JP5897338B2 - Synthetic resin flexible tube - Google Patents

Description

The present invention relates to a flexible tube made of synthetic resin. In particular, the present invention relates to a cable protection tube when installing a power cable or a communication cable.

As this type of cable protection tube, water tightness may be required in addition to the strength of the tube, such as when the protection tube is buried in the ground. In recent years, so-called spiral pipes, in which synthetic resin strips are spirally wound and integrated, are used as cable protection pipes because of the ease of laying protective pipes and the ability to follow ground fluctuations. ing.

For example, Patent Document 1 has a fitting portion that is bifurcated and has a retaining portion on the inner edge of the opening end on one side edge by a specific resin composition, and is slidable in the fitting portion. A belt-shaped synthetic resin profile having a locking portion to be fitted and locked at the other side edge is formed by profile extrusion, and this profile is wound in a spiral shape and is engaged with the fitting portions adjacent to each other in the wound state. There is disclosed a spiral tube (claims) characterized by being formed into a cylindrical shape by fitting a stop portion. And it discloses that the water stop material which consists of elastic bodies, such as a synthetic rubber, is provided in the one side of the opposing surface of this securing part.

The spiral tube disclosed in Patent Document 1 has flexibility and stretchability, and also has a water-stopping property as a tube because a water-stopping material made of an elastic body is provided.

JP 2001-145954 A

However, since the spiral tube disclosed in Patent Document 1 is made of an elastic body such as a synthetic rubber, it has been found that it is difficult to improve both the flexibility and the waterproof property of the tube. did. That is, the elastic body, which is a water-stopping material, does not exhibit water-stopping properties unless it is compressed, but if a water-stopping material is provided in a compressed state, sliding of the synthetic resin profile that forms the flexible tube It has been found that the flexibility of the tube deteriorates and the flexibility of the tube deteriorates. When the flexibility of the tube is deteriorated, the handleability and workability of the tube are deteriorated.

Accordingly, an object of the present invention is to provide a flexible tube made of a synthetic resin that can achieve both flexibility and waterstop.

As a result of intensive studies, the inventors have found that if the water-stopping material is made of a water-swellable non-woven fabric, the slidability between the water-stopping material and the synthetic resin profile is improved, and the present invention has been completed. .

The present invention is a flexible tube formed by spirally winding a strip made of synthetic resin, which is an extruded product having a predetermined cross section, and one side edge of the strip is a bifurcated first fitting The other side edge of the strip is a second mating side edge, and the second mating side edge is a first mating side edge adjacent in a wound state. The first locking portion provided at the first fitting side edge and the second locking portion provided at the second fitting side edge are slidably inserted between the two forks. By doing so, it is prevented that the second fitting side edge is separated from the fork of the first fitting side edge, and the strip is formed as a cylindrical flexible tube, and the first One of the two fitting side edge portions has an extension portion formed longer than the other, and a water-stopping material made of a water-swellable non-woven fabric is connected to the extension portion of the first fitting side edge portion and the first fitting side edge portion. 2 In the area where the mating side edge faces A synthetic resin flexible tube provided in the spirally (first invention). The present invention also relates to a method for producing a flexible tube made of synthetic resin, in which a flexible tube is formed by spirally winding a synthetic resin strip that has been extruded into a predetermined cross section. The side edge is a bifurcated first fitting side edge, the other side edge of the strip is a second fitting side edge, and the second fitting side edge is in a wound state. The first engagement portion provided on the first fitting side edge and the second fitting side edge are slidably inserted between the two forks of the first fitting side edge adjacent to each other. When the second engaging portion is engaged, the second fitting side edge is prevented from coming off between the two forks of the first fitting side edge, and the strip is cylindrical. A water-stopping material made of a water-absorbing expandable non-woven fabric is formed on the flexible tube, and has an extension portion in which one of the forked portions of the first fitting side edge portion is longer than the other. The extension of the mating side edge and 2 mating side edges provided in a spiral shape at a site facing a method for producing a synthetic resin flexible tube (a fourth aspect of the invention).

In the first invention , it is preferable that an extension is formed on the side located on the inner side of the flexible tube in the fork of the first fitting side edge ( second invention). Moreover, in 1st invention or 2nd invention, it is an extension part in the side edge side of the said strip rather than the 1st latching | locking part provided in the side by which the extension part was provided among the two forks of the 1st fitting side edge part. Is preferably arranged ( third invention).

According to the manufacturing method of the synthetic resin flexible tube of the first invention and the synthetic resin flexible tube of the fourth invention , it is possible to obtain the effect that both flexibility and water stoppage of the tube can be achieved. Furthermore, since the extension portion is provided at the first fitting side edge portion and the water stop material is disposed in the extension portion, the manufacturing efficiency and the manufacturing quality of the pipe can be improved.

Also, if further as the second invention, in particular, production efficiency and product quality of the pipe is enhanced. In addition, when the third invention is used, the water stoppage of the tube is further increased.

It is a partial cross section figure of the flexible tube of 1st Embodiment of this invention. It is an expanded sectional view of the tube wall part of the flexible tube of a 1st embodiment of the present invention. It is sectional drawing of the resin strip which comprises the flexible tube of 1st Embodiment of this invention. It is an expanded sectional view of the tube wall part of the flexible tube of a 2nd embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking a cable protection tube buried in the ground as an example. In addition, this invention is not limited to the separate embodiment shown below, The form can also be changed and implemented.

FIG. 1 is a partial cross-sectional view of a flexible tube according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the tube wall portion of the flexible tube according to the first embodiment of the present invention. In these drawings, a state where the flexible tube having elasticity is contracted is illustrated. The flexible tube 1 is a flexible tube formed in a cylindrical shape by spirally winding a synthetic resin strip S that is extruded in a predetermined cross section.

The flexible tube 1 has elasticity and flexibility. For example, the flexible tube 1 is buried in the ground and used for use as a lead-in tube that is piped to a household from a central tube of information communication cables in the ground. The An electric signal line, an optical fiber cable, or the like is inserted into the flexible tube 1, and the flexible tube 1 functions as a cable protection tube.

In FIG. 3, the cross-sectional shape of the synthetic resin strip S which comprises the flexible tube 1 is shown. The strip S is a strip obtained by extrusion molding of a synthetic resin, and one side edge of the strip S is a bifurcated first fitting side edge S1, and the other side of the strip. The edge is a second fitting side edge S2.
The first fitting side edge portion S1 includes an inner fitting piece S11 located inside the flexible tube and an outer fitting piece S12 located outside the flexible tube. The inner fitting piece S11 and the outer fitting piece S12 extend substantially parallel to the central axis of the flexible tube 1, and a space having a predetermined width exists between them. The second fitting portion S2 has a second fitting piece S21 that extends substantially parallel to the central axis of the flexible tube 1.

As shown in FIG. 2, in the state where the strip S is spirally wound into the flexible tube 1, the first fitting side edge S1 and the second fitting side edge S2 are adjacent to each other. Fitting side edges fit together. That is, the adjacent second fitting piece S21 is inserted and fitted into the space between the inner fitting piece S11 and the outer fitting piece S12. That is, the second fitting side edge S2 is inserted between the two forks of the first fitting side edge S1 adjacent in the wound state. And 1st fitting side edge part S1 and 2nd fitting side edge part S2 are not mutually fixed, but fit so that the sliding to the center axis direction of the flexible tube 1 is possible.

A first locking portion S13 is provided at the side end portion of the outer fitting piece S12 of the first fitting side edge S1 so as to protrude toward the inner fitting piece S11. Moreover, the 1st latching | locking part S13 protrudes also in the inner fitting piece S11 of 1st fitting side edge part S1 so that the 1st latching | locking part of outer side fitting piece S12 may be opposed.

On the other hand, a second locking portion S23 is provided at the side end portion (tip end portion) of the second fitting piece S21 of the second fitting side edge portion S2 so as to protrude to the inside and the outside of the hose, respectively. .

In the state where the strip S is the flexible tube 1, the second locking portion S23 is positioned so as to be sandwiched between the inner fitting piece S11 and the outer fitting piece S12, and is opposed to the first engagement member. The second fitting piece S21 is held between the stop portions S13 and S13. Then, when the second fitting side edge S2 tries to disengage from between the two forks of the first fitting side edge S1, the first engaging portion S13 and the second engaging portion S23 are engaged with each other, and are separated. And maintain the cylindrical tube wall structure of the flexible tube.

And in this invention, the water stop material P which consists of a water absorptive expandable nonwoven fabric is provided helically in the site | part which 1st fitting side edge part S1 and 2nd fitting side edge part S2 oppose. In the present embodiment, the inner fitting piece S11 and the second fitting piece S21 are provided at portions facing each other in the radial direction of the pipe. Furthermore, in this embodiment, the water stop material P is bonded and integrated to the inner fitting piece S11 of the strip S. The strip S and the water stop material P may be non-bonded to each other.

Furthermore, in this embodiment, the inner fitting piece S11 extends toward the strip side longer than the outer fitting piece S12. That is, one of the first fitting side edge portions (inner fitting piece S11) has an extension S111 formed longer than the other (outer fitting piece S12).
And it extends in the position used as the side edge side of the said strip S rather than the 1st latching | locking part provided in the side (inner side fitting piece S11) in which the extension part was provided among the two forks of the 1st fitting side edge part. Part S111 is arranged.

And in this embodiment, the water stop material P is arrange | positioned in the part of extension part S111. More specifically, a stopper S14 is provided at the side edge (tip) of the inner fitting piece S11 so as to protrude outside the flexible tube, and the stopper S14, the extension portion S111, and the first locking portion S13. A groove-like space is formed. The water blocking material P is disposed in the groove-shaped space (a space indicated by a broken line in FIG. 3).

Here, the water-swellable non-woven fabric constituting the water-stopping material P is a non-woven fabric in which a water-swellable resin is supported on a non-woven fabric material. The form of supporting the water-absorbing expandable resin can be in the form of powder, fiber, impregnation, coating, or the like. The water-absorbing expandable resin is a resin that has the property of absorbing moisture and swells, and exemplifies a resin containing polyacrylic acid sodium salt as a main component or a resin containing an alkene (alkylene) oxide modified compound as a main component. Can do. In particular, the latter exhibits a water-swelling property even with respect to water having a relatively high ion concentration such as seawater. Therefore, it is preferable to use the latter in an environment where salt is high.
Examples of commercially available water-swellable resins include fibrous products such as Lanseal (registered trademark Toyobo Co., Ltd. product). Examples of the alkene (alkylene) oxide-modified water-absorbent expandable resin include Aqua Coke (registered trademark, Sumitomo Seika Co., Ltd. product).

The base fiber constituting the nonwoven material is not particularly limited, but is preferably a synthetic resin fiber, and synthetic resin fibers such as polyester fiber, nylon fiber, polyethylene terephthalate fiber, acrylic fiber, and polypropylene fiber can be used. . The base fiber may be a poorly hydrophilic fiber such as polypropylene fiber or polyethylene terephthalate (PET) fiber, but is preferably a hydrophilic fiber such as acrylic fiber or nylon fiber.

The expansion ratio or the like of the water-absorbent expandable nonwoven fabric is not particularly limited, but an amount of the water-absorbent expandable nonwoven fabric that can sufficiently fill the space in which the waterstop material P is disposed when it absorbs water and expands is disposed. Is preferable from the viewpoint of water-stopping property.

As the synthetic resin constituting the strip S, a thermoplastic resin can be preferably used. The synthetic resin may be a thermosetting resin such as hard rubber as long as the strip having a predetermined cross section can be formed by extrusion molding. The thermoplastic resin is particularly suitable for extruding a strip having a predetermined cross section. Examples of the thermoplastic resin include olefin-based resins such as polypropylene resin and high-density polyethylene resin, hard vinyl chloride resin, polyamide resin, and polyethylene terephthalate resin.

The flexible tube of the said embodiment can be manufactured with the following manufacturing methods, for example.
First, a strip S is formed by extruding a semi-molten thermoplastic resin into a predetermined cross-sectional shape from a resin extruder.

The strip S immediately after being extruded is supplied to a known hose forming shaft while being appropriately cooled, and is spirally wound. The strip S is spirally wound so that the first fitting side edge S1 and the second fitting side edge S2 are fitted on the hose forming shaft, and the flexible tube 1 is a cylindrical tube. A wall is formed continuously.

Immediately after winding the strip S around the hose forming shaft, a water-swellable non-woven fabric having a tape shape with a predetermined width is recessed by a predetermined position of the strip S (stopper S14, extension S111, and first locking portion S13). Grooved space) and spirally wound so as to be disposed at that position to form a water-stopping material P. When fixing the water-stopping material P to the strip S, the fixing is performed by using a hot melt adhesive, using a double-sided tape, or by fusing using the heat amount of the strip S. be able to.

The second fitting side edge S2 adjacent in the wound state is arranged so as to cover the portion where the water blocking material P is arranged, and the outer side of the second fitting side edge S2 is arranged outside the outer fitting piece S12. The strip S is wound spirally so as to cover. In order to perform this winding efficiently, it is preferable to spread the outer fitting piece S12 toward the outside of the pipe by a guide or the like until the second fitting side edge S2 is arranged. In addition, when the strip S is extruded, it is also a preferable form that the outer fitting piece S12 is formed so as to open toward the outside of the pipe.

If the second fitting side edge portion S2 is disposed at a predetermined position and the outer fitting piece S12 is closed, the structure of the flexible tube 1 is completed. Thereafter, the flexible tube 1 is completed by air cooling as appropriate. .

In the flexible tube of the first embodiment, since the water stop material P (water-absorbing expandable nonwoven fabric) is disposed in the extension portion S111, the work of placing the water stop material P at a predetermined position of the strip S is easy. It can be done efficiently and stably.

When the resin strip S is slightly soft, the manufacturing process of the strip S and the winding step to the flexible tube 1 can be performed separately. In that case, the strip S is first extruded into a predetermined cross section, cooled, and once wound around a reel or the like. Thereafter, the strip S is supplied to a former (pipe molding machine) together with a water-swellable nonwoven fabric tape to obtain the flexible tube 1. The former in this case may be a known former as disclosed in JP-A-01-283126. The strip S and the water-absorbent expandable non-woven tape may be integrated before being supplied to the former.

The strip S supplied to the former is spirally wound while the space between the bifurcated inner fitting piece S11 and the outer fitting piece S12 of the first fitting side edge S1 is expanded. . And between the expanded inner fitting piece S11 and outer fitting piece S12, the second fitting piece S21 of the second fitting side edge S2 wound in a spiral shape and adjacent to each other is sandwiched. After that, the inner fitting piece S11 and the outer fitting piece S12 are closed, and the first fitting side edge S1 and the second fitting side edge S2 are slidably fitted. This process is continuously performed in the former to obtain the flexible tube 1 continuously.

When manufacturing the flexible tube 1 by such a manufacturing process, in order to facilitate the process of inserting the second fitting piece S21 between the inner fitting piece S11 and the outer fitting piece S12, the present embodiment is implemented. As in the embodiment, it is preferable to form a portion where the first locking portion S13, the stopper S14, and the second locking portion S23 are in contact with each other at the time of insertion.

The operation and effect of the present invention will be described.
In the present invention, since the water-absorbing expandable nonwoven fabric is used as the water-stopping material P, the water-stopping material P is not yet expanded when the flexible pipe is constructed. Therefore, compared with the case where an elastic body (such as rubber) of the prior art is used as a water-stopping material, the water-stopping material is almost non-compressed, and the non-woven material is slippery with respect to the tube wall made of synthetic resin. It hardly interferes with sliding (expanding and bending) of the tube wall. Therefore, according to the present invention, flexibility as if there is no water-stopping material P is obtained, and the handleability and piping workability of the tube are excellent.

In addition, in a usage environment of the piped flexible pipe, the water-stopping material P made of the water-absorbing expandable nonwoven fabric expands due to the water under a situation where water-stopping is required, for example, moisture comes around the pipe. Thus, the space between the first fitting side edge portion S1 and the second fitting side edge portion S2 is sealed, and the water blocking performance of the tube is exhibited.

Further, as in the above-described embodiment, one of the first fitting side edge S1 has an extension part S111 formed longer than the other, and the water stop material P is disposed in the extension part S111. If it is made, in the manufacturing process of the flexible tube 1, the operation | work which arrange | positions the water stop material P will become easy, and the manufacturing efficiency and manufacturing quality of the flexible tube 1 can be improved. Further, in this case, after the water stop material P is integrated with the strip S in advance, the strip S can be supplied to the flexible tube 1 and formed into the flexible tube 1. The process can be made simpler and more efficient.

Moreover, if the extension part S111 is formed in the side (inner fitting piece S11) located inside a flexible tube among the fork of the 1st fitting side edge part S1 like the said embodiment, inner side The water blocking material P is wound around the outer periphery of the fitting piece S11 (extension portion S111). Then, it is possible to prevent the water-stopping material P from detaching from the strip S in the step of using the strip S as the flexible tube 1, and to further improve the manufacturing efficiency and manufacturing quality of the flexible tube 1.

Further, as in the above-described embodiment, the first locking portion S13 provided on the side (inner fitting piece S11) provided with the extension portion S111 among the two forks of the first fitting side edge S1 When the extension part S111 is arranged on the side edge side of the strip, the water blocking material P is arranged even if the tube wall expands and contracts and the second locking part S23 of the second fitting side edge part S2 moves. It is possible to reliably prevent the second locking portion S23 from entering the formed space (in this embodiment, a concave groove-shaped space surrounded by the stopper S14, the extension portion S111, and the first locking portion S13). Therefore, the space in which the water blocking material P is arranged can be kept constant regardless of the expansion and contraction state of the tube wall, and the space filling by the expansion of the water blocking material P can be ensured. The aqueous property can be further increased.

The flexible tube 1 of the said embodiment was manufactured with the internal diameter of 100 mm using the strip | belt band S made from a hard vinyl chloride resin (Example). Using the same strip S, a flexible tube without a water blocking material was manufactured (comparative example).

The flexible tube of the example was tested for water blocking (watertightness). In the test, a test sample having a bending radius of 1 m was subjected to a water pressure of 0.2 MPa from the outside for 3 minutes to check whether or not water leaked into the flexible tube. As a result of the test, water leakage was not seen in the flexible tube of the example, and it was confirmed that the flexible tube had sufficient water-stopping property. The flexible tube of the comparative example does not have water-stopping property because it has no water-stopping material.

When the flexibility of the tube was compared between the example and the comparative example, there was no substantial difference in flexibility between the two.
It was confirmed that the flexible tube of the example can achieve both flexibility and water-stopping.

The present invention is not limited to the above embodiment, and can be implemented with various modifications. Other embodiments of the present invention will be described below. However, in the following description, portions different from the above embodiment will be mainly described, and detailed descriptions of the same portions will be omitted. Further, the embodiments described below can be implemented by combining some of them or replacing some of them.

FIG. 4 shows a cross-sectional structure of the tube wall of the flexible tube according to the second embodiment of the present invention. This figure also shows a state in which the flexible tube is contracted, with the upper side of the drawing being the outside of the tube and the lower side of the drawing being the inside of the tube. In this embodiment, the 1st latching | locking part T13 is provided only in the inner side fitting piece T11 of the 1st fitting side edge T1, and the 2nd latching | locking part T23 correspondingly corresponds to the 2nd fitting. It is provided only on the inner peripheral surface side of the second fitting piece T21 of the side edge portion T2. As described above, the first locking portion and the second locking portion only need to be engaged with each other to prevent the strip T from being detached, and the specific arrangement and number can be changed. is there. In addition, as in the present embodiment, it is also possible to form these locking portions in a reverse shape so that they engage with each other when the first locking portion T13 and the second locking portion T23 are locked. It is preferable from the viewpoint of improving the strength.

Moreover, the shape which a 1st fitting side edge part branches in two is not specifically limited. As in the first embodiment, the outer fitting piece may be branched from the portion where the inner fitting piece and the second fitting piece are connected, or, as in the second embodiment, the inner fitting piece may be used. The outer fitting piece T12 may be branched from the position where the joining piece T11 and the second fitting piece T21 are connected to the second fitting piece side. If it is made like 2nd Embodiment, it will become easy to do the process of winding a strip and shape | molding to a pipe | tube, and can improve the manufacture quality and manufacture efficiency of a pipe | tube.

In 1st Embodiment and 2nd Embodiment, the extension part T111 is provided in the inner side fitting piece T11 of the 1st fitting side edge T1, and the water stop material P is between the extension part and the 2nd fitting piece T21. Although the example provided is demonstrated, this invention is not limited to this. For example, the extension portion is not always necessary, and the inner fitting piece and the outer fitting piece may have the same length. In addition, when there exists an extension part, the process of arrange | positioning the water stop material P will become easy.

Moreover, although 1st Embodiment and 2nd Embodiment demonstrated 2nd latching | locking part S23 provided in the side edge part (front-end | tip part) of 2nd fitting piece S21, 2nd latching | locking part Is not limited to the side edge portion (tip portion) of the second fitting piece S21, and the first fitting portion and the second fitting portion that are engaged with the first locking portion S13 are separated. Other positions may be used as long as they can be prevented.

Moreover, you may make it arrange | position the water stop material P between a 2nd fitting piece and an outer fitting piece. In that case, it is preferable to provide an extension part on the outer fitting piece side, and the water-stopping material P is wound so as to be integrated with the second fitting piece of the strip to constitute a flexible tube. Is preferred.

Further, the present invention can be applied to other technical fields other than the underground buried type cable protection pipe described in the above embodiment, and can be used, for example, for a cable protection pipe (pipe) used in a building. .

The synthetic resin flexible tube of the present invention can be used for, for example, an underground cable protection tube, has flexibility and water blocking properties, and has high industrial utility value.

DESCRIPTION OF SYMBOLS 1 Synthetic resin flexible tube S Strip S1 1st fitting side edge S11 Inner fitting piece S111 Extension part S12 Outer fitting piece S13 First latching part S14 Stopper S2 Second fitting side edge S21 2nd Fitting piece S23 Second locking portion P Water-stopping material T Strip T1 First fitting side edge T11 Inner fitting piece T111 Extension portion T12 Outer fitting piece T13 First locking portion T2 Second fitting side edge Part T21 second fitting piece T23 second locking part

Claims (4)

A flexible tube formed by spirally winding a strip made of synthetic resin, which is an extruded product having a predetermined cross section,
One side edge of the strip is a bifurcated first fitting side edge,
The other side edge of the strip is a second fitting side edge,
The second fitting side edge is slidably inserted between the two forks of the first fitting side edge adjacent in the wound state,
By engaging the first locking part provided on the first fitting side edge and the second locking part provided on the second fitting side edge, the second fitting side edge becomes It is prevented from detaching from between the two forks of the first fitting side edge, and the strip is a cylindrical flexible tube,
One end of the first fitting side edge has an extension formed longer than the other, and the water-stopping material made of a water-absorbent expandable nonwoven fabric is the extension of the first fitting side edge. And a synthetic resin flexible tube provided in a spiral shape at a portion where the second fitting side edge is opposed. The synthetic resin flexible tube according to claim 1, wherein an extension portion is formed on a side of the first fitting side edge portion located on the inner side of the flexible tube. The extension portion is arranged on the side edge side of the strip, rather than the first locking portion provided on the side where the extension portion is provided in the fork of the first fitting side edge portion. The synthetic resin flexible tube as described. A method for producing a flexible tube made of synthetic resin, in which a flexible tube is formed by spirally winding a strip made of synthetic resin extruded into a predetermined cross section,
One side edge of the strip is a bifurcated first fitting side edge,
The other side edge of the strip is a second fitting side edge,
The second fitting side edge is slidably inserted between the two forks of the first fitting side edge adjacent in the wound state,
By engaging the first locking part provided on the first fitting side edge and the second locking part provided on the second fitting side edge, the second fitting side edge becomes It is prevented that the first fitting side edge is separated from the fork, and the strip is formed in a cylindrical flexible tube,
One extension of the first fitting side edge has an extension formed longer than the other, and the water stopping material made of a water-absorbent expandable nonwoven fabric is used as the extension of the first fitting side edge. A method of manufacturing a flexible tube made of synthetic resin, which is provided in a spiral shape at a portion where the second fitting side edge portion faces.

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