JPS6229212B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a corrugated pipe with a smooth inner surface from a flat tape of thermoplastic resin, and more specifically, the present invention relates to a method for manufacturing a corrugated pipe with a smooth inner surface from a flat tape of thermoplastic resin, and more specifically, it is difficult to harden by cooling when molding materials such as polyethylene and polypropylene, which have shape retention properties. The present invention relates to a method for manufacturing a corrugated pipe with a smooth inner surface made of thermoplastic resin.

Conventionally, the manufacturing method for this type of corrugated tube with a smooth inner surface involves applying internal pressure to a raw material tube extruded from an extruder's double inner and outer annular dies at a temperature above its softening point and below its melting point, and forming it into a rotating, caterpillar-shaped mold. There is a method of pressing the wall of the tube to shape it, or a method of manufacturing by spirally winding a convex appendage around a virtual cylindrical rotating shaft and polymerizing and bonding it, but the former method is extremely difficult to manufacture. There is a problem in that the device becomes large and complicated, which increases manufacturing costs.On the other hand, in the latter method, since the convex-attached band is wound spirally, cooling may be insufficient. Due to the difference in circumferential speed between the flat part and the bent convex part, the bent convex part becomes flat, and conversely, if it is hardened by forced cooling with cooling water etc., it is difficult to wind it. There were flaws.

The present invention was invented in view of the above, and
A corrugate with a smooth inner surface, in which a corrugated tube with a convex part is spirally wound to have a smooth inner surface without causing deformation of the bent convex part, thereby making it possible to continuously manufacture corrugated pipes having spiral protrusions on the outer surface. The object of the present invention is to provide a method for manufacturing a pipe.

Hereinafter, embodiments of the present invention shown in the drawings will be described, and the features thereof will be described in detail. FIG. 1 is an explanatory plan view showing the manufacturing process of the present invention.
2 is a virtual cylindrical rotating shaft body with protrusions, and 2 is a tape for forming a thermoplastic resin tape B which is wound around the circumferential surface of this virtual cylindrical rotating shaft body 1 with protrusions to form a band-like body A with protrusions. Showing dice.

The imaginary cylindrical rotating shaft body 1 with protrusions shown here consists of a set of a plurality of rolls 3a, 3b, . . . 3i, and each roll 3a, 3b, . Adjacent rolls are arranged in parallel so as to keep a constant distance between them, one end of each of which is connected to the substrate 4, and the other end of which is a bearing plate 5 that is opposite to the substrate 4.
The shafts are each rotatably supported, and the entire combination substantially constitutes one virtual cylindrical rotating shaft body 1 with protrusions.

Further, each of the rolls 3a, 3b, .

Further, in this embodiment, each of the rolls 3a, 3b,
. . . 3i is made into a hollow body, and the shaft 7 at one end thereof is also made into a hollow shaft to communicate with each other, and a water supply pipe 8 for cooling water is connected to each end of this shaft 7, and on the other hand, each roll 3
The other ends of a, 3b, . ,... 3i, the cooling water is supplied to the pipe, the sent cooling water is collected in the hollow part of the central shaft 9 through the pipe material, and the water is drained from the end of the central shaft 9. The shaft body 1 can be internally cooled.

Further, each of the rolls 3a, 3b, .
... 3i is supported by the bearing plate 5 at one end, and by shifting the bearing point of the other end, that is, each roll 3a, 3b, ...3i is aligned with the center line of the virtual cylindrical rotating shaft body 1 with protrusions. By twisting and tilting the thermoplastic resin tape B around the ridge, the thermoplastic resin tape B is wound spirally around the imaginary cylindrical rotating shaft body 1 with protrusions.

Each of the rolls 3a, 3b, . . . 3i is provided with a sprocket (not shown) at the shaft end on the substrate side, and the chain 15 running thereon moves each roll 3a, 3b, . . . 3i in the same direction. Substantially, the circumferential surface of the virtual cylindrical rotating shaft body 1 with protrusions rotates at a constant speed.

Next, 10 in the figure is a virtual cylindrical rotating shaft body 1 with protrusions.
A virtual cylindrical rotating shaft body for forming a tube C by winding the convex band-shaped body A formed above, which is made of several rolls similarly to the virtual cylindrical rotating shaft body 1 with protrusions. The rolls 11a, 11b, . . . 11i are arranged so as to maintain one virtual cylindrical shape, and their base ends are connected to the other rolls 3a, 3b, . . . 3i. These rolls 11a, 11b, . . . 11
The entire combination of i substantially forms one virtual cylindrical rotating shaft body 10.

The thermoplastic resin tape B discharged from the extruder die 2 spirals around the circumferential surface of the virtual cylindrical rotating shaft 1 with protrusions, which is configured as described above. supplied along the direction.

That is, this thermoplastic resin tape B is discharged from the die 2 of the extruder and is transferred to the virtual cylindrical rotating shaft body 1 with protrusions.
The thermoplastic resin tape B is supplied along the helical direction with an inclination angle parallel to the spiral protrusion 6 on the circumferential surface of the tape B and is continuously wound. By winding the thermoplastic resin tape B so that it does not polymerize and pressing it with a press roll 13, a bent convex portion is formed on a part of the circumferential surface of the virtual cylindrical rotating shaft body 1 with protrusions. Continuously mold the convex-attached body A having a convex part D, cool the bent convex part D in a cooling tank 16, and then form a virtual cylindrical body connected to the tip of the virtual cylindrical rotating shaft body 1 with protrusions. It is guided onto the rotating shaft body 10 and wound spirally so that the bent convex portion D of the convex band-like body A that is wound later overlaps with the flat part of the convex-attached band body A that was wound earlier. At the same time, the flat portion E that avoids the bent convex portion D is pressed by a press roll 14 that is in contact with the virtual cylindrical rotating shaft body 10, and the convex-attached strips A are welded together by pressure and are cooled and hardened. However, he was taken away.

As described above, this virtual cylindrical rotating shaft 10 is made up of a set of a plurality of rolls 11a, 11b, . . . . 11i is formed to have a larger diameter than the rolls 3a, 3b, . On the other hand, the other end is supported by an end plate 12, and the entire combination of these rolls 11a, 11b, . . . 11i substantially forms one virtual cylindrical rotating shaft body 10.
It is configured so that

The reason why the rolls 11a, 11b, . . . 11i are made larger in diameter than the rolls 3a, 3b, . In this case, in addition to increasing the diameter, adjustment can also be made by changing the angle of inclination of the band-like body A with the convex portion. Also, the above roll 3
a, 3b, ... 3i and the other end of the rolls 11a, 11
The shaft bearings connected to the base ends of the rolls 11a, 11b, . . . 11i are rotatable to allow the rolls 11a, 11b, .

The present invention has been described above with reference to the embodiments, but as is clear from the above, the present invention is a virtual tape with spiral protrusions on the outer peripheral surface of a heat-meltable thermoplastic resin tape discharged from a die of an extruder. The thermoplastic resin tape is supplied onto the cylindrical rotating shaft at an inclined angle parallel to the helical protrusion and wound in a spiral shape, and during this winding, the thermoplastic resin tape is wound with the previously wound thermoplastic resin tape. A thermoplastic resin tape is wound so as not to polymerize to form a convex band having a bent convex portion in part, and the bent convex portion is cooled and hardened, and then the convex band is formed into a virtual shape. Guided onto a cylindrical rotating shaft body, the bent convex part of the convex part attached band body wound later overlaps with the flat part of the convex part attached band body which was wound first, so that it is spirally wound; At the same time, the flat part avoiding the bent convex part is pressed by a pressure roll that is in contact with the virtual cylindrical rotating shaft body, and the convex appendages are welded together and cooled to harden, making the inner surface smooth and forming a spiral shape on the outer surface. Since the tubular body with the protrusions is manufactured continuously, the convex strip is wound spirally, but deformation due to differences in circumferential speed, such as flattening of the bent convex parts, which is conventionally seen, can occur. This makes it possible to continuously mold the initial target tube body with a smooth inner surface and spiral protrusions on the outer surface.Furthermore, the equipment can be made compact and moldability is significantly improved, making it possible to mold It also has features such as completely eliminating the high cost and inconveniences.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is an explanatory plan view showing the state of supply of the tape, Fig. 2 is a cross-sectional view of the convex-attached body which is the same member, and Fig. 3 is a manufactured example. It is a partially enlarged sectional view of a corrugated pipe cut along the axial direction.

Claims (1)

[Claims] 1. A heat-melting thermoplastic resin tape discharged from a die of an extruder is fed onto a virtual cylindrical rotating shaft with a protrusion provided with a helical protrusion on the outer peripheral surface at an inclination angle parallel to the helical protrusion. At the same time, during this winding, the thermoplastic resin tape that was wound first and the thermoplastic resin tape that was wound later are wound so that they do not overlap, and a bent convex portion is formed in a part. The bent convex portion is cooled and hardened, and then the convex band is guided onto a virtual cylindrical rotating shaft body to form a band-like body with a convex that has been wound previously. Winding the flat part in a spiral manner so that the bent convex parts of the convex-attached belt-shaped body which are later wound overlap, and at the same time pressing the flat part avoiding the bent convex parts against the virtual cylindrical rotating shaft body. A corrugate with a smooth inner surface, characterized in that a tube body having a smooth inner surface and a spiral protrusion on the outer surface is continuously produced by pressing with a roll, welding the convex strips together, and cooling and hardening them. Method of manufacturing tubes.