Protective article

Abstract

A protective article (1) for protecting cables (2) comprises: one or more circular-tube-shaped inner tubes (12) for accommodating the cables (2); an outer wall section (11) accommodating the one or more inner tubes (12), the outer wall section (11) having a circular tube shape of which the curvature of the inner circumferential surface thereof is smaller than the curvature of the outer circumferential surface of the one or more inner tubes (12); a plurality of protective materials (13) disposed in gaps between the one or more inner tubes (12) and the outer wall section (11); and a plurality of cushioning materials (14) respectively wedged between a corresponding one of the plurality of protective materials (13) and the one or more inner tubes (12) to secure the corresponding protective material (13) to the one or more inner tubes (12).

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] Shallowly buried sections of pipelines are at risk of being damaged by excavation machinery and other equipment during road construction and other projects. Figure 4 is an underground cross-sectional view showing an example of a shallowly buried section SH of a pipeline P. As shown in Figure 4, 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 shallowly buried sections SH. Figure 5 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 5, 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 on the outside of the pipeline P. Furthermore, if a component pipe is inserted inside the pipeline P to provide protection, the cable 2 needs to be protected from contact with the cutter CT of the paving machine PM, which cuts the pavement PA, from any angle in the circumferential direction of the pipeline P. However, there is a risk that the component pipe will rotate within the pipeline P due to twisting of the cable 2 or vibration from vehicles traveling on the ground.

[0005] Figures 6A and 6B are diagrams showing the direction in which the component pipes inside the pipeline P rotate. Figure 6A shows the cutter CT moving in the direction indicated by the white arrow into the pipeline P buried under the pavement PA. Figure 6B shows the component pipe inserted into the pipeline P, viewed from diagonally above the end of the pipeline P in Figure 6A. The solid arrows in Figures 6A and 6B indicate the direction in which the component pipes rotate inside the pipeline P relative to the pipeline P. Considering that the component pipes rotate inside the pipeline P, it is necessary to be able to protect the cable 2 from all angles in the circumferential direction of the pipeline P, regardless of the direction in which the cutter CT moves. Furthermore, if the component pipes are destroyed by the impact of contact with the cutter CT, the protective function of the cable 2 may be reduced.

[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, a protective item is a protective item for protecting a cable, and comprises one or more circular tubular inner tubes for accommodating the cable, an outer wall portion accommodating the one or more inner tubes, the outer wall portion being circular tubular and having a curvature of the inner surface that is smaller than the curvature of the outer surface of the one or more inner tubes, a plurality of protective materials arranged in the gap between the one or more inner tubes and the outer wall portion, and a plurality of cushioning materials among the plurality of protective materials that are sandwiched between corresponding protective materials and the one or more inner tubes and fix the corresponding protective materials to the one or more inner tubes, respectively.

[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 a protective material; FIG. 3 is a diagram showing an example of a buffer material; FIG. 4 is a diagram explaining how a cutter comes into contact with a protective item; FIG. 5 is a diagram explaining how a cutter comes into contact with a protective item; FIG. 6 is a diagram explaining how a cutter comes into contact with a protective item; FIG. 7 is a diagram explaining a shallow buried section; FIG. 8 is a diagram explaining a configuration in which a cable protection function is provided on the outside of a pipeline; FIG. 9 is a diagram explaining the rotation of a component pipe relative to the pipeline; FIG. 10 is a diagram explaining the rotation of a component pipe relative to the 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 one or more cylindrical inner pipes 12 for accommodating the cable 2, an outer wall portion 11 accommodating the one or more inner pipes 12, the outer wall portion 11 being cylindrical and having an inner circumferential surface T2 with a curvature smaller than the curvature of the outer circumferential surface T1 of the one or more inner pipes 12, a plurality of protective materials 13 disposed in gaps S between the one or more inner pipes 12 and the outer wall portion 11, and a plurality of buffer materials 14 sandwiched between a corresponding one of the plurality of protective materials 13 and the one or more inner pipes 12 to fix the corresponding protective material 13 to the one or more inner pipes 12, respectively.

[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, even if the cutter CT contacts the protective device 1 and applies an impact, the buffer material 14 connected to the protective material 13 can absorb the impact. This allows the protective material 13 to maintain its shape without being destroyed, improving protective performance. Furthermore, as described below, the combination of the protective material 13 and the buffer material 14 is provided at a rotationally symmetrical position in the cross section of the protective device 1. Therefore, regardless of the angle from which the cutter CT breaks the outer wall portion 11 and enters the pipeline P and hits the protective material 13 immediately inside the outer wall portion 11, the repulsive force generated when the cutter CT hits the protective material 13 is easily transmitted to the worker. This improves the likelihood that the worker will stop the advancement of the cutter CT and reduces the possibility that the worker will unknowingly cut the cable 2 inside the protective device 1. Therefore, it is possible to improve 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 portion 11 accommodates the inner pipes 12. The outer wall portion 11 has a cylindrical shape. As shown in FIG. 1 , the outer wall portion 11 has an inner circumferential surface T2 having a portion that contacts the outer circumferential surface T1 of each of the three inner pipes 12. The curvature of the inner circumferential surface T2 of the outer wall portion 11 is smaller than the curvature of the outer circumferential surface T1 of the inner pipes 12. The outer wall portion 11 is made of any material, such as a synthetic resin material such as rigid polyvinyl chloride, polyethylene, polypropylene, or ABS (acrylonitrile butadiene rubber styrene), or a metal 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 is cylindrical. 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. Referring to FIG. 1 , for each pair of adjacent inner pipes 12, the outer peripheral surfaces T1 of the inner pipes 12 contact each other, and three gaps S are formed between the outer peripheral surfaces T1 of the three inner pipes 12 and the inner peripheral surface T2 of the outer wall portion 11. 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 protective materials 13 are provided in the gaps S formed between the outer peripheral surfaces T1 of each of two adjacent inner pipes 12 and the inner peripheral surface T2 of the outer wall portion 11. The protective materials 13 are made of a hard material such as ceramic or metal. Referring to FIG. 1 , a protective material 13 is provided in each of the three gaps S. In FIG. 1 , the cross section of each of the protective materials 13 is pentagonal, and the vertex of each pentagon facing the inner pipe 12 forms a protrusion 131 protruding toward the inner pipe 12. The cross-sectional shape of the protective materials 13 is not limited thereto and may have any shape having a protrusion 131. For example, the buffer material 14 may have a V-shaped cross section, and the protective material 13 corresponding to the buffer material 14 may have a triangular or sector-shaped cross section. The protective materials 13 may have the same V-shaped cross section as the buffer material 14.

[0017] 2A is a view of the protective material 13 as seen from diagonally above. The length L1 of the protective material 13 may be a single protective material having the same length in the tube axis direction as the protective article 1, or the protective material 13 may have the same length as the protective article 1 by connecting multiple short protective materials in the tube axis direction.

[0018] The buffer materials 14 are sandwiched between the corresponding protective materials 13 and the inner pipe 12 to fix the corresponding protective materials 13 to the inner pipe 12. Referring to FIG. 1 , three buffer materials 14 correspond to the three protective materials 13 that they come into contact with. The three buffer materials 14 have recesses 141 that respectively receive the protrusions 131 of the protective materials 13. The buffer materials 14 are made of a material such as rubber or silicone. The cross section of each of the buffer materials 14 has a wide-angle V-shape, and the inner surface of each V-shape forms a recess 141 that receives the protrusions 131 of the protective materials 13. The cross-sectional shape of the buffer materials 14 is not limited to this and may have any shape.

[0019] 2B is a view of the buffer material 14 viewed from diagonally above. As with the protective material 13, the length L2 of the buffer material 14 may be a single material having the same length in the tube axis direction as the protective article 1, or multiple short buffer materials may be connected in the tube axis direction to form the buffer material 14 having the same length as the protective article 1. The buffer material 14 and the corresponding protective material 13 may be inserted into the protective article 1 after combining the convex portion 131 and the concave portion 141.

[0020] In the cross-sectional view of FIG. 1 , three combinations of buffer materials 14 and corresponding protective materials 13 are arranged at 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 combinations of buffer materials 14 and corresponding protective materials 13 overlap at the same positions before and after rotation. In FIG. 1 , the three combinations are arranged at positions offset from each other by 60° around the tube axis of the outer wall portion 11, but the rotationally symmetric positions of the combinations are not limited to this. For example, if there are two inner pipes 12, two combinations of protective materials 13 and buffer materials 14 for the two inner pipes 12 may be arranged at rotationally symmetric positions, i.e., at positions 180° opposite each other. Alternatively, if there are four inner pipes 12, four combinations of protective materials 13 and buffer materials 14 for the four inner pipes 12 may be arranged at four positions offset by 45° each. That is, one set of rotationally symmetric positions may be positions shifted by an angle equal to the value obtained by dividing 360° by the number N of combinations.

[0021] 3A to 3C are diagrams showing examples of how the cutter CT advances from different circumferential angles toward the protective element 1 rotating inside the pipeline P relative to the pipeline P and contacts the protective element 1. In FIGS. 3A to 3C, the outline arrows indicate the direction of advancement of the cutter CT. Using FIG. 3A as a reference angle, FIG. 3B shows the protective element 1 rotated 30 degrees counterclockwise from the reference angle, and FIG. 3C shows the protective element 1 rotated 60 degrees counterclockwise from the reference angle. In the protective element 1 of FIG. 3A, the cutter CT advances from directly beside the protective material 13. The repulsive force generated by hitting the protective material 13 is transmitted to the operator using the cutter CT, allowing the operator to perceive that the cutter CT has come into contact with the pipeline P. As such, when the protective element 1 of FIG. 3A is at the reference angle, the best protective performance can be achieved. In Figure 3B, as the cutter CT advances, it comes into contact with the ends of the protective materials 13 indicated by star symbols, generating a repulsive force, allowing the worker to perceive the contact of the cutter CT, as in Figure 3A. In Figure 3C, as the cutter CT advances, it immediately comes into contact with the ends of each of the two protective materials 13 indicated by star symbols, generating a repulsive force, allowing the worker to perceive the contact of the cutter CT, as in Figure 3A. The combination of the buffer materials 14 and protective materials 13, which are provided in rotationally symmetrical positions, makes it possible to provide protection for the cable 2 regardless of the angle from which the cutter CT advances in the circumferential direction of the conduit P.

[0022] For example, if the protective material 13 were directly fixed to the inner pipe 12 using an adhesive such as resin, there is a high possibility that the protective material 13 would shatter due to impact. On the other hand, if the protective material 13 were fixed to the inner pipe 12 via a buffer material 14, the buffer material 14 would absorb the impact, allowing the protective material 13 to maintain its shape. By using the buffer material 14 in this way, it is possible to prevent the protective material 13 from cracking and scattering. This makes it possible to avoid a decrease in the protective performance of the cable 2 inside the inner pipe 12.

[0023] 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.

[0024] 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.

[0025] The following additional notes are provided regarding the above-described embodiments.

[0026] [Supplementary Item 1] A protective item for protecting a cable, comprising: one or more circular tubular inner tubes for accommodating the cable; an outer wall portion accommodating the one or more inner tubes, the outer wall portion being circular tubular and having a curvature of the inner circumferential surface that is smaller than the curvature of the outer circumferential surface of the one or more inner tubes; a plurality of protective materials disposed in gaps between the one or more inner tubes and the outer wall portion; and a plurality of buffer materials sandwiched between a corresponding protective material among the plurality of protective materials and the one or more inner tubes to respectively fix the corresponding protective material to the one or more inner tubes. [Supplementary Item 2] The one or more inner tubes are a plurality of inner tubes in which the outer peripheral surface of each inner tube contacts the inner peripheral surface of the outer wall portion and the outer peripheral surfaces of any two adjacent inner tubes contact each other, and the gap is formed by the outer peripheral surfaces of any two adjacent inner tubes among the plurality of inner tubes and the inner circumferential surface of the outer wall portion. [Supplementary Item 3] The protective article according to Supplementary Item 1 or 2, wherein each of the plurality of protective materials has a convex portion protruding toward the one or more inner pipes, and each of the plurality of buffer materials has a concave portion that receives the convex portion of the corresponding protective material. [Supplementary Item 4] The protective article according to any one of Supplementary Items 1 to 3, wherein a combination of each of the plurality of buffer materials and the corresponding protective material is provided at a rotationally symmetric position in a cross section perpendicular to the pipe axis of the outer wall portion.

[0027] REFERENCE SIGNS LIST 1 protective item 11 outer wall portion 12 inner pipe 13 protective material 14 buffer material 131 convex portion 141 concave portion 2 cable

Claims

1. A protective item for protecting a cable, comprising: one or more cylindrical inner tubes for accommodating the cable; an outer wall portion accommodating the one or more inner tubes, the outer wall portion being cylindrical and having an inner circumferential curvature smaller than the outer circumferential curvature of the one or more inner tubes; a plurality of protective materials disposed in the gap between the one or more inner tubes and the outer wall portion; and a plurality of cushioning materials among the plurality of protective materials, which are sandwiched between a corresponding protective material and the one or more inner tubes to fix the corresponding protective material to each of the one or more inner tubes.

2. The protective product according to claim 1, wherein the one or more inner tubes are a plurality of inner tubes in which the outer peripheral surface of each inner tube is in contact with the inner peripheral surface of the outer wall portion and the outer peripheral surfaces of any two adjacent inner tubes are in contact with each other, and the gap is formed by the outer peripheral surfaces of any two adjacent inner tubes among the plurality of inner tubes and the inner peripheral surface of the outer wall portion.

3. A protective article as described in claim 1 or 2, wherein each of the plurality of protective materials has a protrusion protruding toward the one or more inner tubes, and each of the plurality of cushioning materials has a recess that receives the protrusion of the corresponding protective material.

4. A protective article as described in claim 1 or 2, wherein the combination of each of the plurality of cushioning materials and the corresponding protective material is provided at a rotationally symmetrical position in a cross section perpendicular to the tube axis of the outer wall portion.

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