JP2003262742A - Optical fiber anchoring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively anchor the loose tube of the loose tube type unit of an optical cable and an optical fiber. <P>SOLUTION: Inside the pressure-resistant layer 38 of the cable coupling of the optical cable, a cylindrical anchoring disk 61 and a terminal fixing tool 63 are fixed to a base plate 62 to constitute an optical fiber anchoring apparatus 60. The base plate 62 is fixed indirectly to the pressure-resistant layer 38. A submarine optical cable 50 is inserted from a right side, the loose tube type unit 1 at a center part is guided by the center hole of a winding guide 16, wound on the outer peripheral part of the disk 61 a plurality of number of times, and thereafter inserted and held in a radial direction by the terminal fixing tool 63 to anchor the optical fiber inserted to the inside via a loose tube 1d. The anchoring force in the axial direction of the terminal fixing tool is increased by the disk 61 and opposes tension applied to the loose tube type unit from the cable 50. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber of an optical fiber cable using a loose tube type unit as a fiber unit and a device retaining device,
Particularly, it is suitable for use in a submarine cable to which a larger tension is applied than the outside.

[0002]

2. Description of the Related Art As an optical fiber unit to be installed in the center of a submarine optical cable, a tight type optical fiber unit which has been conventionally used has been replaced with a larger number of optical fiber cores in order to meet the increasing demand for communication lines. Loose tube type unit developed for the purpose of inserting is in the trend to be used.

The difference between the tight type unit and the loose tube type unit will be described with reference to FIG. As shown in the schematic cross section in FIG. 8A, a tight type optical fiber unit 80 is provided with a central tensile strength member 80b such as a steel wire in the central portion of the optical fiber unit, and several optical fibers in the peripheral portion. The fiber core wire 1a is filled and held via a urethane acrylate resin 80c, and the outer periphery is formed as a coating layer of urethane acrylate resin or the like having a certain hardness.

In the loose tube type unit 1 shown in FIG. 1B, polybutylene terephthalate (P) is formed by inserting a plurality of optical fiber core wires 1a through a jelly-like filler 1c.
It is inserted into a loose tube 1d formed of a plastic such as BT) or polypropylene (PP).
As shown in the enlarged view E of FIG. 7C, the optical fiber core wire 1a is supplied in the form of an optical fiber tape core wire 1e in which several optical fiber core wires are previously constrained in a tape shape. You can also

Next, a structural example of a submarine optical cable using a loose tube type unit will be described with reference to a perspective view of FIG. 9 and a sectional view of the cable of FIG.
In these figures, 1 is a loose-tube type optical fiber unit, 2 is a pressure resistant layer for protecting the loose-tube type unit 1 from water pressure, and a divided piece 2a made of metal such as iron and having a cross section of a sector is formed into 3 pieces. It is used by combining them vertically. A compound 7 having adhesiveness or adhesiveness is filled between the loose tube 1d and the inner surface of the pressure resistant layer 2, and the loose tube 1d is inserted through the compound 7.
I am trying to restrain you. On the outer periphery of the pressure resistant layer 2, there is a tensile strength layer 3 formed by twisting a plurality of steel wires 3a so as to sufficiently cope with the tensile force applied to the cable, and in this example, it is one layer. The compound 8 is intermittently filled in the space defined by the outer peripheral surface of the pressure resistant layer 2, the inner peripheral surface of the metal tube layer 4, and the outer peripheral surface of the tensile strength wire 3a in the longitudinal direction.

The tensile strength layer 3, which is regarded as one layer in FIG.
It is mainly composed of twisted steel wires so that it can sufficiently handle the tensile force applied to the cable. The tensile strength layer 3 has a single-layer structure or a multi-layer structure, adds a tensile strength that sufficiently withstands a load when the cable is laid, and protects the cable against a failure. Reference numeral 4 denotes a metal tube layer which maintains the binding and airtightness of the strength member layer 3 and serves as a power supply path to the repeater, which is usually made by vertically welding a metal tape made of copper or aluminum to reduce its diameter to form a tube. It was formed.
Further, 5 and 6 are insulating layers (sheaths) formed of polyethylene or the like for the purpose of insulating seawater and mechanically protecting them.

A cable having a structure different from the above is also used for the strength member layer. In the examples shown in FIG. 11 (perspective view) and FIG. 12 (cross-sectional view), the structure of the breakdown voltage layer is changed. That is, the pressure resistant layer is constructed so that the pressure resistant shell is realized on the outer circumference of the loose tube type unit 1 by the competition of the tensile strength wires twisted into two layers, which are the tensile strength wire 3a of the inner layer and the tensile strength wire 3b of the outer layer. Loose tube type unit 1
The outer peripheral surface and the tensile strength wire 3a are loose tube type unit 1
And a curved surface on the opposite side are filled with a compound 7 having adhesiveness or adhesiveness, and a pressure-resistant shell (substantially a shell having a diameter of the inner surface of the tensile strength wire 3a) is passed through the compound 7. Restrains the loose tube 1d. The metal tube layer 4 and the insulating layers 5 and 6 on the outside thereof have the same configurations as those in FIGS.

Since such a submarine optical cable is usually laid between continents or between continents and islands, a long cable is laid on the seabed via a repeater that relays a transmitted signal. Therefore, it is necessary to connect long cables to each other at multiple locations, but this type of submarine optical cable
In order to sufficiently withstand installation and recovery in the deep sea, so-called tensile strength members such as the tensile strength wires 3a and 3b constituting the pressure resistant layer 2 and the tensile strength member layer 3 are firmly fixed, and the cable is optically
It is necessary to connect electrically and mechanically.

The above-mentioned cable retaining device is attached to the terminal connecting device of the submarine optical cable. The terminal connection device is a generic name of, for example, a cable coupling (CPL), a joint box (JB), an end box (EB), and the like. A joint box, which is one type of terminal connection device, will be described with reference to FIG. FIG. 13A shows the entire appearance as a projection view, and FIG. 13B shows the inside of a broken line circle A as a cross-sectional view. Since it is necessary to make the inside of the joint box small in consideration of mechanical characteristics, handling, etc., it is required that the device for retaining the cable tensile member is also small. For example, a taper pin is press-fitted into a taper hole of an anchor disk, and a tension member (2a, 3
There is known a structure in which a and 3b) are clamped and retained (see FIGS. 2 and 14).

In the tight type, the central strength member 80b at the center of the optical fiber unit is firmly fixed (fixed) to the terminal connecting device so that the optical fiber unit is a cable terminal and the unit is not drawn into the cable. ing. FIG. 14 (a) shows a side surface of the coupling as a cross section. Between the outer peripheral surface of the taper pin 13 and the inner peripheral surface of the anchor disk 11 arranged substantially in the central portion, the tensile strength line 3 and the divided piece 3a are formed. Is clamped and held.

The optical fiber core wire 1a is inserted into the connection chamber 70 through the central holes of the taper pin 13, the flange 14 and the clamp nut 15. Further, the strength member 80b at the center of the unit shown in FIG. 8A is fixed by the retaining metal fitting 60A. The connection chamber 70
Inside, the optical fiber core wire 1a and the optical fiber 1a 'in the tail cable 90 introduced from the repeater side are respectively connected.

At the end of the optical cable, each of the strength members, the optical fiber unit and the like are thus retained by a retaining method capable of withstanding the retaining force close to the breaking strength. In the optical cable, compounds between the layers restrain the constituent members of the inner and outer optical fibers to some extent to prevent movement in the longitudinal direction. FIG. 14B schematically shows the tension acting in the axial direction of the optical cable on the minute portion ΔL near the center, which can be regarded as being sufficiently separated from the end of the optical cable. A tension TL directed to the left and a tension TR directed to the right in the figure are applied to this minute portion ΔL. When the optical cable is stationary, the tension TL and the tension TR applied to this minute portion are balanced, and the absolute values of both tensions are equal. That is, in the state where the same tension is applied to each member forming the minute portion ΔL, a slight imbalance of tension between the members does not occur in the axial direction of the members due to the restraining force of the compound or the like.

If the optical cable is cut at point A, as shown in FIG. 14 (c), the tension TR directed to the right becomes 0, so that only the tension TL is applied to the minute portion ΔL and the left portion is left. I have no choice but to move towards it. In FIG. 14 (c),
Due to this cutting, the minute portion ΔL is near the end of the cable. Therefore, at the terminal, in order to make the minute portion ΔL stand still, it is necessary to apply and hold a force equal to the tension TR, and this force constitutes the minute portion ΔL. Must be applied evenly to each member. In this way, if the retaining force applied to the optical cable terminal is not uniform among the members that make up the optical cable,
The above compound or the like cannot be restrained, and there is a high possibility that the loose tube or the optical fiber element wire will move (pull in or the like).

[0014]

Particularly when used as a submarine cable, a large tension is applied from the outside to both ends of the cable at the time of laying, repairing, recovering or the like. The tension from both sides is canceled in the part that is sufficiently inside from the end of the cable, and as described above, the loose tube and the pressure resistant layer of the cable can be adhered to each other, or a compound can be filled between the tube and the pressure resistant layer. If the pressure resistant layer restrains the loose tube, the loose tube as a whole can be kept relatively stable in the cable.

However, in the end portion of the cable, only the tension in one direction exists and the other is close to 0. Therefore, a large tension in one direction is also applied to the loose tube and the optical fiber. In particular, unless the retaining force applied to the terminal is uniform among the members constituting the optical cable, the compound cannot be restrained and the loose tube or the optical fiber element wire may move (retract or the like). That is, unless an effective retaining measure is taken for all the members constituting the cable, the loose tube or the optical fiber will be pulled into the cable. As described above, in the tight type, the central tensile member in the central portion of the optical fiber unit can be firmly retained in the terminal connecting device, but in the loose tube type unit having no central tensile member, another retaining method is required. This is a big difference between a submarine cable and a cable laid on the ground, and in general cables, the terminal was not provided with a retaining measure against such tension. It is a big problem to take effective measures for retaining loose tubes and optical fibers in the cable end, which is peculiar to this submarine cable.

[0016]

In order to solve the above problems, the present invention is installed inside a terminal connecting device for an optical cable using a loose tube type unit as an optical fiber unit. An optical fiber retaining device for retaining an optical fiber in a fiber unit, the base plate fixed to the inside of the terminal connecting device, a cylindrical retaining disc fixed to the base plate, and the retaining device. A disc, or a terminal fixture attached to a predetermined position of the base plate, the loose tube of the optical fiber unit inserted into the optical cable is wound a plurality of times on the outer peripheral surface of the columnar portion of the retaining disc, Provided is an optical fiber retaining device for clamping and retaining the end portion of the loose tube with a terminal fixing tool.

The base plate of the optical fiber retaining device is also used as a fixed portion of the terminal connecting device.
The outer diameter of the columnar portion of the retaining disk is 30 to 1
The range is 00 mm. Further, the loose tube wound around the columnar portion of the retaining disk is wound 4 to 7 times. In addition, the surface of the columnar portion of the retaining disk is rough. Also, abrasive paper is attached to the surface of the columnar portion of the retaining disk.

Further, in this optical fiber retaining device, the cross section of the center hole has an arc shape with a predetermined radius of curvature, and the winding guide whose hole diameter is gradually enlarged is separated from the retaining disk by a predetermined distance. The optical fiber unit, which is installed in the fixed portion of the terminal connecting device and is pulled out from the optical cable, is inserted into the center hole and guided to the retaining disk.

Further, the terminal fixture used in this optical fiber retaining device suppresses the repulsive force of the loose tube trying to separate from the retaining disc, and is required between the loose tube and the retaining disc. It is designed to secure and hold a long winding length. Further, the loose tube is sandwiched between the concave curved surface of the terminal fixing tool forming a part of the concave curved surface corresponding to the outer diameter of the loose tube and the columnar portion of the retaining disk. Further, the loose tube is clamped by the outer peripheral portion of the pressing piece of the terminal fixing tool and the columnar portion of the retaining disk to retain the loose tube. Also, a screw having a concave curved surface corresponding to the outer radius of the loose tube at the lower neck is used as a terminal fixing tool, and the loose tube is clamped and clamped by the concave curved surface and the columnar portion of the retaining disc. It is configured. Then, the terminal fixture is also biased in a direction in which initial tension is applied to the loose tube.

Further, the present invention is a loose tube and an optical fiber holding device for holding an optical fiber with an adhesive, which is installed inside a terminal connecting device of an optical cable using a loose tube type unit as an optical fiber unit. A device for retaining a tube and an optical fiber in an optical fiber unit, in which a loose tube adhesive tool that adheres and retains the outer circumference of a loose tube of the optical fiber unit and an optical fiber are adhered and retained by applying an adhesive. An optical fiber adhesive having a narrow groove to be fastened, and a base plate fixed to the inside of the terminal connecting device and fixed by arranging the loose tube adhesive and the optical fiber adhesive on the same straight line. A second optical fiber retaining device is provided.

The base plate of the second optical fiber holding device may also be used as a fixing portion of the terminal connecting device of the optical cable. Further, the narrow groove has a groove width and a groove depth capable of accommodating a plurality of optical fibers in an aligned manner. Also,
An arcuate chamfer is provided at the end of the narrow groove.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an optical fiber unit retaining device according to the present invention will be described with reference to FIGS.
The example applied to the cable coupling (CPL) of a terminal connection device is shown in figure, and is installed inside the pressure resistant layer 38 of the cable coupling (CPL). FIG. 1 is a perspective view in which a part of the breakdown voltage layer 38 is cut away, and the insulating layer 37 outside the breakdown voltage layer is not shown. Further, FIG. 2A shows a projected front view, and FIG. 2B shows a side view, which is a sectional view that is cut away and omitted. Although the description will be given for a submarine optical cable, the present optical fiber unit retaining device is not limited to the submarine cable and can be widely applied to general optical cables.

First, an example of a method for holding a tensile strength member of a submarine optical cable using a loose tube type unit will be described. The submarine optical cable 50 (described in FIGS. 7 to 10 and the reference numeral also follows) is drawn into the cable coupling (CPL) from the right end of the figure. The insulating layers 5 and 6 are removed, then the metal tube layer 4 is removed, and the strength members (2a, 3a, 3b) are spread and placed on the taper surface inside the anchor disk 11. Here, the anchor disk 11 is fixed to the end plate portion at the right end of the pressure resistant layer 38. The taper pin 13 is press-fitted into the taper surface inside the anchor disk 11 via the tensile strength body, and the tensile strength body is fixed to the anchor disk 11.

Then, the clamp nut 15 is coupled to the anchor disc 11 by a method (not shown) such as screwing the clamp nut 15 to the anchor disc 11, and the taper pin 13 is held via the flange 14. The tensile member of the submarine optical cable is thus firmly held, and the tension of the submarine optical cable is transmitted to the pressure resistant layer 38 via the anchor disc 11 and is connected to the left end of the cable coupling (CPL) ( (Not shown).

The loose tube type unit 1 is inserted into the holes formed in the centers of the taper pin 13, the flange 14 and the clamp nut 15, and is introduced into the pressure resistant layer 38.
The clamp nut 15 has a winding guide 16 in which the cross section of the central hole has an arc shape with an appropriate radius of curvature and the hole diameter is gradually enlarged. The loose tube type unit 1 has the same cross-sectional shape as the winding guide 16. You will be guided comfortably along. The radius of curvature of the cross section of the center hole of the winding guide 16 is made larger than a certain value so as not to affect the transmission characteristics of the optical fiber 1a in the loose tube type unit 1.

In the optical fiber unit holding apparatus of the present invention, the holding disk 61 and the terminal fixing member 63 are provided on the base plate 6.
2 is fixed to a predetermined position. The base plate 62 is fixed to the components fixed to the pressure resistant layer 38 of the cable coupling (CPL) with, for example, screws (not shown), and is indirectly fixed to the pressure resistant layer 38. For example, the anchor disk 1 (fixed to the pressure resistant layer 38)
It may be fixed at 1. It should be noted that the base plate 62 does not have to be an independent member as illustrated by its nature, and the pressure resistant layer of the terminal connecting device and the components fixed thereto may also serve as the base plate.

The retaining disk 61 has a flat columnar shape, and the outer diameter of the column does not affect the transmission characteristics of the optical fiber 1a in the loose tube type unit 1 to be wound and can be accommodated in the terminal connecting device. Limited to, for example,
The range is φ30 to φ100. Retaining disc 61
Various materials such as metal and plastic can be adopted as the material constituting the. As described above, the retaining disk 61 is fixed to the base plate 62 with its end face in contact. Although any fixing method may be used, for example, a plurality of screws may be used for fixing (illustrated in FIG. 5 (a1)).

The loose tube type unit 1 is guided by the winding guide 16 and then wound around the cylindrical portion on the outer periphery of the retaining disk 61. The number of windings is usually 4 to 7
It is supposed to be held, but it may be increased or decreased depending on the situation. After being attached to the retaining disk 61, the end portion of the loose tube type unit 1 is fixed by the end fixture 63. Although the specific structure of the terminal fixture 63 will be described later, the terminal fixture 6
The main purpose of the terminal fixture 63 is to apply a force in the radial direction of the loose-tube unit 1 by 3 to restrain the loose-tube unit 1 and indirectly retain the internal optical fiber 1a. The terminal fixture 63 may not only be fixed to the base plate 62 but also swingably supported.

The loose tube type unit 1 receives rightward tension on the cable end at the right end due to the tension applied to the tensile member and the like of the submarine optical cable, and the tension and the terminal fixture 63.
It is balanced by the binding force of. However, the loose tube type unit 1 is wound around the retaining disk 61 a plurality of times along the way, and receives the frictional force acting between the loose tube 1d and the retaining disk 61 from the retaining disk 61.
Since the frictional force exerted by the retaining disk 61 on the loose tube 1d acts as a kind of booster, this point will be described below.

Here, the operating principle of the present retaining device will be briefly described with reference to FIG. 3 in comparison with a transmission device using a pulley and a flat belt which has been conventionally known in mechanical engineering. Figure 3
(A) is a schematic view of the vicinity of a drive pulley of a belt transmission, and (b) to (e) are a projection view and a partial view schematically showing the vicinity of a retaining disk of the present invention.

In FIG. 3 (a), P is a drive-side pulley, which rotates about the axis S in the direction of arrow ω. B is a flat belt, which contacts the outer periphery of the pulley P at point a. The tension (on the pulling side) applied to the flat belt B is t1, and the flat belt B moves (as the pulley P rotates) due to the frictional force between the flat belt B and the pulley P, and the flat belt B separates from the pulley P at point b. To do. At point b, the tension t2 (on the loosening side) is applied to the flat belt B (t1> t2). The angle between a and ab where the pulley P and the belt B are in contact with each other (bracketing angle) is α (radian).

Now, the minute length ds (dα in angle) of the belt B in contact with the pulley P is taken, the tension on the loosening side is t, the tension on the tension side is t + dt, and this minute portion is received from the pulley P. Let the radial force be Q · ds and the tangential friction force be μ · Q · ds (belt B and pulley P
The friction coefficient with and μ), and the solution is obtained from the force equilibrium condition,
It is known that t1 = t2 · exp (μα). That is, the tension t1 (on the pulling side) is a product of the tension t2 (on the loosening side) and [the power of e, which is the base of the natural logarithm, to the power of (μα)]. Conversely, the tension t2 can be balanced with the force [t1] [e (.mu..alpha.) Times).

A plan view of the retaining device of the present invention is shown in FIG.
A side view is shown in FIG. The end of the loose tube type unit 1 is fixed to the left side by a terminal fixing member 63, the loose tube type unit is wound around the retaining disk 61 several times, and the right side is the cable 50 side extending to the outside of the terminal connecting device. Become. With reference to the enlarged view of the vicinity of the terminal fixing tool in FIG. 3 (e), when the terminal fixing tool restricts the outer diameter portion of the loose tube by the force of F, the optical fiber 1a is also restricted by the terminal fixing tool. .

As described above, the loose tube type unit 1 depicts one optical fiber as a representative in FIG. 3, but a plurality of optical fibers 1a are inserted into the loose tube 1d to form a jelly shape. The filling material 1c is filled in the tube to support the optical fiber. Force F exerted by the terminal fixture on the loose tube of the loose tube type unit
Is a force that reaches the optical fiber 1a through the loose tube 1d and the filler 1c and holds the optical fiber in the axial direction, like the pressure propagation of the liquid. That is, both loose tube 1d and optical fiber 1a are retained by the terminal fixture, even if the retaining force is different.

The operation of the retaining disk will be described. Figure 3
(A) and (b) are compared to compare the rotating pulley P and the non-revolving retaining disk. The loose tube corresponds to the belt B when viewed as the relationship between points X in the enlarged view (d). Similarly, at the point Y inside the loose tube type unit, the filler 1c corresponds to a pulley and the optical fiber 1a corresponds to a flat belt.

Assuming that the coefficient of friction between the filler 1c and the optical fiber 1a is μ, the number of windings n (wrap angle 2πn), and the holding force of the terminal fixing tool is T2, the tension on the cable side is T1 = T
2 · exp (2πμn). The retaining disk is used as an exponential expansion device for the retaining force T2 of the terminal fixture. In addition, the filling material 1c and the optical fiber 1a are actually used.
Not only the friction coefficient between them but also the friction coefficient between the inner surface of the loose tube 1d and the filler 1c, the slip inside the filler 1c, etc. are affected, but the above μ is regarded as the sum of them. Good.

Since the tension applied to the optical fiber 1a is difficult to measure, the retaining force of the optical fiber is estimated from the tension applied to the loose tube 1d and the behavior of the optical fiber. The optical fiber 1a of the end fixed to the loose tube type unit 1 on the cable 50 side by the terminal fixing device 63 by applying tension.
Observe the presence or absence of This is the terminal fixture 63
Loose tube 1d of exposed optical fiber 1a
Whether or not there is a displacement with respect to is measured, and the tension applied to the loose tube type unit 1d at the start of the pull-in (when the above-mentioned displacement is started) is used as the retaining force of the optical fiber.

The retaining device 60 of the present invention shown in FIGS.
FIG. 4 is a graph showing the retention performance of the optical fiber 1a according to FIG. The load at which the optical fiber 1a starts to be drawn is plotted for each number of times the unit is wound by applying a load to the cable side of the loose tube type unit 1 and winding it around a retaining disk. The scale on the vertical axis is expressed as a percentage with the breaking tension of the loose tube type unit being 100.

From the increasing tendency of the graph, it is clarified that the relationship between the number of times of rolling (n) up to four times and the holding force is an exponential function, and the relationship of T1 = T2 · exp (2πμn) is the optical fiber 1a. And the filling material 1c. If the use limit of the tension at the start of drawing is 50% of the breaking tension of the tube, it can be used with the number of rolling n = 3, but from the safety factor, 4 times to 7% showing the breaking tension of 95% or more.
It is appropriate to set the number of times as a practical range. In addition, the number of rolling 5
Indicates that the retaining force greatly exceeds the breaking tension of the loose tube. When the number of times of rolling is 5, exp (2
πμn) is a numerical value of 450 or more.

As described above, in the retaining device of the present invention, by using the retaining disk as an exponential booster, a very large magnification can be obtained with a small number of windings. It is also possible to support various loose tube type units by changing the number of times the disc is rolled. Further, various types of actual shapes of the terminal fixing device can be adopted for the purpose of exerting the force that the terminal fixing device effectively holds the optical fiber inside the loose tube type unit.

Several embodiments of the terminal fixture will be described with reference to FIG. FIG. 5 is a projection view, and the numbers at the end of the drawing numbers indicate the projection directions. That is, 1 is a cross section perpendicular to the axis of the loose tube fixed by the terminal fixing tool, and includes (a1) to (c1) the axis of the retaining disk. (A2) is projected in the same direction as FIG. 2 (b),
(D3) to (f3) show plan views similar to FIG. 2 (a). In addition, the terminal fixing tool shown in FIG. 5 is described only in a typical form which has a simple mechanical structure and can be manufactured at low cost. The type of the terminal fixing tool is shown in FIG. It is not limited to one.

As already explained, the retaining disk 61 is
Insert the mounting screw 61a into the screw hole 61b, and
2 is screwed into the screw hole 62b formed in the base plate 62
Has been fixed. Therefore, the terminal fixture may have a structure that is fixed to the retaining disk 61 or the base plate 62. The first example shown in FIGS. 5 (a1) and 5 (a2) is suitable for being formed of, for example, a metal plate having high elasticity,
One end of a substantially rectangular thin plate is bent into an arc according to the outer diameter of the loose tube to form a terminal fixture A (63a), and the other end has a screw hole for attachment. . The screw 64c is inserted into the screw hole 61c formed in the cylindrical surface of the retaining disk 61 by inserting the screw hole into the screw hole 61c, and the outer diameter portion of the retaining disk 61 and the terminal fixture A (63).
The loose tube is clamped and fixed by the arcuate part of a).

In the second example shown in FIG. 9 (b1), a drum-shaped pressing piece 63e having an appropriate elasticity is used as a terminal fixing tool, and the pipe 6 is used.
The screws 64c are screwed into and fixed to the screw holes 62c formed in the base plate 62 using 4d as a spacer. Similarly to the previous example, the loose tube 1d is held between the pressing piece 63e and the retaining disk 61. The pressing piece 63e can be made of rubber, plastic, or the like.

The third example shown by (c1) is a terminal of a loose tube wound by screwing a cap screw 63f into a screw hole 62c, which has an arc under the neck and is approximately equal to the outer diameter of the loose tube 1d. Hold the disc with the cylindrical surface. This is an example of a fixture that holds all other wound loose tubes at the same time. These three types are advantageous in terms of space because the end of the loose tube 1d can be fixed near the surface of the cylindrical portion of the retaining disk 61.

Terminal fixture B (6) shown by (d1) and (d3)
In 3b), a thin plate is bent into a cylindrical shape, holes are formed in the ears at both ends, and the loose tube 1d is sandwiched between the cylindrical parts, and is fixed to the tip end of the pillar 62a planted on the base plate 62 with screws 64c. The screw 64c serves both to attach to the column 62a and to tighten the loose tube 1d. It is possible to adjust the loose tube 1d so that it faces the tangential direction of the retaining disc 61 when tightening. As shown in the figure, after loosely packing the packing material 64e around the loose tube 1d, the loose tube 1d may be protected by being sandwiched by the inner surface of the cylindrical portion of the terminal fixture B (63b).

The examples shown in (e1) and (e3) are a terminal fixing tool C (63c) having a thick plate structure, which is suitable for being formed mainly of plastic, for example, a screw 64a and a nut 64b.
The loose tube 1d is restrained by. As shown in the figure, it is also possible to loosen the tightening of the screw 64c with respect to the pillar 62a planted in the base plate and aim at the self-centering effect.

Further, as shown in FIG. 6F, it is also possible to use a terminal fixing tool D (63d) provided with a lever portion 63g by extending the entire length of the terminal fixing tool C (63c). The screw 64c is inserted through the hole at the tip of the lever portion 63g, and is screwed into the pillar 62a planted in the base plate 62 as in the case of FIG. (E1) to rotatably support the terminal fixture C (63c). One end 64g of the tension spring 64f is fixed to the lever portion 63g, the other end 64h is fixed to the base plate 62 (not shown), so that the tension spring 64f can move the terminal fixture D (63d) in the direction of arrow d. Urge to.

In this case, the urging of the tension spring 64f causes
Since the initial load can be automatically applied to the loose tube type unit 1 by the terminal fixture D, the stability of the retaining force can be increased. It should be noted that even with a terminal fixing tool other than the terminal fixing tool C, an initial load may be applied to the loose tube type unit 1 by pulling the end of the loose tube and tightening the terminal fixing tool when fixing the loose tube type unit 1. it can.

Of the various terminal fixing tools described above, FIG.
Terminal fixture A (63a) shown in (a1) and (a2)
In the case of, it can be attached to the retaining disk 61. In this case, the base plate 62 only has a function of fixing the retaining disk 61 to a predetermined position of the terminal connecting device body. Also, in the case of other terminal fixing tools, the retaining disk 6
It is also possible to use a member corresponding to the base plate formed by extending from 1. Further, it is also possible to appropriately extend the members constituting the terminal connecting device so as to have the function of the base plate 62. Therefore, when the base plate 62 is referred to in the present specification, it also includes the case where the existence of the base plate is apparently unknown as in the above example. As mentioned above, the base plate 6
The second function serves to restrict the holding disk 61, the terminal fixing member 63, and the winding guide 16 so that they occupy predetermined positions.

As described above, the main purpose of the terminal fixing tool is to retain the internal optical fiber 1a through the loose tube 1d, but it also exerts a retaining force on the loose tube 1d. . As shown in the structure of the submarine optical cable (see, for example, FIGS. 7 and 9), the loose tube type unit 1 is fixed by a compound 7 to a tension member composed of divided pieces 2a on the outer peripheral portion and steel wires 3a and 3b. The loose tube 1d is retained and receives the tension resulting from the external force acting on the cable.

The tension applied to the loose tube 1d is also held by the terminal fixture 63 via the booster of the holding disc 61 of the main holding device 60. The magnification is also exp (2πμn), where n is already 1
Since a is a fixed value for retaining, the magnification of loose tube retaining is determined by substituting the friction coefficient between the retaining disk 61 and the loose tube 1d for μ.

If the retaining disk 61 exerts a small frictional force on the loose tube 1d and the force applied to the terminal fixing member 63 for retaining the loose tube type unit 1d becomes excessive, the retaining disk 61 and It is necessary to increase the friction coefficient between the loose tubes 1d. For this purpose, the surface of the retaining disk 61 is roughened, or an abrasive paper (or an abrasive cloth) having an appropriate grain size (about # 360 in the experiment) is used. It may be attached to the cylindrical surface of the retaining disk 61.

The loose tube retaining device using the retaining disc described above is very effective, and is a necessary measure when the tension applied to the optical cable is large, but when the optical cable is laid in the near sea or shallow water, etc. When the tension is relatively low, a retaining device that retains the loose tube and the optical fiber by adhesion is sufficiently practical.

Referring to FIGS. 6 and 7, a description will be given of an optical fiber unit retaining device 70 according to a second embodiment of the present invention, which employs a bonding method. 6A and 6B are projection views of the optical fiber unit retaining device 70, in which FIG. 6A is a plan view, FIG. 6B is a side view taken along line BB, and FIG. 6C is a CC line. Of the optical fiber adhesive 73 by
(D) has each shown the sectional view of the loose tube adhesive tool 72 by the DD line. Further, FIG. 7A shows the retaining device 70 as a perspective view, and FIG. 7B shows the both ends of the groove 73b of the optical fiber bonding tool 73 as seen in the direction of arrow A in the perspective view of the optical fiber bonding tool 73. The shape as a plan view,
(C) shows the shape of the bottom of the groove as a cross-sectional shape taken along the line BB of the plan view (b) along the center of the groove 73b.

First, a base plate 71 fixed inside a terminal connecting device such as a cable coupling (CPL) is prepared. The base plate 71 is made of, for example, a rectangular thin metal plate. The loose tube adhesive 72 is made of metal or the like, and is placed at a predetermined position on the base plate 71, for example,
It is fixed by screwing with two screws 74, 74. A groove 72a having a width and depth slightly larger than the outer diameter of the loose tube unit 1 is provided on the loose tube adhesive 72.
The loose tube unit 1 is inserted into the groove 72a, and the groove is filled with the adhesive 75 to fix and support the outer diameter portion of the loose tube 1d.

The optical fiber bonding tool 73 is made of metal or the like,
Although illustration is omitted, it is fixed to a predetermined position of the base plate 71, for example, by screwing with screws. A narrow groove 73b is formed in the longitudinal direction on the upper part of the optical fiber bonding tool 73, and the width of the narrow groove 73b is such that one or a plurality of optical fibers can be arranged, and the depth thereof is obtained by stacking a plurality of optical fibers. It is said that it can be accommodated. This narrow groove 73b
A plurality of optical fibers 1a are aligned inside, and a plurality of optical fibers 1a are further aligned on the upper stage thereof, and all the optical fibers are sequentially aligned and stacked and inserted into the narrow groove 73b.
The adhesive 75 is filled in b to fix and support the optical fiber. As shown in FIG. 6C, the adhesive 73 is provided with only a step portion, and the adhesive 73a having a slightly small thickness is used.
The groove 73b may be formed in combination by a method such as attaching sideways and tightening with screws 74.

By the way, in the plurality of optical fibers 1a taken out from the loose tube 1d, the width of the groove 73b is set to be slightly larger than the outer diameter of the optical fiber 1a, and it is necessary to align the grooves in the groove one by one. It is effective to make the holding force uniform, but when a large number of optical fibers are arranged in a row, it is radially expanded from the end of the loose tube 1d at a large angle, so The optical fiber 1a may touch and damage the optical fiber 1a. Therefore, the width and the depth of the groove 73b are set to a size capable of accommodating one or a plurality of optical fibers 1a, a plurality of the optical fibers 1a are aligned as described above, and the development angle is reduced by stacking several stages, The contact between the cut end of the loose tube 1d and the optical fiber 1a is prevented.

Similarly, when fixing the loose tube adhesive 72 and the optical fiber adhesive 73 to the predetermined position of the base plate 71, the centers of the respective grooves are along one straight line L shown in FIG. 7A. Is placed. That is, the straight line L passes through the axis of the loose tube, and the center of the aligned optical fibers coincides with the straight line L. That is, the grooves of the loose tube adhesive 72 and the optical fiber adhesive 73 are arranged on the same straight line. Also in this case, the optical fiber 1a is the loose tube 1
This is a measure to prevent the end surface of d and the edge portion of the end of the groove 73b from being touched and damaged. Further, FIG. 7B viewed from the arrow A so as not to damage the inserted optical fiber 1a.
73b formed in the optical fiber bonding tool 73 as shown in FIG.
The corners of the end of the are rounded in an arc shape, and a chamfered portion in an arc shape is provided. Further, as shown in FIG. 7C showing the BB cross section, the bottom surface of the groove 73b is similarly rounded and provided with an arcuate chamfered portion.

Thus, the groove 72a of the loose tube adhesive 72 and the groove 73b of the optical fiber adhesive 73 are arranged along one straight line L, and the groove 7 of the optical fiber adhesive 73 is arranged.
3b has a width in which a plurality of optical fibers can be arranged, and the depth is a depth capable of accommodating and stacking a plurality of optical fibers. Therefore, the optical fibers exposed from the loose tube should spread widely outward. Instead, it is fixed to the groove 73a with an adhesive, and there is no risk of being damaged by contacting the cut surface of the loose tube or the end surface of the groove 73b of the optical fiber bonding tool 73. In addition, the base plate 71 is not newly manufactured, but the loose tube adhesive 72 and the optical fiber adhesive 73 are fixed to a member constituting the terminal connecting device main body so as to be aligned,
The main body of the terminal connecting device may also serve as the base plate 71.

As an example, the loose tube adhesive 72 has a groove length of 20 mm, and the optical fiber adhesive 73 has a groove length of 100 mm. Therefore, the loose tube has an outer diameter of 20 mm, and the optical fiber is 100 m.
Bonded with a length of m. Further, the groove width of the optical fiber bonding tool 73 has a width such that 4 to 5 optical fibers can be arranged without interfering with each other and a depth sufficient to accommodate 4 to 5 rows. The loose tube adhesive 72 and the optical fiber adhesive 73 in which the loose tube and the optical fiber are actually adhered have obtained good results in the long tensile test. The curing time after the adhesive is applied is a little long, but no human monitoring is required during the curing time of the adhesive, and if the schedule can be spared, sufficient reliability can be obtained with a small number of steps, and the components are simple and workable. This is a cost-effective method because it requires less time.

Although the optical fiber unit retaining device of the present invention has been described as being arranged in the submarine optical cable and the terminal connecting device thereof, as described elsewhere, the retaining device uses a loose tube type unit. It is clear that the above optical cable can be applied to a cable that is used on land, and the installation location can be installed at any of the land connection and branch points.

Further, the structure of the terminal fixing device is not limited to a few examples, and there are many changes in the mechanical structure, and if it conforms to the basic concept, it is regarded as the same kind of idea.

[0063]

As described above, since the optical fiber unit holding device of the present invention is used by connecting the loose tube terminal to the terminal fixing tool via the holding disk which is a reliable booster. The optical fiber in the loose tube type unit can be securely retained, and at the same time, the loose tube can be retained. The end of the loose tube type unit is wound around the retaining disk and attached to the terminal fixing tool. The retaining work is completed only by mechanical work, so the work cost is reduced by shortening the work time, and no adhesive is used. Therefore, there is a merit of resource saving, there is no waiting time, the next step can be started immediately, and the total working time can be shortened. Since the shape of this retaining device is also compact, it has a great effect of being installed in the terminal connecting device of the submarine optical cable having a small internal volume.

All the components such as the retaining discs of these retaining devices have a simple shape, and the manufacturing cost required to manufacture the components can be kept low. In addition, the surface roughness of the cylindrical surface of the retaining disc can be changed to change the friction coefficient between the retaining disc and the loose tube, and the force exerted by the loose tube on the terminal fixture can be increased or decreased. You can also do Further, since various shapes of the terminal fixing tool can be selected, the terminal fixing tool having an optimal function according to the purpose of use can be adopted, which is also excellent.

The loose tube and optical fiber retaining device, in which the grooves of the loose tube retaining device and the optical fiber retaining device are arranged in a straight line and is retained by applying an adhesive, requires only simple shapes of constituent members. Since a plurality of optical fibers are arranged in parallel and a plurality of rows are overlapped with each other, it is less likely to damage the optical fibers in combination with the formation of the circular arc on the end face. In the case of adhesion, there is an effect that excellent cost performance can be obtained by basically adopting a simple member and directly saving labor without lowering reliability.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a fiber unit retaining device of the present invention.

2 is a projection view (front and plan view) of the retaining device of FIG. 1 installed in a cable coupling (CPL), which is an example of a terminal connecting device.

FIG. 3 is a diagram illustrating a retaining action by comparing a general transmission pulley and a belt.

FIG. 4 is a graph showing the optical fiber retaining performance of the fiber unit retaining device of the present invention.

FIG. 5 is a schematic diagram illustrating various terminal fixtures.

FIG. 6 is a schematic perspective view showing an example of a second fiber unit retaining device according to the present invention, which employs retaining by adhesion.

7 is a schematic diagram illustrating a case where the fiber unit retaining device of FIG. 6 is installed inside a cable coupling (CPL).

FIG. 8 is a schematic diagram illustrating the format of an optical fiber unit installed in the center of a submarine optical cable.

FIG. 9 is a perspective view showing the internal structure of a submarine optical cable.

10 is a cross-sectional view of the submarine optical cable shown in FIG. 9 perpendicular to the longitudinal direction.

FIG. 11 is a perspective view showing the internal structure of a submarine optical cable having a different configuration from that of FIG.

12 is a cross-sectional view of the submarine optical cable shown in FIG. 11, which is perpendicular to the longitudinal direction.

FIG. 13 is a projection view showing the external appearance and internal structure of a joint box (JB), which is one type of terminal connection device.

FIG. 14 is a cross-sectional projection view showing an example of a tight unit retaining method, and schematic diagrams showing tensions at the center and the end of the cable.

[Explanation of symbols]

80 tight type optical fiber unit, 80b central strength member, 1a optical fiber, 80 resin, 80d coating layer, 1 loose tube type unit, 1a optical fiber core wire, 1c compound, 1d loose tube, 1
e Optical fiber tape core wire, 2 pressure resistant layer, 2a divided piece, 3 tensile strength layer, 3a, 3b steel wire (tensile strength wire), 4
Metal tube layer, 5, 6 Insulation layer (sheath), 7, Compound (adhesive or adhesive), 8 compound (intermittent filling), 50, 50a, 50b Submarine optical cable, 10 (tensile body) retaining device, 11 Anchor disk, 11a inner taper surface, 13 taper pin, 14 flange, 15 clamp nut, 14c,
15c Through hole, 16 Winding guide, 37 Insulator, 38 Pressure resistant cylinder, 60 Optical fiber holding device, 61 Holding disk, 61a Mounting screw, 61b
Screw hole, 61c screw hole, 62 base plate, 62a
Posts, 62b, 62c, screw holes, 63 Terminal fixtures, 63
a fixture A, 63b fixture B, 63c fixture C, 6
3d fixture D, 63e pressing piece, 63f pressing screw, 63g lever part, 64a screw, 64b nut,
64c screw, 64d pipe, 64e packing material,
64f tension spring, 70 optical fiber retaining device, 71
Base plate, 72 loose tube adhesive, 72a,
Groove, 73 Optical fiber adhesive, 73a Adhesive B, 73
b narrow groove, 74 screw, 75 adhesive,

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Aquino Torres Juan Carlos             1-2-1 Shibaura, Minato-ku, Tokyo Co., Ltd.             In Ocy Sea (72) Inventor Yoshihiro Matsueda             1-2-1 Shibaura, Minato-ku, Tokyo Co., Ltd.             In Ocy Sea F-term (reference) 2H036 RA02 RA14                 2H038 CA67 CA73

Claims (16)

[Claims] 1. An optical fiber retaining device for retaining a loose tube and an optical fiber in an optical fiber unit, the optical fiber retaining device being installed inside a terminal connecting device of an optical cable using a loose tube type unit as an optical fiber unit. A base plate fixed to the inside of the terminal connecting device, a columnar retaining disk fixed to the base plate, the retaining disk, or a terminal fixing tool attached to a predetermined position of the base plate. The loose tube of the optical fiber unit inserted through the optical cable is wound around the outer peripheral surface of the columnar portion of the retaining disk a plurality of times, and the terminal portion of the loose tube is clamped and retained by the terminal fixing tool. Optical fiber retaining device. 2. The optical fiber retaining device according to claim 1, wherein the base plate is also used as a fixed portion of the terminal connecting device. 3. The outer diameter of the cylindrical portion of the retaining disk is 3
The optical fiber holding device according to claim 1, wherein the range is 0 to 100 mm. 4. The optical fiber retainer according to claim 1, wherein the loose tube wound around the columnar portion of the retainer disc is wound 4 to 7 times. 5. The optical fiber retaining device according to claim 1, wherein the surface of the cylindrical portion of the retaining disk is roughened. 6. The optical fiber retaining device according to claim 1, wherein abrasive paper is attached to the surface of the cylindrical portion of the retaining disk. 7. A winding guide having a central hole whose cross section has an arc shape having a predetermined radius of curvature and whose hole diameter is gradually enlarged is provided at the fixed portion of the terminal connecting device, which is separated from the retaining disk by a predetermined distance. The optical fiber retaining device according to claim 1, wherein an optical fiber unit installed and pulled out from an optical cable is inserted into the center hole and guided to the retaining disk. 8. The end fixture suppresses repulsive force of the loose tube tending to separate from the retaining disc, and secures a necessary winding length between the loose tube and the retaining disc to secure the loosen. The optical fiber retaining device according to claim 1, wherein the optical fiber retaining device is an optical fiber retaining device. 9. The loose tube is clamped by the concave curved surface of a terminal fixing tool forming a part of the concave curved surface corresponding to the outer diameter of the loose tube and the columnar portion of the retaining disk. Item 2. The optical fiber retaining device according to Item 1. 10. The loose tube is clamped by the outer peripheral portion of a drum-shaped pressing piece made of an elastic body, which is a terminal fixing tool, and the columnar portion of the retaining disk, and the loose tube is retained. 1. The optical fiber retaining device according to 1. 11. A screw having a concave curved surface corresponding to the outer radius of the loose tube at the lower neck is used as a terminal fixing tool, and the loose curved tube and the columnar portion of the retaining disk clamp and loosen the loose tube. The optical fiber retaining device according to claim 1, wherein: 12. The optical fiber retaining device according to claim 1, wherein the terminal fixture is biased in a direction in which initial tension is applied to the loose tube. 13. A loose tube and an optical fiber holding device for an optical fiber in an optical fiber unit, which is installed inside a terminal connecting device of an optical cable having a loose tube type unit as an optical fiber unit. A loose tube adhesive that adheres and holds the outer peripheral portion of the loose tube, an optical fiber adhesive that has a narrow groove that adheres and holds the optical fiber by applying an adhesive, and is fixed inside the terminal connection device, An optical fiber holding device, comprising: a base plate having the loose tube adhesive and the optical fiber adhesive arranged and fixed on the same straight line. 14. The optical fiber retaining device according to claim 13, wherein the base plate is also used as a fixing portion of the terminal connecting device of the optical cable. 15. The optical fiber retaining device according to claim 13, wherein the narrow groove has a groove width and a groove depth capable of accommodating a plurality of optical fibers in an aligned manner. 16. The optical fiber retaining device according to claim 13, wherein an arcuate chamfer is provided at an end of the narrow groove.