JP2000337565A - Outer pipe for underground buried pipeline - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outer pipe for underground buried pipeline of a pipe structure capable of being accomplished relatively easily with less earth resistance encountered when the pipe is inserted and laid in an underground excavated hole, wherein the pipe itself is equipped with a flexibility to an appropriate degree, is embodied in a lightweight, easy-to-handle structure, and equipped with a sufficient pressure and flattening resisting strength. SOLUTION: The outer pipe for underground buried pipeline is composed of an inner layer 3 formed cylindrically, an outer layer 2 cylindrical installed concentrically with the inner layer 3 and positioned apart with a certain space S in between, and a space keeping member 1 installed in the space S and joined with the two layers 2 and 3, wherein the space keeping member 1 is equipped with protrusive edges 11 and 12 protruding outward to the left and right from the ends of its opposing vertical edge members 15 and 16 in approx. a channel shape with its opening facing down or up so that a space keeping band 1P having a vertically long section shape which is wound round spirally so that the edges 11 and 12 abut or overlap each other, and the outside surfaces of these edges 1 and 2 and the top edge member 13 to form a channel shape together with them are in fusion attachment or adhered to the outside surface of the inner layer 3 and the inside surface of the outer layer 2, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-diameter cable protection tube for protecting a cable buried underground such as an optical fiber cable for communication, and an outer tube (parent tube) used as a conduit for installing and protecting the cable. (Also called a tube).

[0002]

2. Description of the Related Art Conventionally, underground pipes of this kind are provided with handholes or manholes provided at required intervals of the pipes as shown in FIG. A plurality of small-diameter inner pipes p, into which communication cables C and the like are inserted, are inserted into the insides of the pipes, and the inserted small-diameter inner pipes p. Buried underground to protect

[0003]

In order to form such an underground pipe, the soil is usually excavated in a tunnel shape several meters below the ground, and a pipe (outer pipe) is sequentially inserted therein. Means have been taken to do so. The buried pipe buried in the ground must be compressed enough to withstand the strong earth pressure applied to the surrounding area and the compressive load that is repeatedly applied on the buried road surface because the buried place is usually under the road. It is required that the tube has a flat strength. As a tube structure that can withstand this demand, increasing the wall thickness of the tube requires a large amount of synthetic resin material, which not only makes it unprofitable in terms of cost, but also causes the tube to lose flexibility and become rigid. Passing,
The heavy weight makes handling inconvenient, and there is a problem that it becomes difficult to insert a pipe into an underground excavation hole.
In addition, when the outer peripheral surface of the pipe is formed in a corrugated shape, the flexibility of the pipe can be expected, but soil resistance is expected when inserting the pipe into an underground excavation hole. As described above, there is a problem that it is difficult to bury the underground piping.

[0004] Accordingly, the present invention provides a pipe body having a moderate flexibility, being lightweight and easy to handle, having a sufficient pressure-resistant flat strength, and a soil pipe for insertion into an underground excavation hole. It is an object of the present invention to provide an outer pipe for an underground pipe having a pipe structure that can be relatively easily formed with little resistance.

[0005]

The structure of the present invention for achieving the above object will be described with reference to the reference numerals used in the description of the embodiments. An outer tube made of a synthetic resin to be formed, an inner layer 3 formed in a cylindrical shape, a cylindrical outer layer 2 arranged concentrically with the inner layer 3 and separated by a predetermined space S; And the spacing members 1 joined to the two layers 2 and 3, and the spacing members 1 are opposed to each other at the ends of the longitudinal sides 15 and 16 facing each other in a substantially U-shape of a downward opening or an upward opening. The spacing strip 1P having a vertically long cross-sectional shape provided with protruding edges 11 and 12 protruding outward from the left and right sides is formed on the protruding edge 1.
1 and 12 are spirally wound so as to abut or overlap with each other, and the outer peripheral surface of both protruding edges 11 and 12 and a top side 13 forming a U-shape is formed on the outer surface of the inner layer 3. And the inner surface of the outer layer 2.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In carrying out the outer tube P according to the present invention having the above-described structure, the interval maintaining strip 1P is used.
Is preferably set so as to be in the range of 1/10 to 1/50 of the interval T between the outer peripheral surface of the outer layer 2 and the inner peripheral surface of the inner layer 3. In addition, the interval maintaining band 1
It is also a preferable embodiment that the cross-sectional shape of P is set so that the spiral winding pitch p is substantially equal to the vertical height h.

Further, various materials can be used for the inner layer 3, the outer layer 2, and the spacing member 1 in the present invention as long as they are thermoplastic synthetic resins. However, extrusion is easy,
Non-chlorine resins are preferred because they have the required toughness and are easy to dispose of. For example, a polyolefin resin such as a polyethylene resin or a polypropylene resin is preferable.

The inner layer 3 and the outer layer 2 according to the present invention are formed by spirally winding a belt-shaped material extruded in a flat band shape, and abutting or superimposing adjacent side edges to form an abutting surface. It can be formed by either a means for forming the polymerized surfaces by fusing or adhering them together, or a means for extruding the molten material into a tube shape.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are views showing the structure of a first embodiment of the present invention. FIG. 1 is a perspective view showing the overall shape, and FIG.
Is an upper half half sectional side view, FIG. 3 is an enlarged sectional view of a tube wall portion,
4 is a front view, and FIG. 5 is a sectional view taken along line AA in FIG.

The first embodiment shown here is a tube in which the inner layer 3, the outer layer 2, and the spacing member 1 are formed using a polyethylene resin. An outline of one method of the manufacturing method is as follows. First, from the resin extruder, the cross-sectional shape is a substantially U-shape that is open downward and the vertical sides 15 and 1 facing each other.
Projection edge 1 bent from the lower end of 6 toward the left and right sides
The spacing strip 1P integrally provided with the first and second strips 12 and 12 is continuously extruded, supplied onto a tube-forming mandrel, and spirally wound while a part of the projecting edges 11 and 12 are superposed. Then, the overlapped portion 1a is fused and integrated to form a tube as a spirally uneven spacing member 1. At the same time, a strip having a horizontal cross section is extruded from the extruder, and is arranged so as to cover a gap between adjacent tops 13 of the spacing maintaining strip 1P. The edge portion is spirally wound while being superimposed on the top side 13, and the superposed portions 2 a are fused and integrated together, and
Then, they are fused and integrated to form a cylindrical outer layer 2.

On the other hand, a strip having a horizontal cross-sectional shape is extruded from a discharge port of another resin extruder disposed inside a tube serving as the spacing member 1, and the spacing member 1P is extruded.
Are arranged so as to cover the downwardly open gap forming a U-shape, and the both side edges are spirally wound while being superposed on the inner surfaces of the protruding edges 11 and 12, so that the superposed portions 3a are fused together. The cylindrical inner layer 3 is formed by fusing and integrating with the protruding edges 11 and 12 as well.

By doing so, the spacing material 1 for forming the spacing material 1 formed in a spiral uneven shape is provided.
The inner peripheral surface of the left and right protruding edges 11 and 12 of P has a double structure integrated with the inner layer 3 including the overlapping portion 1a of the two protruding edges 11 and 12 and has a spiral uneven shape. A tube as outer tube P having a double structure in which the outer peripheral surface of top side 13 of holding material 1 is integrated with outer layer 2 is obtained.

The outer tube P shown in the first embodiment
As shown in FIG. 3, the apparent thickness of the outer tube P, that is, the outer layer 2 Is set to be approximately 1/20 of the thickness T from the outer peripheral surface to the inner peripheral surface of the inner layer 3. Further, in the tubular body of this embodiment, the shape of the interval maintaining band 1P is set so that one spiral winding pitch p and the vertical height h of the interval maintaining member 1 are substantially equal.

FIGS. 6 and 7 show a second embodiment. In the second embodiment, the projecting edges 11 and 12 of the interval maintaining strip 1P are positioned on the outer peripheral surface side and spirally wound.
The outer peripheral surfaces of the outer layers 1 and 12 are fused to the inner peripheral surface of the outer layer 2, and the outer surface of the top side 13 forming the gap maintaining band 1 P is fused and integrated with the outer peripheral surface of the inner layer 3. Things.

FIGS. 8 and 9 show still another embodiment. In the third embodiment shown in FIG. 8, the left and right protruding edges 11 and 12 of the interval maintaining strip 1P are each bent so as to be gradually thinned from the base end portion.
Overlapping portions 1a are formed in a slanted shape over substantially the entire width of 1, 12. In addition, the outer tube P in this embodiment has a width of the overlapped portion 2a forming the outer layer 2 and a width of the top side 13 forming the gap maintaining strip 1P and a width of the overlapped portion 3a forming the inner layer 3 projecting. The structure is such that the widths of the edges 11 and 12 in the fusion-connected state are the same as the widths of the respective edges and are fused and integrated.

In the fourth embodiment shown in FIG. 9, the left and right protruding edges 11 and 12 of the spacing band 1P are bent so that the base end to the top end are vertically overlapped over the entire width. 1a. In the outer tube P shown in this embodiment, first, a tube constituting the inner layer 3 is formed, and the spacing member 1 is formed on the outer surface thereof by the same means as shown in the first embodiment. And forming an outer layer 2 on the outer surface in the same manner as described above,
It is formed by fusing and integrating the entire polymerized surface. Other points are the same as those in the above embodiments.

FIG. 10 shows an example of a use state of the outer tube P according to the present invention. In this figure, the opening of the outer tube P is opened through the side wall of the manhole or the handhole H into the wall surface of the hole H, and a plurality of inner tubes p (three in the figure) are inserted therein. These inner tubes p are stably fixed in the opening of the outer tube P by the fixing plate B. A communication cable C such as an optical cable is inserted through the inner pipes p and is partitioned by the respective inner pipes p.
Each inner tube p and outer tube P are doubly protected.

Although the embodiments which are considered to be representative of the present invention have been described above, the present invention is not necessarily limited to only the structures of the embodiments, and has the above-mentioned constitutional requirements according to the present invention, and The present invention achieves the object of the present invention and can be appropriately modified and implemented within the range having the following effects.

[0019]

As is clear from the above description, the outer pipe forming the underground pipe according to the present invention has a concavo-convex spiral pipe structure between the inner layer and the outer layer arranged concentrically. Since the spacing material is arranged and is formed in a spiral shape in the space between the inner layer and the outer layer to form a vertically long rectangular shape, the cross section 2 of the pipe wall of the outer tube is formed.
The next moment is strengthened. Furthermore, since the bonding lap position of the wound interval maintaining strips is arranged at the overlapping portion with the outer layer or the inner layer, even if the thickness of the outer layer and the inner layer is reduced, it can sufficiently withstand a large earth pressure. Thus, it is possible to avoid being destroyed at the polymerized portion. Therefore, even if the thicknesses of the outer layer and the inner layer are reduced, sufficient flat strength can be maintained. In particular, since the outer pipe according to the present invention has the inner layer and the outer layer formed in a cylindrical shape without irregularities, it is possible to minimize the resistance when inserted into a hole excavated in the ground. As a result, a remarkable effect is obtained in that even when the inner tube p to be inserted into the tube is inserted, the insertion can be performed smoothly without hindering the insertion.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an outer tube of a first embodiment.

FIG. 2 is a partially cut-away side view of the upper half.

FIG. 3 is an enlarged sectional view of the pipe wall portion.

FIG. 4 is a front view of the same.

FIG. 5 is a sectional view taken along line AA in FIG. 2;

FIG. 6 is an upper half partially cutaway side view showing the outer tube of the second embodiment.

FIG. 7 is an enlarged sectional view of the pipe wall portion.

FIG. 8 is an enlarged sectional view of a tube wall portion of an outer tube according to a third embodiment.

FIG. 9 is an enlarged sectional view of a tube wall portion of an outer tube according to a fourth embodiment.

FIG. 10 is a perspective view for explaining a use state of the outer tube of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spacing material 11 Projecting edge 12 Projecting edge 13 Top side 15 Vertical side 16 Vertical side 1a Overlapping portion 1P Spacing maintaining strip 2 Outer layer 3 Inner layer P Outer tube

Continuation of the front page (72) Inventor Yasushi Sakane 1-2-1 Sakaecho, Takatsuki-shi, Osaka F-term (reference) 3H111 AA01 BA15 CA13 CA14 CA53 CB24 CC22 DA07 DB17 DB23 EA04

Claims (3)

[Claims] An outer tube made of a synthetic resin for forming an underground pipeline, comprising: an inner layer (3) formed in a cylindrical shape; and a predetermined space (S) concentric with the inner layer (3). A cylindrical outer layer (2) arranged at an interval and a spacing material (1) arranged in the space (S) and joined to both layers (2) and (3). Spacing material
(1) The protruding edges (11), (12) projecting outward from the left and right sides from the ends of the vertical sides (15), (16) facing each other in a substantially U-shape of the downward opening or upward opening. The longitudinally-elongated cross-section holding strip (1P) provided is spirally wound so that its protruding edges (11) and (12) abut or overlap,
Top (13) forming a U-shape with these protruding edges (11) and (12)
Outer pipes for underground conduits whose outer peripheral surfaces are respectively fused or adhered to the outer surface of the inner layer (3) and the inner surface of the outer layer (2). 2. The thickness (t) of the interval maintaining strip (1P) is:
One-third of the distance (T) between the outer peripheral surface of the outer layer (2) and the inner peripheral surface of the inner layer (3).
The outer pipe for an underground pipe according to claim 1, wherein the outer pipe is set within a range of 10 to 1/50. 3. The cross-sectional shape of the interval maintaining strip (1P) is as follows:
The outer pipe for an underground pipe according to claim 1 or 2, wherein the spiral winding pitch (p) and the vertical height (h) are set to be substantially equal.