JPH08129120A - Optical cable - Google Patents

Abstract

PURPOSE: To enable easy housing a coated optical fiber ribbon into a groove for housing this coated optical fiber ribbon by forming this groove to a straight shape along the longitudinal direction of a housing member. CONSTITUTION: The coated optical fiber ribbon 3 is housed in the straight groove 2a formed on the outer peripheral surface of the housing member 2, thereby constituting an optical cable 1. A retaining tape is wound on the periphery of the housing member 2, by which a retaining winding layer 4 is formed. The periphery thereof is provided with a sheath 5. This housing member 2 consists of a long-sized round bar formed by using plastic and one piece of the straight groove 2a is formed on its outer peripheral surface, by which the member is formed to an approximately U shape in section. This straight groove 2a is formed to the straight shape along the longitudinal direction of the housing member 2 and the size thereof is properly changeable with the size of the coated optical fiber ribbon 3a housed in the straight groove 2a. Two pieces of tension members 6, 6 are inserted into the housing member 2. These tension members 6, 6 are parallel with each other and are so inserted into the member as to parallel with the straight groove 2a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical cable in which an optical fiber tape core wire is housed in a housing member, and the circumference of the housing member is covered with a sheath. The present invention relates to an optical cable capable of continuously performing a sheath forming process.

[0002]

2. Description of the Related Art FIGS. 3A and 3B show an example of a conventional optical cable. FIG. 3A is a sectional view of the optical cable and FIG. 3B is a perspective view of a slot used for the optical cable. The optical cable 11 is of a so-called slot type, and a plurality of optical fiber ribbons 14 are stacked and housed in a plurality of spiral slot grooves 13 formed on the outer peripheral surface of the slot rod 12. A tensile strength member 16 made of a twisted metal wire, a fiber reinforced plastic (FRP) rod, or the like is inserted through the center of the slot rod 12. A sheath 17 made of polyvinyl chloride or the like is provided on the circumference of the slot rod 12. As the optical fiber accommodated in the slot groove 13 of the slot rod 12, one in which a plurality of optical fiber tape core wires 14 are stacked and accommodated as shown in FIG. 3 or one in which a plurality of optical fiber element wires are twisted Is also used.

In manufacturing such an optical cable 11, first, the optical fiber ribbon 14 is housed in each slot groove 13 of the slot rod 12, and then the sheath 17 is extruded on the circumference of the slot rod 12 by extrusion coating. Form. FIG. 4 is an explanatory diagram showing a step of storing the optical fiber ribbon 14. In the figure, reference numeral 20 is a feed rod drum for the slot rod, and 21 is the optical fiber ribbon 1 in the slot groove 13.
A take-up drum for taking up the fiber unit accommodating 4 and a reference numeral 22 is an optical fiber tape core wire sending-out drum. Usually, the slot groove 13 of the slot rod 12 is formed in a spiral shape of a certain direction or a so-called SZ twisted spiral shape in which the spiral direction changes midway. This is because when the optical cable 11 is bent, the strain generated in the optical fiber tape core wire 14 housed in the slot groove 13 is reduced and the adverse effect of the bending is prevented. When the optical fiber tape core wire 14 is stored in each slot groove 13 of the slot rod 12 as described above, the slot rod 12 and the take-up drum 21 are rotated in the same direction and at the same speed, whereby the slot rod 12 is rotated. Is rotated in the circumferential direction so that the position of the opening of the slot groove 13 at any gathering position 23 between the slot rod feed drum 20 and the winding drum 21 is always constant. Then, a plurality of the optical fiber ribbons 14 are supplied from the optical fiber ribbon sending-out drum 22 to the collecting position 23, and the respective optical fiber ribbons 14 are housed in the respective slot grooves 13 here. There is.

[0004]

However, the unit in which the optical fiber tape core wire 14 is housed in the slot groove 13 of the slot rod 12 as described above is once wound on the winding drum 21. Therefore, when the sheath is formed next time, it must be taken out from the drum 21 again. In the conventional optical cable, when the optical fiber tape core wire 14 is stored, it is necessary to rotate the slot rod 12 in the circumferential direction as described above. The sheath forming process could not be performed continuously, and the number of manufacturing processes increased, resulting in poor production efficiency. The present invention has been made in view of the above circumstances, and provides an optical cable in which the optical fiber ribbon core wire can be easily housed and the optical fiber tape core wire housing step and the sheath forming step can be continuously performed. With the goal.

[0005]

In order to solve the above-mentioned problems, an optical cable of the present invention comprises a storage member having a groove for storing an optical fiber tape core wire, and an optical member stored in the groove. The fiber tape core wire and a sheath provided on the circumference of the storage member, the groove is provided linearly along the longitudinal direction of the storage member, and two parallel tensile members are provided. The storage member is inserted so as to be parallel to the groove. The optical fiber ribbon may be housed in the groove either in a state of being twisted in a certain direction or in a state of being twisted into an SZ twist shape. Alternatively, the optical fiber ribbon may be housed in the groove in a straight state along the longitudinal direction of the housing member without being twisted.

[0006]

According to the optical cable of the present invention, since the groove for accommodating the optical fiber ribbon is provided linearly along the longitudinal direction of the accommodating member, the optical fiber ribbon or SZ twisted in a fixed direction is provided. The twisted optical fiber ribbon can be easily stored in this groove. Therefore, it is possible to easily obtain an optical cable that is less affected by distortion such as bending. Further, unlike the conventional case where the tape core wire is stored in the storage member having the twisted storage groove, it is not necessary to rotate the storage member, so that the storage step and the sheath forming step can be performed continuously. it can. Further, according to the optical cable of the present invention, the two tensile members parallel to each other are inserted into the storage member so as to be parallel to the groove, so that when an external force such as bending is applied to the optical cable, The bending direction of the optical cable is defined by the strength member.
Therefore, even when the optical fiber ribbon is stored in a straight line, it is possible to avoid applying an unreasonable force in the edgewise direction of the stored optical fiber ribbon. In addition, since the direction of the opening of the groove is always fixed when the optical cable is bent, it becomes easy to store the optical fiber ribbon. Further, when branching the optical cable, a part of the sheath is peeled off and the optical fiber tape core wire in the groove is taken out. However, in the optical cable of the present invention, even when the optical cable is covered with the sheath. Since the position of the opening of the groove can be easily known, the workability in such branch connection is good.

[0007]

The present invention will be described in detail below. 1A and 1B show an embodiment of an optical cable of the present invention. FIG. 1A is a sectional view of the optical cable, and FIG. 1B is a perspective view of a storage member.
Reference numeral 1 in the figure is an optical cable. In this optical cable 1, an optical fiber ribbon 3 is housed in a linear groove 2a formed on the outer peripheral surface of a housing member 2. A holding tape is wound around the circumference of the storage member 2 to form a holding winding layer 4, and a sheath 5 is further provided on the circumference.

The storage member 2 is a long rod-like member made of plastic such as polyethylene or polypropylene, and has a straight groove 2a formed on the outer peripheral surface thereof to have a substantially U-shaped cross section. ing. The linear groove 2a is formed in a linear shape along the longitudinal direction of the housing member 2, and the size thereof is the optical fiber tape core wire 3 housed in the linear groove 2a.
Can be changed as appropriate depending on the size of. Further, the cross-sectional shape of the linear groove 2a can be appropriately changed to a concave shape other than the substantially U shape as shown in FIG. Further, two strength members 6 and 6 are inserted into the storage member 2. Tensile strength members 6 and 6 are single steel wire, twisted steel wire, various fiber reinforced plastics (FR
P), a string-shaped material made of tensile strength fiber or the like. These two strength members 6 and 6 are parallel to each other and have a linear groove 2.
It is inserted into the storage member 2 so as to be parallel to a.
In this embodiment, the tensile strength members 6 and 6 are provided near both sides of the linear groove 2a, but the positions where the tensile strength members 6 and 6 are provided can be appropriately changed as necessary.

In the linear groove 2a of the housing member 2, about 1 to 8 cores of optical fiber tape are stacked and housed in about 1 to 5 layers as needed. The laminated optical fiber tape core wire 3 is for suppressing the strain generated in the optical fiber core wire when the optical cable 1 is bent, as small as possible.
The optical cable 1 according to the present invention is accommodated in the accommodating member 2 although it is accommodated in a fixed direction or in a state of being twisted into an SZ twisted shape.
Since the tensile strength members 6 and 6 are embedded in parallel on both sides of the linear groove 2a, the bending moment in the horizontal direction with respect to the linear groove 2a is larger than the bending moment in the vertical direction. The core wire 3 may be laminated on the bottom of the linear groove 2a without being twisted. Presser winding layer 4
Is formed by winding a holding tape made of non-woven fabric, a water-absorbing tape or the like around the storage member 2. A sheath 5 made of polyethylene, polyvinyl chloride, or the like is extrusion-coated on the circumference of the press-winding layer 4.

In the optical cable 1 of this embodiment, the housing member 2 has an outer diameter of 8.0 to 9.0 mm, the linear groove 2a has an opening width of 3.0 to 4.0 mm, and a depth of 3.0 to 4. 0 mm, the outer diameter of the tensile strength wire 6 inserted in the storage member 2 is 1.0 to
The outer diameter of the optical cable 1 covered with the sheath 5 is 2.0 mm and the outer diameter is preferably 12 to 13 mm. Such an optical cable 1 can be suitably used as an optical cable for a small number of subscribers connected to a subscriber such as a general household.

When manufacturing the optical cable 1, the storage member 2 wound around the drum is pulled out, and the optical fiber tape core wire 3 wound around the drum is pulled out separately from the storage member 2.
The optical fiber tape core wire 3 is housed in the linear groove 2a of the housing member 2. Subsequently, after the pressing tape is wound around the storage member 2, the sheath 5 is formed by extrusion coating. As described above, in the optical cable 1 of the present invention, the step of accommodating the optical fiber ribbon 3 and the step of forming the sheath 5 can be continuously performed.

Here, since two parallel tensile strength members 6 and 6 are inserted into the storage member 2, as shown in FIG.
The storage member 2 can be bent only in the bending direction such that the surface including the two strength members 6 and 6 becomes the peripheral surface. That is, when the storage member 2 in this embodiment is wound around the drum, the linear groove 2a is always outside or always inside. In this way, the linear groove 2a can be wound on the drum with the openings thereof aligned in the same direction. Therefore, in the step of storing the optical fiber ribbon 3, if the storage member 2 is simply pulled out from the drum, The opening is in a fixed direction, and the optical fiber ribbon 3 can be easily accommodated in the straight groove 2a. Further, when the optical cable 1 is branched and connected, even if the optical cable 1 is covered with the sheath 5, the linear groove 2a is formed depending on the bending direction of the optical cable 1.
Since the position of the opening can be easily found, the work of peeling and removing a part of the sheath 5 and taking out the optical fiber ribbon 3 in the linear groove 2a can be easily and efficiently performed. .

[0013]

As described above, in the optical cable of the present invention, the groove for accommodating the optical fiber ribbon is provided linearly along the longitudinal direction of the accommodating member. The fiber tape core wire can be stored easily. And when storing the optical fiber tape core wire,
Since it is not necessary to rotate the storage member, the storage step and the sheath forming step can be performed continuously. Further, according to the optical cable of the present invention, the two tensile members parallel to each other are inserted into the storage member so as to be parallel to the groove, so that when an external force such as bending is applied to the optical cable, The bending direction of the optical cable is defined by the strength member. Therefore, since the optical cable bends only in a certain direction, even if the optical fiber ribbon is stored without being twisted, it is not necessary to apply an unreasonable force to the optical fiber ribbon. Furthermore, when branching the optical cable, the optical fiber ribbon inside the sheath can be easily pulled out, resulting in good work efficiency.

[Brief description of drawings]

1A and 1B show an embodiment of an optical cable of the present invention, FIG. 1A is a sectional view of the optical cable, and FIG. 1B is a perspective view of a storage member.

FIG. 2 is an explanatory view of a bending direction of a storage member according to the present invention.

FIG. 3 shows an example of a conventional optical cable,
(A) is sectional drawing, (b) is a perspective view of a slot.

FIG. 4 is an explanatory diagram of a conventional optical cable manufacturing process.

[Explanation of symbols]

1 ... Optical cable, 2 ... Storage member, 2a ... Straight groove,
3 ... Optical fiber ribbon, 5 ... Sheath, 6 ... Strength member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Suehiro Miyamoto 1440 Rokuzaki, Sakura City, Chiba Fujikura Ltd. Sakura Factory

Claims (3)

[Claims] 1. A storage member having a groove formed therein for storing an optical fiber tape core wire, an optical fiber tape core wire housed in the groove, and a sheath provided on the circumference of the storage member. In addition, the groove is provided in a straight line along the longitudinal direction of the storage member, and two tensile members parallel to each other are inserted into the storage member so as to be parallel to the groove. Characteristic optical cable. 2. The optical fiber tape core wire is housed in the groove either in a state of being twisted in a fixed direction or in a state of being twisted in an SZ twist shape. The optical cable according to claim 1. 3. The optical cable according to claim 1, wherein the optical fiber tape core wire is accommodated in the groove in a linear state along the longitudinal direction of the accommodation member without being twisted.