JPH0820055A - Synthetic resin coated pipe - Google Patents

Abstract

PURPOSE:To impart high elasticity by the coating layer of a soft synthetic resin by coating the outer periphery of a pipe with a soft synthetic resin and forming cavities to the coating layer of the soft synthetic resin over the total length of the pipe so as to leave a required interval in the peripheral direction of the pipe. CONSTITUTION:A coated pipe P is obtained by coating the outer periphery of an iron pipe with a soft vinyl chloride resin and forming cavities 3 to the coating layer 2 over the total length of the pipe so as to leave a desired interval in the peripheral direction of the pipe. In place of the iron pipe 1, various pipes such as a hard synthetic resin pipe, an aluminum pipe or a bamboo can be used. The elasticity of the coating layer 2 is set to an appropriate value by compounding an appropriate amt. of a plasticizer and, in place of the vinyl chloride resin, other resin can be employed. The size and shape of the cavities 3, the number of them and the interval between them are appropriately set and no aperture is pref. provided to the inner and outer surfaces of the cavities 3. In this case, since the inner surface 2a of the coating layer 2 is in contact with the entire outer surface of iron pipe l and the outer surface shape thereof can be set to various shapes such as a flat circumferential surface or a corrugated surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin coated pipe used for handrails, fences and the like, and a manufacturing apparatus therefor.

[0002]

BACKGROUND OF THE INVENTION This type of synthetic resin coated tube uses a soft one, and further a soft foamed one, for its good touch.

On the other hand, this synthetic resin coated tube is generally
A pipe is passed through the center of a nipple of an extruder, and a synthetic resin is continuously coated on the pipe through a die during the passage (see Examples).

By the way, an electric wire, which is subjected to the same extrusion molding,
In the field of cable manufacturing, Japanese Patent Laid-Open No. 57-9501
As shown in Japanese Patent Laid-Open No. 9-214510 and Japanese Patent Laid-Open No. 3-214510, hollow coated cords (electric wires / cables) and their manufacturing apparatuses have been developed.

[0005]

In the above-mentioned soft synthetic resin-coated pipe, the elasticity of the coating depends on the elasticity and the degree of foaming of the synthetic resin itself, and the higher elasticity is imparted to improve the feel. There is a limit to Also for infants,
As a fence for people with physical disabilities, etc., there is a demand for a fence having elasticity, but there is still a limit in improving synthetic resin itself.

Under such circumstances, the first object of the present invention is to impart high elasticity to the above coating, and the second object is to provide a manufacturing apparatus for such a synthetic resin coated tube. To do.

[0007]

In order to solve the above-mentioned first problem, in the present invention, the outer circumference of the pipe is coated with a soft synthetic resin, and this coating is provided with a cavity over the entire length in the pipe length direction. That is, the synthetic resin-coated pipe has a configuration in which it is formed at required intervals in the pipe circumferential direction. In this structure, it is preferable that the cavity does not open to the inner and outer surfaces of the coating.

In order to solve the above-mentioned second problem, according to the present invention, a nipple through which a pipe passes through the center is formed in a die of an extrusion molding machine, and a required resin flow path is formed between the peripheral dies. Are disposed so that the nipple tip has a resin flow suppressing blade projecting in the resin extruding direction having a necessary gap with the land inner surface of the die at a peripheral required distance, and this resin flow suppressing blade has A ventilation hole is formed so as to penetrate in the protruding direction, and the ventilation hole is a manufacturing apparatus configured to allow air to flow in through the ventilation hole of the nipple and the nipple holder.

In the manufacturing apparatus having this structure, the resin flow suppressing blade may be arranged so as to have a required distance from the outer surface of the pipe passing through the nipple.

[0010]

In the synthetic resin-coated pipe according to the present invention having the above-described structure, due to the presence of the cavity, the coating has higher elasticity due to the elasticity of the synthetic resin itself and the expansion and contraction into the cavity. It will be soft to the touch. At this time, if the cavity is not opened on the inner and outer surfaces of the coating, the appearance is beautiful and the entire outer surface of the tube is in close contact, so that the coating is firmly attached to the tube.

Further, in the manufacturing apparatus according to the present invention, when the pipe is passed through the nipple and the soft synthetic resin is extruded between the die and the nipple, the resin is coated on the pipe as in the conventional case. Then, a synthetic resin coated tube can be obtained. At this time, the resin flow is suppressed by the resin flow suppressing blade to form a cavity in the coating, and air is introduced into the cavity from the ventilation hole to smoothly manufacture the synthetic resin coated tube with the cavity.

[0012]

EXAMPLE An example of a synthetic resin coated tube is shown in FIGS. 1 and 2, and a coated tube P of this example is such that the outer circumference of an iron tube 1 is coated with soft vinyl chloride, and the coating 2 is covered over its entire length. Thus, the cavity 3 is formed. Instead of the iron pipe 1, various types of pipes such as a hard synthetic resin pipe, an aluminum pipe, and bamboo can be used. The elasticity of the coating 2 can be set to an appropriate value by adding an appropriate amount of a plasticizer, and another resin can be used instead of vinyl chloride. The size, shape, number and spacing of the cavities 3 are appropriate.

As shown in the figure, it is preferable that the cavity 3 does not open to the inner and outer surfaces, and in this case, the inner surface 2a of the coating 2 is in contact with the entire outer surface of the iron tube 1 so that it is firmly adhered to the iron tube 1. It has been done. The outer surface shape of the coating 2 may be a flat circumferential surface, or may be a corrugated surface or other various shapes.

Next, the manufacturing apparatus for the synthetic resin-coated pipe P will be described with reference to FIGS. 3 to 6. The die 12 is mounted on the crosshead 10 of the extrusion molding machine through the die holder 11, and A nipple 14 is provided in the die 12 via a nipple holder 13,
The resin a is fed into the crosshead 10 through the strainer 16 by the screw 15, and has a sectional shape formed by the inner surface of the die 12 and the outer surface of the nipple 14,
The iron pipe 1 passing through the nipple 13 is covered.

As shown in FIG. 5, the lands 12a of the die 12 are formed by forming arcuate concave portions at equal intervals, and the outer surface shape of the coating 2 shown in FIGS. 1 and 2 is extruded by the shape of the lands 12a. To be done. At the tip of the nipple 14,
Resin flow suppressing blades 17 are provided at equal intervals around the periphery, and the blades 17 form cavities 3 in the extruded coating 2. The blade 17 can be projected from the front surface of the die 12.

A ventilation hole 18 is formed in the resin flow suppressing blade 17 in the longitudinal direction thereof, and the ventilation hole 18 communicates with the inside of the nipple 14 as shown in FIGS. 3 and 4.
And the cavity 3 through the ventilation hole 19 of the nipple holder 13.
The air flows into the inside of the cavities 3 and the cavities 3 having a sufficient bulge are smoothly formed. As shown in FIG. 3, the vent hole 18 (cavity 3) is
It is also possible to force air supply with a fan F or the like. In addition,
In the figure, 20 is a heater.

The manufacturing apparatus of this embodiment has the above-mentioned structure. When the iron pipe 1 is fed into the nipple 14 and the resin a is fed into the die 12 by the screw 15 as shown by the arrow in FIG. The resin a is extruded and coated, and the cavity 2 is formed in the coating 2 by the resin flow suppressing blades 17, and the coated pipe P shown in FIGS. 1 and 2 is manufactured.

At this time, the iron pipe 1 is fed in the crosshead 10 by the pushing force of the resin a. Therefore, if the iron pipe 1 is fed into this manufacturing apparatus, the iron pipe 1 is fed naturally thereafter. The sending is also done manually
Alternatively, the feeding device shown in FIG. 6 may be used. This feeder is
It consists of a pair of upper and lower feed rollers 30 and guide rollers 31 on both sides. By rotating the feed rollers 30, the iron pipe 1
Send out. The feed roller 30 is made of an elastic body such as rubber. The guide roller 31 may be provided on only one side. If a feeder is used, the feed rate can be adjusted and the thickness of the coating 2 can be varied.

If the iron pipe 1 is fed into the nipple 14 while rotating in the forward and reverse directions, the uneven pattern of the jacket 2 will be wavy, and if the iron pipe 1 is fed while being rotated,
The uneven pattern has a spiral shape.

[0020]

Since the cladding tube according to the present invention is constructed as described above, it has a higher elasticity than the conventional one and is comfortable to the touch.

Further, since the manufacturing apparatus according to the present invention is configured as described above, it is possible to smoothly manufacture the above-mentioned coated tube having a good feel.

[Brief description of drawings]

FIG. 1 is a partial perspective view of an embodiment of a synthetic resin coated tube.

FIG. 2 is a cut side view of the same embodiment.

FIG. 3 is a schematic sectional view of an embodiment of a manufacturing apparatus.

FIG. 4 is an enlarged sectional view of the same embodiment.

FIG. 5 is an exploded perspective view of an essential part of the embodiment.

FIG. 6 is a schematic front view of an iron pipe feeding device.

[Explanation of symbols]

 P Synthetic resin coating pipe F Fan a Resin 1 Iron pipe 2 Coating 3 Cavity 10 Crosshead 11 Dice holder 12 Dice 13 Nipple holder 14 Nipple 15 Screw 16 Strainer 17 Resin flow restraining blades 18, 19 Vent hole 20 Heater 30 Feed roller 31 Guide roller

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B32B 15/08 E E04F 11/18 // B29L 9:00 23:00

Claims (4)

[Claims] 1. A flexible synthetic resin (a) is coated on the outer circumference of the tube (1), and a cavity (3) is formed in the coating (2) over the entire length of the tube (1) in the circumferential direction of the tube (1). Synthetic resin coated tube. 2. The synthetic resin-coated pipe according to claim 1, wherein the cavity 3 is not opened on the inner and outer surfaces of the coating 2. 3. A nipple 14 through which the pipe 1 passes through the center of the die 12 of the extruder is arranged so that a required resin flow path is formed between the peripheral dies 12, and the tip of the nipple 14 is provided. Is provided with resin flow restraining blades 17 projecting in the resin extruding direction having a required clearance from the inner surface of the land 12a of the die 12 at required peripheral intervals. The resin flow restraining blades 17 have vent holes penetrating in the projecting direction. 18 is formed,
The synthetic resin coated pipe manufacturing apparatus according to claim 1, wherein air can flow into the air holes 18 through the air holes 19 of the nipple 14 and the nipple holder 13. 4. The synthetic resin-coated pipe manufacturing apparatus according to claim 3, wherein the resin flow suppressing blade 17 includes the nipple 1.
The synthetic resin-coated pipe manufacturing apparatus according to claim 2, wherein the outer surface of the pipe (1) passing through the inside of the pipe (4) also has a required space.