JPS63319128A - Manufacturing of corrugated pipe - Google Patents

Abstract

PURPOSE:To obtain a strong corrugated pipe by pressingly joining with pressing force, which is controlled at respective stages in the axial shifting of the corrugated pipe, for long time enough for joining by a method wherein projecting portions or recessed portions are engagingly pressed with a plurality of specified endless belts intermittently in regular succession. CONSTITUTION:A spiral pipe C is continuously made by spirally and pilingly winding a band-like body A and a pipe-like body B, both of which are respectively supplied from both extruders, round a rotating mandrel 4. In the spiral pipe C, the overlapped parts of the band-like body A are pressingly joined to each other over every nearly semicircular peripheries of respective belts of an endless belt set 5. Since the joining of the overlapped parts is intermittently done by the separate endless belts 5x, 5y..., the band-like body is pressingly joined for long time enough for joining and pressing force can be controlled at respective stages in the axial shifting of a corrugated pipe, resulting in fully ensuring the bonding property between the bodies irrespective of the fact whether the bodies are made of non-rigid synthetic resin or rigid synthetic resin. Further, due to the control of the pressing force and the shaping action of the belt 5x, the section of the pipe-like body B is held in the predetermined perfect circular form and consequently the desired strength to pressure of the pipe is obtained.

Description

[Detailed Description of the Invention] (a) Industrial Application Field The present invention relates to a method for manufacturing corrugated pipes, and more specifically, because they have a high pressure resistance, they are often buried in the ground and used as drainage pipes. The present invention relates to a method of manufacturing a corrugated pipe, particularly a corrugated pipe having a spiral convex portion on its surface.

(B) Conventional technology In general, there are two types of corrugated pipes: those in which the concave and convex shapes of the pipe wall are axially symmetrical, and those in which the concave and convex shapes are spiral.
In other words, corrugated pipes with spiral protrusions are produced by, for example, winding a molten band of synthetic resin in a spiral around the circumferential surface of a rotating mandrel. A flexible material having a specific cross-sectional shape along the length direction of the strip is supplied between the overlapping strips as the strips are fed so that some of the parts of the strips are overlapped. It is obtained by supplying a magnetic core material and forming spiral protrusions on the surface.

The overlapping portions of the strips are pressed together by a row of pressing rollers (multiple rollers are attached to one roller shaft) that are arranged parallel to the circumferential surface of the rotating mandrel. Is it formed into an integral corrugated pipe (see Japanese Patent Publication No. 56-101832),
4~5 corrugated pipes with one endless belt
JP-A-53-72082, in which the circumference is continuously compressed and joined, thereby forming a similar integral corrugated pipe.
(see publication).

(C) Problems to be Solved by the Invention However, as mentioned above, when pressing and joining the overlapping parts of the strips using a row of pressing rollers, there is only one row of pressing rollers, and the pressing force of each roller is Since the bonding is done by almost point contact, it is not possible to take a long press bonding time, and if the synthetic resin is hard, bondability may be lacking, while if the synthetic resin is soft, the cross-sectional shape of the spiral protrusions may be distorted. ,
There was a problem in that it was difficult to obtain a corrugated pipe with a certain strength.

On the other hand, when one endless belt is used to continuously press and join the overlapping parts of the strips around 4 to 5 circumferences of the corrugated pipe, since only one belt is used, the pressing force against the strips is applied to the entire belt. There is no choice but to be uniform about this. However, the band-shaped body changes from a high temperature molten state to a low temperature slightly hard state in the direction of axial movement of the corrugated pipe, and if it is uniformly suppressed, the pressing force will be too strong in the high temperature molten state, which is important. There is a problem in that when the spiral protrusions collapse or are slightly hard, the pressing force is too weak and the overlapping portions cannot be sufficiently joined. Furthermore, endless belts are usually made of rubber-based material, and even if the material is heat resistant, it has a problem of lacking durability because it spends a long time in contact with a high-temperature belt.

(d) Means for solving the problem and its operation This invention provides (1) supplying a molten synthetic resin strip from an extruder around a cylindrical mandrel and partially overlapping it. At this time, (n) the synthetic resin strip is supplied so that its cross section is bent or hollow, or a pre-molded flexible reinforcing material is wound around the synthetic resin strip. A flexible reinforcing material of the same or different synthetic resin from the extruder or another extruder is supplied continuously and simultaneously to the inside or back side of the synthetic resin strip. (v) while the corrugated tube, thereby forming a convex portion on its surface, is held on the mandrel, the overlapping portions of the strips of corrugated tube are applied to the convex portion of the corrugated tube; By using a plurality of endless belts having concave and/or convex cross sections that engage with the concave portion or the concave portion, each endless belt is intermittently pressed every 1/4 to 1/2 circumference of the corrugated pipe to perform joining and shaping. This is a characteristic method for manufacturing corrugated pipes.

That is, this invention consists of steps ω to (v), and among these five steps, step (v) is one of the main structural features, and none of the other steps 0 to -v- These are all known processes, and any one of the processes Oi) to (c) is selected and adopted.

In short, this invention enables a plurality of specific endless belts to sequentially and intermittently engage and press the convex and/or concave portions around 1/4 to 1/2 of the circumference of the corrugated pipe, thereby forming a strip. While press-joining the corrugated pipe for sufficient time, it is possible to adjust the pressing force at each stage of the axial movement of the corrugated pipe (lower the pressing force in soft areas, increase the pressing force in hard areas), Regardless of whether it is soft or hard, the corrugated pipe has good jointability, good shaping properties, and strong corrugated pipe. Furthermore, it uses multiple separate endless belts. The influence of heat can be distributed to each belt, thereby extending the life of the endless belt.
The effort required to replace endless belts can be reduced.

In this invention, a plurality of endless belts are used,
The range in which each endless belt engages and presses the convex portion and/or the concave portion of the corrugated pipe is from 1/4 to 172 times around the 61 corrugated pipe. Then, the engagement and pressing of each endless belt is performed intermittently in sequence. Here, the interval between the engagement and suppression of each endless bell 1, that is, the period during which the engagement is not suppressed, is preferably 1/6 to 1 circumference of the corrugated pipe. While the entire endless belt is on the corrugated pipe or mandrel, it may be engaged and pressed as much as possible, but the total length of the engagement and pressing should be limited to 2 turns (helix angle 2 x 360 degrees - 5 turns). The convex portions and/or concave portions of the corrugated pipe are engaged and suppressed for a period of 3 to 4 turns, preferably for 3 to 4 turns.At this time, the engaging and pressing direction of each endless belt with respect to the corrugated pipe is the same direction. The engagement and pressing by each of these endless belts may be performed not only from the first winding but also after the first 2 to 3 turns. Note that if the overlapping portion is along a concave portion, it is desirable to determine the cross section of the endless belt so that the overlapping portion can be directly suppressed.

Since each of the endless belts configured as described above comes into contact with the high-temperature synthetic resin, albeit slightly, in a molten state, it is desirable that the endless belt has heat resistance in addition to its original toughness and flexibility. A specific example of the material is a cloth laminated with rubber, and heat-resistant rubber is particularly used as the rubber. Of course, such an endless belt is preferably cooled by cold water, cold air, or the like.

Examples of other endless belt materials include hard rubber, synthetic resin, leather, and metals such as aluminum and aluminum alloys.

In this invention, a cylindrical mandrel spirally winds a part of a synthetic resin strip supplied in a molten state from an extrusion gate so as to overlap, and continuously sends out a corrugated pipe in one direction to form a corrugated pipe. . Therefore, in a cylindrical mandrel, a large number of rotors are rotatably supported obliquely (obliquely to the axial direction) on the body surface of the cylindrical mandrel, or the mandrels are arranged in a cylindrical shape. The tub is formed by thin cylinders parallel to each other and diagonally (
(with respect to the virtual cylindrical axis of the mandrel). Furthermore, if the cylindrical mandrel itself does not have the function of feeding the corrugated pipe in one direction, the mandrel itself can be moved laterally in the axial direction with a rail, etc., or the mandrel can be fixed and the synthetic resin extruder can be moved with a rail, etc. It may also be moved laterally.

Furthermore, according to one aspect, the present invention provides the following (+)(i
The present invention provides an apparatus for manufacturing corrugated pipes according to i).

(+) A synthetic resin extruder that extrudes a molten synthetic resin strip, and a flexible reinforcing material made of the same or different synthetic resin from this extruder or another extruder, or a pre-molded flexible material. A reinforcing material extruder that extrudes the reinforcing material, and a reinforcing material extruder that spirally winds the strip from the synthetic resin extruder and inserts the reinforcing material inside or on the back side of the strip along the longitudinal direction of the strip. A flexible reinforcing material is supplied from the above to form a convex part on the surface, and a part of the part of the band-like body to be wound later is overlapped with the part of the band-like body wound earlier to form a convex part on the surface. A rotating mandrel forming a corrugated pipe having a corrugated section, and while the corrugated pipe is held on this mandrel, a convex section and/or a concave section formed between the convex sections. A corrugated pipe manufacturing apparatus comprising: a plurality of endless belts that sequentially and intermittently engage at least every 1/4 to 1/2 circumference of the corrugated pipe and press the overlapping portions of the band-shaped bodies of the corrugated pipe.

(Ii) A synthetic resin extruder that extrudes a molten synthetic resin strip so that its cross section becomes curved or hollow, and while winding the strip from this synthetic resin extruder in a spiral shape,
A reinforcing space is defined inside or on the back side of the strip in the longitudinal direction of the strip, and a convex strip is formed on the surface, and then the part of the strip that was wound earlier is wound later. A rotating mandrel for forming a corrugated pipe having a convex part on its surface by overlapping a part of the parts of the strips, and while the corrugated pipe is held on this mandrel, the convex part and/or the convex part A plurality of devices are sequentially and intermittently engaged with grooved portions formed between the corrugated pipes at least every 1/4 to 1/2 circumference of the corrugated pipe, and press the overlapped portions of the strips of the corrugated pipe. Corrugated pipe manufacturing equipment consisting of a dress belt.

Furthermore, according to another aspect, the present invention provides a corrugated pipe itself having a specific configuration.

That is, the corrugated pipe is made by winding a synthetic resin strip in a spiral shape, and inserting a flexible reinforcing material or defining a reinforcing space inside or on the back surface of the strip in the longitudinal direction of the strip. This is a corrugated pipe with protrusions formed on its surface. During manufacturing, this corrugated pipe is engaged and pressed by a plurality of endless belts intermittently every 1/4 to 172 turns of the corrugated pipe, so that the strips are overlapped. Pressure bonding of the mating portions and formation of the protruding portions are sufficiently performed, and therefore it can be suitably used as a drain pipe that requires particularly strong toughness.

(iii) Embodiment The method of the present invention will be explained in detail based on a specific example of the apparatus shown in the figure below. Note that this does not limit the method of this invention.

First, in FIG. 1, a continuous production system H1 for corrugated pipes includes a synthetic resin extruder 2 that continuously extrudes a molten synthetic resin strip A, a flexible reinforcing material and a synthetic resin tubular body B at I. a reinforcing material extruder 3 that continuously extrudes the reinforcing material, and a rotating mandrel 4 that continuously forms a helical tube C by overlapping and winding the strip A and the tubular body B supplied from these two extruders in a spiral shape. , and an endless belt 5 for pressing and joining the overlapping portions of the obtained spiral tubes C and shaping the spiral convex stripes described later.

The rotating mandrel 4 has multiple hollow shafts 6.7...
・ are arranged in parallel at predetermined intervals along the circumferential surface of one virtual cylinder, and each hollow shaft has a shaft end (not shown).
A chain is attached to a sprocket provided on the sprocket (on the left in FIG. 1) so that the sprocket rotates in the same direction at a constant speed, thereby substantially rotating the rotating mandrel 4.

For example, one of the endless belts 5x has a cross section corresponding to the cross-sectional shape of the spiral groove E (described later) of the spiral tube C to be obtained, and the roller 8x
, 9x, and iox. Here, the rollers 8X and 10X are rotatably supported by common roller shafts 8z and 10z, respectively 1, and the roller 9x is supported by an independent roller shaft gxz so as to be movable left and right, thereby reducing the pressing force of the belt against the spiral tube C. It is possible to adjust the Specifically, in FIG. 2 in particular, the independent roller shaft 9xz of the roller 9x is rotatably supported approximately at the center of the arm 11x, the upper end of which is pin-coupled to the tip of the bolt and 13x, and the lower end is connected to the fixed shaft 12X. Pin-connected. And bolt 13x fixes the rear plate 14x
It is positioned so that it can be moved left and right using adjustment nuts 15X and 16X.

The other endless belt 5y... is connected to the above endless belt 5x by an independent roller shaft (not shown).
It has the same configuration as the endless belt 5x, except that it is supported so as to be movable left and right separately from the independent roller shaft 9xz, and the explanation thereof will be omitted.

Next, a corrugated pipe continuous manufacturing apparatus 1 having the above configuration
The operation will be explained based on FIGS. 1 to 3, and the continuous manufacturing method of corrugated pipes will be explained accordingly.

When the rotating mandrel 4 is rotated (substantially) and the molten polyethylene resin strip A is supplied from the synthetic resin extruder 2 around the rotating mandrel 4, the strip is spirally wound. A tube C is formed. Furthermore, when the strip A is wound, a polyethylene resin tubular body B is formed on the back side of the strip from a reinforcing material extruder 3 in the longitudinal direction of the strip A.

supply. In this way, the spiral convex stripes as convex portions are formed on the surface of the helical tube C, and the appearance of the corrugated tube F is substantially arranged.

In addition, the above-mentioned spiral tube C is formed by overlapping a portion of the band-like body A that is wound earlier with a part of the band-like body that is to be wound later, and this overlapping portion is the part of the endless belt. Each belt of set 5 sequentially presses each belt approximately every 1/2 turn, thereby joining them. Normally, the speed at which the belt-shaped body A and the tubular body B are pulled by the rotation of the rotating mandrel 4 is faster than the speed at which each of these bodies is extruded, and the object is still in a soft state, and furthermore, it becomes harder and harder as it is extruded. Therefore, the joining of the overlapping portions of the above-mentioned strips is often insufficient. Conventionally, a suppression roller or an endless belt is used to press the overlapping parts, but since the pressing force is uniform and the suppression time (or distance) is instantaneous or continuous and long, Depending on the condition of the resin, the effect may not be sufficient. However, according to the intermittent wrapping-like compression by each belt of the endless belt set 5 described above, that is, the intermittent compression of about 0.5 helical rotations (about 360 x O, 5 degrees), the overlapping parts are joined. This is done intermittently by separate endless belts 5x, 5V, etc., so that it is possible to adjust the pressing force at each stage of the axial movement of the corrugated pipe while compressing and welding the strips for sufficient time. (The pressing force should be relatively small in soft areas and relatively large in hard areas.) Regardless of whether the synthetic resin is soft or hard, the corrugated pipe's bondability is guaranteed. In addition, since the cross section of the endless belt 5 corresponds to that of the four spiral threads (concave portions) formed between the spiral convex threads, the desired shape, that is, the corrugate with the desired pressure resistance strength as shown in Fig. 3 is obtained. A tube F is obtained.

In particular, the rotation of the rotating mandrel 4, immediately after extrusion,
Since the belt-like body A and the tubular body B in a molten state are kept in tension, for example, the tubular body B tends to become flattened in the direction parallel to the rotation axis of the rotating mandrel 4, and therefore a decrease in pressure resistance is usually unavoidable. , the above endless belt set 5
By adjusting the pressing force and shaping action of the belt 5x, the cross section of the tubular body B is maintained in a predetermined perfect circular shape, and the desired pressure resistance strength is obtained.

Here, the suppressing force of each belt of each endless belt set 5, for example belt 5x, against the corrugated pipe is determined by adjusting nut 15x in FIG.

Bolt 13x by adjusting the tightening position of 16x
can be moved almost horizontally left and right, thereby adjusting the strength or weakness. Note that the through hole of the fixing plate 14x through which the bolt 13X passes is a long hole that is long in the vertical direction.

Furthermore, if the endless belt set 5 is made up of four endless belts as shown in Fig. 1 instead of the conventional single endless belt, assuming that the suppression times are the same, then
At least the time each endless belt is exposed to high temperatures can be reduced to about 1/4, and the life of each endless belt can be extended.

Unlike the above example, the manner in which the strips are superimposed and the tubular body is interposed between these strips can be changed as shown in FIG. 4. In other words, the band-shaped body Aa has one width and covers the two-wound tubular bodies 3a, 3a from the outside (hereinafter, different embodiments with corresponding configurations will be described with reference numerals a, b, (The description may be omitted and the description may be omitted.)

Next, the spiral tube as described above can also be constructed into a double tube structure. In other words, the continuous manufacturing apparatus 1b for corrugated pipes shown in FIG. 5 includes two synthetic resin extruders 2b and 2'b,
Furthermore, two sets of endless bells 1-5b and 5'b are provided. And Figs. 5 and 6, the rotary mandrel 4b
A molten polyethylene resin strip A'b is supplied from the extrusion f12"b around the extrusion f12"b, and the strip is spirally wound to form a spiral tube C'b.Then, this spiral □
Pipe C'b is a pipe that does not have any spiral concave or convex ridges, and its spiral overlapping portion is used as each endless belt (approximately rectangular in cross section) of endless belt set 5-b similar to Figs. 1 and 2. and press to ensure a bond. Next, on the obtained helical tube C'b, the band-shaped body Ab and the tubular body Bb are stacked in the same manner as in FIGS. 1 and 2. Although the explanation is omitted, the obtained corrugated pipe Fb has a double pipe structure as shown in FIG. 6. In addition, Gb and Gb are band-shaped bodies A' b
This is the overlapping part of .

Unlike each of the above-mentioned pieces, a synthetic resin tubular body may be inserted into the inside of the band-shaped body and wound spirally. That is, in FIG. 7, a synthetic resin tubular body Bc is inserted into the synthetic resin strip AC in a molten state, and is spirally wound around a rotating mandrel (not shown) to form a spiral tube.

Then, the overlapping portion Go of the strip AC is pressed and joined by the endless belt 5xc shown by the dashed line, and the spiral convex line [ )C of the strip AC is shaped. The strip AC is obtained by feeding the previously molded tubular body Bc into a synthetic resin extruder and extruding it together with the molten synthetic resin from an extrusion nozzle while keeping the tubular body 3c in the center. Of course, the opening cross section of the extrusion nozzle is formed into a substantially inverted T-shape corresponding to the cross section of the strip AC.

Furthermore, the spiral tube as described above can be placed over (on the outside of) the inner spiral tube as shown in FIGS. 4 and 6 to form a double structure as shown in FIG. 8.

Examples of other cross-sectional structures of corrugated pipes are listed below.

9 to 11 FIG. 9 shows an example in which a flexible reinforcing material Be, such as a hard vinyl chloride resin, is inserted into the back surface of the strip Ae along the longitudinal direction of the strip Ae. Note that the example in FIG.
The overlapping portion Gf of f is structured in a stepped manner, and the flexible reinforcing material B111 shown in FIG. 11 is characterized in that it is structured to have a square cross section.

12-14 and 15-17 The cross-sectional structure of the strip consists of an inverted U-shaped piece Hh and large and small horizontal pieces Ih and Jh extending horizontally outward from both ends of this piece. The joint portion, the small horizontal piece Jh, and the tip of the large horizontal piece ih are overlapped and joined by an endless belt (not shown) as appropriate. 15 to 17 show three examples in which the cross-sectional structure of the strip is different from the above.

Figures 18-20 and 21-27 The cross-sectional structure of the band-like body is an inverted U-shaped piece Hρ, a horizontal piece Jρ extending horizontally outward from one end (right end) of this piece, and an inclined piece extending slightly downward from the other end. The hard piece part is made of Iρ, and the soft piece part that closes the downward opening part of this hard piece part is made of ρ. 21 to 27 show examples in which the cross-sectional structure of the strip is slightly different from the above.

The strip shown in FIG. 28 has a hollow portion (Lt) formed by profile extrusion. Further, in the corrugated pipe obtained here, the convex portion and the concave portion are both engaged and pressed by an endless belt (5Xt).

Unlike the above example, two flexible reinforcing materials are simultaneously inserted side by side inside or on the back side of one synthetic resin strip and wound spirally, thereby forming a corrugated pipe with two spiral ridges. You may.

(F) Effects of the Invention According to this invention, the convex portion or the concave portion of the corrugated pipe is engaged and pressed intermittently every 1/4 to 1/2 circumference of the corrugated pipe using a plurality of specific endless belts. Therefore, it is possible to adjust the pressing force at each stage of the axial movement of the corrugated pipe while compressing and joining the strips for a sufficient amount of time. As a result, a corrugated pipe suitable as a drain pipe requiring particularly strong strength is obtained.

[Brief explanation of drawings]

Fig. 1 is a perspective view illustrating the main functions of an example of a corrugated pipe manufacturing apparatus for carrying out the method of the present invention, Fig. 2 is a diagram illustrating the configuration of an endless belt of the apparatus, and Fig. 3 is a diagram illustrating the structure of the endless belt of the apparatus. 4th longitudinal cross-sectional explanatory diagram of the main part of the corrugated pipe
The figure is a diagram equivalent to Figure 3 showing another example, Figure 5 is a diagram equivalent to Figure 1 showing another example, Figures 6 to 11 are diagrams equivalent to Figure 3 showing other examples, and Figure 12 is a diagram equivalent to Figure 3 showing other examples. 13 is a longitudinal sectional view of the corrugated pipe, FIG. 14 is an enlarged sectional view of the main part of the longitudinal sectional view, and FIGS. 15 to 17 are FIGS. 18 to 20 are views equivalent to FIG. 14 showing still other examples, M21 to M28 are views equivalent to FIG. 14 showing still other examples. . 1... Korgu 1 ~ Continuous pipe manufacturing equipment, 2...
...Synthetic resin extruder, 3.Reinforcement extruder, 4.Rotating mandrel, 5.Endless belt set, A..
Band-shaped body, B...Flexible reinforcing material, C...
Spiral tube, D...Spiral convex strip (convex portion), F...
corrugated pipe. 12th concave Dh Absolute 13 Fig. 25 Fig. 27 Fig. G's Fig. 28 G'r

Claims (1)

[Claims] 1. (i) A molten synthetic resin strip is supplied from an extruder around a cylindrical mandrel, and is wound spirally so that some parts are overlapped. (ii) The synthetic resin strip is supplied so that its cross section is curved or hollow, or (iii) A pre-molded flexible reinforcing material is continuously provided inside or on the back surface of the synthetic resin strip. and (iv) continuously and simultaneously supplying a flexible reinforcing material of the same or different synthetic resin as the synthetic resin from the extruder or another extruder to the inside or back surface of the synthetic resin strip. (v) while the corrugated pipe, thereby forming a convex portion on its surface, is held on the mandrel, the overlapping portions of the strips of corrugated pipe are applied to the convex and/or concave portions of the corrugated pipe; Manufacturing of a corrugated pipe characterized by joining and shaping the corrugated pipe by intermittently pressing each endless belt every 1/4 to 1/2 circumference of the corrugated pipe using a plurality of engaging endless belts with concave or convex cross sections. Method.