JPH11142702A - Optical cable and its laying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it easy to lay and wire an optical cable between a computer and relative equipment and in a panel. SOLUTION: An optical cable is provided with a spectacles type optical cord 1 in which coated optical fibers 1a are arranged in parallel, fiberous buffer materials 1b are applied on the respective coated optical fibers, a common resin 1c is applied on them and a constricted part is provided at their connection parts, a high tensile body 2 and a buffer material 3 and is made by applying a sheath 5 at its outermost periphery. When the optical cable is used for a part of interior wiring between a computer and relative equipment to be connected, the optical cable is laid in the state that the optical fibers are protected by a sheath and the buffer material and for wiring at a part where flexibility in panels of these equipment is required, the sheath and other cable constituent materials are removed from the end part of the optical cable to carry out wiring in the state of the spectacles type optical cord.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical cable for in-panel and indoor wiring used for data communication between computers or between a computer and related equipment.

[0002]

2. Description of the Related Art Conventionally, an optical cable for wiring in a panel of a computer or related equipment used for data communication or the like is made of polyethylene or the like on a plurality of optical fiber cores arranged in parallel in order to facilitate wiring. There is known an optical fiber cable (hereinafter referred to as an eyeglass-type optical cord) in which a plastic resin is coated and integrated so that the cross section becomes like an eyeglass, and a constriction is formed in a connecting portion thereof in a longitudinal direction. JP-A-52-25787).

[0003] The glasses-type optical cord is coated with a soft coating material because it is easy to bend and, if necessary, tears and separates a constricted portion between the optical fibers to separate the optical fibers. Rich in sex.

[0004]

However, although the glasses-type optical cord is suitable for wiring in a panel of a computer or related equipment, it is provided under a floor or a rack between the devices to be connected. When used for wiring to wiring routes, that is, indoor wiring, workers may step on it when laying it,
There is a drawback in that it is weak against external forces applied during the work of laying, such as being sharply bent at the corner of the device by being dragged.

[0005] In order to solve this problem, flexible glasses-type optical cords are used for wiring in panels of computers and related equipment, and a sheath strong against external force is separately provided for indoor wiring between these equipments to be connected. It is conceivable to use a coated optical cable, but this method requires the connection of an optical fiber, which increases the transmission loss at the connection, and also requires members and space to protect the connection. With disadvantages.

[0006]

SUMMARY OF THE INVENTION The present invention provides an optical cable capable of overcoming the above-mentioned problems.
That is, in the present invention, the optical fiber core wires are arranged in parallel, a fibrous cushioning material is applied on each optical fiber core wire, a common resin is applied thereon, and a glasses type light having a constriction at a connection portion thereof. A cord, a tensile member, and a cushioning material,
An optical cable characterized in that a sheath is provided on the outermost periphery.

Further, according to the present invention, the optical cable is laid in a state of an optical cable in which an optical fiber is protected by a sheath and a cushioning material when the optical cable is used in an indoor wiring section between a computer to be connected and related equipment. Wiring in a portion of the panel of the device where flexibility is required is also characterized in that the optical cable is wired in a state of a glasses-type optical cord by removing a sheath at the end of the optical cable and other cable constituent materials.

According to the present invention, it is possible to arbitrarily select and use each state of an optical cable having a sheath or an optical cable without a sheath, which is suitable for laying and wiring work in an indoor wiring and a panel of equipment, respectively. And connection between them becomes unnecessary. For this reason, work efficiency can be increased, transmission loss associated with the connection can be increased, and a space required for a connection member can be eliminated.

[0009]

FIG. 1 to FIG. 6 and Tables 1 and 2
An embodiment of the present invention will be described based on FIG. Note that the same parts are assigned the same numbers, and duplicate descriptions are omitted.

As shown in FIGS. 1 and 2, the optical cable of the present invention wraps the glasses-type optical cord 1, the tensile strength member 2 disposed near the constriction of the connecting portion of the glasses-type optical cord 1, and the like. Of the buffer material 3 arranged in such a manner, a press-wrap layer 4 wound around the outer periphery thereof, and a sheath 5 coated on the outermost periphery.

The glasses-type optical cord 1 is usually formed by coating an optical cord buffer layer 1b such as Kevlar made of aramid fiber on two optical fibers 1a and a resin layer such as polyvinyl chloride or polyethylene. Optical cord coating 1
c, and these resin-coated optical fibers are connected in the longitudinal direction. The connecting portion has a constriction in the longitudinal direction and has a glasses-like cross section. The glasses-type optical cord 1 is not limited to the one made up of two optical fibers 1a, but may be made up of two or more. In addition, a plurality of glasses-type optical cords 1
Can also be arranged.

The optical cord coating 1c, which is a resin layer of plastic or the like, divides the optical fiber by tearing a constricted portion as needed to make the glasses-shaped optical cord 1 easy to bend and to facilitate wiring in a panel. It is made of a soft resin material to make it possible. The constricted part is
They may be connected continuously in the longitudinal direction or may be connected intermittently.

The optical fiber 1a is made of quartz and has a central core and a peripheral clad, and the outermost periphery is coated with an ultraviolet curable resin.

The tensile strength member 1 has a function of resisting a tension applied to an optical cable when laying or the like.
High-strength linear bodies such as FRP and fiber bundles, and these linear bodies are coated with a resin such as polyethylene as needed.

The cushioning material 3 is a material such as a fiber bundle or a foamed plastic which can absorb the lateral pressure and protect the glasses-type optical cord, and is preferably Kevlar made of aramid fiber. The holding roll layer 4 is formed by winding a tape of polyethylene, polyvinyl chloride, or the like. The sheath 5 is formed by extruding plastic such as polyethylene or polyvinyl chloride resin using an extruder.

The optical cable is manufactured by using the glasses-type optical cord 1
In the state where the tensile strength member 2 is arranged in the vicinity of the constriction and covered with the cushioning material 3, twisting is applied to suppress an increase in transmission loss when bending stress is applied to the optical cable, and a spiral having a predetermined pitch is provided. After forming the shape, the presser winding 4 is wound around the outer periphery to form the presser winding layer 4, and the outermost periphery is covered with the sheath 5 to be completed.

The optical cable of the present invention is laid in the state of an optical cable having a sheath 5 in a portion of a floor wiring between a computer to be connected and a related device, and in a panel of the device, the sheath 5 and the like are removed to form a glasses type. The optical cord 1 is taken out and wired.

When an optical cable is laid and wired, the sheath 5 and the like are removed from the end and the glasses-type optical cord 1 is taken out. After the floor wiring between the devices is completed, the wiring in the panel is started. In the case where the length of the glasses-type optical cord 1 required for the wiring in the panel is known in advance, as shown in FIG. Alternatively, the sheath or the like at the end can be removed in advance at the stage of manufacturing the optical cable.

That is, at the stage of manufacturing the optical cable, the cable constituent materials such as the sheath and the buffer layer at the end of the optical cable are removed, and the glasses-type optical cord 1 is exposed to a length required for wiring in the panel. It is also possible to provide an optical cable that enables wiring in a panel immediately without laying the end portion after laying it at the laying place.

In the case of the optical cable in which the cable constituent material at the end is removed and the glasses-type optical cord 1 is exposed, the sheath 5 at the end of the optical cable is removed at the stage of wiring in the panel, and the glasses-type optical cord 1 is taken out. This eliminates the need for work such as tearing at the constricted part, and improves the efficiency of wiring work in the panel. In this case, if the connector 1d or the like is attached to the tip of the glasses-type optical cord 1, connection with the electric system in the panel becomes extremely easy, and the operation is further efficient. This type of optical cable is particularly effective when the working environment is poor and the working environment is poor.

When the optical cable is laid and wired, the optical cable is transported to the laying and wiring place, indexed, and the like.
Until the floor wiring is completed, the glasses-type optical cord 1 at the end must be protected.
The end portion is covered with a protective cover 6 surrounding the entire portion to be protected. The protective cover 6 is removed at the stage of panel wiring, and the glasses-type optical cord 1 can be wired.

The protective cover 6 must at least be able to physically protect the glasses-type optical cord 1 at the end of the optical cable from external force, and is preferably as compact as possible in handling.

Also, in consideration of the convenience of transporting the optical cable, handling the index, etc., the tensile strength member 2 at the end of the optical cable is not removed but is exposed together with the glasses-type optical cord 1, and the terminal is connected to the glasses-type optical cord. 1, a pulling end 6 having a hook 6b for cable indexing.
A member such as a can also be attached. In this case, FIG.
As illustrated in (b), if the strength member 2 is twisted, the flexibility is increased and the cable index and the like are further facilitated.

In this case, the cable indexing hook 6b and the pulling end 6a are members that mediate an external force applied when the optical cable is indexed and moved when the optical cable is laid or the like, and the tensile strength member 2, and are connected to the external force. Connector function. In addition, as shown in FIG. 6, the ceiling portion of the protective cover 6 can be shared with the pulling end 6a.

[0025]

Embodiment (Structure of Optical Cable) The structure of an optical cable according to this embodiment is shown in FIG. The optical cable according to the present embodiment includes a glasses-type optical cord 1 located at the center and a glasses-type optical cord 1.
Strength members 2 arranged in the vicinity of the constricted portion of the connecting portion 2
And a cushioning material 3 arranged so as to wrap them, a presser-wound layer 4 wound around the outer periphery thereof, and a sheath 5 coated on the outermost periphery.

The glasses-type optical cord 1 is formed by forming an optical cord buffer layer 1b made of Kevlar on two optical fibers 1a and forming an optical cord coating 1c made of polyvinyl chloride resin. With a diameter of 2 mm, these resin-coated optical fibers are connected in the longitudinal direction,
The connecting portion has a constriction in the longitudinal direction, and the cross section has an eyeglass-like shape.

The optical fiber 1a has a core diameter of 62.5 μm,
UV curable resin coating on cladding diameter 125 μm, outer diameter 9
The thickness was set to 00 μm.

The tensile strength member 1 is formed by coating a 0.4 mm polyethylene resin on an FRP having a diameter of 0.9 mm.

As the cushioning material 3, Kevlar made of aramid fiber was used. The holding roll layer 4 was formed by winding a polyethylene tape. The sheath 5 was formed by extruding polyethylene with an extruder.

The manufacture of the optical cable is performed by using the glasses type optical cord 1
A tensile member 2 is arranged near the constriction, and a cushioning material 3 is placed thereon.
After applying a predetermined twist to give a helical shape, the holding roll 4 is wound to form a holding winding layer 4, and the outermost periphery is covered with the sheath 5 so as to have an outer diameter of 9 mm. Completed.

(Side pressure resistant characteristics of optical cable) The optical cable protected by the sheath 5 of the present embodiment and the cable in which only the glasses-type optical cord 1 is removed from the cable 5 such as the sheath 5 and the like, are respectively evaluated for the lateral pressure resistant characteristics. It was measured.
The results are shown in Table 1 in comparison. The pressure applied as the lateral pressure is such that when the operator steps on the
Assuming that a worker weighing 2 kg presses with shoes of 50 mm width for 20 seconds, a change in transmission loss and a state of cable deformation are shown.

[0032]

[Table 1]

From Table 1, it can be seen that the transmission loss of the optical cable having the sheath 5 and the like is not increased both when the lateral pressure is applied and after the lateral pressure is released. It can be seen that the deformation of the cable is completely restored after the release of the lateral pressure, and no deformation remains.

On the other hand, for the cable in which the sheath 5 is removed and only the glasses-type optical cord 1 is in use, an increase in transmission loss is observed during the lateral pressure load. After the side pressure is released, as shown in FIG.
However, when the lateral pressure is applied to the glasses-type optical code 1 as shown in FIG. 3A, the transmission loss increases. Remains. Regarding the residual deformation after the lateral pressure is released, about 30% is recognized when the lateral pressure is applied in the vertical direction.

From the results in Table 1, it can be seen that in the state of the glasses-type optical cord 1, if a worker steps on the cable during the installation, the deformation remains and transmission loss increases. It can be seen that the optical cable provided with the polyethylene sheath 5 has no problem in both the lateral pressure resistance and the deformation resistance and is suitable for indoor wiring.

On the other hand, in the wiring stage after the optical cable is drawn into the panel of a device such as a computer, flexibility is required to facilitate the wiring. In this regard,
FIG. 2B shows the optical cable and the glasses-type optical cord 1.
The bending stiffness when bending the glasses-type optical cord 1 shown in FIG.

[0037]

[Table 2]

The bending stiffness was determined by assuming an actual wiring work in a panel, and measuring a force required to bend 180 degrees at a radius of curvature of 40 mm. From the results in Table 2, it can be seen that the optical cable having the sheath 5 has a large bending stiffness of 220 grams and a large repulsive force for returning to the original shape, so that the workability at the time of wiring is inferior. In contrast, in the state of the glasses-type optical cord 1, the weight is only 16 grams, and it is understood that the cord has sufficient softness necessary for wiring work.

As shown in FIG. 4, even in the same radius of curvature, the transmission loss is smaller in the glasses-type optical code 1 state,
The wiring of a portion having a small radius of curvature and requiring flexibility is more suitable in the state of only the glasses-type optical cord 1 in terms of transmission loss.

According to the present invention, at the stage of indoor wiring requiring the anti-lateral pressure characteristics, the sheath 5 is laid in the state of an optical cable covered with the sheath 5 and drawn into a panel such as a computer. This trade-off is solved by taking out only the glasses-type optical cord 1 and wiring it.

(Effect of Twisting Glasses-Type Optical Cord) When a bending stress or the like is applied to an optical cable to deform it, and a lateral pressure is applied to the internal glasses-type optical cord 1, transmission loss increases. In this case, the glasses-type optical cord 1 is set inside the optical cable.
If the extra length is given as a helical shape by twisting the cable, even if the optical cable is bent, it is possible to avoid the influence of the lateral pressure on the glasses-type optical cord 1 and suppress an increase in transmission loss. . FIG. 5 shows the relationship between the spiral pitch of the glasses-type optical cord 1 and the increase in transmission loss when the optical cable is bent by 180 degrees.

In an optical cable, the bending angle is generally 18
At 0 °, the lateral pressure characteristic is determined by an increase in transmission loss when a deformation is applied so that the radius of curvature becomes 10 times the cable diameter. Therefore, in FIG. 5, an optical cable in which the spiral pitch of the glasses-type optical cord 1 included therein was variously changed from 150 mm to infinity was prototyped, and for each optical cable, the radius of curvature R was 1 mm for the optical cable having a diameter of 9 mm.
Using a measuring light of 1.3 μm in a state where a deformation of 90 mm which becomes 0 times and a bending angle becomes 180 degrees is applied,
The results of measuring the maximum increase in transmission loss obtained for each optical cable having a different helical pitch are shown.

From the results shown in FIG. 5, it can be seen that the transmission loss of the optical cable having an infinite spiral pitch, ie, no twist, is the largest, and the smaller the spiral pitch, ie, the greater the degree of twist, the smaller the loss increase. Is 280m
When it is less than m, no increase in loss occurs.

The boundary condition that the pitch is 280 mm is πRmm (= 90π ≒ 28) which is a half circumference of the optical cable in a state where the radius of curvature R is 90 mm and bent in a direction of 180 degrees.
0 mm) corresponds to a state in which the helical glasses-type optical code 1 of one pitch (280 mm 2) is included. In this state, a tensile stress acts on the portion of the glasses-type optical cord 1 corresponding to the outside of the bent optical cable, and a compressive stress acts on the portions of the glasses-type optical cord 1 corresponding to the inside. Since both are just canceled, no increase in transmission loss occurs. The same applies to the case where the pitch of the glasses-type optical cord 1 is further reduced.

[0045]

According to the present invention, when used in a part of an indoor wiring between a computer and related equipment to be connected, the optical fiber with the optical fiber protected by a sheath and a cushioning material is laid and laid. Wiring in a portion of the panel where flexibility is required can be wired only with the glasses-type optical cord in which the sheath and other cable constituent materials have been removed from the optical cable.

As a result, it is possible to use cables suitable for laying and wiring work in the indoor wiring and in the equipment panel, respectively, and the connection work between them becomes unnecessary.
For this reason, the efficiency of the laying and wiring work can be increased, the increase in transmission loss due to the connection can be suppressed, and the space required for the connection member is not required. In addition, since the tensile strength of the glasses-type optical cord is about several kilograms, it is possible to increase the tensile strength of the optical cable to a level that can withstand laying by combining with a tensile strength member.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the structure of an optical cable according to the present invention.

FIG. 2 is a cross-sectional view showing the structure of another optical cable according to the present invention.

FIG. 3 is a diagram showing a load direction of lateral pressure when measuring lateral pressure characteristics.

FIG. 5 is a diagram showing the relationship between the twist pitch of the glasses-type optical cord and the maximum transmission loss.

FIG. 4 is a diagram showing the relationship between the radius of curvature of the optical cable of the present invention and the increase in transmission loss.

FIG. 6 is a perspective view showing a state in which a cable constituent material and the like at an end of the optical cable of the present invention are removed and a glasses-type optical cord is exposed.

[Explanation of symbols]

 1: Glasses type optical cord 1a: Optical fiber 1b: Optical cord buffer layer 1c: Optical cord coating 1d optical connector 2: Tensile member 3: Buffer material 4: Pressing winding 5: Sheath 6: Protective cover 6a: Pulling end for cable index 6b: hook for cable index

Claims (7)

[Claims] An optical fiber cord in which optical fiber cords are arranged in parallel, a fibrous cushioning material is applied on each optical fiber cord, a common resin is applied thereon, and a constriction is formed at a connection portion thereof. An optical cable comprising: a tensile strength member; a cushioning material; and a sheath provided on the outermost periphery. 2. The optical cable according to claim 1, wherein the glasses-type optical cord is spirally arranged in the optical cable.
Optical cable described in 3. The optical fiber according to claim 2, wherein a pitch of the spiral is not more than 10π times an outer diameter of the optical cable.
The optical cable according to the above. 4. The optical cable according to claim 1, wherein the strength member is disposed near the constriction of the glasses-type optical cord. 5. An end of the optical cable, wherein a cable constituent material excluding the glasses-type optical cord and the strength member is removed, and an optical connector is attached to a tip of the glasses-type optical cord. The optical cable according to any one of claims 1 to 4. 6. The optical cable according to claim 5, wherein a tensile end for a cable index is attached to a tip of the tensile member at an end of the optical cable. 7. A method of laying using the optical cable according to any one of claims 1 to 6.