JPH0268821A - Sheath covering method for metallic wire shielded cable - Google Patents

Abstract

PURPOSE:To make it possible to continue working for a long time without causing any peeling of plating from metallic wire or requiring any cleaning of nipples by applying plastic powder on the shield of metallic wire of a cable core fed into an extruding machine, and feeding the wire into the machine for extrusion coating of plastic sheath. CONSTITUTION:A box 7 containing plastic powder is installed at an appropriate location of an extruding machine on its cable feeding side. A cable core 1 of a plated metallic wire with a braided or spirally wound shield is passed through the box 7 and then fed into the extruding machine 2 to give it a plastic sheath. If ultrasonic vibration was then given to the box 7, the plastic powder is applied more effectively. Since the procedure eliminates the peeling of plating from the metallic wire shield and the accumulation of its refuse, it makes it possible to work continuously for hours and to greatly improve the work efficiency. Furthermore, the appearance of cable itself is good and the metallic wire in the shield is free from any disorder.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a plastic sheath by extrusion over a cable core with a braided or cross-wound shield of metal wire.

(Prior art) Cables with a shield made of braided or horizontally wound metal wires are commonly used in electrical cords, but these cables are made of plastic such as polyethylene or vinyl chloride directly on the braided or horizontally wound shield. Many have a sheath. Copper wire is used as metal wire for shielding, except in special cases, and is often tin-plated or solder-plated for cable connections, terminal attachment, and other reasons. Figure 2 is a schematic diagram of the standard method of coating a plastic sheath using an extruder on a cable core with metal wire shielding as described above. be.

In the same figure, a cable core 1 with metal wire shielding is shown.
is drawn in the direction of the arrow through the nipple 3 made of hardened steel material, and the molten plastic 6 introduced from the plastic input port 4 is pushed out from the gap between the nipple 3 and the die 5 and passes through the die 5 onto the cable core 1. covered in a cylindrical shape.

(Problem to be solved by the invention) If the work continues for a long time to apply a plastic sheath to a cable core that has been shielded with plated metal wires as described above, the plating of the metal wires will be scraped off due to friction with the inner wall of the nipple. Plating slag builds up in the land of the nipple, especially in the case of solder plating, which causes eccentricity and deterioration of the appearance of the plastic sheath, and in extreme cases can lead to the cable core being severed. In order to prevent this, it is necessary to clean the nipples frequently, but especially in recent years, there is a tendency for unmanned operation and continuous operation for long periods of time, so frequent cleaning has a large negative impact on work efficiency. bring.

(Means and effects for solving the problems) The present invention has been made to solve the problems as described above, and includes applying plastic powder to the metal wire shield of the cable core fed into the extruder. The present invention provides a sheath coating method in which a plastic sheath is extrusion coated by feeding the plastic sheath.

By adopting the above sheath coating method, the plastic powder acts as a lubricant, reducing the friction between the metal wire shield of the cable core and the inner wall of the nipple, eliminating peeling of the metal wire plating and preventing the accumulation of slag. It is possible to work continuously for a long time without having to clean the nipples.

As the plastic powder, one with a small coefficient of friction such as tetrafluoroethylene resin may be used, but it is preferable to use one made of the same material as the plastic sheath, that is, polyethylene powder for a polyethylene sheath, and vinyl chloride powder for a vinyl chloride sheath. When the plus 1,700 sheath is extruded and covered, plastic powder will adhere to the sheath due to the heat during extrusion, so when the sheath is removed when connecting cables or installing terminals, no plastic powder will remain on the shield. Connection or installation work becomes easier.

(Example) FIG. 1 is a schematic diagram showing an example of the sheath covering method according to the present invention. In the same figure, 2 is an extruder similar to the conventional one, and a box 7 containing plastic powder is installed at an appropriate position on the (1) pull inlet side of the extruder 2, and a box 7 containing plated metal wire or The cable core l, which has been shielded by horizontal winding, is passed through a box 7 and fed into an extruder 2, where a plastic sheath is applied. In this case, applying ultrasonic vibration to the box 7 will more effectively apply the plastic powder.

The sheath was coated using the sheath coating method described above and the work was continued for a long time, but no abnormality was observed even after the operation was performed for a much longer time than with the conventional method. In addition, no abnormalities were observed in the electrical properties of the sheathed cable, and even when the sheath was removed and observed, no signs were found that the mechanical properties of the cable would be affected. .

(Effects of the Invention) According to the sheath coating method of the present invention, the metal wire shielding plating does not peel off and its slag does not accumulate, so it is possible to work continuously for a long time, and the work efficiency is greatly improved. It has a good appearance, and there is no disturbance in the shielding metal wires, making it possible to manufacture stable products. In addition, the lifespan of the nipple itself is also extended.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the sheath coating method according to the present invention, and FIG. 2 is a schematic diagram showing a conventional standard extrusion sheath coating method. 1: '7-7 with metal wire shielding (braided or horizontally wound)
'Lucoa, 2: Extruder, 7: Box containing plastic powder.

Claims (1)

[Claims] 1. A sheath for a metal wire shielded cable, characterized in that a manufacturing method for extrusion coating a plastic sheath on the metal wire shielding of a cable core is characterized in that plastic powder is applied onto the metal wire shielding and then the plastic sheath is extruded and coated. Coating method.