JPS6237489B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for simultaneously extruding and coating the outside of a wire body such as a twisted electric wire core in multiple layers with a molten insulating material such as rubber or plastic.

As shown in FIG. 2, the cable is formed by extruding and covering multiple layers of insulating material such as rubber or plastic, and as shown in FIG. A cable 16 is known which has a structure in which a solid intervening layer 14 is provided, and a sheath (outer covering) 15 made of a second covering insulator 3 is provided on the outside thereof. As an extrusion coating method for the first covering insulating material 2 and the second covering insulating material 3, (a) a stepwise extrusion method in which the first covering insulating material 2 is first extruded and coated, and then the second covering insulating material 3 is extruded and coated; Alternatively, (b) a multilayer co-extrusion method is carried out in which the first covering insulating material 2 and the second covering insulating material 3 are extruded and coated together.

Therefore, in the case of the method (a), the first covering insulator 2 is the intervening layer 14 and the second covering insulator is the sheath 15.
Since the covering insulator 3 is not fused to the core 13, the so-called opening operation of the cable 16, in which the intervening layer 14 and the sheath 15 are removed step by step from the outside of the core 13, can be carried out smoothly. However, since the extrusion of the coated insulators 2 and 3 is carried out step by step using dedicated extrusion devices arranged in tandem, the equipment becomes large-scale, and it is difficult to operate, maintain, etc. The problem is that it makes things more complicated. On the other hand, when using the method (b) above, there arises a problem opposite to the method (a) above. That is, since the first and second coated insulators 2 and 3 are extruded simultaneously using a common extrusion device, the scale of the equipment is reduced accordingly, and operation, maintenance, etc. are also facilitated. Since the first and second coated insulators 2 and 3 are simultaneously extruded from a common extrusion head, when the cable 16 is constructed, the intervening layer 14 and the sheath 15 are fused and integrated with each other at their contact surfaces. A situation arises,
Therefore, there is a possibility that the work of pulling out the cable 16 as described above becomes extremely difficult.

The object of the present invention is to provide a multilayer coextrusion device for coated insulators that advantageously solves the above-mentioned problems, that is, eliminates both of the disadvantages found in the methods (a) and (b). It is.

Next, the present invention will be explained in detail using illustrated examples.

FIG. 1 shows an embodiment of the device according to the present invention, in which the outer periphery of the front end is formed into a tapered surface, and the center of the longitudinal direction has a stranded core 13 of an insulated conductor inserted through the wire. A core nipple 6 whose front part 10 is tapered and has a truncated conical thickness is disposed coaxially with a gap on the outside of the nipple 5 having an insertion hole 17 for running. 1, an extrusion passage 7 for the insulator 2 is defined. At least the tip side portion or the entire tip portion 10 of the core nipple 6, which has a tapered truncated conical wall thickness, is formed of a porous metal, and the tip portion 10 is formed of a porous metal so as to communicate with the porous metal portion. Core nipple 6
An extrusion passage 11 for the release agent 4 is bored in the flesh of the non-porous metal part. On the outside of the core nipple 6, a die 8 having a tapered inner wall hole 18 is coaxially arranged with a gap therebetween, and an extrusion passage 9 for the second insulator 3 is defined between them. ing.

In order to extrude and coat the intervening layer 14 and sheath 15 of the cable 16 as shown in FIG. 2 using this apparatus, the first insulator 2 and the second insulator 3 are The outer surface of the core 13 after passing through the nipple 5 through the extrusion passages 7 and 9 is simultaneously extruded and coated,
At this time, the release agent 4 as the third coating is extruded and interposed between the first insulator 2 and the second insulator 3 through the extrusion passage 11 and the tip 10 of the core nipple 6 made of porous metal. This release agent 4 is press-fitted into the tip 10 made of porous metal of the core nipple 6 in the final stage of its molten and fluid state, and is extruded so as to ooze out from the tip 10, so that Unlike the second and second insulators 2 and 3, the coating does not have a constant thickness, but instead becomes a film-like or membrane-like inclusion with almost no thickness, as if a thin coating has been applied. It serves only the essential role of preventing the intervening layer 14, which is the first covering insulator, from being fused and bonded to the sheath 15, which is the second covering insulating material.

According to the apparatus of the present invention, not only can the first and second coated insulators 2 and 3 be extruded simultaneously from a common extrusion head, but also the tip 10 of the core nipple 6 has numerous fine holes. Since it is made of a porous metal having
Therefore, the peeling agent 4 for preventing the first and second covering insulators 2 and 3 from being fused and integrated can be interposed in the form of a thin film between both the covering insulators 2 and 3. Therefore, effects such as not needlessly increasing the size (outer diameter) or weight of the product cable can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view showing one embodiment of the device according to the present invention, and FIG. 2 is a cross sectional view showing an example of a cable having a multilayer extruded coating of insulating materials such as rubber and plastic. In the figure, 1 is a filament, 2 is a first covering insulator, 3 is a second covering insulator, 4 is a release agent, 5 is a nipple, 6 is a core nipple, 7 is a first insulator extrusion passage, 8 9 is the die, 9 is the second insulator extrusion passage, 1
0 is a front part, and 11 is a release agent extrusion passage.

Claims (1)

[Claims] 1 A core nipple 6 is coaxially arranged with a gap on the outside of the nipple 5 through which the filament 1 runs, and a first insulator extrusion passage 7 is formed between the two, and the core nipple 6 A die 8 is disposed coaxially with a gap on the outside of the die 8, and a second die 8 is placed between them.
An insulator extrusion passage 9 is formed, and the front part 10 of the core nipple 6 is formed of porous metal, and a release agent is extruded into the flesh part of the core nipple 6 so as to communicate with the front part 10. A multilayer coextrusion device for coated insulators, characterized in that a passage 11 is provided.