JPS6095509A - Manufacture of optical fiber cable - Google Patents

Abstract

PURPOSE:To manufacture an optical fiber cable which has optical fibers stored in its grooved center member with high efficiency by covering a tensile-strength wire with plastic and forming the nearly circularly sectioned center member, and embedding and assembling plural optical fibers spirally around the center member while heating the center member. CONSTITUTION:The center member 8 with a coating layer 7 formed by covering the tensile-strength wire 1 made of a stainless steel wire, etc., with plastic so that the section is nearly circular is sent out to an assembling machine by a supplying machine 10. Optical fibers 4 supplied from bobbins 12 are positioned with a scale plate 13, assembled spirally in the softened plastic coating layer 7 of the center member 8 with a mandrel 15 right after the coating layer 7 made of plastic is softened by heating the center member 8 by a heater 14, and thus embedded in the plastic coating layer 7. In this case, it is preferable that each optical fiber 4 does not project from the external surface of the coating layer 7 even a little. The whole is cooled by a cooler 16 to solidify the coating layer 7, and a presser tape is wound by a tape winding machine 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method of manufacturing an optical fiber □ cable in which optical fibers are housed in a spiral shape in a central member. □ [Prior Art] □ Conventionally, as shown in Fig. 1, plastic has a plurality of helical fall grooves 2 on its surface around a tensile strength line 1, or grooves 2 in which the direction of the spiral □ is reversed at appropriate intervals. A coating layer consisting of L is provided, and an optical fiber is stored in the groove 2.
, a pressing layer 5 and a protective layer 6 are known.

The characteristics of this type of cable are that the optical fiber 4 is movable within the groove 2, so that an elongation relaxation effect can be expected, and that the optical fiber 4 is not easily affected by external pressure.

Conventionally, in manufacturing this type of cable, first the grooved center member shown in Figure 1 is manufactured by profile extrusion using a rotary die in a process different from the process for storing the optical fiber bag [2, In this way, the optical fiber forest was housed in the center part I, which had already been grooved in the previous step, and the holding tape 5 was wrapped around it, and in some cases, the protective layer 6 was immediately provided. [7] However, if the manufacturing of the grooved base member and the step of housing the optical fiber in the grooved center member are performed in separate steps as described above, the following problems arise. Collective pitch P1 of optical fiber 4
is determined by the equipment, so there is almost no error, but
Conventionally, the pitch P2 of the grooves 2 of the grooved center member was detected while controlling the take-up speed of the grooved center member. However, with this method, as the linear speed increases, the above-mentioned control becomes difficult, so the linear speed cannot be increased very much, and furthermore, it is necessary to constantly monitor the storage condition, which causes problems in poor manufacturing efficiency.

[Purpose of the invention]

In view of the above problem, an object of the present invention is to provide a manufacturing method with high manufacturing efficiency in a method of manufacturing an optical fiber cable in which an optical fiber is housed in a grooved central member.

[Structure of the invention]

In order to achieve the above object, the method for manufacturing an optical fiber cable of the present invention is to heat a central part having a roughly circular cross section, which is made by covering a tensile strength wire with plastic, and to heat a plurality of fiber cables around the central member. The present invention is characterized in that the optical fibers are embedded and assembled in the plastic coating in a spiral manner, or while the direction of the spiral is smoothly reversed at appropriate intervals.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail with reference to the drawings.

In the present invention, as shown in FIG. 2, a central member 8 having a coating layer 7 formed by coating a tensile strength line 1 made of stainless steel wire or the like with a plastic having a roughly circular cross-section, As shown in Figure 5, the supply machine 10 collects the collection machine 1.
Send it to 1. A necessary number of optical fibers 4 are wound around a bobbin 12 and attached to the concentrator 11. The optical fiber 4 supplied from this bobbin 12 is positioned by a batten 15, and immediately after heating the above-mentioned center member 8 with a heater ill to soften the coating layer 7 made of plastic, the center member is The softened coating layer Y of 8 is assembled into a spiral shape or an inverted spiral shape by smoothly reversing the direction of the spiral at appropriate intervals.
The optical fiber 1] is embedded in the plastic coating layer 7. In this case, each optical fiber (1) is preferably completely buried in the coating layer 7 by the base 15, as shown in FIG. ~stomach.

After the optical fiber 4 is embedded in the central member 8 as shown in FIG. 4, the entire fiber is cooled by the cooler 16 and the coating layer 7 is solidified. After that, a tape winding machine 17 winds the presser tape. If the protective layer 6 is to be provided as shown in FIG. It is wound up with a winding machine 21.

By heating the central member 8 and softening the coating layer 7 in this way, the optical fiber 4 is wound around the surface layer in a spiral shape or an inverted spiral shape and buried.
There is no need for the conventional difficult control technology of making the pitch P2 of the grooves 2 of the central member and the collective pitch P1 of the optical fibers perfectly match in the longitudinal direction, and as a result, the manufacturing line speed can be increased. In addition, the monitoring work that was always required is now almost unnecessary, and manufacturing efficiency has significantly improved. <Improve. Also, when the coating layer 7 is cooled by the cooler 16, the coating layer 7 contracts slightly, creating a gap between the groove 2 and the optical fiber back in FIG. 4, and as a result, the optical fiber 1# can move. A space is created. Therefore, it also has a sufficient elongation relaxation effect, which is a characteristic of this type of cable.

〔Effect of the invention〕

As described above, the method for manufacturing an optical fiber cable of the present invention makes it possible to produce an optical fiber cable in which an optical fiber is housed in a spiral or inverted spiral in the central member, which has excellent elongation relaxation effects and is resistant to external pressure. It can be manufactured efficiently.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional optical fiber cable, FIG. 2 is a cross-sectional view of an embodiment of the central member used in the present invention, and FIG.
The figure is a schematic diagram showing an embodiment of the manufacturing apparatus according to the present invention, and FIG. 4 shows the optical fibers manufactured according to the present invention immediately after the optical fibers are collectively buried around the heated central member. FIG. 2 is a cross-sectional view of one embodiment of a cable.

Claims (1)

[Claims] While heating a central member with a roughly circular cross section, which is made by covering a tensile strength wire with plastic, a plurality of optical fibers are spirally arranged around the central member, or the direction of the spiral is smoothed at appropriate intervals. A method for manufacturing an optical fiber cable, comprising embedding and assembling optical fibers in the plastic coating while inverting the cable.