JPS5849383B2 - Manufacturing method and device for corrugated pipe with spiral protrusions - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuously manufacturing corrugated pipes from a flat tape of molten synthetic resin, and an apparatus therefor. The tape of the resin is wound in a spiral direction, and the tapes that are wound back and forth are partially overlapped on the rotating shaft to form a spiral tube. When winding the tape, a part of the molten tape is placed on a spiral guide rod placed opposite to the rotating shaft to make it bulge, and this raised part is continuously shaped so that it can be rolled on the same surface of the tube. This paper relates to a continuous manufacturing method for corrugated pipes in which spiral protrusions are integrally shaped, and to its equipment.

Conventionally, a method of manufacturing a spiral resin tube body by spirally winding a resin tape around the circular surface of a rotating shaft body is generally known. A corrugated pipe has a spiral protrusion on its circumference, and by winding a flat synthetic resin tape along the spiral protrusion, the tube wall is raised in a spiral shape and the cross section is shaped into a corrugated shape. It is also known to manufacture

In particular, corrugated pipes with the above-mentioned corrugated cross-section have high flat strength and are therefore highly useful as buried pipes, and are widely used as wiring pipes, drainage pipes, and the like.

This corrugated corrugated pipe has been manufactured by various methods in the past, but due to various advantages such as ease of shape and simplicity of manufacturing equipment, the method of providing a spiral protrusion on the dark side of the shaft as described above has been adopted. Many methods have been put into practical use in which corrugated pipes with a corrugated cross section are manufactured by winding a joint resin tape around a rotating shaft in a helical direction so that the front and rear tapes partially overlap.

As mentioned above, the corrugated pipe manufactured by this method has excellent flatness strength, and since this method can be manufactured by winding it on the same surface of the rotating shaft, it is highly practical. Since this corrugated pipe has a corrugated pipe wall, the inner wall of the pipe has an uneven surface. Therefore, if this corrugated pipe is used as a wiring pipe, it will cause resistance when inserting electric wires, and it will not be used as a drainage pipe. If this occurs, problems such as flow resistance and sediment accumulation in the recesses occur.

For these reasons, the inventor of the present invention continued to develop corrugated pipes with a smooth inner circumferential surface and high flatness strength, and as a result, succeeded in developing a new corrugated pipe that can be expected to have the desired effect. , the development of efficient manufacturing methods and manufacturing equipment.

The most distinctive feature of this invention is that it can be easily manufactured by continuously winding a synthetic resin tape around a rotating shaft with a smooth circumferential surface, similar to the above-mentioned spiral-shaped resin tube. In this manufacturing process, spiral protrusions are integrally formed on the same surface of the pipe body, and the corrugate has spiral protrusions that have the same flatness strength as corrugated corrugated pipes while making the inner wall of the pipe a smooth surface. The reason is that the tubes can be manufactured continuously.

Hereinafter, a practical example illustrating the present invention will be explained, and its characteristics will be explained in detail.

FIG. 1 is an explanatory perspective view showing a manufacturing process in which a flat tape 2 of heated and melted polyethylene resin is supplied to the circumferential surface of a rotating shaft 1 and shaped into a tube 3 on the rotating shaft. Figure 2 is a partially omitted perspective view of the main parts of the apparatus for manufacturing corrugated pipes, and Figure 3 is a diagram of the main parts showing the process of shaping the tape 2 into the pipe body 3 on the same surface of the rotating shaft. FIG. 4 is an enlarged longitudinal sectional view, and FIG. 4 is an enlarged partial sectional view of the manufactured corrugated pipe.

The rotating shaft body 1 shown in this example has a plurality of rolls 1a arranged in parallel along a virtual circle, and a collection of these rolls 1a forms a single shaft body, with one end of each roll being arranged in parallel. As shown in the figure, each roll is rotatably supported on a bearing plate 4, and the other end is similarly supported on a substrate (not shown) to form a single shaft body, and a sprocket is provided on the other end shaft portion (not shown) of each roll. A chain is suspended from this so that each roll rotates in the same direction at a constant speed, so that the rotating shaft body 1, which is substantially constituted by a collection of these rolls, rotates in one direction.

In this actual example, in order to ensure the support of the bearing plate 4, a support rod is extended from the substrate (not shown) through the cavity surrounded by the roll 1a, and the bearing plate 4 is fixed to the tip of the support rod to support the roll. It's stabilized.

In the figure, reference numeral 5 denotes guide rods that are arranged so as to be wound along the outer circumferential surface of the rotating shaft 1, and 6 is a guide rod that presses the tape 2 wound around the circular surface of the rotating shaft, This is a pressure roll that is adhesively attached to the body 3.

The guide rod 5 is made of a hollow pipe material and has a tapered shape that gradually decreases in diameter from the lower end toward the tip, and has a number of small holes on the same surface communicating with the hollow portion 5'. Hole 7 has been opened.

This guide rod is arranged opposite to the rotating shaft 1 so as to wrap around it in a helical direction while maintaining a gap larger than the thickness of the tape 2 between itself and the outer peripheral surface of the rotating shaft. The length is such that the rotating shaft body is the same length.

On the other hand, the pressure rolls 6 are disposed opposite to each other along the length direction of the rotary shaft body 1, and a gap equal to the thickness of the tubular body to be formed is provided between the pressure rolls 6 and the solid surface of the shaft body.

As will be explained in detail later, in this actual winding example, the tape 2 is superimposed into three layers on the rotating shaft to form the pipe body, so here the above-mentioned gap is determined by the thickness of the tape 2 being supplied. The gap is defined as a gap that does not exceed three times the size of the gap.

This pressing roll 6 has a concave groove 8 on the same surface, the axial center is hollow, and an intake passage 9 is provided therein, and a large number of intake holes 10 communicating with the intake passage 9 are provided on the sides of the concave groove 8. There is.

The push roll 6 is provided with the guide rod 5, which is placed opposite to the same surface of the rotary shaft body, through the groove 8 so as to straddle the same, and furthermore, the guide rod 5 is placed so as to straddle the groove surface. A gap wider than the thickness of the tape 2 is secured between the tape 2 and the guide rod 5.

When winding the flat tape 2 around the rotating shaft, the guide rod 5 has a part raised along its length, and a spiral protrusion is formed on the circumferential surface of the tubular body 3 formed by the continuation of this. Article 11
On the other hand, the press roll 6 is used to press and adhere the overlapping tapes on the circumferential surface of the rotating shaft body to form a spiral tube.

In the apparatus configured in this manner, the tape 2 is discharged in a molten state from the die 12 of the extruder, and is supplied to the same surface of the rotating shaft 1 along the helical direction of the guide rod 5.

At this time, the tape 2 is supplied so that the leading edge 2a side part is covered with the guide rod 5 as shown in the figure, and the guide rod bends and bulges this part, and the trailing edge 2b
The side portion is placed directly on the same surface of the rotating shaft 1 and wound as the rotating shaft rotates, and as the winding progresses, the raised portion continues in the direction of the guide rod to form a spiral protrusion 11. to give formal precepts.

Then, the tape to be supplied here is arranged so that the part to be wound later overlaps with the part to be wound by supplying it to the shaft body 1 first.
More specifically, the tape is fed so that the raised part of the tape to be wound later overlaps with the flat part on the trailing edge 2b side of the tape wound earlier.

When the tape 2 is supplied in this way, after one rotation on the rotating shaft, the front and rear tapes overlap to form a spiral tube, and at the same time, the tape 2 is formed into a spiral by the continuation of the above-mentioned ridges on the same surface of the tube. The protrusion 11 will be reprimanded.

In this case, since the guide rod 5 is fixed, there is a risk that the tape portion covering it may adhere.

Therefore, in this X, we finished the same side of the guide rod as a smooth surface.
Furthermore, the surface is treated with Teflon to reduce frictional resistance, while
As mentioned above, it is tapered to make it easier for the guide rod to come out.

In addition, in this practical example, liquid is oozed out from a large number of small holes 7 opened on the same surface through the hollow part 5' of the guide rod, to improve the smoothness of the tape and to reduce the tension of the tape wound around the rotating shaft. This eliminates this problem and allows the ridges to be shaped smoothly along the length of the tape.

Furthermore, when the liquid from the small hole 7 is sprayed together with pressurized cold air, this cold air forcibly cools the sliding surface of the tape, that is, the inner circumferential surface of the raised part, which helps to quickly fix the raised state and also improves the adhesion. It is effective in erasing gender.

The tape thus wound while forming the raised portions then passes through the pressing roll 6 and is pressed against the same surface of the shaft 1, pressing the weight portion of the tape to form a complete tube.

As described above, this suppression roll 6 is equipped with an intake passage 9 and an intake hole 10 on the same surface of the groove 8. During operation of the device, the suppression roll 6 is forcibly rotated at the same fixed speed as the rotating shaft, and the tape is wound. At the same time, external air is sucked in from the intake hole 10 to attract the raised part of the tape passing through the concave rod 8, maintain the raised state, and pull it away from the guide rod, thereby promoting rapid winding. We will assist you in doing so.

The pressure roll shown here has a plurality of concave grooves 8 arranged in a row in accordance with the pitch of the spiral protrusions 11, and continues to suck the protrusions 11 after leaving the guide rod 5 into a raised state. During this time, the molten tape is cooled and hardened, creating a stable tube.

The present invention is to continuously manufacture a corrugated pipe having a spiral protrusion 11 on the circumferential surface from a tape of melted resin as described above, and the manufactured pipe is shown in Fig. 4. As shown in the figure, it has protrusions only on the outer circular surface, making it a flat corrugated tube with high strength, and the inner peripheral surface of the tube is a smooth surface because the flat part of the tape is exposed, making it a tube body with good insertion performance. Become.

The manufacturing efficiency of the corrugated pipe according to the present invention is high because it can be manufactured continuously by supplying a molten synthetic resin tape to the rotating shaft along the spiral direction and winding it. Since the device also has a simple configuration, it has the advantage that it can be easily installed compared to conventional manufacturing devices of this type.

In addition, in actual practice of the present invention, the tape width and wall thickness of the tape wound around the rotating shaft body will be selected appropriately depending on the pipe diameter, but at the same time, the tape width and wall thickness will also be selected depending on the polymerization ratio of the front and rear tapes. Needless to say, they are individually selected.

In particular, regarding the polymerization of this tape, in the actual example described above, two ridges of the tape to be wound later overlap with the flat part of the tape to be wound, so that essentially three layers of tape overlap. However, even if the tape overlaps in two layers,
Also, it may be made to overlap in four layers.

Further, the rotating shaft body 1 shown in the above-mentioned practical example has a plurality of holes 1a.
However, this does not exclude those consisting of a single shaft.

Furthermore, although the length of the guide rod 5 is set to approximately make one revolution around the rotating shaft body, it may be further extended.

This guide rod is covered with a flat tape and then bent and raised to form a spiral protrusion.The length of the guide rod is determined by the length of the tape that hardens and the raised part stabilizes while being wound around the rotating shaft. Since it is sufficient to maintain this protruding state during the process, the decision is made based on the molten state of the tape, the wall thickness, the rotational speed of the rotating shaft, the cooling effect, etc.

[Brief explanation of the drawing]

The drawings show an example of the present invention, and Figure 1 shows the process of shaping a corrugated pipe by supplying and winding a molten resin tape around the circular surface of a rotating shaft. Fig. 2 is a perspective view of the main parts of the apparatus for manufacturing corrugated pipes, with some parts omitted, and Fig. 3 shows the process of forming the pipe from the tape on the circumferential surface of the rotating shaft. FIG. 4 is an enlarged partial sectional view of the manufactured corrugated pipe. 1 is a rotating shaft body, 2 is a tape made of resin, 3 is a tube body, 5 is a guide rod, 5' is a hollow part, 6 is an extrusion hole, 7 is a small hole,
8 is a concave groove of the pressure roll, 9 is an intake passage, 10 is an intake hole,
11 is a spiral protrusion, 12 is a die, 2a is a leading edge of the tape, and 2b is a trailing edge of the tape.

Claims (1)

[Scope of Claims] 1. A guide rod that is arranged so as to be wound in a helical direction with a required gap maintained between it and the same outer surface of the shaft body, and a curved surface along the length direction of the shaft body. from the die of the extruder to the surface of the rotating shaft body, which has a pressure roll arranged in parallel with a required gap between the two and having a concave groove spanning the guide rod on the same surface. A flat tape made of heated and melted resin is discharged, and a part of the front edge side of the tape is fed along the spiral direction so as to cover the guide rod, and the guide rod raises a part of the tape and continuously At the same time, the raised part of the tape to be wound later is overlapped with the upper surface of the trailing edge side of the previously wound tape, and this overlapped part is pressed with the pressure roll, thereby making the rotating shaft A method for producing corrugated pipes having spiral protrusions, characterized by continuously shaping the pipe body on the same surface of the body. 2 A prescribed gap is maintained between a rotating shaft and the same outer surface of the shaft, and a guide rod is arranged oppositely so as to be wound along a spiral direction, and A helical protrusion is provided on the same surface of the guide bar, which is arranged in parallel with the same surface with a predetermined gap therebetween, and is provided with a concave groove on the same surface that straddles the guide rod. Corrugated pipe manufacturing equipment. 3. The corrugated pipe manufacturing apparatus according to claim 2, wherein the guide rod is a tapered rod whose cross-sectional area gradually decreases from the base end to the distal end. 4. The guide rod is hollow inside and has a large number of small holes on the same surface, and the gas or liquid sent through the hollow portion can be discharged from the small holes. The corrugated pipe manufacturing apparatus according to item 3. 5. The corrugate according to claim 2, wherein the press roll is hollow inside and has an intake passage, and the concave groove surface is provided with a large number of intake holes communicating with the intake passage. Pipe manufacturing equipment.