JPH06100702B2 - Optical fiber cable manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing an optical fiber cable in which an optical fiber is spirally twisted around the outer circumference of a core body.

[Conventional technology and its problems]

As shown in FIG. 6, a conventional optical fiber cable is generally constructed by helically twisting an optical fiber 2 around the outer periphery of a core body 1 such as a spacer or a power cable core. This cable, like the power cable, supplies an optical fiber by a reel of a rotating cage to a core body running from a supply device to a winding device, and the supply fiber is arranged in front of the cage. However, the optical fiber cable having such a structure has a drawback of lacking reliability.

That is, the reliability of the optical fiber cable depends on the magnitude of bending force and tensile force applied to the optical fiber. This is because the optical fiber is weak in bending and pulling. However, in the above-described optical fiber cable, since the optical fiber has no extra length in the length direction, excessive tensile force is easily applied, and there is a high possibility that the fiber will be broken.

Therefore, as a solution to such a problem, as shown in FIG. 7, it is considered that the optical fiber 2 is corrugated and vertically attached to the outer periphery of the core body 1. However, this structure is not suitable for the optical fiber. Although it is possible to add a length, a specific optical fiber is located inside the bend when the cable is wound, and not only the bending stress in that fiber but also the compressive stress in the longitudinal direction due to the extra length caused by the bending. May cause buckling of the fiber.

Further, as shown in JP-A-50-21756, a composite band in which an optical fiber is corrugated and embedded between resin films is formed, and the band is spirally wound around the outer periphery of a core to form a spiral path of the optical fiber. It is also considered to meander,
According to this method, since the manufacturing process of the composite band is required,
Manufacturing becomes complicated, and there is a cost disadvantage. In addition, the use of the composite band makes branching of each optical fiber at the cable end inconvenient, and the restraining force of the film causes loss of freedom of movement of the optical fiber in the lateral direction (direction perpendicular to the longitudinal direction). Therefore, the effect of relaxing the tensile force of the optical fiber due to the extra length may be weakened.

[Means for Solving the Problems]

An object of the present invention is to provide a method for manufacturing an optical fiber cable which can be directly twisted around the outer periphery of a core while taking a meandering path with respect to a regular spiral axis in order to eliminate the above-mentioned inconvenience. It is in.

In order to achieve such an object, in the present invention, in a cable manufacturing method in which an optical fiber supplied from a reel of a rotating cage is helically twisted around the outer periphery of a running core, a feeder for the core or a rotating cage is provided. One of the optical fibers is rotated in a fixed direction, the other is intermittently reversed or rotated while reversing at a predetermined cycle, and the winding device of the assembly is rotated in synchronization with the supply device of the core body. To find a way to make the spiral axis of the meander meander when gathering.

The core may have a simple circular cross section, or a core having a meandering spiral groove on the outer circumference and accommodating an optical fiber twisted in the groove.

It is also possible to provide a plurality of rotating cages in the traveling direction of the core and twist the optical fibers into multiple layers. in this case,
If the rotation directions of the respective rotation cages are the same, the optical fibers of the respective layers are all twisted in a synchronized direction, and if the rotation directions are not the same, the optical fibers of the respective layers are alternately twisted in reverse winding.

〔Example〕

First, a specific example of an optical fiber cable manufactured by the method of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 is a diagram showing a basic structure of a cable to be manufactured, in which the optical fiber 2 spirally twisted around the outer periphery of the core 1 is
The center line A indicated by the alternate long and short dash line meanders left and right with respect to the regular spiral axis a indicated by the alternate long and two short dashes line, and the meandering length is used as an extra length to weaken or eliminate the tension acting on the optical fiber. .

2 and 3 show a plurality of optical fibers 2 having a spiral axis meandering and laminated around a core body 1 in a plurality of layers.
The cable of FIG. 2 has the optical fibers of each layer all twisted in a synchronized orientation, while the cable of FIG. 3 has the optical fibers of each layer twisted in opposite turns alternately between layers. When these cables are used as they are, it is considered that the twisting is returned due to the excess length and the optical fiber is lifted from the core body. Therefore, it is desirable to provide an outer shape holding member such as a holding tape or a jacket on the outer circumference. Another cable structure with its jacket is shown in FIG. This cable has a meandering spiral groove 3 on the outer circumference and a composite spacer having a tensile strength wire 4 inside to form a core body 1 ', and an optical fiber 2 is housed in the groove 3 on the outer circumference thereof, and then a jacket 5 is formed. It is made by applying.

In each of the optical fiber cables described above, since the optical fiber is spirally wound while taking a meandering path, extra length is generated in the fiber to reduce extension strain, and when the cable is bent, the specific optical fiber is bent inside. It is also prevented from getting irritated. Also, unlike the one disclosed in Japanese Patent Laid-Open No. 50-21756, since the optical fiber is wound directly without being made into a tape core wire, the number of manufacturing processes is small, and the branching work at the cable end is time-consuming. Also, there is no concern that the lateral movement of the optical fiber will be obstructed and strong tensile force will act on the optical fiber due to this (the one in Fig. 4 is also free to move in the direction perpendicular to the longitudinal direction if there is play between it and the groove). Degree occurs).

When multiple layers of optical fibers are provided around the core,
Structurally, the one shown in FIG. 3 has excellent stability. However,
In a cable subjected to lateral pressure, it is desirable to twist the optical fibers of each layer in a synchronized direction as shown in FIG. 2 because the transmission loss increases if the optical fibers cross each other.

Further, when higher lateral pressure resistance is required, it is preferable to protect the optical fiber from lateral pressure by a central body or a jacket as shown in FIG.

Further, the core body 1 is made of a material having high tensile strength, such as steel wire,
The use of fiber reinforced plastic, aramid fiber or a composite material in which such materials are combined with polyethylene resin or the like is effective in increasing the tensile strength of the entire cable.

Next, the manufacturing method of the present invention will be described in detail with reference to FIG.

The point in manufacturing the above-mentioned optical fiber cable lies in the twisting of the meandering optical fibers, but in the present invention, the supply device 10 for the core body 1, the winding device 11 for the assembly that rotates in synchronization with this device, Using a manufacturing apparatus whose basic constituent elements are a rotating cage 13 having a supply reel for the optical fiber 2 and a collecting die 14, one of the rotating cage 13 and the core feeding apparatus is rotated in a certain direction, and the other is rotated. By intermittently reversing or rotating while reversing every predetermined period, it is possible to spirally wind the optical fiber while meandering around the outer periphery of the running core.

That is, now, in the illustrated device, the winding device from the supply device 10
The central body 1 traveling toward 11 is a supply device 10 at a constant speed.
When it is considered that the optical fiber 2 rotates in a fixed direction together with the rotation cage 13 and stops, the optical fiber 2 is spirally wound on the center core along a normal path. However, if the rotation cage 13 is intermittently reversely rotated or once reversely rotated, and then the operation of rotating the rotation cage 13 in the same direction as the core at a speed higher than that of the core is repeated, the optical fiber becomes a regular fiber. A desired cable can be obtained by taking a meandering path with respect to the spiral axis and twisting it along the core with a collecting die.

This meandering winding of the optical fiber can also be performed by rotating the rotating cage 13 in a fixed direction and reversing the core body and its supply device at a constant cycle. Will also be possible.

For example, when a plurality of rotating cages arranged in the traveling direction of the central body 1 are rotated in the same direction, the optical fibers of each layer are twisted in a synchronized direction as shown in FIG. If the rotating cages of No. 1 and the even numbered rotating cages rotate in opposite directions, the winding directions of the optical fibers of the respective layers are alternately reversed as shown in FIG.

In order to maintain the shape of the assembled core after twisting, immediately after passing through the assembly die 14 or a shape-retaining mechanism such as a capstan arranged in the vicinity of the rear of the die, the assembly core is fed to the outer periphery from the tape supply device 15. It is desirable to provide a shape-retaining member such as a tape or a jacket formed by a coating device.

When a grooved spacer is used for the core, the rotation angle of the groove is detected, and the rotation speed of the rotating cage or the winding device is changed or the running speed of the core is changed according to the detected angle. It is preferable to assemble the optical fiber and the core, and by adopting this method, the fiber can be inserted accurately without applying an external force to the optical fiber.

〔effect〕

As described above, according to the method of the present invention, either one of the core body including the supplying and winding device and the rotating cage for supplying the optical fiber is rotated in a certain direction, and the other is rotated in a predetermined cycle. Since the meandering spiral winding on the core of the optical fiber is made possible by reversing the optical fiber,
Unlike the one shown in Japanese Patent No. 21756, it does not require a tape core wire forming step in advance, and it is possible to easily and efficiently manufacture the target optical fiber cable at a low cost by slightly improving the conventional manufacturing equipment. it can.

Also, if a tape core wire (composite band) is wound to make the optical fiber meander, the branching of the optical fiber at the cable end becomes inconvenient, and the freedom of lateral movement of the optical fiber is lost. Although the effect of relaxing the tensile force of the optical fiber due to the length may be weakened, such a problem does not occur because the independent optical fiber is directly wound in the present invention, and the reliability of the optical fiber cable is excellent.

[Brief description of drawings]

FIG. 1 is a front view showing a basic structure of an optical fiber cable obtained by the method of the present invention, FIGS. 2 to 4 are perspective views of other optical fiber cables obtained by the method of the present invention, and FIG. A diagram showing the method of the present invention, FIGS. 6 and 7 are perspective views showing a conventional optical fiber cable. 1 ... core core, 2 ... optical fiber, 3 ... groove, 4 ... tensile strength wire, 5 ... envelope, 10 ... core core supply device, 11 ... collection winding device, 13 ... … Rotation cage, 14 …… Assembling die, 15 …… Tape feeder.

Claims (1)

[Claims] 1. An optical fiber is supplied from a reel of a rotating cage to the outer periphery of a core body which runs from a supply device toward a winding device of the aggregate body, and the supplied optical fiber is passed through an assembly die to form the core body. In the method for manufacturing an optical fiber cable in which the outer circumference is spirally twisted, either one of the feeding device for the core and the rotating cage is rotated in a certain direction, and the other is intermittently reversed or reversed at a predetermined cycle. A method for manufacturing an optical fiber, characterized in that the optical fiber is meandered with respect to a regular spiral axis by rotating the optical fiber while rotating the optical fiber and rotating the assembly winding device in synchronism with the feeding device for the core.