JPS60199529A - Manufacture of corrugated tube having flat inner surface - Google Patents

Abstract

PURPOSE:To form a prescribed corrugated tube by arranging the 1st imaginary cylindrically-arranged projection-forming rotating body and the 2nd imaginary cylindrically-arranged flat-surface rotating body closely to each other on the same axis, and supplying melted-out thermoplastic-resin tapes to the outer circumferences of respective rotating bodies, to press-form into a titled tube. CONSTITUTION:The 1st imaginary cylindricall-arranged rotating body 1 is formed by fitting one of plural axes 8 which have spiral projections 18 respectively and are beared by bearings 9, 10, 21 supported by bearing plates 7, 19 connected to a fixed bearing plate 5 by a hollow base-axis 6, to an axis 23 having a spiral projection 24, to rotate the axes 8 respectively by a motor 13 through belts 15, 17. Further, the 2nd imaginary cylindrically-arranged rotating body 2 is formed by plural flat rolls 20. A thermoplastic resin tape A melted out of a die 3 is bonded with a preceding tape into a cylindrical form while being formed into a projection by rolls 8a, 23, and is sent out in sequence. A tape B melted out of a die 4 is bonded with the previously melted-out tape A together with the preceding tape B by rolls 20. Accordingly, a corrugated tube having flat inner surface is well manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuously manufacturing a corrugated pipe having a spirally uneven outer surface and a smooth inner surface from a flat thermoplastic resin tape. An effective manufacturing method for corrugated pipes molded from thermoplastic resins such as polyethylene and polypropylene, which are difficult to cool and harden and have poor shape retention when molded, especially corrugated pipes with an uneven outer surface and a smooth inner surface. Conventionally, as a manufacturing method for this type of corrugated pipe with a smooth inner surface, a raw material cheese extruded from an extruder with double inner and outer annular dies is used.
9. Apply internal pressure to the tube at a temperature above its softening point and below its melting point and place it in a caterpillar-shaped rotating formwork. There are known methods such as pressing the surface to form the shape, or spirally winding a band-shaped body with convex parts around a virtual cylindrical rotating shaft body, polymerizing and bonding it, and molding it into a tube. In this case, there is a problem in that the device becomes extremely large and complicated, which increases the manufacturing cost.On the other hand, in the latter method, since the belt-shaped body with convex portions is wound helically around the circumferential surface of the rotating shaft, If the cooling is insufficient, the bent part will become flattened due to the difference in the curvature ratio between the flat part and the bent part, and conversely, if the part is forcedly cooled with cooling water etc., it will harden. This not only makes winding difficult, but also makes it difficult to fuse the strips together, making it impossible to form a tube.

The present invention has been researched and developed in view of the various drawbacks of the conventional manufacturing methods described above, and consists of a thermoplastic resin tape in a heated molten state discharged from a die of one extruder, and a spiral protrusion formed on the circumferential surface. The outer tube is wound in a helical direction around the circumferential surface of a rotary shaft body that is forcibly rotated to form an outer tube with an uneven cross section, while the heated and molten resin tape discharged from the other die is wound to make the circumferential surface smooth. An inner tube with a smooth circumferential surface is formed by winding it around the circumferential surface of the rotating shaft body, and the inner tube and the outer tube are overlapped on the inside and outside and pressed and fused using the molten state of the material. An object of the present invention is to provide an extremely efficient manufacturing method capable of continuously manufacturing a corrugated pipe whose outer circumferential surface has an uneven surface with spiral protrusions running through it, while its inner circumferential surface has a smooth surface. .

Hereinafter, the fully illustrated embodiments of the present invention will be explained, and II.
? To explain in detail, Fig. 1 is a partially cross-sectional front view of the main parts of the manufacturing equipment, Fig. 2 is a left side view of the above figure, and Fig. 3 is a corrugated pipe with a smooth inner surface produced by the equipment. 7i - A partially cutaway front view illustrating the manufacturing process, and FIG. 4 is a right side view of the above figure partially cut away.

In the drawings (IC), reference numeral 1 indicates a first rotating shaft, and 2 indicates a second rotating shaft provided continuously at the tip of the first rotating shaft.
In the body, 3 is an outside die for discharging and molding the thermoplastic resin Dezo A, which is placed opposite to the outer peripheral surface of the first rotating shaft body 1, and 4 is installed near the axial center of the second rotating shaft body. fever 0
This is an inside die for molding T plastic resin tape Bi.

The first rotary transport body 1 includes a base-end bearing plate 5 vertically erected on a table (not shown), a base shaft 6 made of a metal pipe that extends horizontally through the base-end bearing plate 5, and a base shaft 6 made of a metal pipe that extends horizontally through the base-end bearing plate 5, and a base shaft 6 made of a metal pipe that extends horizontally through the base-end side bearing plate 5, and a base shaft 6 that extends horizontally through the base-end side bearing plate 5. 5
A 11 bearing 7 is provided facing the 11 bearings, and 14 rolls 3a, 8b, 8 are passed to both bearings and counters.
c, ...81.

The bearing plates 5.7 are provided with bearing members 9.10 at equal intervals along an imaginary circumference drawn around the axis of the horizontally protruding base shaft 6, and both ends of the grooved roll are supported on these bearing members 9.10. As a result, each of the rolls is rotatably supported, and the collection of these rolls constitutes one rotating shaft body having a substantially cylindrical shape.

Then, through one bearing plate 5, the other side 'till VC
Sprockets 11 and 12 are provided at the end of each protruding roll, and one group of sprockets 11 aligned on the same circumference VC has an adjustment sprocket 1 rotated by a drive motor J3.
4, the chain 15 is turned, and the tension adjustment sprocket 1 is attached to the other sprocket 11 group aligned on the same circumference.
Chain 17 hanging on 6? The hook is rotated so that all nine grooved rolls 8a, 8b, . . . 81 are forced to rotate in the same direction and at a constant speed.

In this implementation vll, as shown in Figure i2, sprockets 11 are provided clockwise from the uppermost grooved roll 8a to roll 8f, and sprockets 12 are provided at the ends of rolls 8g to 80. The movement of the chain 15 causes all the grooved rolls to partially rotate in the same direction, essentially as if one rotating body were to be rotated.

Each of the above-mentioned grooved rolls has a ring member having a trapezoidal cross section fitted to a round rod-shaped shaft rod, and these are arranged at regular intervals.
It is formed into a grooved roll having fixed protrusions 18 at a constant pitch. Furthermore, these grooved rolls rotate the other bearing plate 7 by a required angle in one direction about the base shaft 6 with respect to one bearing plate 5, and rotate the opposing bearing member 9°I.
By making O into the λ phase, each roll is twisted around the entire center of the base shaft 6 to give an inclination, thereby aligning the ring-shaped protrusion 18 formed on the roll in the helical direction between adjacent grooved rolls, A continuous spiral protrusion is formed on the circumferential surface of the first rotary shaft constituted by a collection of nine grooved rolls.

On the other hand, the second rotating shaft body 2 has a plurality of rolled rods formed between it and a front end bearing plate 19 provided opposite to the bearing plate 7.
. . 1, the coil 1 is formed into a single cylindrical rotating body in the same way as the rotating shaft body.

As shown in the figure, the second rotating shaft body 2 is constituted by a combination of eight rolls, and each roll is arranged equally along an imaginary circumference drawn around the extension of the axis of the base shaft 6. They are arranged at intervals and have a cylindrical shape with a hollow shaft center. These eight rolls are rotatably supported at both ends by bearing portions 21 provided opposite to each other on the bearing plate 7 and the front end bearing plate I9, and their substantial diameter is The body 2 is formed to have a diameter substantially equal to or slightly smaller than the diameter of the concave portion of the first rotating shaft body 1.

As described above, with respect to the first rotary shaft body l and the second rotary shaft body 2 which are provided one behind the other on a common axis centering on the base shaft 6, the outside die 3 is formed on the outer peripheral surface of the first rotary shaft body. The inside die 4 in the housing is installed in the hollow shaft center of the second rotating shaft body 2 . The latter inside die 4 faces the inside of the second rotary shaft body 2 via a die leg 22 that passes through the inside of the hollow base shaft 6. The die leg is connected to an extruder (not shown), and heat is supplied from the two inner and outer dies respectively. Melted thermoplastic resin tape A.

B can be discharged.

Next, a method for manufacturing a corrugated pipe with a smooth inner surface according to the present invention will be explained using the apparatus configured as described above.

In the manufacturing process, the resin tapes A and B heated and melted are simultaneously discharged from the two dies and supplied to each rotating shaft, but for the sake of explanation, the resin tapes A and B discharged from the outside die 3 are Let me explain first.

The resin tape discharged from the outside die 3 with the required width and thickness is tangentially directed toward the outer peripheral surface of the proximal end of the first rotating shaft 1 and in the direction of the spiral protrusion formed on that surface. It is supplied so as to straddle the protrusion 18 of the roll.

The tape A to be supplied here is determined by the relationship between the pitch of the spiral protrusions and the tape width, but for the first rotating shaft 1, this tape is wound once to the supply point with respect to the previously wound tape part. When the tape is wound around the next tape portion, it is fed so that some of the tape overlaps on the rotating shaft, and is formed into a spiral tube shape by a series of curves.

The tube formed here is a spiral tube with a wave-shaped cross section of the tube wall because the tape A is bent by straddling the spiral protrusion, and this tube rotates as the tape is continuously supplied. It is formed into an outer tube C on the first rotating shaft, grows sequentially, and advances onto the second rotating shaft 2 while rotating.

In the figure, O indicates a suppression roll installed in parallel with one of the grooved rolls 8a of the rotating shaft body 1 at a required interval, and the peripheral surface of this roll has the same protrusions as the protrusions 18. are arranged at the same pitch and press the tape A wound around the surface of the rotary shaft body, forming it into uneven shapes along the protrusions 18, and the overlapping melted tapes 7° A is pressed together to form a tube body.

In contrast to the thus formed outer tube C, the heated and melted resin tape B discharged from the inside die 4 is formed into an inner tube on the second rotating shaft.

In the embodiment of tape B, as shown in FIG. 4, it is discharged from a downward die, hangs vertically, and is automatically guided out of the rotating shaft through the gap between the roll holes.

The tape B guided here is first formed on the first rotating shaft body 2, and the outer tube C rotates and advances onto the second rotating shaft body 2.
The roll 2 is guided by the rotation of the outer tube.
It is wound on the second rotating shaft body so as to be drawn in between 0 and 10 degrees (see FIG. 4).

This CVC-wound tape B is formed into a spiral tube shape with a portion of it tied together in the same way as the tape A, forming an inner tube, and this inner tube is connected to a second rotating shaft with a substantially smooth circumferential surface. The body becomes a smooth tubular body, and is molded in a shape that extends inside the outer tube C having a spiral protrusion.

Both tubes C and D are extended onto the second rotating shaft body, pressed by the pressure roll 20 opposite to one roll 20, and fused together to form a double tube structure with a smooth corrugated inner surface. The outer tube C is molded into a tube, and as the outer tube C is extruded, the two are fed out through the second rotating shaft.

Figure 3 shows that two inner and outer pipes C9D are formed by winding the above-mentioned inner and outer tapes A and B around each rotating shaft, and both pipes are press-joined on the second rotating shaft to form one corrugated pipe. FIG. 5 shows a partially enlarged sectional view of the completed corrugated pipe of the present invention.

Although it is unnecessary to explain, both resin tapes A and B, which are supplied and wound around each rotary shaft when molding the tube, are heated and molten, and melt when wound around the rotary shaft. At temperatures below the softening point and above, the weight portions of the tapes are suppressed and fused to form a tube body, and at the same time, tape B is also fused to the inner wall surface of the outer tube C on the second rotating shaft body, becoming integrated. .

As explained above, the present invention provides that each die 3
．． From step 4, all of the melted resin tapes A and B are individually discharged and wound onto each shaft body to form a spiral tube. While forming, these two tubes are fused on the second rotating shaft 2 and integrated to produce a corrugate i1 with spiral protrusions on the outer surface and a completely smooth inner surface. For example, by supplying and winding the resin tape in accordance with the rotation of the rotating transparent body, continuous production is possible, and 4! The remaining corrugated pipe has a spiral protrusion on its outer surface, making it a pipe with high flat strength, and the smooth inner pipe provides a corrugated pipe with a smooth inner surface.

In the corrugated pipe according to the present invention, the outer tube molded on the first rotating shaft rotates and advances onto the second rotating shaft, and the tape B' (i7) from the inside die is rolled up and integrated. As a result, the joint of the inner tube becomes stable, and a high-quality corrugated tube is obtained, making it possible to provide a complete range of products with even higher reliability.

Although the means of forced cooling has not been specifically mentioned in the illustrated embodiment, if each roll of the first and second rotating shafts is made hollow and the entire cooling water circulation channel is formed, a tubular shape can be formed on each rotating shaft. By cooling each I11 tape wound with VC, the tube shape can be hardened and stabilized at an early stage. Therefore,
In practice, the combination of this forced cooling means to increase the manufacturing speed is exactly the same as in conventional manufacturing equipment of this type.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; Fig. 1 is a partially cross-sectional front view of the main parts of the manufacturing equipment, Fig. 2 is a left side view of the above figure, and Fig. 3 is a partial cross-sectional view of the main parts of the manufacturing equipment. A partially cutaway front view illustrating the process of manufacturing a corrugated pipe with a smooth inner surface, Part 4
The figure is a partially sectional right side view of the above figure, and FIG. 5 is a partially enlarged sectional view of the fc corrugated pipe left by the method of the present invention. 1... First rotating shaft body, 2... Second rotating shaft body, 3...
・Outside die, 4...Inside die, 5°7
... Bearing plate, 6... Base shaft, 8a-81... Grooved roll, 18... Thread, 19... Front end bearing plate, eggplant...
...Roll, Ru...press roll, A, B...thermoplastic resin tape, C...outer tube, D...
...Inner tube.

Claims (1)

[Claims] A first rotary shaft body that is forcibly rotated and has a virtual cylindrical shape with a spiral protrusion on its outer peripheral surface, and a second rotary shaft body that is freely rotated and has a virtual cylindrical shape whose outer peripheral surface is a smooth surface. For a device arranged in a continuous manner front and back on the axis, first, a heated and melted thermoplastic resin tape discharged from the outside die of the extruder is applied to the surface of the first rotating shaft so as to straddle the helical protrusion. The tape is wound at an inclination angle along this spiral protrusion, and then the tape wound later is fed so that it overlaps the tape wound first, and the tape is wound to create a concave and convex shape on the pipe wall. While the outer tube is rotated and sequentially sent out onto the second rotating shaft, heating is discharged from an inside die of an extruder installed near the axis of the second rotating shaft. A molten thermoplastic resin tape is guided between the outer peripheral surface of the second rotating shaft body and the inner wall surface of the outer tube which is fed out while rotating on this outer peripheral surface, and is first wound as the outer tube rotates. A part of the tape to be wound later is supplied so as to overlap the tape to be wound, so that a smooth inner tube is formed on the rotating shaft, and the tape is also placed parallel to the second rotating shaft. The concave portion of the outer tube is pressed with a pressure roll to fuse the inner wall surface and the outer wall surface of the inner tube, and this is cooled and hardened to smooth the inner surface and continuously produce a tube body having spiral protrusions on the outer surface. A manufacturing method for a corrugated pipe with a smooth inner surface, characterized by