JPH0480274B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application This invention relates to a corrugated pipe, its pressing member, and core type, and more specifically, it has a large pressure resistance, so it can be buried in the ground and used as a drainage pipe. The present invention relates to a corrugated pipe often used as a corrugated pipe, particularly a corrugated pipe having a spiral convex portion on its surface, a pressing member for joining the corrugated pipe, and a core mold for shape retention.

(B) Prior art In general, there are two types of corrugated pipes, one in which the concave and convex shapes of the pipe wall are axially symmetrical and the other in a spiral shape. For example, a strip made of molten synthetic resin is wound spirally around the circumferential surface of a rotating mandrel, and during this winding, a portion of the strip to be wound later is separated from a portion of the strip that is wound first. At the same time, along with the supply of the strip, a flexible core material having a specific cross-sectional shape is supplied along the length of the strip, and a spiral convex strip is formed on the surface. can get.

The overlapping parts of the strips are pressed together by one pressure roller installed parallel to the peripheral surface of the rotating mandrel, thereby forming an integral corrugated pipe (Japanese Patent Laid-Open No. 56-101832 (see publication).

(c) Problems to be Solved by the Invention However, as described above, when pressing and joining the overlapping parts of the strips using a pressing roller, there is only one pressing roller and the pressing is performed almost by point contact. If the synthetic resin is hard, the bonding properties may be lacking, and if the synthetic resin is soft, the cross-sectional shape of the spiral convex strips may be distorted, resulting in the failure of the specified strong corrugated material. There was a problem that tubes were difficult to obtain.

On the other hand, as mentioned above, these corrugated pipes are often buried in the ground and used as drainage pipes, but if the joints of the overlapping parts of the strips are insufficient, drainage may leak or water in the soil may leak. There is a problem in that water invades and therefore it is difficult to adjust and manage the amount of drainage.

(d) Means for Solving the Problems and Their Effects This invention involves supplying a molten synthetic resin strip from an extruder around a mandrel, winding it spirally and overlapping it, and then In a corrugated pipe in which a reinforcing space is defined on the back side along the longitudinal direction of the strip and a spiral concave/convex portion is formed on the surface, the convex portion is formed when the corrugated tube is held on a mandrel. During this time, the shape-retaining core mold is inserted into the reinforcing space formed by the molten synthetic resin strip to retain its shape, and then the partitioning layer of the reinforcing space is cut to remove the shape-retaining core mold. After the cut portion is taken out, the cut portion is closed from the outside with a separately supplied strip material, and at least the top portion of the outer peripheral surface of the strip material has a large number of fine reinforcing ridges along the longitudinal direction of the top portion. It is a corrugated pipe.

That is, this invention closes the cut portion with a strip material after taking out the shape-retaining core inserted into the reinforcing space for shape-retaining purposes, and provides specific reinforcement at least on the top of the strip material. By forming the protrusions, the convex portion mechanically weakened by the cut is reinforced, thereby providing a strong corrugated pipe with a simple structure.

In this invention, a specific linear pressing member continuously engages and presses a convex portion and/or a concave portion of a corrugated pipe over half the circumference or more in a linear manner. Due to this pressing, at least the bondability of the corrugated pipe becomes better regardless of whether the synthetic resin is soft or hard, and at the same time, the shaping property is improved, and a strong corrugated pipe can be obtained.

Here, the linear pressing member refers to a linear pressing member that continuously presses the convex portion of the corrugated pipe or the concave portion formed between the convex portions over about half the circumference of the corrugated pipe or more, that is, over a helical angle of about 180 degrees or more. It means a member that engages and presses at the same time, and specifically, an endless belt as in the embodiment is preferred. The range in which the linear pressing member engages and presses the convex portion and/or the concave portion may be the entire range while the corrugated pipe is on the mandrel, but the range of the corrugated pipe being engaged with and pressed against the convex portion and/or the concave portion may be within the range of 1 to 5 turns (helical angle of 360 degrees). is preferable, and more preferably 2 to 4 turns around the body. Of course, these windings may be performed not only from the first winding but also after the first two or three turns. Note that when the overlapping portion is along a concave portion, it is desirable to determine the cross section of the linear pressing member so that the overlapping portion can be directly pressed.

Since the endless belt with the above structure constantly comes into contact with the high temperature synthetic resin in a molten state, it is required to have particularly 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.

In this invention, a cylindrical mandrel is used to continuously feed a corrugated tube in one direction by winding a synthetic resin strip supplied in a molten state from an extruder in a helical manner so as to overlap a portion of the synthetic resin strip. Therefore, in a cylindrical mandrel, a large number of rotors are rotatably supported obliquely (with respect to the axial direction) on the original body surface of the cylindrical mandrel, or the mandrels are arranged in a cylindrical shape. The thin cylinders are arranged substantially parallel to each other and obliquely (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 may be axially moved laterally using a rail or the like, or the mandrel may be fixed and the synthetic resin extruder may be moved laterally using a rail or the like.

The present invention provides a pressing member for joining corrugated pipes or a shape-retaining core mold as shown in () below.

() A molten synthetic resin strip is supplied from an extruder around the mandrel, and while it is spirally wound and overlapped, a flexible reinforcing material is added inside or on the back of the strip along the longitudinal direction of the strip. While the corrugated pipe, which has spiral concave and convex portions formed on its surface, is held on the mandrel, the convex and/or concave portions of the corrugated pipe are A pressing member that engages over half the circumference of a corrugated pipe and presses and joins the overlapping portion of the corrugated pipe onto a mandrel, and includes an endless belt-shaped base layer and a surface of this base layer. A pressing member for joining corrugated pipes, which comprises a sliding layer formed at least in a portion close to the mandrel, which has a small sliding friction coefficient and allows slipping when in contact with the mandrel before engagement with the corrugated pipe.

() A molten synthetic resin strip is supplied from an extruder around the mandrel, and while it is spirally wound and overlaid, a reinforcing space is created inside or on the back side of the strip along the longitudinal direction of the strip. While the corrugated pipe, which is partitioned and has spiral concave and convex portions formed on its surface, is held on a mandrel, the molten state is continuously inserted into the reinforcing space formed by the synthetic resin strip. The overlapping part of the corrugated pipe strips is pressed onto a mandrel to join them, and then the partitioning layer of the reinforcing space is cut and taken out. A pressing member for joining corrugated pipes, comprising a sliding layer formed on at least a portion of the surface of the base layer close to the mandrel, which has a small sliding friction coefficient and allows slipping when in contact with the mandrel before being inserted into the corrugated pipe.

() A molten synthetic resin strip is supplied from an extruder around the mandrel, and while it is spirally wound and overlaid, a reinforcing space is created inside or on the back side of the strip along the longitudinal direction of the strip. While the corrugated pipe, which is partitioned and has spiral concave and convex portions on its surface, is held on the mandrel, it is continuously inserted into the reinforcing space formed by the molten synthetic resin strip. An endless belt-like shape-retaining core mold from which the reinforcing space partition layer is cut and taken out, and an endless belt-like base layer, and the surface of this base layer. Among them, a shape-retaining core type consisting of a sliding layer formed at least in a portion close to the mandrel, which has a small sliding friction coefficient and allows slipping when in contact with the mandrel before being inserted into the corrugated pipe.

That is, unlike a normal endless belt, the pressing member for joining corrugated pipes or the shape-retaining core mold according to the present invention has a layer with a low sliding friction coefficient at least in the contact area of the mandrel. Before engagement with the body (including during partial engagement), there is little disturbance of the helical pitch due to contact with the mandrel, and as a result, a corrugated pipe with a uniform helical pitch can be obtained.

(E) Embodiments The present invention will be described in detail below based on specific examples of devices shown in the figures. Note that this invention is not limited to this.

First, in FIGS. 1 and 2, a corrugated pipe continuous manufacturing apparatus 1 includes a synthetic resin extruder 2 that continuously extrudes a synthetic resin strip A in a molten state, and a synthetic resin tubular body B as a flexible reinforcing material. A reinforcing material extruder 3 that continuously extrudes a reinforcing material, and a rotating mandrel 4 that continuously forms a spiral tube C by overlapping the strip A and the tubular body B supplied from these extruders in a spiral manner. , a metal wire supplying means 11 that continuously supplies and interposes an elongated metal wire M between the overlapped portions of the strips, and presses and joins the overlapped portions of the obtained helical tube C, and also forms a spiral to be described later. Convex D
It mainly consists of an endless belt 5 as a linear pressing member for shaping.

The rotating mandrel 4 has a plurality of hollow shafts 6, 7...
... are arranged approximately parallel to each other at predetermined intervals along the circumferential surface of one virtual cylinder, and each hollow shaft has a chain attached to a sprocket provided at the shaft end (left side in Fig. 1), not shown. The rotating mandrel 4 is configured to rotate at a constant speed in the same direction, thereby substantially rotating the rotating mandrel 4.

The endless belt 5 has a cross-section corresponding to the cross-sectional shape of a helical groove E, which will be described later, of the obtained helical tube C, and is movably supported by rollers 8, 9, and 10.

The metal wire supply means 11 includes a roller 14 and a guide 15 that guides the metal wire M from the roller to the overlapping portion of the strips.

Next, the operation of the continuous manufacturing apparatus 1 for corrugated pipes having the above configuration will be explained based on FIGS. 1 and 2.
A continuous manufacturing method for corrugated pipes will now be explained.

The rotating mandrel 4 is rotated (substantially), and the synthetic resin extruder 2 is placed around the rotating mandrel 4.
When a molten polyethylene resin strip A is supplied, the strip is spirally wound to form a spiral tube C. Further, when the strip A is wound, a polyethylene resin tubular body B is supplied from the reinforcing material extruder 3 to the back side of the strip A along the longitudinal direction of the strip A. In this way, the spiral protrusions D 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 superimposing a part of the band-like body A that is previously wound on a part of the band-like body A that is wound later by sandwiching a part of the part through the metal wire M. This overlapping portion is pressed in a wrap-around manner by the endless belt 5, thereby making it more strongly joined. Normally, the speed at which the belt-like 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 both bodies are still in a soft state, so that the overlapping portions of the above-mentioned belt-like bodies are joined. Although this is done to some extent, it may not be sufficient. Conventionally, a pressure roller has been used to press the overlapping portions, but since the pressing time (or distance) is instantaneous, the effect may not be sufficient depending on the state of the synthetic resin.
However, the above-mentioned endless belt 5 presses around the body, that is, about 3.5 turns of spiral rotation (about 360×
If the pressure is continued between 3.5 degrees and 3.5 degrees, the overlapping portions will continue to be joined for a long period of time, so it is sufficiently guaranteed. In addition, the cross section of the endless belt 5 corresponds to that of the spiral concave strips (concave grooves) as the concave portions formed between the spiral convex strips, and is similarly engaged continuously for a long time, so that the desired shape, that is, the desired shape. A corrugated pipe F having a pressure resistance strength of . In particular, the rotation of the rotating mandrel 4 puts the molten state A in the molten state and the tube body B in tension, so that, for example, the tube body B tends to become flat in the direction parallel to the rotation axis of the rotating mandrel 4. However, the above-mentioned endless belt 5
Due to the shaping action, the cross section of the tubular body B is maintained in a predetermined perfect circular shape, and the desired pressure resistance strength is obtained. The metal wire M is mainly used to check whether the overlapping parts of the strips are sufficiently joined (it also has a reinforcing effect).
Dielectric terminal of high voltage/high frequency generator (not shown)
This dielectric terminal and the metal wire M are brought close to each other from the outside.
If a stable spark occurs between the two, it is determined that the bond is insufficient.

Unlike the above example, the overlapping of strips and
The third method of interposing the tubular body between these strip-shaped bodies is
It can also be changed as shown in the figure. That is, the band-like body A has one width and covers the two-wound tubular bodies Ba from the outside.

Next, the continuous corrugated pipe manufacturing apparatus 1b shown in FIG. 4 includes two synthetic resin extruders 2b, 2'b,
Equipped with two endless belts 5b and 5'b,
Furthermore, two metal wire supply means 11'b, 11b are provided. That is, first, a molten polyethylene resin strip A'b is supplied from an extruder 2'b around a rotating mandrel 4b, and the strip is spirally wound and a metal wire M'b is attached to the overlapped portion. A spiral tube C′b is formed therebetween. Since this spiral tube C'b does not have any spiral concave or convex lines, the overlapping part of the spiral lines is pressed by the endless belt 5'b, thereby ensuring the connection. Next, the strip Ab and the tubular body Bb are superimposed on the obtained spiral tube C'b, as in FIG. 1, and a metal wire Mb is further interposed in the overlapped portion. Although the explanation will be omitted, the obtained corrugated pipe Fb has a double pipe structure as shown in FIG. In addition, Gb,
Gb is the overlapping portion of the strip A'b.

Different from each of the above examples, a synthetic resin tubular body may be inserted into the inside of a band-shaped body and wound spirally, and furthermore, a roughly L-shaped cross section can be basically used as a metal member interposed between the overlapped parts. You may use what you have. That is, in FIG. 6A, a synthetic resin tubular body Bc is inserted into the synthetic resin body Ac in a molten state, and is spirally wound around a rotating mandrel (not shown), and a cross section is formed at the overlapped portion. It is formed into a spiral tube with a substantially U-shaped metal member interposed therebetween. And the endless belt 5 shown by the dashed line
c, the overlapping portion Gc of the band-like body Ac is pressed and joined, and the spiral convex line Dc of the band-like body Ac is shaped. The strip body Ac is obtained by feeding the previously molded tube body Bc into a synthetic resin extruder, and extruding it together with the molten synthetic resin from an extrusion nozzle while keeping the tube body Bc in the center. Of course, the opening of the extrusion nozzle has a cross-sectional shape of an approximately inverted T shape corresponding to the cross-section of the strip Ac. The example shown in FIG. 6B is a case where the cross section of the metal member is approximately F-shaped.

The elongated metal member interposed in the overlapped portion of the corrugated pipes may be supplied by a separate feeder from the extruder for the strip, or may be extruded together with the strip by the extruder for the strip. . In addition, by using a metal member with an irregular cross section that has a roughly L-shaped section (basic cross-sectional structure), it is possible to achieve even greater pressure resistance (larger section modulus).
You can get corrugated pipe. In particular, applications that require pressure resistance, such as drain pipes for roads, railways, developed areas, etc., various water supply/drainage pipes such as sewage supply/drainage pipes for factory sites, high-rise housing complexes, etc.
or underground wiring, piping, and their protective pipes;
It is more suitable for a wide range of applications as other buried pressure tubes.

As a further different example, as shown in FIG. , elongated metal wires Myc and Mzc may be interposed in the overlapping portion. In this example, unlike the above example, the inner surface of the corrugated pipe is not flat but has a spiral groove.

Furthermore, belt-shaped bodies as shown in A, B, and C in Figure 6D
When supplying Aαc, Aβc, and Aγc and winding them in a spiral shape so that some overlap, they are simply supplied so that the cross section is flat, and elongated metal wires Mαc, Mβc, and Mγc are interposed in the overlapped portions, respectively. You can also do it. In these cases, the tube is not a corrugated tube, but a simple cylindrical tube, and of course has flat inner and outer cylindrical surfaces.

Furthermore, the spiral tube as described above can be placed over (outside of) the inner spiral tube as shown in FIGS. 4 and 5 to form a double structure as shown in FIG. 7.

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

FIG. 8 FIG. 8 shows an example in which a flexible reinforcing material Be such as hard vinyl chloride resin is inserted on the back surface of the strip Ae along the longitudinal direction of the strip Ae.

Figures 9 to 10 Figure 9 shows a metal member M'xd having a substantially U-shaped cross section being extruded (inserted) together with a molten synthetic resin to form a spiral inner tube A'xd, and then inserted into the inner tube. An example of an apparatus for forming a helical outer tube Axd by extruding (inserting) a synthetic resin tubular body Bxd as a reinforcing member together with a molten synthetic resin around the helical outer tube Axd is shown corresponding to FIG. 1 or 4. It is something. FIG. 10 shows a cross section of the corrugated pipe obtained. In this corrugated tube, since both overlapping portions are at different positions in the tube axis direction, the occurrence of non-adherent portions can be reduced.

Figures 11 to 13 The double-sided 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, and a spiral concave bottom that connects the two pieces, The small horizontal piece Jh and the tip of the large horizontal piece Ih are overlapped and connected by an endless belt (not shown) as appropriate.

Figures 14 to 16 The cross-sectional structure of the strip is shown in Figure 14 as an inverted U.
A hard piece part consisting of a letter piece Hm, a horizontal piece Jm extending horizontally outward from one end (right end) of this piece, and an inclined piece Im extending slightly downward from the other end, and a downward opening part of this hard piece. Consists of a closed hard piece Km. 15 and 16 show examples in which the cross-sectional structure of the strip is slightly different from the above.

FIG. 17 A separate reinforcing layer may be formed around the outer periphery of the spiral convex portion of the corrugated pipe obtained as described above.
In particular, a large number of fine protrusions may be formed on the surface in order to strengthen the reinforcing force. In the example shown in Figure 17, a large number of fine protrusions Ns, Ns are formed on the surface of the top of the protruding part, and by increasing the section modulus of the protruding part, the structure is air-permeable, so it does not sink. The top part, which is prone to scratches and holes, is reinforced. In addition, scratches tend to be noticeable at the top of the protruding parts, but these fine protrusions solve this problem, and these protrusions can also be used as fins to promote heat exchange (especially for reinforcing the molten state). (This has the effect of cooling the layer quickly).

Next, still other embodiments of the present invention will be described in detail based on the drawings.

This embodiment device shown in FIGS. 18 to 20 is applied to a manufacturing device for synthetic resin corrugated pipes in which the pipe diameter and the helical pitch of reinforcing strips can be changed. In the figures, 101 is the base. stand, 10
Reference numeral 2 denotes a face plate that is fixedly supported on the base 101 via a number of support rods 103, and the base 101 and the face plate 102 rotatably support the operating shaft 104.

Several shaping shafts 105 are arranged along a virtual cylindrical surface centered on the operating shaft 104, and each shaping shaft 105 is connected to a respective universal joint 106.
It is composed of a long axis 105a with a large diameter and a short axis 105b with a small diameter, which are connected through It is slightly inclined with respect to the operating axis 104. Further, each of the short shafts 105b is connected to a driving means (not shown) via a connecting shaft 107 which can be expanded, contracted and bent, and this driving means causes each of the forming shafts 105 to move simultaneously in the same direction. It is designed to be driven.

Further, the actuating shaft 104 is equipped with top members 108a and 108b that move toward or away from each other in the axial direction by rotating the actuating shaft 104. Connecting rods 109a, 109b
The respective forming shafts 105 are supported on the actuating shaft 104 so as to be movable in the radial direction by being pivotally mounted via the
08b relative to the operating shaft 104, the inclination angle of each forming shaft 105 with respect to the operating shaft 104 is changed.

In this embodiment, a plurality of molding shafts 105 are used to vary the diameter of the synthetic resin pipe to be molded and the helical pitch of the reinforcing strips, and the construction is as described above. If the tube diameter and helical pitch are not variable, a general molding shaft may be used. The general forming shaft referred to here is one that is conventionally known, such as a forming shaft constructed by arranging and supporting a large number of roller shafts in an inclined manner around the outer periphery of a single forming main spindle using a cylindrical cage. It may have any structure.

The strip material 110 wound over the above-mentioned molding shafts 105 is made of, for example, polyolefin-based hard synthetic resin such as polyethylene resin or polypropylene resin, or vinyl chloride resin, and is formed by extrusion molding means. 112 molding die 1
13 is extruded into a desired shape, for example, a flat plate, and is supplied in a semi-molten state onto each forming shaft 105, and is spirally wound so as to span between the upper parts of each forming shaft 105, and the overlapping portion is filled with metal. A wire 100M is fed from a roller 111 via a guide 115. Then, on each molding shaft 105, as shown in FIG. 19, a molding core mold 114 (to be described later) forms a U-shaped cross section (inverted U-shaped piece) 110a, and from the lower end of one side of the U-shaped portion 110a. An extending plate-shaped long side portion (large horizontal piece) 110b and a plate-shaped short side portion (small horizontal piece) 110c extending from the lower end on the other side are formed in series.

On the other hand, a flexible, endless molding core mold 114 is wound spirally over the molding shafts 105.

The above-described molding core mold 114 is, for example, a strip material 1
It is made of a single piece of flexible belt material having approximately the same cross-sectional shape as the U-shaped portion 110a of No. is extended to the starting end of the winding, and both ends are connected to form an endless shape. Note that the top of the core mold 114 is provided with a V-shaped groove 1 that allows a cutter 118 (to be described later) to enter.
14a is formed, and if necessary, a guide roller 115 is provided at the starting end where the strip material 110 enters during winding, as shown in FIG.
The approach position is regulated.

In addition, similar to the core mold 114, this core mold 11 extends over each molding shaft 105 and is spirally wound.
An endless body 116 for holding down the strip material 110 is wound spirally so as to be located between the ends of the strip material 110.
Like the core mold 114, this endless body 116 also extends the winding end to the winding start end and connects both ends to form an endless shape. 110 is formed and then wrapped over it. In the figure, 117 is a guide roller that guides the endless body 116 to enter.

Therefore, as described above, the strip material 110 is spirally wound using the molding core mold 114 and the endless body 116 on each molding shaft 105 to form a spiral reinforcing strip (protruding strip portion) 100B around the outer periphery. Synthetic resin pipe 1 equipped with
When forming 00A, a cut groove 100C is continuously formed on the top of the reinforcing strip 100B, and then,
It is configured to close the kerf 100C, and
A cutter 118 is disposed in front of the synthetic resin pipe 100A in the helical advancing direction, and this cutter 1
Extrusion molding means 119 ahead of 18 in the spiral advancing direction
A molding die 120 is disposed to form the reinforcing strip 10.
A synthetic resin strip material (strip material) 111 of the same quality as the strip material 110 is supplied and attached to the top of 0B.

Next, the operation of this corrugated pipe manufacturing apparatus will be explained.

First, the molding die 113 of the extrusion molding means 112
The semi-molten strip material 110 supplied from the forming shaft 105 is wound so as to span between the forming shafts 105 that are driven and rotated simultaneously. At this time, between the upper parts of each molding shaft 105,
Since the molding core 114 is wrapped in advance, the strip material 110 is formed to form a U-shaped portion 110a, a long side portion 110b, and a short side portion 110c. In addition, each molding shaft 105
Since the strip material 110 is slightly inclined, the strip material 110
is spirally wound, and each preceding material 1
The strip material 11 that follows on the long side portion 110b of 10
The U-shaped portion 110a of 0 and the short side portion 110c overlap, and a metal wire 100M is further interposed in the overlapping portion. Then, they are integrally welded to form a synthetic resin tube 100A having a spiral reinforcing strip 100B on the outer periphery and a flat inner surface of the tube wall. In particular, the spiral reinforcing strips 100B are formed by the U-shaped portion 110a, and the long side portions 11 overlap with each other.
0b and the short side portion 110c form a tube wall, and the inner surface of this tube wall is flat.

On the other hand, the reinforcing strip 100 of the synthetic resin pipe 100A
An endless body 116 is supplied to the outer periphery between B, and the long side portions 11 overlap each other as described above.
0b and the short side portion 110c are pressed together to further enhance the state of polymerization, thereby ensuring reliable welding.

Next, the cutter 118 is inserted into the top of the reinforcing strip 100B of the synthetic resin pipe 100A that is continuously molded as described above to continuously form the kerf 100C at the top of the reinforcing strip 100B. 10
The core mold 114 is extracted from within the reinforcing strip 100B via 0C and returned to the winding start end. In addition,
The cutter 118 is connected to the V-shaped groove 1 of the core mold 114.
Since the cutting edge penetrates up to 14a, the cutting can be performed completely. In addition, the reinforcement strip 100B
The core mold 114 is cooled to such an extent that it does not lose its shape when removed.

After this, the molding die 12 of the extrusion molding means 119
A reinforcing strip 100 is formed from a semi-molten strip material 111.
It is supplied to the top of reinforcing strip 100B and closes kerf 100C at the top of reinforcing strip 100B. This strip material 1
Reference numeral 11 is made of the same synthetic resin as the shape material 110, and is formed into a plate shape having the same width as the top of the reinforcing strip 100B. Also, the above cut groove 100C
, which expands when the core mold 114 is extracted;
After being extracted, the material does not close completely and remains slightly open, but the semi-molten strip material 111 partially enters into the kerf 100C and solidifies, resulting in the reinforcing strip separated by the kerf 100C. It plays the role of a binder to firmly join the top of 100B.

Although the synthetic resin pipe 100A formed as described above clearly shows the joining boundaries of the strip material 110 and the strip material 111 in the illustrated example, in reality, all of the same materials are thermally welded and integrated. ing.

As shown in FIG. 22, the synthetic resin pipe 100A manufactured by the apparatus of this embodiment has a pipe wall formed by a long side portion 110b and a short side portion 110c that overlap each other and are continuous in the tube axis direction. Something,
Its inner surface is flat, achieving flexibility and low resistance to the flow path inside the pipe, and the spiral reinforcing strip 100B is formed by the U-shaped portion 110a, providing high pressure collapse resistance. It can give strength.

It should be noted that the present invention is not limited to the structure described in the above-mentioned embodiments, and design changes and improvements can be made as appropriate. For example, as shown in FIGS. 23 and 24, from the lower part of the molding die 113 in the extrusion molding means 112,
14 may be sent out together with the strip material 110, wound spirally around the forming shaft 105, and the end of the winding may be returned to the lower part of the forming die 113.

Further, as shown in the figure, one or several ring-shaped endless bodies 116a are used, and this is attached to the forming shaft 10.
Reinforcement strip 1 of synthetic resin pipe 100A to be shaped on 5
00B spirals, and a sliding body 116b such as a pulley having a weight 116c is hung from the lower end of each ring-shaped endless body 116a.
10 overlapping long and short side portions 110b, 11
0c and prevention of deformation of the U-shaped portion 110a may be performed. At this time, the weight 116c is made replaceable, and the long and short side portions 100
It may also be possible to adjust the crimp loads of b and 110c.

In addition, in any of the above embodiments, the strip material 11
0 is molded into a flat plate shape, which is then wrapped in a semi-molten state around a core mold 114, but instead of this, a U-shaped portion 110a, a long side portion 110b, and a short side portion 110c are formed. Strip material 1 consisting of
10 is molded in advance with a molding die 113,
This formed strip material 110 may be supplied onto a forming shaft 105, and in addition to the strip material 110 provided with a single U-shaped portion 110a, the strip material 110 may be provided with two U-shaped portions as shown in FIG. Individually formed,
Alternatively, three or more may be formed and each may be polymerized during molding. Further, as shown in FIG. 26, a thin wall portion 110d may be formed in advance at the top of the U-shaped portion 110a, so that the subsequent formation of the kerf 100C can be easily and reliably performed.

Further, the strip material 111 may enter into the cut groove 100C as in the previously described embodiment, but it may also not enter into the groove 100C as shown in FIGS. 27 to 29, or as shown in FIG. As shown, the width of this strip material 111 may be slightly larger than the width of the cut groove 100C, and further, as shown in FIG.
It may be shaped so as to cover the entire area.

Moreover, the cut groove 1 formed at the top of the reinforcing strip 100B
For 00C, the blade thickness of the cutter 118 may be made extremely thin so that there is no gap as shown in FIG.

In addition, the molding core mold 114 and the endless body 116 can be made of hard rubber, synthetic resin, leather, etc., in addition to being made of belt material, and can also be made of metal such as aluminum or aluminum alloy. can. In this case, it may be divided into a large number of blocks, and these blocks may be connected in a bendable manner using wires or the like. At this time, a thin belt material may be attached to the inner surface. In addition to the trapezoidal cross section, the cross section may also be semicircular, square, or round, if necessary.

FIG. 31 shows an example of a synthetic resin pipe having a reinforcing strip 100B with a semicircular cross section, and the same reference numerals are given to the parts corresponding to the parts of the previous embodiment, and the explanation thereof will be omitted.

Here, the obtained corrugated pipe has a band-shaped material (reinforcing layer) on its surface that closes the kerf 100C to be formed and also reinforces the protruding portion. As shown in the figure, a large number of fine protrusions 100Nt, 100Nu, and 100Nv may be provided to strengthen the reinforcing force.

Now, when manufacturing the above corrugated pipe, in order to press and join the overlapping parts of the strips, pressing members (5 in Fig. 1, 5b and 5'b in Fig. 4, 5xb and 5 in Fig. 9) are used. 'xb, 1 in Figure 18
16) and core mold for endless belt-like molding (first
114) in Figure 8 is used. However, as these pressing members and core types, endless belts that are normally used for power transmission can be easily used, but since the main purpose of this endless belt is to transmit power, the surface of the endless belt is similar to that of the pulley to which power is transmitted. It has been treated to prevent slipping as much as possible (the coefficient of sliding friction is large).

However, as for the pressing member and the core mold used in manufacturing the above-mentioned corrugated pipe, on the contrary, as shown in FIG. 35, among the base layer 221 of the core mold 214 and the surface of this base layer,
A sliding layer 222 is formed near the mandrel, has a small sliding friction coefficient, and allows sliding when in contact with the mandrel before engagement with the corrugated pipe.
Those consisting of the following are preferably used.

In other words, by making the pressing member and the core mold slippery against the mandrel, the pressing member and the core mold can be easily slid against the mandrel before the pressing member and the core mold engage with the molten synthetic resin strip as shown in FIG. ), even if it makes contact with the mandrel 204, the contact resistance is small, so the helical pitch P is uniformly maintained at a predetermined size as a whole, thereby obtaining a corrugated pipe with a predetermined pressure resistance strength. That's why. Note that a pressing member is wrapped around the mandrel 204 in FIG. 36, similar to the core mold 214, but is not shown. Further, 223 is another mandrel for stretching the core mold 214 and the mandrel 204.

The same applies to the pressing member 314 as shown in FIG. 37, but as shown in FIGS. 38 to 39, the side wall of the pressing member 314 may come into contact with the pressing member 314 while being wound in a spiral shape, and in order to reduce this contact resistance. A slipping layer 322 is also provided on the spiral pattern to prevent the spiral pattern from being deformed.

Here, the material of the sliding layer 222 of the core mold 214 and that 322 of the pressing member 314 is a synthetic resin such as tetrafluoroethylene resin (Teflon resin), polyamide resin (nylon resin), polyacetal resin (Dyuracon resin), or cotton. Woven fabrics such as woven fabrics and Tetoron woven fabrics can be suitably used. Specifically, Kotsuton woven fabric is 1.2 mm thick, made by weaving cotton single fibers with a thickness of 0.3 mm in a criss-cross pattern.
mm (referred to as “CC canvas”) is an example.
Synthetic rubber (cushion rubber) is laminated to this woven fabric, and the rubber is adhered to the pressing member or the base layer of the core type with an appropriate adhesive. On the other hand, as Tetoron woven fabric,
A specific example is one in which 0.8 mm thick thread made from single fibers of saturated polyester resin (such as Tetron) is woven in a criss-cross pattern and hardened with adhesive (for example, "Tetron Canvas").

Note that as the materials for the pressing member and the base layer of the core type, materials applicable to ordinary endless belts can be used as they are.

(f) Effects of the Invention According to this invention, since the pressing member for joining corrugated pipes or the shape-retaining core mold has a layer with a small sliding friction coefficient at least in the contact portion with the mandrel, it is possible to easily synthesize the molten state. Before engagement with the resin strip (including during partial engagement), there is little disturbance of the helical pitch due to contact with the mandrel, thereby making it possible to obtain a corrugated pipe with a uniform helical pitch.

[Brief explanation of the drawing]

FIG. 1 is a functional explanatory perspective view of an example of a corrugated pipe manufacturing apparatus according to the present invention, and FIG. 2 is a vertical cross-sectional view of a corrugated pipe obtained by the apparatus.
Figure 3 is a diagram equivalent to Figure 2 showing another example, Figure 4 is a diagram equivalent to Figure 1 showing another example, Figure 5 is a diagram equivalent to Figure 2, Figure 6 A, B, C, D, E, Figures 7 and 8 are all equivalent to Figure 2 showing other examples;
Fig. 9 is a diagram corresponding to Fig. 1 showing still another example, and Fig. 10 shows another example.
The figure is a diagram corresponding to Figure 2, Figure 11 is a partial side explanatory view of a corrugated pipe showing another example, Figure 12 is a vertical cross-sectional view of the corrugated pipe, and Figure 13 is an essential view of the vertical cross-sectional view. 14 to 17 are views corresponding to FIG. 13 showing still another example, FIG. 18 is a plan view showing another embodiment of the present invention, and FIG.
The figure is a partially cutaway enlarged plan view of the main part, Figure 20 is a side view, Figure 21 is a sectional view of the strip material molded on the forming axis, Figure 22 is an explanatory diagram of the molding process, and Figure 23 is FIG. 24 is a side view of the main part showing another embodiment, FIG. 24 is a plan view thereof, and FIGS. 25 to 34 are cross-sectional or end views showing different patterns of the strip material. FIG. 35 is a cross-sectional view showing another embodiment of the core mold, FIG. 36 is a plan view showing how the core mold is used, and FIG. 37 is a cross-sectional view showing another embodiment of the pressing member. 38 is a view corresponding to FIG. 2 when the pressing member is used, and FIG. 39 is an explanatory diagram of the entire structure of the pressing member. DESCRIPTION OF SYMBOLS 1... Continuous manufacturing apparatus for corrugated pipes, 2... Synthetic resin extruder, 3... Reinforcement extruder, 4... Rotating mandrel, A... Band-shaped body, B... Flexible reinforcing material, C... Spiral tube, D...Spiral convex line (convex line part),
F...Corrugated pipe.

Claims (1)

[Scope of Claims] 1. A molten synthetic resin strip is supplied from an extruder around a mandrel, and while it is spirally wound and overlapped, a synthetic resin strip is supplied inside or on the back side of the strip along the longitudinal direction of the strip. By forming a reinforcement space into sections,
In a corrugated pipe that has spiral concave and convex portions formed on its surface, the convex portions are inserted into the reinforcing space formed by the molten synthetic resin strip while the corrugated tube is held on the mandrel. The shape-retaining core mold is inserted and shape-retained, and then the partitioning layer of the reinforcing space is cut and the shape-retaining core mold is taken out, and the cut portion is closed from the outside with a separately supplied strip material. and a corrugated pipe in which at least the top portion of the outer circumferential surface of the strip material has a large number of fine reinforcing ridges along the longitudinal direction of the top portion. 2. A molten synthetic resin strip is supplied from an extruder around the mandrel, and while it is spirally wound and overlaid, a flexible reinforcing material is attached inside or on the back side of the strip along the longitudinal direction of the strip. While the corrugated pipe, which defines a space for insertion or reinforcement and has a spiral concave and convex portion on its surface, is held on a mandrel, the corrugated pipe is attached to the convex portion and/or concave portion of the corrugated tube. A pressing member that engages over more than half the circumference of the corrugated pipe and presses and joins the overlapping portion of the corrugated pipe band onto the mandrel, and includes an endless belt-shaped base layer and the surface of this base layer. A pressing member for joining corrugated pipes, comprising a sliding layer formed at least in a portion close to the mandrel and having a small sliding friction coefficient that allows slipping when in contact with the mandrel before engagement with the corrugated pipe. 3. A molten synthetic resin strip is supplied from an extruder around the mandrel, and while it is spirally wound and overlapped, a reinforcing space is defined inside or on the back side of the strip along the longitudinal direction of the strip. form,
Spiral concave on the surface. While the corrugated tube in which the convex portion is formed is held on the mandrel, it is continuously inserted into the reinforcing space formed by the molten synthetic resin strip, and the corrugated tube is inserted into the overlapping portion of the strip. Press onto the mandrel to join.
Next, the dividing layer of the reinforcing space is cut and taken out.The pressing member is in the form of an endless belt, and is formed on the surface of this base layer at least in a portion close to the mandrel to prevent sliding friction. A pressing member for joining corrugated pipes, comprising a sliding layer that has a small coefficient and allows slipping when in contact with a mandrel before being inserted into a corrugated pipe. 4. A molten synthetic resin strip is supplied from an extruder around the mandrel, and while it is spirally wound and overlaid, a reinforcing space is defined inside or on the back side of the strip along the longitudinal direction of the strip. form,
While the corrugated pipe, which has spiral concave and convex portions formed on its surface, is held on the mandrel, it is continuously inserted into the reinforcing space formed by the molten synthetic resin strip, and the corrugated pipe is An endless belt-like shape-retaining core mold that maintains the shape of the strip and then cuts and takes out the partitioning layer of the reinforcing space, the endless belt-like base layer and at least the surface of this base layer. A shape-retaining core type consisting of a sliding layer that is formed near the mandrel and has a small sliding friction coefficient that allows it to slip when it comes into contact with the mandrel before being inserted into the corrugated pipe. 5 The slip layer is made of cotton woven fabric, Tetoron woven fabric,
The pressing member according to claim 2 or 3, or the shape-retaining core mold according to claim 4, which is a Teflon resin layer or a nylon resin layer.