JPS62212610A - Slot type optical fiber cable and its manufacture - Google Patents

Abstract

PURPOSE:To completely eliminate the torsional strain of an optical fiber by extending a plastic member which has plural U-shaped slots along the periphery of an optical fiber unit center material so that the lengthwise direction of the slots is parallel the center axis of the optical fiber unit. CONSTITUTION:The unit center material is constituted by being provided to the periphery of a steel wire 17 as shown in figure (b). The plastic member 19 is extended longitudinally along the periphery of the center material 18 and optical fiber tapes 21a-21d are put in the slots 20 provided to the plastic member 19. Pressure winding 22 is provided to its periphery to constitute the optical fiber unit. The optical fiber unit is stranded around the cable center material composed of a tension member 23 and a tension coating 24 as shown in figure (c). Then, pressure winding 25 and a clad 26 are provided after said stranding to constitute a cable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical fiber cable constructed by storing optical fibers in slots, and a method for manufacturing the same.

(Prior art) Figure 5 shows an example of a conventional cable of this type (Japanese Unexamined Patent Publication No. 51-6
5646) is a cross section showing the structure of 1
2 is a steel wire, 2 is an optical fiber storage body, 3 is an optical fiber, 4 is a presser winder, and 5 is an outer jacket. An optical fiber housing 2 made of thermoplastic resin is formed around the steel ml. The optical fiber storage body 2 is provided with a plurality of slots for storing optical fibers, and the optical fibers 3 are loosely stored in the slots. Note that the slot is provided in a spiral shape. With the optical fiber housed in the slot, a presser winder 4 is applied, and a jacket 5 is provided around the optical fiber.

FIG. 6 shows an optical fiber cable that can be considered as an application of the optical fiber cable shown in FIG. 5, in which (a) is a sectional view of the cable, and (b) is a sectional view of an optical fiber tape.

In FIGS. 6(a) and (b), 1 is a steel wire, 2 is an optical fiber storage body, 4 is a press winding, 5 is an outer cover, 6 is a laminated optical fiber tape, 78 to 7e are optical fibers, 8 is a coating. The difference from the optical fiber cable in Figure 5 is:
As shown in FIG. 6(b), the optical fibers are bundled into a tape, and a plurality of optical fiber tapes are stacked and housed in the slot.

The characteristics of slot-type optical fiber cables represented by the above two types of optical fiber cables are as follows.

(1) Since the optical fiber 3 is loosely stored in the slot of the optical fiber housing 2 and there is a clearance between the slot and the optical fiber, external forces acting in the radial direction of the cable (for example, when laying the cable Optical fibers can be protected from the straining forces that sometimes occur. As a result, the risk of micro-bending, breaking, etc. of the optical fiber is reduced.

(2) Since the slot is provided in a spiral shape, even if the cable is bent, the extensional strain and compressive strain of the optical fiber cancel each other out, and the optical fiber strain can be reduced.

(3) The slot is provided in a spiral shape, and the optical fiber is loosely stored inside it, and there is a clearance between the slot and the optical fiber, so even when the cable is pulled, the cable does not stretch. It is not transmitted to the optical fiber, so optical fiber distortion can be reduced.

However, traditional slotted fiber optic cables
It had the following drawbacks.

(Since the 11 slots are provided in a spiral shape, when storing the optical fiber in the slot, it is necessary to rotate it while letting out the slot, or to wind the optical fiber while letting out the slot.) .This rotating or winding action does not increase the production speed of the cable.

(2) In an optical fiber cable containing an optical fiber tape, such as the optical fiber cable shown in FIG. 6(a), torsional strain occurs in the optical fiber. This will be explained in detail below.

In the optical fiber cable as shown in FIG. 5, the optical fiber 3 is housed in the slot in a "twisted" manner. The "twisted" method is a storage method in which the optical fiber 3 itself rotates when the optical fiber 3 is stored (revolutions) in the spiral slot. By storing the optical fiber with a twist, the torsional strain of the optical fiber can be reduced to zero. The opposite of this case is the method of storing without twisting. In the case of the optical fiber cable shown in FIG. 6(a), since the shape of the slot and the shape of the laminated optical fiber tapes are almost the same, the only way to store it is "without twisting". That is, when stored in the slot, the laminated optical fiber tapes 6 only revolve around the sun and do not rotate.

As a result, there is a problem in that the optical fibers 73 to 7e suffer from torsional strain.

The problem of torsional strain is a big problem, and as a solution to this problem,
A method of pre-twisting each optical fiber in an optical fiber tape was proposed (Ryozo Yamauchi et al., "Residual stress in fibers in tape-type optical cables and its reduction method", Transactions of the Institute of Electronics and Communication Engineers, J, 63-8, 8, 1980)
However, in this method, torsional strain is applied in advance to the tape state of the optical fiber, so it is difficult to say that it is a very suitable method.

Therefore, it can be said that until now, there has been no optical cable in which an optical fiber tape is housed in a slot and has a structure in which torsional strain does not occur in the optical fiber.

(Problems to be Solved by the Invention) The present invention provides a low-cost, high-density optical fiber cable and a method for manufacturing the optical fiber cable that improves the manufacturing speed of the optical fiber. There is a particular thing.

(Means for Solving the Problems) The present invention configures an optical fiber cable as an aggregate of a plurality of optical fiber units, and provides a slotted plastic cable for housing coated optical fibers that are constituent elements of the optical fiber unit. In order to provide the longitudinal direction of the slot of the member parallel to the central axis of the optical fiber unit and to realize the above structure, a plastic plate having a plurality of U-shaped slots is used.
The optical fiber unit is constructed by vertically aligning the pick member around the central member of the optical fiber unit.

The differences from conventional technology are as follows.

(1) In the conventional technology, the slot is provided in a spiral shape, but in the present invention, the slot and the central axis of the optical fiber unit are parallel to each other. (Differences in structure) (2) If the unit is manufactured with the slot and the center axis of the optical fiber unit parallel to each other, significant elongation strain will occur in the optical fiber when the optical fiber unit is wound, so this should be avoided. For this purpose, an optical fiber unit is constructed by vertically extending a plastic member having a plurality of U-shaped slots around a central member of the optical fiber unit. (Differences in structure) (3) In the conventional cable, the slot was provided in a spiral shape, so the manufacturing speed of the optical fiber unit was not improved, but in the cable of the present invention, the slot and the optical fiber unit are provided in a spiral shape. Since the central axis is parallel, the manufacturing speed of the optical fiber unit is improved. (Differences in Effects) (4) In conventional cables, since the slots are provided in a spiral shape, there was a problem of torsional strain of the optical fiber, but this problem is solved by the present invention. (Difference in effectiveness) One type of conventional cable is a cable in which a plastic tape is spirally wound around a tension member with continuous slots in the length direction, and an optical fiber is housed in the slot. Utility Model Publication No. 52-13851)
. An example is shown in FIG. In FIG. 7, 9 is a tension member, 10 is a slotted plastic member, ll
a to llf are optical fibers, 12 is a presser wrap, 13 is a slotted plastic tape, 14a to 14d are optical fibers, 15 is a presser wrap, and 16 is an outer cover.

The slotted plastic member 10 is provided with a spiral slot around its periphery, into which an optical fiber is housed. A presser wrap 12 is applied around it,
Furthermore, the slotted plastic tape 13 is placed around it.
is provided so that it can be wrapped around it. An optical fiber is housed in a spiral slot cut into a slotted plastic tape 13, and is surrounded by a presser winding 15 and a jacket 1.
6 is applied to form the cable.

The invention described in Japanese Utility Model Application Publication No. 52-13851 also does not achieve the goals of the present invention of increasing the manufacturing speed and solving the problem of torsional strain. This is because the slots are provided in a spiral shape, making it beyond the scope of conventional cables.

FIG. 1 shows an embodiment of the present invention, FIG. 1(a) is a sectional view showing the entire cable, FIG. 1(b) is a perspective view showing an optical fiber unit, and FIG. 1(c) is a sectional view showing the entire cable. It is a perspective view showing twisting of an optical fiber unit. Figure 1(a),
In (b) and (c), 17 is a steel wire, 18 is a core material, 19 is a plastic member, 20 is a slot, 21
, 21a to 21d are laminated optical fiber tapes, 2
2 is a presser winding, 23 is a tension member, 24 is a tension member cover, 25 is a presser winder, and 26 is an outer cover.

As shown in FIG. 1(b), a core material 1 is placed around the steel wire 17.
8 to constitute the unit core material. A plastic member 19 is vertically arranged around the center member 18, and optical fiber tapes 21a to 21d are housed in slots 20 provided in the plastic member 19. A presser winding 22 is applied around them to form an optical fiber unit. The optical fiber unit is shown in Figure 1 (C).
As shown in FIG. 2, the cables are twisted around a central cable consisting of a tension member 23 and a tension member sheath 24. However, in FIG. 1(C), only one slot and one optical fiber unit are depicted for simplicity, but in reality, a plurality of slots and six optical fiber units are twisted together. After twisting in this way, the first
As shown in Figure (a), the cable is constructed by applying a presser winding 25 and a jacket 26.

FIG. 2 is a perspective view of an example of a plastic member provided with slots, where 19, 27, and 28 are plastic members, and 20 is a slot. FIG. 2(a) shows a plastic plate in which a slot with a rectangular cross section is provided in the axial direction. This can be easily manufactured by extrusion. Suitable plastic materials include thermoplastics such as high-density polyethylene, low-density polyethylene, polypropylene, and nylon. Figure 2 (
In b), the plastic member is improved so that it can be easily placed vertically around the center material of the unit, and a single-shaped slit is provided on the bottom surface. FIG. 2(c) has a groove with a rectangular cross section provided on the bottom surface for the same purpose as FIG. 2(b). The plastic member shown in FIG. 2(c) can be manufactured not only by extrusion molding of plastic but also by processing a plastic film by applying heat.

The novelty of the embodiment described above using FIGS. 1 and 2 is that, as shown in FIG. 1(b), the core material 18 of the optical fiber unit, the slot 20, and the The optical fiber tapes 21a to 21d are parallel, and the plastic member 19 with slots 20 is placed lengthwise around the central member 18. By doing this, there are the following two effects.

(11 In the cable shown in this example, the optical fibers are not spirally wound around the central material of the optical fiber unit, but are parallel to each other, so the torsional strain of the optical fibers is completely zero. However, as shown in Fig. As shown in (c),
Since the optical fiber units are twisted around the cable center material, bending strain of the optical fibers occurs, but the amount of strain is extremely small.

For example, in the case of an optical fiber with an outer diameter of 125 μm, the radius of bending of the optical fiber due to unit twisting is 200 μm.
If it is **, the strain will be about 0.03%, which is no problem.

(2) In the manufacturing process of the optical fiber unit, only the slotted plastic member 19 is vertically aligned around the core material 18, so the manufacturing speed is improved. This will be explained using FIG. 3.

Although the configuration example of the present invention and its effects have been explained using FIG. 1, the form of the optical fiber need not be limited to the laminated optical fiber tape as shown above;
The effects of the present invention can be achieved with either a piece of optical fiber tape, a single optical fiber, multiple individually coated optical fibers, or the like.

FIG. 3 is an explanatory diagram of a method for manufacturing an assembly of a plastic member and an optical fiber that forms part of an optical fiber unit, and FIG. 3(a) is a conceptual diagram of the manufacturing method, and FIG. 3(b) is a sectional view taken along line A-A' in Fig. 3(a), Fig. 3(c)
is a sectional view taken along line BB' in FIG. 3(a). Third
In figures (a), (b), and (c), 20a
21a to 21e are stacked optical fiber tapes, 27 is a plastic member, 29 is a drum, 30a to 30d are bobbins, 31a to 31d are optical fiber tapes, 32 is a gathering part, 33a, 33b 34 is a winding drum that winds up the plastic member containing the optical fiber tape. A plastic member 27 with a slot 71 is fed out from the drum 29;
Optical fiber tapes 31a to 31d unwound from the bobbins 30a to 30d are stored in slots of the plastic member 27 and collected in the collecting section 32.

The tape-shaped assembly consisting of the plastic member 27 and the optical fiber tapes 31a to 31d assembled in this way is taken up by the take-up a33a and 33b and wound onto the take-up drum 34.

At the position BB', the tape-shaped assembly made of the plastic member 27 and the optical fiber tapes 31a to 31d may be pressed and wound.

FIG. 4 is an explanatory diagram of the cable core manufacturing method,
4a and 34b are winding drums 35a on which a plastic member containing an optical fiber tape is wound;

35b is a drum around which the core material of the optical fiber unit is wound;
6a and 36b are optical fiber units, 37 is a drum, 38 is a cable core material, 39 is a collection machine, 40 is a cable core, and 41 is a cable core winding drum. A plastic member housing the optical fiber tape that is unwound from the winding drums 34a and 34b, and a drum 35a.
, integrate the optical fiber unit core material fed out from 35b, apply pressure winding, and create an optical fiber unit/unit.
36a and 36b.

At this time, the plastic member housing the optical fiber tape is placed vertically so as to wrap around the core material of the optical fiber unit, without twisting the two together, and then pressure winding is performed. The part of the mechanism that applies presser winding is omitted.

Furthermore, the cable core material 38 is paid out from the drum 37.
and the optical fiber units 36a and 36b to the concentrator 39
The cable cores 40 are twisted together to form a cable core 40, and wound onto a cable core winding drum 41. When twisting the optical fiber units 36a, 36b and the cable core material 3, the winding drums 34a, 34b and the drums 35a, 35b are integrated into the cable core material 3.
Rotate around 8. A cable is completed by applying an outer sheath around the cable core manufactured as described above.

Using the manufacturing method of the present invention increases manufacturing speed. The reason for this is that, as shown in FIG. 3, the assembly of the plastic member 27 and the optical fiber tapes 31a to 31d is first constructed, but at that time there is no twisting step at all. Compared to the production speed of the twisting process, a speed three to five times faster is possible in principle. This is equivalent to being able to reduce the manufacturing cost for this part to a fraction of that.

Furthermore, a plastic member 27 as shown in FIG. 3(a)
By the method of manufacturing a tape-shaped assembly consisting of the optical fiber tapes 31a to 31d, the constituent elements of the optical fiber unit can be realized in an almost strain-free state. Torsional strain has zero validity. Since the tape-shaped assembly consisting of the plastic member 27 and the optical fiber tapes 31a to 31d is wound onto the winding drum 34, the optical fibers are bent and strain is generated, but the strain is minute. For example, assuming that the radius of the winding drum 34 is 300 mm, the diameter of the optical fiber is 0.125 mm.
As m, the bending strain is about 0.02%, and there is no problem at all.

The manufacturing process of the cable core shown in FIG. 4 is almost the same as the conventional method.

(Effects of the Invention) As explained above, if the slotted optical fiber cable and the manufacturing method thereof according to the present invention are used, the slot/nod that accommodates the optical fiber is parallel to the central axis of the optical fiber unit, so that the optical This has the advantage of increasing the manufacturing speed of the fiber unit and the ability to completely eliminate torsional strain on the optical fiber.

The advantages of conventional slotted fiber optic cables are: ■
As described in the description of the prior art, there are protection from external forces, (1) relaxation of optical fiber strain due to bending, and (2) reduction of elongation strain due to tension, but these advantages are not lost in the present invention. That is, since the optical fiber is housed in the slot, it can be protected from external forces. Since the optical fiber unit is twisted around the cable core, the elongation and compression strains of the optical fiber due to bending can cancel each other out. Furthermore, the reduction in elongation strain due to tension can be achieved in the same way as in conventional cables.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, in which (a) is a sectional view of a cable, (b) is a perspective view of an optical fiber unit, and (c) is a perspective view of an optical fiber unit.
2(a), (b), and (c) are perspective views showing an example of a plastic member with slots, and FIG. 3(a) is a perspective view showing an example of a plastic member with slots. An explanatory diagram of a method for manufacturing a tape-shaped aggregate composed of optical fibers, FIG. 3(b) is a cross-sectional view taken along line A-A' in FIG. 3(a), and FIG. ), Figure 4 is an explanatory diagram of the cable core manufacturing method, Figure 5 is a cross-sectional view showing an example of a conventional cable, and Figure 6 is another example of a conventional cable. , (a) is a cross-sectional view of the cable, (b)
is a sectional view of an optical fiber tape, and FIG. 7 is a perspective view showing the structure of another example of a conventional cable. ■...Steel wire 2...Optical fiber housing 3...Optical fiber 4...Press winder 5...
Outer covering 6...Laminated optical fiber tapes 7a to 7e...Optical fibers 8...Coating 9...
Tension member 10... plastic member with slot 11a-11
f...Optical fiber 12...Press winding 13...Slotted plastic tape 14a-1
4d...Optical fiber 15...Pressure winding 16...Sheath 17...
・Steel wire 18...Central material 19...Plastic member 20, 20a to 20e...Slot 21, 21a to 21e...Laminated optical fiber tape 22...Press winder 23...Tension member 24... Tension member covering 25... Presser winding 26... Outer covering 27, 2
8...Plastic member 29...Drum 30...Bobbin 31a
~31d...Optical fiber tape 32...Gathering part
33a, 33b... Take-up machine 34... Winding drum 35a, 35b... Drum 36a
, 36b...Optical fiber unit 37...Drum 38...Cable core material 39...Collector 40...Cable core 41...Cable core winding drum Fig. 1(a) f7.-・#1 line te--・8th grade; talented tq--・-arasura niriichi ρhonsai 20...-slot 23...Tension member. 24...Tension member) Skin a 25---Weighing section ze--External order Figure 1 (b) 2fa ~ 2fd-8! Iiiire Ei7 Fiber ° Tef 0 Fig. 2 27 Delastic part not + 2EJ Glaztic p, Fig. 3 20a~ZOe-S a7F <C) 'lfa~Zfe-... Raiku 4? Tailor 0 Figure 5 Figure 7

Claims (1)

[Claims] 1. An optical fiber cable in which a cable core is constructed by twisting a plurality of optical fiber units around a cable center member, and an outer sheath is provided around the cable core,
In this optical fiber unit, a plastic member having a plurality of U-shaped slots is vertically arranged around a linear optical fiber unit core material so as to wrap the optical fiber unit core material, and the plastic member has a plurality of U-shaped slots. The direction is parallel to the central axis of the optical fiber core, and one or more coated optical fibers are housed in the U-shaped slot, and a presser wrap is applied around the plastic member. A slot-shaped optical fiber cable characterized by: 2. At the same time that a tape-shaped plastic member having a plurality of linear U-shaped slots provided in parallel in the longitudinal direction is fed out from a drum, one or more coated optical fibers are each fed out from a plurality of bobbins. Then, the optical fibers are respectively housed in the plurality of U-shaped slots to form an assembly of optical fibers and plastic members, and this assembly is once wound onto a winding drum, and then wound from the plurality of drums. The core material of each optical fiber unit is paid out, and the winding is performed so that the core material of the optical fiber unit is wrapped around the core material of the optical fiber, and the axis of the core material of the optical fiber is parallel to the longitudinal direction of the slot. After the assembly is laid out vertically while being let out from a take-up drum, it is pressed and wound around it to form a plurality of optical fiber units, and the cable core material is let out from another drum, and the cable core material is 1. A method for manufacturing a slot-type optical fiber cable, which comprises twisting and assembling a plurality of optical fiber units around the periphery of the cable, and applying an outer sheath around the strands. 3. In the method for manufacturing a slotted optical fiber cable according to claim 2, after the assembly of optical fibers and plastic members is vertically aligned on the central material of the optical fiber unit, no pressing and winding is performed around the assembly. , instead of
A method for manufacturing a slot-shaped optical fiber cable, which comprises storing a coated optical fiber in a U-shaped slot and then pressing and winding it around a plastic member.