JPH0522709Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is made of synthetic resin that is flexible and resistant to strong pressure from inside and outside, such as when buried underground like an underdrain drain pipe. This relates to flexible tubes.

(Prior Art and Problems) Conventionally, a synthetic resin flexible tube is well known, in which a hard synthetic resin reinforcing wire is helically wound and fixed on the outer peripheral surface of a soft synthetic resin tube. For example, because a reinforcing wire with a solid or square-shaped cross section is wound and fixed to the outer peripheral surface of the soft pipe over its entire width, the peripheral wall of the soft pipe at this fixed part becomes rigid due to the reinforcing wire. In addition, the elasticity of the surrounding wall material tends to deteriorate due to the bending of the synthetic resin pipe, and the internal stress caused by the expansion and contraction of the soft pipe surrounding wall that occurs when the synthetic resin pipe is bent is almost non-existent in the part where the reinforcing wire is integrated. It doesn't work,
If the reinforcing wire is concentrated only on the portions located between the helical pitches, a phenomenon of localized stress concentration will occur, which not only tends to cause fatigue in the soft pipe, but also causes damage to the synthetic resin pipe. As a result, flexibility, which is one of its functions, was hindered.

In order to improve this drawback, for example,
No. 26725 proposes a synthetic resin pipe in which a reinforcing wire made of soft synthetic resin is formed into a U-shape, and the open end of the reinforcing wire is spirally wound and fixed to the outer peripheral surface of the pipe. I see, if the reinforcing wire is made into a U-shape, the inside of the open end of the U-shape becomes free when the synthetic resin pipe is bent. It is understood that the soft parts between the reinforcing wires (pitch intervals) also expand and contract as one, so the internal stress caused by expansion and contraction is dispersed throughout the soft pipe, preventing local stress concentration and preventing local fatigue. I can do it. However, on the other hand, if the reinforcement wire wound spirally on a soft tube is U-shaped, the open end of the U-shape is a free end, so if external pressure is applied perpendicular to the axis of the tube. Unlike a solid or hollow structure, the open end is subject to large deformation, and the pressure resistance is weak when a large external pressure is sometimes applied.
For example, when it is buried in the ground and used as a drainage pipe, or when it is used underground as a suction/drainage pipe by drilling holes in the pipe body, the pressure resistance strength against earth pressure is particularly weak, which causes problems. Furthermore, when the tube is bent, deformation occurs in the direction in which the U-shaped open ends approach each other on the inside of the bend, and in the direction in which the U-shaped open ends spread out from each other on the outside, so that twisting occurs in the middle. However, there were problems in that it was prone to buckling and its compressive strength was weakened.

(Means for solving the problems) The present inventor arrived at this invention in order to improve the above-mentioned problems.

That is, in the present invention, in a tube consisting of a soft synthetic resin pipe and one or more hard hollow threads made of synthetic resin that are integrally wound around the outer periphery of the soft pipe, one hard hollow thread is formed along its longitudinal direction. It is integrated with the soft tube by a set of spiral contact parts consisting of two or more linear parts continuous in the direction, and between the set of spiral contact parts there are (1) soft pipes, counting from the inside. It is characterized by a structure in which three walls are separated from each other by a space: a part of the wall, (2) a fold that is the inner wall of the hard hollow strip, and (3) an outer wall (rib) of the hard hollow strip. It is a flexible tube.

In the present invention, one hard hollow strip is integrated with a soft tube through a pair of spiral contact parts made up of two or more strip parts,
A concrete example of a structure in which three walls are spaced apart between the pair of contact portions is shown in FIG. 1. In FIGS. 1a to 1g, only the portion where the hard hollow strip 1 is integrated with the soft tube 2 is schematically shown in cross section. The part where the hard hollow strip contacts and integrates with the soft tube is not integrated over the entire width of the hollow strip as in the case of the square-shaped hard hollow strip of the prior art, but at both ends of the hollow strip. The present invention is characterized in that it is integrated by a set of spiral contact parts made up of two or more linear parts continuous in the longitudinal direction. Therefore, as seen in FIG. 1, between the pair of spiral contact parts, counting from the inside, there are (1) a part of the soft pipe wall, and (2) a pleat part that is the inner wall of the hard hollow strip. , (3) It has a structure in which three outer walls (ribs) of hard hollow strips are separated from each other by a space. The folds are not only simple chevrons, but also arcuate (Fig. 1c) and twin chevrons (Fig. 1a).
Any shape is acceptable as long as it is curved so as to create a space between it and the outer wall of the soft tube. As shown in FIG. 1e, there may be a portion that comes into contact with and integrates with the intermediate soft tube. The cross-sectional shape of the outer wall (rib) of the rigid hollow strip may be gate-shaped (Fig. 1 a to e), arc-shaped (Fig. 1 f), chevron-shaped (Fig. 1 g), etc. Any shape that is curved so as to separate a space and exhibits a reinforcing effect against pressure from inside and outside may be used. With this structure, even when the synthetic resin pipe is bent, the folds 3 facing the soft pipe can be bent.
This produces an accordion effect, and there is no buckling phenomenon as in the U-shaped case, resulting in a flexible tube with excellent pressure resistance, flexibility, and durability.

The manufacturing method may be a known method, but for example, two extruders may be used, one extruding the soft resin as a tape-like object and rolling it overlappingly to form a pipe-like object, and the other extruding machine extruding the hard resin into a hollow tape-like object. This is a method of superimposing a soft tube that has been extruded into a strip structure, winding it spirally, and integrally joining each other by heat fusion.The specific tube manufacturing equipment is
30399, Japanese Patent Publication No. 46-12000, Japanese Patent Publication No. 46-17919, methods include Japanese Utility Model Application Publication No. 60-14918, and Japanese Patent Application Publication No. 60-18333. Alternatively, the resin streams from the two extruders may be extruded from one extrusion die and wound to overlap to form a pipe. Furthermore, a method may also be used in which a hollow strip is extruded from an extrusion die that rotates around the extruded tube and wound around the extruded tube.

The flexible tube of the present invention has an appearance as shown in FIG. 2, but the soft tube between the hollow strips may have through holes as shown in FIG. 3. When a through hole is bored in this way, it is suitable for use as an intake/drainage pipe for regulating the groundwater level of golf courses, grounds, roads, etc., and is especially suitable for developed areas that require pressure resistance. It is also good for underdrain drainage pipes for agricultural fields. If there are no through holes, it is suitable for civil engineering work, construction work, and ocean-related drainage that require pressure resistance. For example, rainwater drainage pipes running along roads, pipes attached to drainage basins, forest roads, work roads, drainage when constructing farm roads, sewage rainwater attachment pipes for sewers, drainage running across tunnels, drainage when constructing land, irrigation drainage from rice fields, bridge culvert drainage, etc. suitable for

(Effects of the Invention) Since the present invention is constructed as described above, the part where the hollow strip and the soft tube are integrated in a square shape is flexible without becoming a rigid body, so the flexible tube is It has good durability as the expansion and contraction does not concentrate between the hollow strips when it is bent. Also, unlike U-shaped hollow strips, it does not buckle under pressure and is suitable for burial underground.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of various hollow strips of the flexible tube of the present invention, Fig. 2 is a schematic external view of one example of the flexible tube of the present invention, and Fig. 3 is another example of the flexible tube of the present invention. FIG. 2 is a schematic external view of an example. 1 is a hollow strip, 2 is a soft tube, 3 is a fold, and 4 is a through hole.

Claims (1)

[Scope of utility model registration request] In a tube consisting of a soft synthetic resin pipe and one or more hard hollow threads made of synthetic resin that are integrally wound around the outer periphery of the soft pipe, one hard hollow thread is continuous in its longitudinal direction. It is integrated with the soft tube through a set of spiral contact parts made up of two or more filament parts, and between the set of spiral contact parts there is (1) part of the soft pipe wall, counting from the inside. (2) a pleat part which is an inner wall of the hard hollow strip, and (3) an outer wall (rib) of the hard hollow strip, each having a structure in which three walls are separated from each other by a space. Flexible tube.