JPS5987407A - Production of watertight optical cable unit - Google Patents

Abstract

PURPOSE:To supply resin without danger and to prevent disconnection by doubling and twisting each optical fiber core with an under layer, covering a thick diameter with thermoplastic resin having low melting point viscosity and filling the gap with the resin through a throttle mouth piece to throttle excess resin and bubbles. CONSTITUTION:A center core 1 is supplied from a supplier 7 to a twisting mouse piece 6 and an optical fiber core 2 is supplied to the mouse piece 6 to form a twisted body 9 of the under layer. The twisted body 9 is passed through a resin coating machine 10 to coat the twisted body 9 with thermoplastic resin 11 having low melting point viscosity so as to form more thick diameter than the final unit diameter, so that an optical cable unit 12' is obtained. The unit 12' is passed through a heating furnace 17 and the melted resin is passed through the throttle mouse piece 18 to replace the gap between respective cores by the resin 11 and bubbles 19 are also throttled together with the excess resin, so that the watertight cable 12 having the final unit diameter is obtained. Thus, twisting work can be attained safely without using unnecessary force.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a watertight optical cable unit suitable for use in optical submarine cables and the like.

In the conventional watertight optical cable unit, as shown in FIG. It had a structure in which the thermoplastic resin 4 was filled and coated.

The centerline 1 has a structure fC, in which a centerline coating layer IB made of soft glass or the like is provided around the outer periphery of a centerline main body IA made of piano wire or the like.

The optical fiber core wire 2 consists of a primary coating layer 2B'f of silicone or the like on the outer periphery of the optical fiber 2A, or a buffer layer as needed on the outer periphery of the optical fiber 2C. Gel filler #2D such as silicone gel,
It has a structure in which core wire coating layers 2E made of nylon or the like are sequentially provided.

Conventionally, manufacturing of such an optical cable unit 5 is as follows.
As shown in FIG. 2, a center line 1 and a plurality of optical fiber cores 2 are fed into the twisted 90 gold 6 to form a twisted body 3, and each optical fiber core is inserted in front of the twisted white gold 6. Before the wires 2 are bundled, a thermoplastic resin 4 is applied, and this resin 4 is bitten between each optical fiber core wire 2, and twisted white metal 6 is passed through it to form the structure shown in FIG. A watertight optical cable unit 5 was obtained.

However, in such a manufacturing method, resin melting means, resin supply means, etc. must be installed near the twisting cage that rotates at high speed to supply the resin.
It had some dangerous drawbacks.

Further, in such a method, there is a risk that the input fiber core wire 2 may be broken due to concentration of force at the convergence point of the twist. In order to avoid this, a certain amount of clearance is required for the hole in the twisting cap 6, but since the diameter of the twisting cap inevitably depends on the unit diameter, it is not possible to freely set the optimum clearance. There were drawbacks.

An object of the present invention is to provide a method for manufacturing a watertight optical cable unit, which allows resin to be supplied without danger and also allows for 11IJ construction while preventing optical fiber breakage.

A method for manufacturing a watertight optical cable unit according to the present invention includes twisting a plurality of optical fiber core wires on an underlayer around the outer periphery of a center line so that gaps are created between the core wires to form a twisted body; After coating the twisted underlayer with a low melt viscosity thermoplastic resin so that the diameter of the final unit becomes larger, the molten thermoplastic resin is passed through a drawing iron to remove excess resin. Squeeze, final unit)? It is characterized by finishing at ¥4-.

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

In this embodiment, as shown in FIG. 6, the center line 1 is supplied from the center line reply 7 to the twisting base 6, and each optical fiber core 2 is supplied from each core line 8 to the twist base 6. By twisting them together, a twisted underlayer body 9 as shown in FIG. 4 is formed. Twisting of the underlayer refers to twisting in such a way that the outer diameter of the center line 1 is slightly thicker than the outer diameter of each optical fiber core wire 2, and there is a gap between each optical fiber core wire (2). Let's do something.

Next, this underlayer suppression body 9 is passed through a resin coating machine 10 as shown in FIG. Thermoplasticity 1. iiJ fat 11f: 5th
It is coated as shown in the figure to obtain an optical cable unit 12'. As the resin coating machine 10, for example, as shown in FIG. 6, an extruder cross head 13 with a nozzle 14.15 set therein is used. A low melt viscosity thermoplastic resin 11 such as ethylene vinyl acetate copolymer is supplied from the crosshead 13 between the mouthpieces 14 and 15 to coat the twisted body 9 of the underlayer. Heater 1 is installed in resin coating machine 10.
6 to prevent the resin 11 from cooling down. Next, the obtained optical cable unit 12' is passed through a heating furnace 17 to melt the low melt viscosity thermoplastic resin 11, as shown in FIG. At this time, if the melt viscosity of the resin 11 is less than 1000 CI), the resin 11 will sag, which is undesirable. Next, this low melt viscosity thermoplastic resin 1
Pass the optical cable unit 12' in which 1 is in a molten state through the aperture cap 18 as shown in FIG. When the aperture cap 18 is used with a diameter of Dl, the resin 11 is forced into the gap between the optical fiber cores 2 and between the cores and between each core wire and the center line 1. The voids are replaced with the resin 11, and the air bubbles 19 are squeezed out together with the excess resin, resulting in a watertight optical cable 12 with a final unit diameter of I as shown in FIG. It is preferable to attach a heater 20 to prevent the resin 11 from cooling.The obtained watertight optical cable unit 12 is cooled by an appropriate means such as water cooling, and then passed through a take-up machine 21 and taken up while being taken up by a take-up machine 22. Wind it up.

Example Optical fiber wire 2C: Outer diameter 0.3 mm Silicone rubber coated optical fiber gel filler layer 2D: Outer diameter 1.0 mm. φ Silicone gel layer Core wire coating layer 2E; Outer diameter 1.2w1Iφ Nylon layer Center line main body IA: Outer diameter 0.4-φ Stainless steel wire center fine coating layer IB: Outer diameter 1.21rmφ As a nylon layer, the melt index is 800 ethylene acetic acid copolymer was used. The temperature of the crosshead 13 and gold 14.15 of the resin coating machine 10 was set to 140°C, and the ethylene acetic acid copolymer was extruded and coated with a melt viscosity of 40,000 cp, and the outer diameter was set to 4.0 dia. And so. The temperature of the heating furnace 17 and the temperature of the drawing nozzle 18 were set to 180°C, the melt viscosity of the ethylene acetic acid copolymer was set to 10,000 cp, the excess ethylene acetic acid copolymer was squeezed out, and the final unit diameter was 58 mm.
Finished. The temperature of the heating furnace 17 and drawing iron 18 is 180°C, so that the melting point of nylon (180°C) is not exceeded so as to avoid problems such as foaming even if the special effort of drying the nylon is omitted. It was selected so that the coalescence has a low viscosity and good bubble removal properties.

In FIG. 6, the assembly of the wires and the filling of the resin are performed in tandem, but they may be performed in separate steps.

As explained above, in the method of manufacturing the optical fiber cable unit according to the present invention, the fiber core wires of each party are twisted into an under layer around the center line, and a low melting viscosity thermoplastic resin is applied around the outer periphery to match the diameter of the final unit. It is coated with a large diameter, and then passed through a drawing nozzle and squeezed, filling with resin to avoid creating gaps and squeezing out excess resin and air bubbles, so there is no danger. Watertight optical cables can be manufactured safely.

Moreover, unnecessary force is not applied during twisting, and the twisting work can be performed without causing breakage of the optical fiber core wires.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional watertight optical cable unit, FIG. 2 is a cross-sectional view of the twisting and covering process in the conventional manufacturing method, and FIG. 5 is an example of an apparatus for carrying out the manufacturing method according to the present invention. A schematic configuration diagram, FIGS. 4 and 5 are cross-sectional views showing two states of the manufacturing process of the cable unit manufactured by the method of the present invention, and FIG. 6 is a vertical cross-sectional view of the coating process of this embodiment. Fig. 8, a cross-sectional view showing an example of a le j' history knit.
The figure is a longitudinal sectional view of the drawing process of this embodiment.

Claims (1)

[Claims] A plurality of optical fiber cores are twisted together in an underlayer around the outer periphery of the center line so that gaps are created between the core wires to form a twisted body, and this twisted body of the underlayer has a low melt viscosity. After coating the thermoplastic resin so that it is thicker than the final unit diameter, melting the thermoplastic resin,
A method for manufacturing a watertight optical cable unit, which comprises passing the resin through a squeezing metal to squeeze out excess resin and finishing the unit to the final diameter.