Protector

Abstract

A protector (1) according to the present disclosure comprises: one or more circular tube-shaped inner tubes (12) which accommodate cables (2); an outer tube (11) which accommodates the one or more inner tubes (12), and of which the curvature of the inner peripheral surface is smaller than the curvature of the outer peripheral surface of the one or more inner tubes (12); a plurality of protective members (13) which are disposed in gaps S between the one or more inner tubes (12) and the outer tube (11); and tubes (14) which are disposed in the gaps S and serve as elastic members for fixing each of the plurality of protective members (13) in a state in which the protective members (13) are biased toward the inside of the protective members (13) from both ends of the protective members (13).

Description

Protective equipment

[0001] The present disclosure relates to protective gear.

[0002] There are known techniques for protecting cables such as optical fibers and power lines laid in underground structures such as underground conduits from damage caused by heavy machinery such as pavement cutters used in road construction. For example, Non-Patent Document 1 discloses a technique for placing protective concrete, steel plates, ceramic plates, etc., on the outside of an underground buried object depending on the buried depth of the underground buried object. Patent Document 1 also discloses a technique for providing a protective member made of a hard material such as ceramic inside a conduit that houses a cable.

[0003] International Publication No. 2024 / 042622

[0004] Ministry of Land, Infrastructure, Transport and Tourism, "Case Studies on Utility Pole Removal," National Institute for Land and Infrastructure Management, No. 789, March 2014

[0005] In shallowly buried sections of a conduit accommodating a cable, there is a risk of damage from excavation machinery and the like during road construction work. FIG. 8 is a diagram showing an example of placing a protective material such as a steel plate S on the outside of the conduit P to protect the cable 2 from the cutters CT of a paving machine PM that cuts the pavement PA in a shallowly buried section. As shown in FIG. 8, when the distance d between the ground surface and the conduit P is short and the soil covering of the conduit P is shallow, it is difficult to protect the cable 2 by placing a protective material on the outside of the conduit P, as in the technology disclosed in Non-Patent Document 1. On the other hand, the technology disclosed in Patent Document 1 makes it possible to protect the cable 2 housed in the conduit P regardless of the buried depth of the conduit P.

[0006] In the technology disclosed in Patent Document 1, a cable housing section for housing the cable 2 is provided inside the conduit P, and a protective member must be placed in the limited space inside the conduit to protect the cable 2. To maximize the protective function, the thickness of the protective member must be maximized, but to prevent the protective member from shifting position during transportation and installation, the protective member must be fixed with a fixing member or the like. Fixing the protective member with a fixing member imposes restrictions on the size of the protective member by the amount of the fixing member, which may result in a reduction in the protective function.

[0007] The object of the present disclosure, made in consideration of the above-mentioned problems, is to provide a technology that can improve the protection function of the housed cable.

[0008] One embodiment of the protective gear is a tubular protective gear for protecting a cable, and includes one or more circular tubular inner tubes that house the cable, an outer tube that houses the one or more inner tubes and has a circular tubular outer tube with an inner circumferential surface having a curvature that is smaller than the curvature of the outer circumferential surface of the one or more inner tubes, a plurality of protective members arranged in the gap between the one or more inner tubes and the outer tube, and an elastic member that is arranged in the gap and fixes each of the plurality of protective members in a state in which the protective members are biased from both ends of the protective member toward the inside of the protective member.

[0009] According to an embodiment of the present disclosure, it is possible to provide a technology that can improve the protection function of a housed cable.

[0010] FIG. 2 is a cross-sectional view showing a configuration example of protective gear according to an embodiment of the present disclosure. FIG. 3 is a view showing an example of a protective member shown in FIG. 1. FIG. 4 is a view for explaining fixation of the protective member shown in FIG. 1. FIG. 5 is a view showing an example of a tube shown in FIG. 1. FIG. 3 is a cross-sectional view showing another configuration example of protective gear according to an embodiment of the present disclosure. FIG. 4 is a view for explaining insertion of a structure into the protective gear. FIG. 5 is a view for explaining insertion of a structure into the protective gear. FIG. 6 is a view for explaining how a cutter comes into contact with the protective gear. FIG. 7 is a view for explaining how a cutter comes into contact with the protective gear. FIG. 8 is a view for explaining a configuration in which a cable protection function is provided on the outside of a conduit.

[0011] Hereinafter, embodiments 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 the present embodiments, duplicated descriptions of the same parts may be omitted or simplified as appropriate.

[0012] FIG. 1 is a cross-sectional view showing an example configuration of a protective gear 1 according to an embodiment of the present disclosure inserted into a conduit P. The protective gear 1 according to this embodiment is cylindrical and protects a cable 2 laid in the conduit P. As shown in FIG. 1 , the protective gear 1 according to this embodiment includes one or more circular inner tubes 12 that house the cable 2; an outer tube 11 that houses the one or more inner tubes 12, the outer tube 11 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 tubes 12; a plurality of protective members 13 disposed in gaps S between the one or more inner tubes 12 and the outer tube 11; and tubes 14 provided at both circumferential ends of each of the plurality of protective members 13 of the protective gear 1. The tubes 14 are an example of an elastic member.

[0013] The protective gear 1 according to this embodiment is disposed inside a pipeline P, which is an underground structure. Therefore, no space is required for placing protective ceramic plates or the like outside the pipeline P. Even if the cutter CT comes into contact with the protective gear 1, the protective members 13 can protect the cable 2 housed in the inner pipe 12. As described below, the protective members 13 are arranged at rotationally symmetric positions in a cross section perpendicular to the axial direction of the protective gear 1. Therefore, regardless of the angle from which the cutter CT breaks the outer pipe 11 and hits the protective member 13 located inside the outer pipe 11 in the circumferential direction of the pipeline P, the repulsive force generated when the cutter CT hits the protective member 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 likelihood that the worker will unknowingly cut the cable 2 inside the protective gear 1. Therefore, the protective gear 1 according to this embodiment can improve the protection function of the housed cable 2.

[0014] The configuration of the protective gear 1 will be described in detail with reference to Fig. 1. In this embodiment, the protective gear 1 includes one or more inner tubes 12 that are installed inside the outer tube 11 and that house the cables 2. The number of inner tubes 12 is three in the example shown in Fig. 1, but it may be less than three or four or more.

[0015] The outer tube 11 houses the inner tubes 12. The outer tube 11 has a cylindrical shape. As shown in FIG. 1 , the outer tube 11 has an inner circumferential surface T2 having a portion that contacts the outer circumferential surface T1 of each of the three inner tubes 12. The curvature of the inner circumferential surface T2 of the outer tube 11 is smaller than the curvature of the outer circumferential surface T1 of the inner tubes 12. The outer tube 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.

[0016] The inner pipe 12 is disposed inside the outer pipe 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 circumferential surface T1 of each inner pipe 12 contacts the inner circumferential surface T2 of the outer pipe 11. The outer circumferential 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 circumferential surfaces T1 of the inner pipes 12 contact each other, and three gaps S are formed between the outer circumferential surfaces T1 of the three inner pipes 12 and the inner circumferential surface T2 of the outer pipe 11. The inner pipe 12 is made of any material, such as a synthetic resin material such as rigid polyvinyl chloride, polyethylene, polypropylene, or ABS, or a metal including steel.

[0017] The protective members 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 pipe 11. The protective members 13 are made of a hard material such as ceramic. Referring to FIG. 1 , a protective member 13 is provided in each of the three gaps S. In FIG. 1 , the protective members 13 have a pentagonal cross section. Specifically, the protective member 13 has a shape in which the apex on the inner pipe 12 side protrudes toward the inner pipe 12. The cross-sectional shape of the protective members 13 is not limited to this and may be, for example, a triangle or a sector.

[0018] 2 is a view of the protective member 13 as seen from diagonally above. The length L1 of the protective member 13 may be the same as the axial length of the protective gear 1 when used alone, or may be the same as the axial length of the protective gear 1 when multiple protective members 13 are connected together.

[0019] As shown in FIG. 1 , the tubes 14 serving as elastic members are disposed at both ends of the protective members 13 in the gap S. The tubes 14 fix the protective members 13 while biasing them inward from both ends of the protective members 13. The tubes 14 have lower strength than the outer tube 11. The tubes 14 are made of a material such as polyethylene, silicone, or polyvinyl chloride. This provides the tubes 14 with flexibility and elasticity. The flexibility and elasticity of the tubes 14 provided at both ends of the protective members 13 allows the multiple protective members 13 to be fixed in a state of being biased inward by the tubes 14 (elastic members) provided at both ends of the protective members 13. Specifically, as shown in FIG. 3 , the tubes 14 are pressed against the inner circumferential surface T2 of the outer tube 11 and the outer circumferential surface T1 of the inner tube 12 near the ends of the gap S, thereby biasing the protective members 13 toward the inside of the protective members 13. The protective member 13 is biased inward by the tube 14 (elastic member), so that the protective member 13 is fixed in abutting contact with the inner surface T2 of the outer tube 11 and the outer surface T1 of the inner tube 12, as shown in Figure 1.

[0020] The tube 14 contains a colorant. 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, red, yellow, or white. This allows workers to easily notice if the colorant leaks into soil, concrete, or the like. The colorant may be sealed in the tube 14 at a pressure higher than atmospheric pressure. The ends of the tube 14 may be configured to be sealable while the colorant is sealed inside. This allows the colorant inside the tube 14 to spray out when the cutter CT comes into contact with and breaks the tube 14. As shown in FIG. 1 , the protective gear 1 according to this embodiment includes a tube 14 at each circumferential end of each of the three protective members 13. That is, the protective gear 1 according to this embodiment includes a total of six tubes 14.

[0021] 4 shows the tube 14 as viewed from a direction perpendicular to the longitudinal direction. The length of the tube 14 may be the same as the axial length of the protective gear 1 when it is a single tube 14, or may be the same as the axial length of the protective gear 1 when multiple tubes 14 are connected together.

[0022] As described above, the protective member 13 is made of, for example, ceramic. Because ceramic is made by pressing a powder material, the tolerances are large. Therefore, the protective member 13 needs to be made to a size that allows some margin for the accommodation space (gap S). Therefore, the protective member 13 cannot be fixed and placed in the gap S by itself. If a fixing member is used to fix the protective member 13, the size of the protective member 13 will be reduced by the amount of the fixing member, and the protective function of the cable 2 will be impaired. In particular, if a fixing member is provided in the thickness direction of the protective member 13 (the radial direction of the protective gear 1), the thickness of the protective member 13 will be reduced, which will affect the reduction in the cutting speed of the cutter CT.

[0023] On the other hand, in this embodiment, the protective member 13 is fixed in a state where it is biased inward by the tube 14 as an elastic member provided to make it easier for the worker to recognize the breakage of the protective gear 1, thereby eliminating the need for a separate fixing member. Since there is no need for a fixing member, the size of the protective member 13 can be made as large as possible within the range that can be placed in the gap S. As a result, the protective gear 1 according to this embodiment can improve the protection function of the housed cable 2.

[0024] Referring again to FIG. 1 , the protective members 13 are arranged at rotationally symmetric positions in a cross section perpendicular to the tube axis of the protective gear 1. Rotational symmetry means that when the protective gear 1 is rotated by a predetermined angle around the tube axis, the cross sections of the protective members 13 overlap at the same position before and after the rotation. In FIG. 1 , three protective members 13 are arranged at positions offset from each other by 120° around the tube axis of the protective gear 1, but this is not limited to this. For example, if there are two inner tubes 12, two protective members 13 may be arranged at rotationally symmetric positions for the two inner tubes 12, i.e., at positions 180° opposite each other. Furthermore, if there are four inner tubes 12, four protective members 13 may be arranged at rotationally symmetric positions for the four inner tubes 12, i.e., at positions offset from each other by 90°. That is, N protective members 13 may be arranged at positions offset by an angle equal to 360° divided by N.

[0025] When a structure made up of protective member 13 and tubes 14 as elastic members provided on both ends of protective member 13 is placed in gap S, the structure made up of protective member 13 and tubes 14 is inserted into gap S from the axial direction of protective equipment 1. In this case, with a configuration in which tubes 14 are provided on both ends of protective member 13, there is a risk that it may become difficult to insert the structure into gap S due to friction.

[0026] Therefore, as shown in FIG. 5 , the tube 14 may include an elastic region 14a that abuts against the protective member 13 and has elasticity, and a hard region 14b that abuts against the outer peripheral surface T1 of the inner tube 12 and the inner peripheral surface T2 of the outer tube 11 at the circumferential end of the gap S of the protective gear 1 and is made of a material harder than the elastic region 14a. In this case, the hard region 14b may have a substantially triangular cross section. Specifically, the hard region 14b may have a shape such that two sides of the substantially triangular cross section of the hard region 14b follow the outer peripheral surface T1 of the inner tube 12 and the inner peripheral surface T2 of the outer tube 11. By having the hard region 14b have such a shape, the tube 14 is positioned so that the hard region 14b abuts against the outer peripheral surface T1 of the inner tube 12 and the inner peripheral surface T2 of the outer tube 11 at the circumferential end of the gap S, as shown in FIG. 5 . In addition, at the circumferential end of the gap S of the protective gear 1, the hard region 14b is inserted between the inner surface T2 of the outer tube 11 and the outer surface T1 of the inner tube 12, thereby ensuring a larger space for the protective member 13.

[0027] In the protective gear 1 shown in FIG. 5 , when assembling the protective gear 1, a structure consisting of the protective member 13 and the tube 14 is inserted axially into a gap S defined by the inner circumferential surface T2 of the outer tube 11 and the outer circumferential surface T1 of the inner tube 12. As shown in FIG. 6A , the structure is pushed in from both sides of the structure, compressing the elastic region 14a of the tube 14 before being inserted into the gap S. Here, hard regions 14b are provided on both ends of the tube 14. Therefore, even if the hard regions 14b of the tube 14 come into contact with the inner circumferential surface T2 of the outer tube 11 and the outer circumferential surface T1 of the inner tube 12 when the structure is inserted into the gap S, friction due to contact can be reduced. As a result, the structure can be easily inserted into the gap S.

[0028] After insertion into the gap S, the structure is released from the pressure, causing the elastic region 14a of the tube 14 to return to its original shape, as shown in Fig. 6B. As the elastic region 14a of the tube 14 returns to its original shape, the tube 14 urges the protective member 13 toward the inside of the protective member 13, with the hard region 14b of the tube 14 abutting against the outer peripheral surface T1 of the inner tube 12 and the inner peripheral surface T2 of the outer tube 11 at the circumferential end of the protective gear 1 in the gap S.

[0029] 7A to 7C are diagrams showing how the cutter CT advances from different circumferential angles toward the protective gear 1 rotating inside the pipeline P relative to the pipeline P and comes into contact with the protective gear 1. In FIGS. 7A to 7C, the outline arrows indicate the direction of advancement of the cutter CT. Using FIG. 7A as a reference angle, FIG. 7B shows the protective gear 1 rotated 30 degrees counterclockwise from the reference angle, and FIG. 7C shows the protective gear 1 rotated 60 degrees counterclockwise from the reference angle. In FIGS. 7A to 7C, the protective gear 1 is assumed to be configured to include the protective member 13 and tube 14 shown in FIG. 1.

[0030] 7A, the cutter CT advances from directly beside the protective member 13. The repulsive force generated when the cutter CT hits the protective member 13 is transmitted to the worker using the cutter CT, allowing the worker to tactilely recognize that the cutter CT has come into contact with the pipeline P. Furthermore, if the tube 14 is damaged by the cutter CT, the coloring agent contained in the tube 14 will leak out, allowing the worker to visually recognize that the cutter CT has come into contact with the pipeline P.

[0031] In Figure 7B, as the cutter CT advances, it comes into contact with the tube 14 provided at the end of the protective member 13, causing coloring agent to leak from the damaged tube 14. This allows the worker to visually recognize that the cutter CT has come into contact with the pipeline P. As the cutter CT advances further, it comes into contact with the protective member 13, generating a repulsive force. This allows the worker to tactilely recognize that the cutter CT has come into contact with the pipeline P, similar to Figure 7A.

[0032] In Figure 7C, as the cutter CT advances, it comes into contact with the tube 14 attached to one end of one protective member 13 and with the tube 14 attached to one end of another protective member 13 adjacent to that protective member 13, causing colorant to leak from the damaged tube 14. This allows the worker to visually recognize that the cutter CT has come into contact with the pipeline P. Furthermore, as the cutter CT advances further, it comes into contact with the one protective member 13 and another protective member 13 adjacent to that protective member 13, generating a repulsive force. This allows the worker to tactilely recognize that the cutter CT has come into contact with the pipeline P, similar to Figure 7A.

[0033] For example, if the protective member 13 is directly fixed to the inner tube 12 using an adhesive such as resin, there is a high possibility that the protective member 13 will shatter due to impact. On the other hand, if the protective member 13 is fixed by being biased by the tube 14 as an elastic body, as in this embodiment, the impact is absorbed by the tube 14, allowing the protective member 13 to maintain its shape. By fixing the protective member 13 by being biased by an elastic body in this way, it is possible to prevent the protective member 13 from cracking and scattering.

[0034] The following additional notes are provided regarding the above-described embodiments.

[0035] [Supplementary Item 1] A cylindrical protective gear for protecting a cable, comprising: one or more circular tubular inner tubes that house the cable; an outer tube that houses the one or more inner tubes and has a circular tubular outer surface with a curvature that is smaller than the curvature of the outer surface of the one or more inner tubes; a plurality of protective members that are arranged in gaps between the one or more inner tubes and the outer tube; and elastic members that are arranged in the gaps and that fix each of the plurality of protective members in a state in which they are biased from both ends of the protective member toward the inside of the protective member.

[0036] [Supplementary Item 2] The protective equipment according to Supplementary Item 1, wherein the protective equipment comprises a plurality of the inner tubes, the plurality of inner tubes are arranged such that the outer peripheral surface of each inner tube contacts the inner peripheral surface of the outer tube and the outer peripheral surfaces of any two adjacent inner tubes contact each other, the gap is formed by the outer peripheral surfaces of any two adjacent inner tubes of the plurality of inner tubes and the inner peripheral surface of the outer tube, and the elastic member biases the protective member while being pressed against the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube.

[0037] [Supplementary Item 3] The protective gear according to Supplementary Item 2, wherein the elastic member comprises an elastic region that abuts against the protective member and has elasticity, and a hard region that abuts against the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube at a circumferential end of the protective gear in the gap and is made of a material that is harder than the elastic region, and wherein the elastic member urges the protective member toward the inside of the protective member with the hard region abutting against the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube.

[0038] [Supplementary Item 4] The protective equipment according to any one of Supplementary Items 1 to 3, wherein the elastic member contains a coloring agent.

[0039] [Supplementary Item 5] The protective equipment according to any one of Supplementary Items 1 to 4, wherein the plurality of protective members are provided at rotationally symmetric positions in a cross section perpendicular to the tube axis of the protective equipment.

[0040] Although the above-described embodiments have been described as typical examples, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the present disclosure. Therefore, the present invention should not be interpreted as being limited by the above-described embodiments, and various modifications and alterations are possible without departing from the scope of the claims. For example, multiple building blocks shown in the block diagrams of the embodiments can be combined into one, or one building block can be divided.

[0041] REFERENCE SIGNS LIST 1 Protective equipment 2 Cable 11 Outer tube 12 Inner tube 13 Protective member 14 Tube (elastic member) 14a Elastic region 14b Hard region

Claims

1. A cylindrical protective device for protecting a cable, comprising: one or more circular inner tubes that house the cable; an outer tube that is circular and houses the one or more inner tubes, the outer tube having a curvature of its 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 members that are placed in the gap between the one or more inner tubes and the outer tube; and elastic members that are placed in the gap and that fix each of the plurality of protective members in a state in which they are biased from both ends of the protective member toward the inside of the protective member.

2. Protective equipment according to claim 1, comprising a plurality of the inner tubes, the plurality of inner tubes being arranged so that the outer peripheral surface of each inner tube is in contact with the inner peripheral surface of the outer tube and so that the outer peripheral surfaces of any two adjacent inner tubes are in contact with each other, the gap being formed by the outer peripheral surfaces of any two adjacent inner tubes of the plurality of inner tubes and the inner peripheral surface of the outer tube, and the elastic member biasing the protective member while being pressed against the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube.

3. Protective equipment according to claim 2, wherein the elastic member comprises an elastic region that abuts against the protective member and has elasticity, and a hard region that abuts against the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube at the circumferential end of the protective equipment in the gap and is formed of a material that is harder than the elastic region, and wherein the elastic member urges the protective member toward the inside of the protective member with the hard region abutting against the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube.

4. Protective equipment according to claim 1, wherein the elastic member contains a coloring agent.

5. Protective equipment according to claim 1, wherein the plurality of protective members are provided at rotationally symmetric positions in a cross section perpendicular to the tube axis of the protective equipment.

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