating on the spliced ends is peeled off, and the two ends are butted together with the glass portion exposed. Therefore, after the fusion splicing is completed, the glass portion of the joint is exposed, and this portion is extremely vulnerable to external forces. Therefore, we covered this connection with a heat-shrinkable tube and heated it to form a protective layer.
I'm trying to make some reinforcements. Conventionally, after conducting a proof test, the heat-shrinkable tube is heated to be reinforced. This proof test is to confirm the reliability of the strength of the fusion splice.
This is done by applying a predetermined tension to the fusion spliced optical fibers before heating the heat shrinkable tube.

[Problem to be solved by the invention]

However, when reinforcing the heat-shrinkable tube by heating and shrinking it after a proof test, slippage may occur between the optical fiber and the clamper that holds the optical fiber during proofing, or the glass of the optical fiber may slip. Due to slippage between the part and the coated part, sag appears in the optical fiber within the heat-shrinkable tube at the end of proofing. Furthermore, slack when setting the optical fiber in the heater also causes the optical fiber to sag after the proof test. Therefore, if the heat-shrinkable tube is heated and shrunk as it is, it will be fixed in a bent state, causing a problem in the strength and reliability of the reinforced optical fiber. This becomes a problem particularly when a plurality of optical fiber cores such as tape-shaped optical fiber cores (ribbon tape core wires) are collectively fused and spliced to perform collective reinforcement. In other words, when inserting multiple optical fiber cores into a single heat-shrinkable tube and applying heat to it, if each core is bent, the inside of the tube is different from the case with a single fiber. This is because they are fixed while being connected or overlapped with each other, and mechanical interference between them greatly reduces reliability of strength, and in the worst case, may lead to breakage. Therefore, after the proof test, it may be possible to apply light tension to the optical fibers to take up the slack, keep the optical fibers straight, and heat them in an aligned state to shrink the heat-shrinkable tube.
However, in this case, using a tensioning mechanism for proof testing and a tensioning mechanism for preventing sagging not only complicates the structure, but also creates redundant structural and economical configurations, which is wasteful. It is. The present invention provides an optical fiber connection reinforcing device that is mechanically simple and economically superior, and that is capable of reinforcing an optical fiber immediately after a proof test. The purpose is to

[Means to solve the problem]

In order to achieve the above object, the optical fiber joint reinforcing device according to the present invention includes a heater that houses and heats the optical fiber joint covered with a heat-shrinkable tube, and a heater that accommodates and heats the optical fiber joint covered with a heat-shrink tube. two clampers positioned on both sides of the optical fiber for clamping the optical fiber, a mechanism for holding one of the clampers so as to be movable in the longitudinal direction of the optical fiber, and a moving block positioned in a predetermined direction in the longitudinal direction of the optical fiber. a drive mechanism for reciprocating within a stroke; an elastic member interposed between the moving block and the one clamper; and controlling the drive mechanism to stop the moving block at a predetermined position of the reciprocating stroke. It is characterized by having a control mechanism for controlling the

[Effect]

Clampers are provided on both sides of the heater.
Optical fibers are clamped by these clampers. During the proof test, the drive mechanism causes the moving block to make one reciprocation in the longitudinal direction of the optical fiber.
At this time, since both clampers clamp the optical fiber, the movable clamper cannot move freely, and as a result, the elastic member is compressed. In other words, as the moving block moves, the movable clamper
A force is applied in a direction that moves this clamper away from the other clamper. This force is applied to the optical fiber as tension, and as the moving block moves back and forth, this force gradually increases, reaches a peak, and then gradually decreases. Therefore,
Dynamic load proof testing can be performed on optical fibers. When the drive mechanism is controlled to stop the moving block at a predetermined position in its reciprocating stroke, a certain amount of tension is placed on the optical fiber. This tension can take up the slack. By heating the heat-shrinkable tube with a heater under this tension and shrinking it, the optical fibers are fixed in a straightened or aligned state. Of course, it is also possible not to perform a proof test. In that case, the drive mechanism is simply moved so that a certain low tension is applied to the optical fiber, and the moving block is stopped at that position, and the slack is taken up by this tension. The heat-shrinkable tube can be heated using a heater. In this way, the heat-shrinkable tube is heated by the heater with the optical fiber core wires straightened or aligned, so that the optical fibers after reinforcement remain straightened or aligned due to the contracted tube. It is fixed in the same state. Therefore, especially when reinforcing tape-shaped optical fibers all at once, each core wire can be aligned in a heat-shrinkable tube and the tube can be shrunk in that state, so that each core wire can bend and overlap with each other. There is no longer any need for reinforcement while contacting or overlapping each other, and the reliability in terms of strength of the connection portion of the tape-shaped optical fiber core wires is improved.

【Example】

Next, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, two clampers 3, 4 are placed on either side of the heater 2. Heater 2 and one (right) clamper 4
is attached and fixed to the base 1, while the other (left side) clamper 3 is attached to the moving block 5 and moves in the longitudinal direction (from the bottom left to the top right of the figure) of the optical fiber (not shown). It is kept movable. The heater 2 includes a rectangular case 21, a lid 22,
The lid 22 is made up of a hinge 23 that attaches the lid 22 to the case 21 so as to be openable and closable, and a flat ceramic heater 24 arranged on the bottom of the case 21. Guide grooves 25 and 26 are provided on both side walls of the case 21 on the side of the clampers 3 and 4. The clampers 3 and 4 are for holding down the optical fiber, and are connected to the substrates 31 and 41 and the holding plates 32 and 4.
2 and the holding plates 32, 42 to the substrates 31, 41
It consists of hinges 33 and 43 that are attached to the hinges so as to be openable and closable. Although not shown in the figure, pressing blocks pressed by coil springs are attached to the pressing plates 32, 42 of the clampers 3, 4.
When the angle between the holding plates 32, 42 and the substrates 31, 41 becomes 90° or less, the holding plates 32, 42
is designed to fall down toward the substrates 31 and 41 due to its own weight. Further, although not shown, magnets are built into the substrates 31, 41 and the holding plates 32, 42, so that the attractive force between them acts in the direction of closing the holding plates 32, 42. Holding plate 32,
When the optical fiber 42 falls toward the substrates 31 and 41 and is attracted by the magnet, the pressing block presses the optical fiber with the force of the coil spring, thereby clamping the optical fiber. An elastic plate such as a rubber plate is attached to the opposing surfaces of the substrates 31, 41 and the pressing plates 32, 42 (specifically, the surface of the pressing block described above), and the substrates are pressed as described above. This prevents damage to the optical fiber. In addition, in the above, clampers 3 and 4
The holding plates 32, 42 are supposed to fall down toward the substrates 31, 41 due to their own weight, but springs are built into the hinges 33, 43 so that the angle between the holding plates 32, 42 and the substrates 31, 41 is 90° or less. When the spring is bent, the holding plates 32 and 42 are held against the substrate 3.
It may also be biased towards the 1st and 41st sides. An L-shaped lever 34 is rotatably attached to one of the left and right clampers 3 and 4, in this embodiment the left clamper 3, by a rotating shaft 35, and the upright part of the lever 34 is attached to the presser plate 32. It is engaged with a pin 36 provided in the. A shaft 11 is fixed to the base 1, and this shaft 1
A moving block 5 is fitted into the shaft 11, and the moving block 5 can freely slide along this shaft 11 by means of a bearing (not shown) or the like. A shaft 51 is attached to the moving block 5, and a moving block 53 is fitted onto this shaft 51. This moving block 53 can freely slide along this shaft 51 by means of a bearing (not shown) or the like. Moving block 5, 53
A coil spring 52 is attached to the shaft 51 so as to be interposed therebetween. A follower 61 of the cam 6 is attached to the moving block 53. Cam 6 is rotated by motor 7.
Two pins 6 are placed at predetermined positions (angles) of this cam 6.
2, 63 are attached, and these pins 62, 63
is adapted to press limit switches 64 and 65. The angle between pins 62 and 63 is K°. In the case of the optical fiber connection reinforcing device shown in Fig. 1,
The operation when attempting to actually reinforce the connection portion is as follows. Hold an optical fiber (not shown) whose connection part is covered with a heat-shrinkable tube with your right and left hands on both sides of the connection part, and drop it into the guide grooves 25 and 26 while gently pulling it against the heater 2. and pass it from side to side. At this time, the connection portion covered with the heat-shrinkable tube is made to enter the case 21 of the heater 2. In this embodiment, it is configured as a dedicated optical fiber connection reinforcing device for collectively reinforcing tape-shaped optical fiber core wires, and the width of guide grooves 25 and 26 is such that each core wire of the tape-shaped optical fiber core wires is aligned. The width is said to be slightly wider than the width when lined up in the open state. In this way, the optical fiber held in the left and right hands is placed in the guide groove 25,
26, the optical fiber pushes against the horizontal portion of the L-shaped lever 34, causing the L-shaped lever 34 to rotate clockwise.
Then, the upright portion of the L-shaped lever 34 pushes the pin 36, so the presser plate 32 moves in the closing direction, and the angle it makes with the board 31 becomes 90° or less. the result,
The holding plate 32 closes by its own weight or the force of a spring built into the hinge 33, thereby clamping a large number of optical fibers in an aligned state on the left side of the connection portion. Since the optical fiber is thus clamped by the left clamper 3, the left hand can be removed from the optical fiber. Then, with the free left hand, the presser plate 42 of the right clamper 4 is closed, and the optical fiber is clamped on the right side as well. Then, a large number of optical fibers are clamped in an aligned state by the clampers 3 and 4 on both sides. Therefore, when performing a proof test, the motor 7 is rotated. Then, the cam 6 rotates, the follower 61 is pushed, and the moving block 53 moves to the left. As a result, the moving block 5 also tries to move to the left, but since the clampers 3 and 4 clamp the optical fiber, the moving block 5 can hardly move, and the coil spring 52 is compressed. As a result, tension is applied to the optical fiber. This tension changes from an initial tension A to a peak tension P as shown in FIG. 2 while the cam 6 makes one rotation (360°). This means that a dynamic load proof test has been performed on the optical fiber. This proof test usually ends with one rotation of the cam 6. One pin 62 corresponds to the start and end points of rotation of the cam 6, and the other pin 63 is located an angle K° in front of the pin 62. When cam 6 rotates and reaches K° before 360°,
This pin 63 pushes the limit switch 65. The rotation of the motor 7 is stopped by the output of the limit switch 65. The tension Q at this time is Q=A+(P-A)(K/180), and a low tension can be applied to the optical fiber to prevent sagging. At this time, the lid 22 is closed and the ceramic heater 24 is turned on to heat and shrink the heat-shrinkable tube. In this way, a large number of optical fibers are held straight and aligned, and are fixed and reinforced by the heat-shrinkable tube. When not performing a proof test (proof test is performed separately and not performed with this connection reinforcement device), the optical fibers can be aligned by applying a certain amount of tension to the optical fibers to prevent them from sagging. Since it is maintained in this state, it is sufficient to keep it in this state and heat it. Therefore, in this case, for example, after clamping the optical fiber with the clampers 3 and 4, the motor 7 is reversed and the pin 6 is clamped.
The rotation angle may be maintained at K° by controlling the rotation angle to be stopped when the user 3 presses the limit switch 65.

【Effect of the invention】

According to the optical fiber connection reinforcing device of this invention,
A single reciprocating drive mechanism can apply a dynamic load to the optical fiber, and by controlling the drive mechanism, the tension can be adjusted between the tension for proof testing at high loads and the tension for preventing sag at low loads. is obtained, the structure is simplified, miniaturization can be achieved, and economical efficiency is also improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, and FIG. 2 is a graph showing the relationship between the rotation angle of the cam and the tension. 1... Base, 2... Heater, 3, 4... Clamper, 5, 53... Moving block, 7... Motor, 11, 51... Shaft, 21... Case, 22...
... Lid, 23, 33, 43 ... Hinge, 24 ... Ceramic heater, 25, 26 ... Guide groove, 3
1,41...Substrate, 32,42...Press plate, 3
4... Lever, 35... Rotating shaft, 36, 62, 6
3...Pin, 52...Coil spring, 61...
...Follower, 64, 65...Limit switch.

Claims (1)

[Claims] 1. A heater that houses and heats an optical fiber connection portion covered with a heat-shrinkable tube;
Two clampers for clamping the optical fiber are placed on both sides of the optical fiber in the longitudinal direction, a mechanism for holding one of the clampers so as to be movable in the longitudinal direction of the optical fiber, and a moving block for clamping the optical fiber. a drive mechanism that reciprocates within a predetermined stroke in the longitudinal direction; an elastic member interposed between the moving block and the one clamper; An optical fiber connection reinforcement device comprising a control mechanism for stopping a moving block.