JPS60177312A - Manufacture of optical fiber cable - Google Patents

Abstract

PURPOSE:To maintain transmission characteristics for a long period by stranding plural units around one tensile strength body, and passing a torsion catcher which inverts the stranding direction periodically and inverting and stranding the units at its upstream side at specific intervals. CONSTITUTION:Units 2 are sent out of plural supply bobbins 1 and stranded around the tensile strength body 3 fed out of a supply bobbin 3a while passed through a comber board 4 and a die 5 successively, and then the stranded wire is passed through the torsion catcher 12. This torsion catcher 12 is inverted periodically as shown by arrows A and B and stranded at its upstream side at specific intervals while the inversion stranding is pressed with a binder 16 which rotates in mutually opposite directions. Then, the torsion pitch of the units is set to >=50cm, the external diameter of the optical fiber 20 is preferably 15- 80mm., and the inversion pitch is 10-1,000cm. Thus, the transmission characteristics are maintained for a long period.

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing an optical fiber cable.

Conventionally, on the outer surface of a reinforcing material with a small outer diameter (for example, 1 mm),
A structure of reverse twisting in which thin (for example, 0.9 mm diameter) optical fibers are twisted together and the direction of twisting is reversed at appropriate intervals has been proposed in Japanese Utility Model Application No. 51-120755. However, no manufacturing method for actually performing such reverse twisting has been disclosed, and in reality, it is extremely difficult or impossible to perform reverse twisting on extremely thin optical fibers to reinforcing materials with small outer diameters as described above. It is possible.

Part of the twisting and twisting device must be frequently reversed, and from an accuracy perspective, the optical fiber itself may be damaged during manufacturing, or unreasonable bending force may be applied to the optical fiber itself at the reversed portion. This is because there are problems such as lateral pressure exerting a large force on extremely localized areas.

As a result, it is expected that the transmission characteristics of the product (optical fiber cable) will deteriorate, and there will be a high probability that a portion of the optical fiber will break within a short period of time after installation.

In particular, optical fibers are more sensitive to internal stress (strain) than copper wires, etc., and break after a certain period of time.
Even if there is no transmission characteristic, the transmission characteristics will be significantly degraded. Furthermore, if the optical fiber is scratched on its surface, its durability and moisture resistance will be significantly impaired. Therefore, it can be said that it is actually extremely difficult or impossible to manufacture the known optical fiber cable having the above-mentioned reverse twist structure.

The present invention was made in view of these points, and it is possible to cleverly reverse twist even optical fibers that are sensitive to even slight distortion and have characteristics close to perfect rigidity. Therefore, it is an object of the present invention to easily manufacture an optical fiber cable that can maintain stable transmission characteristics for a long period of time after installation and has a long service life. Therefore, the feature of the present invention is that a plurality of units are sent out from a plurality of supply bobbins and gathered around one tensile strength member, so that the wire does not obstruct the passage in the advancing direction but prevents the wire from wandering. A torsion catcher to be restrained is provided at a predetermined distance from the supply bobbin, and the torsion catcher is passed through the 1-john catcher, and the torsion catcher is periodically reversed to twist the yarn at predetermined intervals on the upstream side of the torsion catcher. The method consists in that, while performing a reverse twist to reverse the twist, the reverse twist is pressed and wound, and further, a winding device is provided at a predetermined distance downstream of the torsion catcher, and the winding device winds it up.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

In FIG. 1 or 2, 1... is a supply bobbin on which unit 7 is wound, 3a is a supply bobbin on which a tensile strength member 3 is wound, 4 is a batten, and 5 is a supply bobbin on which a tensile strength member 3 is wound. It's dice.

As shown in FIG. 3, the unit 2 is, for example, one in which six optical fiber core wires 6 are twisted around a reinforcing material 15, and the outside thereof is covered with a buffer layer 7 such as polypropylene yarn. It will be done. The reinforcing material 15 is made of twisted steel wire, single wire, or the like, and each of the core wires 6 is twisted in one direction, either right-handed or left-handed. The core wire 6 is an optical fiber 8 coated with a silicone resin coating 91 and a plastic coating 9, and can be freely selected from graded index type, stamped index lath type, and various other types. . In addition, as the tensile strength body 3, as shown in FIG.
A wire having a steel wire 10 in the center and integrally covered with a plastic layer 11 such as polyethylene can be used.

12 is a 1-1 shock catcher that does not prevent the wire from passing in the traveling direction but restrains (restricts) the twisting of the wire; In FIG. 2, an example using three-point rolls 14 is illustrated. And multiple supply bobbins...
The Uniso 1 to 2... are sent out respectively from the X-ray bobbin 38 and gathered around the tensile strength body 3 sent out from the Zaburi bobbin 38 while passing through the batten board 4 and the die 5 in order. 12 to pass through the collection line.

The distance β' between this 1--shicon catcher 12 and the No. ply bobbin ■ is set to a predetermined value as described later, and as shown by arrows A and B, 1--shicon catcher 1
2 is periodically inverted. In this way, on the upstream side of the torsion catcher 12 (on the left side in FIGS. 1 and 2), the twisting direction is reversed at predetermined intervals, such as reversal 1, and the twisting direction is rotated by an opposing force of 1. This reverse twist is held down with a binder or taping 16.16.

FIG. 6 is a diagram illustrating how one unit 2 is representatively twisted around the tensile strength member 3 in order to explain this state of reverse twisting. The twisting direction is reversed periodically at a predetermined interval H, and the reversal pinch Q is twice this interval H. = 2H holds true. Furthermore, as shown in the cross section of FIG. 4, four units 2 are twisted around the tensile strength member 3, and an additional
The intervening strings 17... of the book are twisted in reverse at the same time (in Figures 1 and 2, the intervening strings 17... and their sublime bobbins are omitted from illustration), and the intervening strings 17... and the units 2... are twisted at equal pitches on the circumference. A string 17... is provided. It is covered from the outside with a pressing layer 18 made of the binder or taping 16. As the intervening string 17, a plus deck string such as polyethylene is used, and is a so-called dummy unit, but it is of course possible to make it all unit 2 without this dummy unit.

As shown in FIG. 1 or 2, a winding device 19 is provided downstream of the torsion catcher 12 (on the right side in the figure) at a predetermined distance β, and after passing through the torsion catcher 12, the winding device 19 is It is wound up by the winding device at (V).

In addition, if the optical fiber cable 20 is used, then the fourth
As shown in FIGS. 5 to 5, the finished product is covered with a sheath 21 or the like.

Next, in the manufacturing equipment shown in Figures 1 and 2,
Assuming that the predetermined distance between the torsion catcher 12 and the winding device 19 is l, the linear speed is V, the rotation speed is n, and the number of twists between the above predetermined distance β is y, the following relational expression for the cable or single wire is obtained. holds true.

△y=n△t-2V△t...■ ■ Integrate the equation and find the initial twist number y when t=Q as the initial condition. ,y. If it is -0, then ■ Therefore, the torsion pitch P between the winding and the torsion catcher 12 is P=-. Therefore, if the distance l is long to some extent and t is short, the torsion pitch P will be very long, and there is no need to loosen or tighten the binder or taping 16, making it easy to manufacture. Ru.

Next, when the arrow rotates in the opposite direction from A to B (or from B to 8), if there are N untwisting times, then when t=Q, y
,=N, △y=−n△t −□ vΔt ・・・■! If we integrate this and include the initial conditions, we get ■ ■. Therefore, if the distance l is long to some extent and t is short i, the torsion pitch P will be very long, and there is no need to loosen or tighten the binder or taping 16, and manufacturing is easy.

As mentioned above, the twisting by the torsion catcher 12 is
Naturally, twist is imparted to the upstream wire 22, but when looking at the entire winding, the twist is essentially zero by performing the same number of twists in the forward and reverse directions A and B.

However, supply bobbin 1 and torsion catcher 1
Next, let's consider the twist between the two. In the manufacturing equipment shown in Figs. 1 and 2, the distance between the Xabry and the torsion catcher 12 is β', the linear speed is 71, and the number of revolutions is n'.
If the number of torsions between the supply and the torsion catcher 12 is y', then by integrating the equation 0, the initial number of torsions when t'=Q is y°.

If we set y9゜=0, then becomes.

Therefore, by appropriately selecting the distance β" and t, the torsion pitch I
)" changes the direction in a non-directional manner compared to the pitch Q of the reverse I, so it is possible to achieve a reverse twist of almost 100%. In other words, only the twist of P" is added to the unit 2. It is.

Next, when the arrow rotates in the opposite direction from A to B (or from B to 8), if there are N" untwisting times, (when -0, y".-N", then formula The following equation is obtained in the same way as equation 0.

■ Thus, the twist pitch P' of the unit is l.

If and t are appropriately selected, they can be set to extremely large values, and although the unit is twisted, the twisting of the unit can be suppressed to a level that does not substantially cause any performance problems.

In the above explanation, the winding device 19 is fixed, but the winding device 19 is rotated in synchronization with the torsion catcher 12 as shown by broken line arrows C and l in FIG. It is also preferable to avoid over-tightening. In addition, the number ply bobbin 3a of the tensile strength body 3 is also
It is desirable to rotate in synchronization with the torsion catcher 12 as shown by the broken line arrow r; Use body 3.

As a result of repeating various experiments based on the above-mentioned theory, it was found that the twist pitch P' should be set to 50 cm or more.

In addition, the outer diameter of the optical fiber cable 20 is 15 mm to 80 mm.
In mm, the reversal pitch Q is 10cm to 1000cm
It is desirable to set it to 30 cm to 60 cm, especially
Neighborhood is preferred. The predetermined distance a' between the supply bobbin I and the torsion catcher 12 and the predetermined distance β between the torsion catcher 12 (!: winding device 19) are both desirably 1 m to 2 Qm. For example, the linear velocity is v-5 m 7
Distance in minutes! , β° is less than 1 m, the reversal interval of the torsion catcher becomes short and sagging cannot be smoothly handled. On the other hand, the distance β! .

If the length is increased to exceed 20 m, the manufacturing equipment becomes uneconomical, and there are problems such as fries occurring during manufacturing.

Overall, it was found that it is preferable to set the distances e and a'' to 3 to 20 times the pitch Q in terms of accumulating twisting.Furthermore, depending on the twisting pitch, the twisting and torsion If the distance β' and the period t are determined so that the torsional pinch of the unit 2 with the catcher 12 is 50 cm or more, a sufficiently favorable result can be obtained.

In addition, FIG. 7 shows the externally applied tension T (kg) and the optical fiber tension when the 24-core optical fiber cable illustrated in FIGS. 3 and 5 is manufactured using the manufacturing equipment shown in FIG. 1. 8 is a diagram illustrating the relationship between the amount of distortion (%) and the amount of distortion (%). The optical fiber core wire 6 has a core diameter/fiber diameter -
50/125 μm graded index type,
The outer diameter of Uniso l-2 is 4 mm, and the outer diameter of the tensile strength member 3 is 10 mm.
mm, unit 2 is entangled around tensile strength member 3 (twisting pitch R is 40cm, twisting pinch of unit 2 is 80cm)
m, and a reversal pitch Q of 120 cm was used. In the figure, the straight line indicates the manufacturing method according to the present invention,
Straight line M is when the unit is manufactured by twisting it in one direction (without reversing) with a 40cm twisting pinch (unit 2).
, the same tensile strength member 3 as in the example was used). From FIG. 7, it can be seen that when the same tension of 1'' is applied from the outside, the amount of strain on the optical fiber cable obtained by the manufacturing method of the present invention is extremely low. Therefore, the present invention has stable transmission characteristics against lightning, and especially has a small increase in optical loss before and after installation.
Accidents in which the optical fiber breaks after cable installation can be prevented, and an optical fiber cable with excellent durability can be obtained.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can of course be freely modified in various ways without changing the gist thereof.

As described in detail above, the present invention sends out a plurality of units 2 from a plurality of supply bobbin parts and gathers around one tensile strength member 3 to prevent the wire from passing in the traveling direction. Torsion catcher 12 that restrains the twisting of the wire
at a predetermined distance from the Zaburai bobbin 1 above! ``provided with ``to pass through the torsion catcher 12, and
By periodically reversing the torsion catcher 12,
-- While performing reverse twisting in which the twisting direction is reversed at predetermined intervals on the upstream side of the torsion catcher 12, the reverse twist is pressed and wound, and further, the winding device 19 is installed downstream of the torsion catcher 12 at a predetermined distance β. Since this is a manufacturing method in which the winding device 19 is provided and the winding device 19 is used,
Reverse twisting, which was previously thought to be extremely difficult or impossible due to the characteristics of optical fibers, can be achieved, and the optical fiber itself can be easily manufactured without causing surface scratches or internal stress (distortion) during manufacturing. . In addition, compared to a large cage-type twisting machine that rotates the supply bobbin section, it is only necessary to rotate the middle part of the torsion key, making the device extremely compact and economical. In addition, since the optical fibers are reversely twisted around the relatively large-diameter tensile strength member 3 as the unit 2..., there is leeway in the operating conditions of the manufacturing equipment, and excessive precision and strict setting conditions are not required. Easy to manufacture. Since the optical fiber cable manufactured in this way has almost no distortion in the fiber itself even if tension is applied from the outside, it can maintain stable performance for a long period of time after installation. The service life has also been significantly extended.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention together with a manufacturing apparatus, FIG. 2 is an explanatory diagram showing another embodiment, and FIGS. 3, 4, and 5 are illustrations of a manufacturing method according to the present invention. A cross-sectional view of a semi-finished product or a finished product shown in the order of steps, FIG. 6 is a front view representatively showing only one unit to explain the manufacturing method according to the present invention, and FIG. FIG. 3 is a diagram showing the characteristics of an optical fiber cable manufactured by such a manufacturing method. ■...Zaburi bobbin, 2...unit, 3...
Tensile strength body, 12...Torsion catcher, 19...
- Winding device, H...predetermined intervals. Patent Applicant: Dainichi Nippon Electric Cable Co., Ltd. Figure 3 (6) Figure 4 (Figure 5)

Claims (1)

[Claims] (1) A torsion catcher in which a plurality of units are sent out from a plurality of Xabry bobbins and assembled around a single tensile strength body, and which does not hinder the passage of the wire in the advancing direction but restrains the twisting of the wire. While passing through the torsion catcher provided at a predetermined distance from the Zaburai bobbin, and periodically reversing the torsion catcher to perform reversal twisting in which the twisting direction is reversed at predetermined intervals on the upstream side of the torsion catcher, A method for manufacturing an optical fiber cable, which comprises: pressing and winding the reverse twist; and further, providing a winding device at a predetermined distance downstream of the torsion catcher, and winding the cable using the winding device. 2. The method for manufacturing an optical fiber cable according to claim 1, wherein the twist pitch of the unit is 50 cm or more. 3. The method for manufacturing an optical fiber cable according to claim 1 or 2, wherein the outer diameter of the optical fiber cable is 15 mm to 80 mm, and the reverse twisting pinch is set to 10 cm to 1000 cm.