JPS623529B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a watertight electric wire manufacturing method.

Conventionally, watertight electric wires have been manufactured as shown in FIG. That is, a twisting die 2 that twists together seven strands 1 to form a strand, for example, a seven-core twisted wire.
And, on each inlet side of the twisting die 3, which twists 12 strands of wire onto a 7-core twisted wire to form an electric wire,
Tape-shaped watertight materials 4 and 5 are each supplied to the assembled strands, and a gas burner is placed on the inlet side of each die to heat it, so that the tape-shaped watertight material melts and permeates between the strands. I have to.

In the conventional method described above, the watertight material is processed into a tape shape, which may result in high costs. Also,
When processing a watertight material into a tape shape, it is difficult to make the tape thinner than a certain limit, so the thickness may become too thick relative to the amount of filling in the electric wire, and there is a risk of loss of watertight material. Further, excessive watertight material may adhere to the surface of the electric wire, causing unevenness on the surface. Furthermore, since the wire is heated by a gas burner at the inlet of the twisting die, the hard wire may be softened and its tensile strength may be reduced. Moreover, there is a possibility that the wire may change color due to heating. Furthermore, there was a drawback that it was difficult for the watertight material to enter the gaps between the strands. Furthermore, since the watertight material is supplied in the form of a tape and permeated by heating, it has been difficult to increase the working line speed.

The present invention has been made based on the above-mentioned circumstances, and provides a watertight electric wire manufacturing method that eliminates the above-mentioned conventional drawbacks.

The invention will be explained in detail below with reference to the drawings. As shown in FIG. 2, in the present invention, a twisting end die having a configuration shown in detail in FIG. 11 is provided, and the twisting shown in FIG. 3B is also applied to the twisting opening of the second wire twisting machine 13 which twists 12 strands of wire onto the seven twists 12 formed by the twisting machine 10 to form an electric wire. A die 14 is provided. Furthermore, an extruder 15 is installed above the line, and the nozzle 1 of the extruder 15
6 has a branch 16a on the inlet side of the twisting die 11 of the first twisting machine 10 and a branch 16b on the outlet side. Further, a heater 17 is attached to the nozzle 16.

The extruder 15 extrudes a watertight material such as ethylene-ethyl acrylate copolymer or ethylene vinyl acetate copolymer in a molten state, and extrudes it into each branch 1 of the nozzle.
It flows out from 6a and 16b.

The twisting dies 11 and 14 have a concave curved surface on the inlet side as shown in FIGS. 3A and 3B, and the nozzle 16
It is supplied from branches 16a, 16b of
The watertight material 18 that rides on the strands and enters the die hole is squeezed by the concave curved surface.

As described above, in the present invention, the watertight material is supplied in a molten state and is not processed once into a tape shape and supplied as in the conventional method, so that the cost increase due to tape formation can be avoided. In addition, since an appropriate amount can be supplied using an extruder, there is no loss of watertight material. Moreover, no unevenness is caused on the surface of the electric wire due to adhesion of the watertight material. Furthermore, since heating with a gas burner is not performed, there is no risk of softening of the hard wire, decrease in tensile strength, or discoloration. In addition, since the watertight material is supplied in a molten state, it can easily penetrate between the strands of wire, and the working wire speed can be increased.

Note that the present invention is not limited to the above embodiments. For example, an extruder may be installed at each twisting port of each wire twisting machine without using a branched nozzle.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional manufacturing method, FIG. 2 is a schematic diagram of an embodiment of the present invention, and FIGS. 3A and 3B are enlarged sectional views of essential parts thereof. 10, 13... wire twisting machine, 11, 14... twisting die, 12... 7 twists, 15... extruder, 16
... Nozzle, 16a, 16b ... Branch, 17 ...
Watertight material.

Claims (1)

[Claims] 1 Immediately before the twisting die of the first wire twisting machine that twists the strands to form the base of the electric wire, and the twisting die of the second wire twisting machine that twists the wires onto the above-mentioned twisting die and the base. A watertight electric wire manufacturing method characterized by supplying a watertight material in a molten state between.