Protective article

Abstract

This protective article (1) for protecting a cable (2) comprises: an outer wall section (11) which is exposed to the outside; and one or more tubes (13) which are installed along the direction in which the outer wall section (11) extends while being shielded by the outer wall section (11), said one or more tubes (13) containing a colorant and having lower strength compared to the outer wall section (11).

Description

protective equipment

[0001] The present disclosure relates to protective articles.

[0002] There are known techniques for protecting underground structures, such as buried conduits that house various cables, including optical fibers and power transmission lines, from damage caused by heavy machinery, such as pavement cutters, used in road construction. For example, Non-Patent Document 1 discloses a protection technique in which buried sheets, protective concrete, etc. are placed on the outside of the buried structure depending on the burial depth. Also, for example, Non-Patent Document 2 discloses a PIT (Pipe Insertion Type) technique in which repair member pipes are inserted into the conduit to protect the cable from earthquake damage.

[0003] Ministry of Land, Infrastructure, Transport and Tourism, "Collection of Case Studies on the Elimination of Utility Poles," National Institute for Land and Infrastructure Management, No. 789, March 2014. NTT Access Service Systems Laboratories, "1. Overview of the New PIT Pipe System," [online], [Retrieved August 29, 2023], Internet<URL: https: / / www.rd.ntt / as / times / 082 / 01 / 01.html>

[0004] In shallowly buried sections of pipelines, there is a risk of the pipeline being damaged by excavation machinery and the like during road construction and other work. Figure 6 is an underground cross-sectional view showing an example of a shallowly buried section SH of a pipeline P. As shown in Figure 6, the section between a manhole M and a bridge-mounted equipment BR, as well as sections that avoid underground structures such as culverts CL, correspond to the shallowly buried section SH. Figure 7 is a diagram showing protective materials such as steel plates S placed outside the pipeline P in the shallowly buried section SH. As shown in Figure 7, when the distance d between the ground surface and the pipeline P is short and the soil cover of the pipeline P is shallow, it is difficult to provide protection for the cable 2 outside the pipeline P. Furthermore, if a component pipe is inserted inside the pipeline P to provide protection, the cutter CT of the paving machine PM that cuts the pavement PA must be stopped after contacting the pipeline P and before reaching the cable 2.

[0005] 8A and 8B show the cutter CT of the paver PM coming into contact with the pipeline P. FIG. 8A shows the cutter CT moving into the buried pipeline P. FIG. 8B shows a cross-sectional view of the pipeline P in FIG. 8A. The white arrows in FIGS. 8A and 8B indicate the direction of travel of the cutter CT relative to the pipeline P. As shown in FIG. 8B, the distance dp from when the cutter CT comes into contact with the component pipe inside the pipeline P to when it reaches the cable 2 housed in the component pipe is very short. Furthermore, due to the engine noise and vibration of the paver PM, there is a risk that the operator operating the cutter CT will continue to move the cutter CT without realizing that it is coming into contact with the pipeline P. Therefore, it is necessary for the operator operating the cutter CT to be able to immediately recognize that the cutter CT is coming into contact with the pipeline P and stop the cutter CT from moving forward.

[0006] An object of the present disclosure is to provide a technology that can improve the protection function of cables housed in underground structures.

[0007] In one embodiment, the protective item is a protective item for protecting a cable, and comprises an outer wall portion exposed to the outside, and one or more tubes that are shielded by the outer wall portion and installed along the direction in which the outer wall portion extends, the one or more tubes containing a colorant and having lower strength than the outer wall portion.

[0008] According to one embodiment of the present disclosure, a technology can be provided that can improve the protection function of cables housed in underground structures.

[0009] 1 is a cross-sectional view showing an example of the configuration of a protective item inserted into a pipeline; FIG. 2 is a diagram showing an example of the configuration of a tube; FIG. 3 is a partially enlarged view of a cross section of a protective item; FIG. 4 is a diagram explaining a state in which a coloring agent is coming out of a tube; FIG. 5 is a diagram explaining a state in which a coloring agent is coming out of a tube; FIG. 6 is a diagram explaining a protective item applied to an underground structure; FIG. 7 is a diagram explaining a protective item applied to an underground structure; FIG. 8 is a diagram explaining a protective item applied to an underground structure; FIG. 9 is a diagram explaining a protective item applied to an underground structure; FIG. 10 is a diagram explaining a shallow buried section; FIG. 11 is a diagram explaining a configuration in which the outside of a pipeline has a function of protecting the cable; FIG. 12 is a diagram explaining a state in which a cutter comes into contact with a pipeline; FIG. 13 is a diagram explaining a state in which a cutter comes into contact with a pipeline.

[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, duplicated descriptions of the same parts may be omitted or simplified as appropriate.

[0011] An overview of this embodiment will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view of a protective device 1 inserted into a conduit P. The protective device 1 is for protecting a cable 2 and includes an outer wall portion 11 exposed to the outside, and one or more tubes 13 that are shielded by the outer wall portion 11 and installed along the direction in which the outer wall portion 11 extends, the one or more tubes 13 containing a colorant and having lower strength than the outer wall portion 11.

[0012] The protective device 1 according to this embodiment is installed inside the pipeline P, which is an underground structure, and therefore does not require additional space outside the pipeline P. Furthermore, with the protective device 1 according to this embodiment, when a cutter CT or the like contacts and advances from the outside of the protective device 1, the cutter CT breaks the outer wall 11, and then breaks the tube 13 immediately inside the outer wall 11, the coloring agent contained in the tube 13 is released. A worker operating the cutter CT who visually recognizes the coloring agent can stop further advancement of the cutter CT. This reduces the possibility that the worker will unknowingly cut the cable 2 inside the protective device 1. This improves the protection function of the cable 2 housed in the underground structure.

[0013] The configuration of the protective article 1 will be described in detail with reference to Fig. 1. In this embodiment, the protective article 1 further includes one or more inner pipes 12 for accommodating the cables 2, which are installed inside the outer wall portion 11. The number of inner pipes 12 is three in the example shown in Fig. 1, but it may be less than three or four or more.

[0014] The outer wall 11 is exposed to the outside of the protective article 1 and houses the inner pipes 12. The outer wall 11 has a cylindrical shape. As shown in FIG. 1 , the outer wall 11 has an inner circumferential surface T2 having a portion that contacts the outer circumferential surfaces T1 of the multiple inner pipes 12. The curvature of the inner circumferential surface T2 of the outer wall 11 is smaller than the curvature of the outer circumferential surfaces T1 of one or more of the inner pipes 12. The outer wall 11 is made of a synthetic resin material such as rigid polyvinyl chloride, polyethylene, polypropylene, or ABS (acrylonitrile butadiene rubber styrene), or a metal material including steel.

[0015] The inner pipe 12 is installed inside the outer wall portion 11 and accommodates the cables 2. The number of cables 2 accommodated in one inner pipe 12 is not limited to one, two, or three as shown in FIG. 1 , and may accommodate, for example, four or more cables. As shown in FIG. 1 , the cables 2 accommodated in the inner pipe 12 may have different diameters. The inner pipe 12 has a cylindrical shape. The outer peripheral surface T1 of each inner pipe 12 contacts the inner peripheral surface T2 of the outer wall portion 11. The outer peripheral surfaces T1 of two adjacent inner pipes 12 contact each other. The inner pipe 12 is made of a synthetic resin material such as rigid polyvinyl chloride, polyethylene, polypropylene, or ABS, or a metal including steel.

[0016] The tube 13 is installed along the direction of extension of the outer wall 11 while being shielded by the outer wall 11. The tube 13 contains a colorant. The tube 13 has lower strength than the outer wall 11. The tube 13 is made of a material such as polyethylene, silicone, or polyvinyl chloride. This provides flexibility to the tube 13, allowing it to be contained in the gap between the inner circumferential surface T2 of the outer wall 11 and the outer circumferential surface T1 of the inner pipe 12 without wasting space while in contact with both the inner circumferential surface T2 of the outer wall 11 and the outer circumferential surface T1 of the inner pipe 12. The colorant is a liquid made of any material, such as a pigment or paint. Alternatively, the colorant may be in powder form. The colorant has a high saturation color with a saturation equal to or greater than a predetermined value, specifically, may be red, yellow, white, or the like. This makes the colorant conspicuous when it comes into contact with soil, concrete, or the like, allowing workers to easily notice it. The colorant may be sealed in the tube 13 at a pressure higher than atmospheric pressure. The ends of the tubes 13 may be configured to be hermetically sealed with the coloring agent enclosed therein. This allows the coloring agent inside the tubes 13 to be ejected to the outside when the cutter CT comes into contact with the tubes 13 and breaks them. As shown in Figure 1, the protective article 1 of this embodiment includes a total of six tubes 13, each of which is in contact with both the inner circumferential surface T2 of the outer wall portion 11 and the outer circumferential surface T1 of the corresponding inner pipe 12.

[0017] 2 shows the tube 13 as viewed from a direction perpendicular to the longitudinal direction. The length of the tube 13 may be the same as that of the protective article 1 in the axial direction as a single tube, or may be the same as that of the protective article 1 by connecting multiple short tubes in the axial direction.

[0018] Although the cross section of the tube 13 shown in FIG. 1 is elliptical, this is not limiting, and the tube 13 may have any cross-sectional shape, such as triangular or rectangular. For example, the tube 13 may have a substantially triangular cross section that fits into the gap between the outer circumferential surface T1 of the inner tube 12 and the inner circumferential surface T2 of the outer wall portion 11. FIG. 3 is a partially enlarged view of the cross section of a protective article 1 including a tube 13 having a substantially triangular cross section. As shown in FIG. 3, the tubes 13 may be able to fill the gap between the outer circumferential surface T1 and the inner circumferential surface T2 of the outer wall portion 11, with two sides of the substantially triangular cross section of each of the two tubes 13 aligned with the outer circumferential surface T1 of the inner tube 12 and the inner circumferential surface T2 of the outer wall portion 11, respectively.

[0019] As shown in FIG. 1 , in this embodiment, the tubes 13 are provided in pairs corresponding to one inner tube 12. The number of tubes 13 corresponding to one inner tube 12 is not limited to this, and may be, for example, one, three, or four. Thus, the number of tubes 13 may be an integer multiple of the number of inner tubes 12. In this embodiment, the three pairs of tubes 13 are provided in rotationally symmetric positions in a cross section perpendicular to the tube axis of the outer wall portion 11. Rotational symmetry means that when rotated by a predetermined angle around the tube axis, the cross sections of the tubes 13 overlap at the same positions before and after rotation. In FIG. 1 , the three pairs of tubes 13 are provided at positions offset from each other by 60° around the tube axis of the outer wall portion 11, but the rotational symmetry of each pair is not limited to this. For example, if there are two inner tubes 12, two sets of tubes 13 may be provided for the two inner tubes 12 in positions that are rotationally symmetrical with respect to each other, i.e., positions that are 180° apart. Alternatively, if there are four inner tubes 12, four sets of tubes 13 may be provided for the four inner tubes 12 in four positions that are offset by 45° each. That is, the rotationally symmetric positions of each set of tubes 13 may be positions that are offset by an angle equal to 360° divided by the number N of sets of tubes 13. With the tubes 13 provided in such rotationally symmetric positions, even if the cutter CT advances from any angle in the circumferential direction of the pipeline P and destroys the outer wall portion 11, the tube 13 immediately inside the outer wall portion 11 will break, making it easier for the colorant to escape.

[0020] 4A and 4B show the state in which the cutter CT comes into contact with the pipeline P, causing the tube 13 to break and the coloring agent to leak out. As shown in Fig. 4A and 4B, the coloring agent leaking out of the pipeline P allows the operator to visually perceive the contact of the cutter CT.

[0021] The protective device 1 is installed in the pipeline P by being inserted from the end of the pipeline P. Specifically, a worker may enter a manhole and insert the protective device 1 from the end of the pipeline P that is exposed in the manhole. However, this is not limited to this, and the protective device 1 may also be installed in the pipeline P by removing the pipeline P that has already been buried underground, detaching the pipeline P from its joints, and so on.

[0022] The present disclosure is not limited to the above-described embodiments, and the configurations shown in the drawings can be modified without departing from the spirit of the present disclosure.

[0023] For example, the protective article 1 may be applied to underground structures other than the pipeline P. For example, the protective article 1 can be applied to underground structures such as a culvert, handhole, or utility tunnel shown in FIG. 5A , or to arched or inverted arched underground structures such as a tunnel or arch culvert shown in FIGS. 5B and 5C . The protective article 1 can also be applied to underground structures such as a manhole shown in FIG. 5D , or to underground structures such as a U-shaped trench shown in FIGS. 5E and 5F . FIGS. 5A to 5F show examples of the outer wall 11 and tube 13 of the protective article 1 integrated into an underground structure. In FIGS. 5A to 5F , the cross section of the tube 13 is circular. The tube 13 is installed along the direction in which the outer wall 11 extends, while being shielded by the outer wall 11. In the example shown in Fig. 1, the tube 13 is provided inside the outer wall portion 11 by being housed between the outer peripheral surface T1 of the inner pipe 12 and the inner peripheral surface T2 of the outer wall portion 11, whereas in the examples shown in Fig. 5A to Fig. 5F, the tube 13 is directly embedded in the outer wall portion 11. In the examples shown in Fig. 5A to Fig. 5F, as in the example shown in Fig. 1, it is possible to improve the protection function of the cable housed in the underground structure.

[0024] 1 protective article 11 outer wall portion 12 inner pipe 13 tube 2 cable

Claims

1. A protective device for protecting a cable, comprising: an outer wall portion exposed to the outside; and one or more tubes that are shielded by the outer wall portion and installed along the extension direction of the outer wall portion, the one or more tubes containing a coloring agent and having a strength lower than that of the outer wall portion.

2. The protective article according to claim 1, further comprising one or more circular tubular inner tubes for accommodating the cable, the one or more inner tubes being located inside the outer wall portion, the one or more tubes being in contact with both the inner surface of the outer wall portion and the outer surface of the one or more inner tubes.

3. A protective article as described in claim 1 or 2, wherein the one or more tubes are a plurality of tubes, and each of the plurality of tubes is provided at a rotationally symmetrical position in a cross section perpendicular to the tube axis of the outer wall portion.

4. The protective article according to claim 3, wherein the one or more inner tubes are a plurality of inner tubes, the number of tubes included in the plurality of tubes is an integer multiple of the number of inner tubes included in the plurality of inner tubes, and each of the plurality of tubes is in contact with the inner surface of the outer wall portion and the outer surface of a corresponding inner tube among the plurality of inner tubes.

Images