Embedded pipe

Abstract

A buried pipe 1 (1a, 1b, 1c) comprises a first inner pipe 12 which can accommodate a cable 9, a second inner pipe 11 which accommodates the first inner pipe 12, and an outer pipe 10 which accommodates the second inner pipe 11, wherein the second inner pipe 11 is rotatable about a central axis L of the first inner pipe 12, with respect to the first inner pipe 12 and the outer pipe 10.

Description

Technical Field

[0001] The present disclosure relates to buried pipes.

Background Art

[0002] When burying various cables such as optical fibers and transmission lines underground, it is known to use buried pipes for accommodating the cables. When a buried pipe is buried underground, such as under a road, to form a buried pipeline, in a shallow layer section where sufficient soil cover cannot be ensured between the ground surface and the buried pipe, there is a high risk that the buried pipeline will be damaged by excavating machines such as backhoes, breakers, or cutters due to road construction or the like.

[0003] In order to prevent damage to the buried pipeline in the shallow layer section, it is known to install a marking sheet indicating that the buried pipe is buried, or an iron plate, ceramic plate, or metal plate for preventing the intrusion of heavy machinery between the ground surface and the buried pipe (Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional configuration, a corresponding space is required above the buried pipe. However, depending on the structure of the terrain or strata, etc., it may be difficult to ensure the separation from the ground surface to the buried pipe, so the buried pipeline may not be properly protected in some cases.

[0006] An object of the present disclosure is to provide a buried pipe that can appropriately protect a buried pipeline even when it is difficult to ensure a separation from the ground surface to the buried pipe.

Means for Solving the Problems

[0007] The buried pipe according to one embodiment includes a first inner pipe capable of accommodating a cable, a second inner pipe accommodating the first inner pipe, and an outer pipe accommodating the second inner pipe, and the second inner pipe is rotatable with respect to the first inner pipe and the outer pipe about the central axis of the first inner pipe. ri 、 Between the first inner tube and the second inner tube, a first rotating layer is further provided to facilitate the rotation of the second inner tube relative to the first inner tube. 。

Effects of the Invention

[0008] According to the present disclosure, it is possible to appropriately protect a buried pipeline even when it is difficult to ensure a separation from the ground surface to the buried pipe.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, parts having the same configuration or function are denoted by the same reference numerals. In the description of this embodiment, redundant descriptions of the same parts may be omitted or simplified as appropriate.

[0011] The present disclosure is provided with a configuration for protecting the buried pipeline inside the buried pipe 1 (1a, 1b, 1c), thereby reducing the protection space compared with the conventional configuration, and making it possible to protect the buried pipeline even when it is difficult to secure the separation (depth) from the road surface. FIG. 1 is a cross-sectional view showing a configuration example of the buried pipe 1 (1a) according to an embodiment. FIG. 2 is a side view of the buried pipe 1a in FIG. 1. The buried pipe 1a is buried in the ground and protects various cables 9 such as optical fibers and transmission lines. The buried pipe 1a includes an outer pipe 10, inner pipes 11, 12, and rotating layers 21, 22.

[0012] The inner pipe 12 as the first inner pipe is a tubular member capable of accommodating the cable 9. The inner pipe 11 as the second inner pipe is a tubular member that accommodates the inner pipe 12. The inner pipes 11, 12 may be made of a hard material such as steel, for example. The outer pipe 10 is a tubular member that accommodates the inner pipes 11, 12. The outer pipe 10 may be made of a material such as vinyl chloride resin or a metal containing steel. The outer pipe 10 may be fixed in the ground by members such as joints. In the example of FIG. 1, the inner pipes 11, 12 and the outer pipe 10 all have a concentric cross-section having a common central axis L (see FIG. 2). In this way, since the inner pipe 12 that accommodates the cable 9 is accommodated in the inner pipe 11 and the outer pipe 10, the buried pipeline is protected from damage caused by the intrusion of excavation machines such as backhoes, breakers, or cutters due to its multi-layered structure.

[0013] The inner pipe 11 is rotatable with respect to the outer pipe 10 about the central axis L of the inner pipes 11, 12 (as a rotation axis). Therefore, even if the cutting edge of an excavation machine or the like penetrates the outer pipe 10, the inner pipe 11 rotates with respect to the outer pipe 10 to deflect the cutting edge, preventing the cutting edge from cutting the inner pipe 11 and its interior, or preventing the impact of the cutting edge from directly transmitting to the interior of the inner pipe 11. In this way, since the buried pipe 1a is provided with a configuration in which the inner pipe 11 is rotatable with respect to the outer pipe 10, even if the cutting edge of an excavation machine or the like penetrates the outer pipe 10, the buried pipeline and the cable 9 disposed in the buried pipeline can be protected.

[0014] Furthermore, the inner tube 11 is rotatable with respect to the inner tube 12 about the central axis L of the inner tube 12 (as a rotation axis). Therefore, even if the cutting edge of an excavating machine or the like penetrates the outer tube 10 and the inner tube 11 rotates, it is possible to suppress the rotation of the inner tube 12 accordingly. Thus, even if the inner tube 11 rotates, by absorbing the rotational force between the inner tubes 11 and 12, it is possible to prevent the inner tube 12 from rotating and the cable 9 accommodated in the inner tube 12 from being twisted and damaged.

[0015] The rotating layer 21 as the second rotating layer is provided between the inner tube 11 and the outer tube 10 and is a layer that facilitates the rotation of the inner tube 11 with respect to the outer tube 10. The rotating layer 22 as the first rotating layer is provided between the inner tube 12 and the inner tube 11 and is a layer that facilitates the rotation of the inner tube 11 with respect to the inner tube 12. The rotating layers 21 and 22 are any layers that reduce the friction between the outer tube 10 and the inner tube 11 and between the inner tubes 11 and 12. For example, the rotating layer 21 may be a slippery coating material such as fluorine, wax, or silicon applied to at least one of the surfaces of the outer tube 10 and the inner tube 11. Similarly, the rotating layer 22 may be a slippery coating material such as fluorine, wax, or silicon applied to at least one of the surfaces of the inner tubes 11 and 12. Alternatively, the rotating layers 21 and 22 may facilitate rotation by having a mechanical structure such as a ball bearing (bearing). Further, instead of providing the rotating layers 21 and 22, the outer tube 10 and the inner tubes 11 and 12 may be made of a material with low friction when in contact with other members.

[0016] FIG. 3 is a cross-sectional view showing an example of the buried pipe 1 in FIG. 1. FIG. 3 shows an example of the buried pipe 1b in which the rotating layers 21a and 22a are constituted by ball bearings. The rotating layer 21a of the buried pipe 1b includes an outer ring 211, a plurality of spheres 212, an inner ring 213, and a holding portion 214. The outer ring 211 is fixed to the inner surface of the outer pipe 10, for example, and has a groove portion on the inner surface side where the spheres 212 contact and can rotate. The inner ring 213 is fixed to the outer surface of the inner pipe 11, for example, and has a groove portion on the outer surface side where the spheres 212 contact and can rotate. The holding portion 214 holds the relative positional relationship of the plurality of spheres 212 so that the plurality of spheres 212 can rotate. When a relative rotational force with respect to the inner pipe 11 centered on the central axis L is applied to the outer pipe 10, between the outer ring 211 fixed to the inner surface of the outer pipe 10 and the inner ring 213 fixed to the outer surface of the inner pipe 11, the spheres 212 rotate to guide the rotation of the inner pipe 11 with respect to the outer pipe 10. Thus, in the buried pipe 1b, since the plurality of spheres 212 whose relative positional relationship is held by the holding portion 214 rotate between the outer ring 211 and the inner ring 213, the friction when the inner ring 213 rotates with respect to the outer ring 211 is reduced. Therefore, the buried pipe 1b is provided with the rotating layer 21a constituted by a ball bearing between the outer pipe 10 and the inner pipe 11, so that the inner pipe 11 can easily rotate with respect to the outer pipe 10. Thus, the buried pipe 1b can effectively protect the buried pipeline and the cable 9 disposed in the buried pipeline.

[0017] The rotating layer 22a of the buried pipe 1b includes an outer ring 221, spheres 222, an inner ring 223, and a holding portion 224. The outer ring 221 is fixed to, for example, the inner surface of the inner pipe 11 and has a groove portion on the inner surface side with which the spheres 222 come into contact and can rotate. The inner ring 223 is fixed to, for example, the outer surface of the inner pipe 12 and has a groove portion on the outer surface side with which the spheres 222 come into contact and can rotate. The holding portion 224 maintains the relative positional relationship of the respective spheres 222 so that the plurality of spheres 222 can rotate. Similar to the rotating layer 21a, when a relative rotational force about the central axis L is applied to the inner pipe 11 with respect to the inner pipe 12 serving as a reference, the friction when the outer ring 221 rotates with respect to the inner ring 223 due to the rotation of the spheres 222 is reduced. Therefore, the buried pipe 1b is provided with the rotating layer 22a constituted by a ball bearing between the inner pipes 11 and 12, making it easier for the inner pipe 11 to rotate with respect to the inner pipe 12. Thus, even if the outer pipe 10 rotates, the buried pipe 1b can effectively prevent the cable 9 accommodated in the inner pipe 12 from being twisted and damaged by absorbing the rotational force in the rotating layer 22a.

[0018] FIG. 4 is a diagram schematically showing a state in which the buried pipe 1a in FIG. 1 protects the cable 9 from the cutter C. In the example of FIG. 4, a cutter C that rotates clockwise on the drawing approaches the buried pipe 1a and applies a rotational force D1 to the outer pipe 10. Along with this, the inner pipe 11 rotates counterclockwise with respect to the outer pipe 10, deflecting the point where the cutting edge of the cutter C contacts and preventing it from entering the inner pipe 11. Therefore, according to the buried pipe 1a, it is possible to prevent the inside of the inner pipe 11 from being damaged. Further, since the buried pipe 1a is provided with the inner pipe 12 for accommodating the cable 9 that can rotate about the central axis L with respect to the inner pipe 11 inside the inner pipe 11, even if the inner pipe 11 rotates, the rotation of the inner pipe 12 can be suppressed. In this way, since the buried pipe 1a has a multi-layer structure of the inner pipes 11 and 12 that can rotate relative to each other, it is possible to suppress the rotation of the inner pipe 12 that accommodates the cable 9 and the twisting of the cable 9.

[0019] FIG. 5 is a diagram schematically showing how the buried pipe 1 in FIG. 1 protects the cable 9 from the breaker B. In the example of FIG. 5, on the drawing, the tip of the breaker B pierces through the outer pipe 10 from the upper right part of the buried pipe 1a and penetrates into the inside of the rotating layer 21, applying a rotational force D1 downward. Along with this, a clockwise rotational force D2 is generated in the rotating layer 21, and a clockwise rotational force D3 is also generated in the inner pipe 11. Here, between the inner pipes 11 and 12, a rotating layer 22 is provided to facilitate the rotation of the inner pipe 11 with respect to the inner pipe 12, and the rotating layer 22 suppresses the transmission of the rotational force D3 to the inner pipe 12. In FIG. 5, the action of such a rotating layer 22 is schematically shown as a force D4 that cancels out the rotational force D3. As a result of the suppression by the rotating layer 22, the rotational force D5 applied to the inner pipe 12 becomes extremely small even if it exists. Therefore, according to the buried pipe 1a, the cable 9 can be prevented from being twisted. Also, by providing a plurality of inner pipes 11 and 12 inside the outer pipe 10, the tip of a boring machine or the like has to pass through a large number of outer pipes 10 and inner pipes 11 and 12 in order to reach the buried pipe line. Therefore, the buried pipe line and the cable 9 arranged in the buried pipe line can be protected more effectively.

[0020] The buried pipes 1a and 1b include two inner pipes 11 and 12 that are rotatable with respect to each other inside the outer pipe 10, but the buried pipe 1 may have a multi-layer structure of three or more inner pipes that are rotatable with respect to each other. FIG. 6 is a cross-sectional view showing a configuration example of a buried pipe 1c provided with three inner pipes 11 to 13 that are rotatable with respect to each other. In addition to the configuration of the buried pipe 1a, the buried pipe 1c further includes an inner pipe 13 and a rotating layer 23. The inner pipe 13 may be made of a hard material such as steel, similar to the inner pipes 11 and 12. The inner pipe 13 can accommodate the cable 9. The rotating layer 23 is provided between the inner pipes 12 and 13 and is a layer that facilitates the rotation of the inner pipe 12 with respect to the inner pipe 13. Similar to the rotating layers 21 and 22, the rotating layer 23 may be a slippery coating material applied to at least one of the surfaces of the inner pipes 12 and 13, or a ball bearing or the like. Instead of providing the rotating layer 23, the inner pipes 12 and 13 may be made of a material with low friction when they come into contact with other members.

[0021] As shown in Fig. 6, when the buried pipe 1c has a multi-layer structure of three or more inner pipes 11 to 13 that can rotate relative to each other, even if the inner pipe 11 rotates, the rotational force transmitted to the inner pipe 13 that houses the cable 9 can be further reduced. By providing the rotating layers 21 to 23, the rotational force is absorbed, and it is possible to more effectively prevent the cable 9 housed in the inner pipe 13 from being twisted and damaged. Also, since the cutting edge of an excavator or the like must pass through the outer pipe 10 and the multiple inner pipes 11 to 13 to reach the buried pipe line, the buried pipe line and the cable 9 disposed in the buried pipe line can be more effectively protected.

[0022] As described above, since the buried pipe 1 (1a, 1b, 1c) according to the present disclosure is provided with a configuration for protecting the buried pipe line inside thereof, it reduces the protection space compared to the conventional configuration, and it is possible to protect the buried pipe line even when it is difficult to secure the separation (depth) from the road surface.

[0023] The present disclosure is not limited to the above-described embodiments, and modifications can be made without departing from the spirit of the present disclosure.

Explanation of Reference Numerals

[0024] 1a, 1b, 1c Buried pipe 9 Cable 10 Outer pipe 11 to 13 Inner pipes 21 to 23 Rotating layers 211, 221 Outer rings 212, 222 Spheres 213, 223 Inner rings 214, 224 Holding parts L Central axis B Breaker C Cutter

Claims

1. a first inner tube capable of accommodating a cable; a second inner tube accommodating the first inner tube; an outer tube accommodating the second inner tube; comprising: the second inner tube is rotatable with respect to the first inner tube and the outer tube about the central axis of the first inner tube; further comprising a first rotation layer between the first inner tube and the second inner tube to facilitate rotation of the second inner tube with respect to the first inner tube; a buried pipe.

2. The buried pipe according to claim 1, wherein the first rotation layer includes at least one of a coating material and a bearing.

3. A first inner tube capable of accommodating a cable; a second inner tube accommodating the first inner tube; an outer tube accommodating the second inner tube; comprising: the second inner tube is rotatable with respect to the first inner tube and the outer tube about the central axis of the first inner tube; further comprising a second rotation layer between the second inner tube and the outer tube to facilitate rotation of the second inner tube with respect to the outer tube; a buried pipe.

4. The buried pipe according to claim 3, wherein the second rotation layer includes at least one of a coating material and a bearing.

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