Protective cover

Abstract

To provide a novel protective cover capable of easily replacing an existing synthetic resin pipe which has been aged.SOLUTION: A protective cover is a protective cover for a cable, and includes: a cylindrical main body portion; a first enlarged diameter portion that is provided at an end portion of the main body portion and has a first inner diameter larger than a main body inner diameter of the main body portion; and a second enlarged diameter portion that is provided at an end portion of the first enlarged diameter portion opposite to the main body portion and has a second inner diameter larger than the first inner diameter, and the second inner diameter increases with distance from the main body portion.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to protective covers. [Background technology]

[0002] Patent Document 1 discloses a synthetic resin pipe for protecting a ground wire installed along a utility pole. This synthetic resin pipe is partially buried in the ground together with the ground wire with the ground wire housed inside.

[0003] Such synthetic resin pipes may deteriorate over time depending on the number of years they are used. In particular, the portions of the synthetic resin pipes exposed above ground are susceptible to deterioration over time due to ultraviolet rays and wind and rain. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-254635 A Summary of the Invention [Problem to be solved by the invention]

[0005] The synthetic resin pipe is replaced after a certain period of time has passed since its installation. In such a case, it is desirable to be able to selectively replace the synthetic resin pipe in areas where deterioration with age has progressed.

[0006] An object of the present invention is to provide a novel protective cover that can easily replace an existing synthetic resin pipe that has deteriorated over time.

[0007] A protective cover according to one embodiment of the present disclosure is a protective cover for a cable, comprising: a cylindrical main body portion; a first expansion portion provided at an end of the main body portion and having a first inner diameter larger than the main body inner diameter of the main body portion; and a second expansion portion provided at an end of the first expansion portion opposite the main body portion and having a second inner diameter larger than the first inner diameter, the second inner diameter increasing away from the main body portion. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a novel protective cover that can easily replace an existing synthetic resin pipe that has deteriorated over time. [Brief description of the drawings]

[0009] [Figure 1] FIG. 4 is a schematic diagram showing a state in which the protective cover is used. [Diagram 2] 4A and 4B are a side view and a cross-sectional view showing a protective cover. [Diagram 3] FIG. 4 is an explanatory diagram showing a method for installing a protective cover. [Figure 4] FIG. 4 is a schematic diagram showing a connection state of the protective cover. [Diagram 5] FIG. 4 is an explanatory diagram showing a method for installing a protective cover. [Figure 6] FIG. 4 is a schematic diagram showing a connection state of the protective cover. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0011] As shown in Fig. 1, a protective cover 1 according to an embodiment of the present disclosure protects an existing cable. The protective cover 1 of this embodiment protects a ground wire C extending along a utility pole T. The ground wire C runs along the side of the utility pole T to the ground G around the utility pole T. However, the protective cover 1 may also protect a cable routed along the exterior wall of a building, a communication line routed inside a building, or the like.

[0012] The protective cover 1 protects the ground wire C together with an existing pipe 10 installed adjacent to the utility pole T. The existing pipe 10 in this embodiment is, for example, a cylindrical protective pipe installed when installing the utility pole T. The existing pipe 10 is made of synthetic resin such as polyethylene (PE) or polyvinyl chloride (PVC).

[0013] The protective cover 1 is preferably made of a thermoplastic resin having weather resistance or flame retardancy. The protective cover 1 of this embodiment is made of a thermoplastic resin having a thermal softening temperature of about 75°C to about 220°C and a flexural modulus of about 900 MPa to about 3000 MPa, modified polyphenylene ether, or flame-retardant polyvinyl chloride.

[0014] Examples of thermoplastic resins include polyethylene, polypropylene (PP), polystyrene (PS), polyvinyl acetate (PVAc), polyurethane (PUR), acrylonitrile butadiene styrene (ABS resin), acrylonitrile styrene (AS resin), acrylic resin (PMMA), polyvinyl chloride (PVC), polyvinylidene chloride, and modified polyphenylene ether.

[0015] The protective cover 1 of this embodiment is preferably made of a thermoplastic plastic having excellent weather resistance, flame retardancy, dimensional stability with a low linear expansion coefficient, high temperature resistance so that the material can stably maintain its performance in a high temperature environment, and processability so that it can be softened and deformed by heating. In particular, the protective cover 1 is preferably made of an engineering plastic having excellent weather resistance, flame retardancy, dimensional stability, high temperature resistance, etc., such as modified polyphenylene ether.

[0016] The protective cover 1 made of such a resin material is suitable for use outdoors where it is subject to strong influences from wind, rain, and ultraviolet rays. Furthermore, the protective cover 1 can be easily deformed into a desired shape by softening a part of it by heating it to a predetermined temperature or higher.

[0017] The protective cover 1 of this embodiment is disposed adjacent to the utility pole T. The protective cover 1 is connected to the existing pipe 10 in the ground G around the utility pole T. A ground wire C is inserted through the protective cover 1 and the existing pipe 10. In this embodiment, the connection point between the protective cover 1 and the existing pipe 10, and the existing pipe 10 are buried in the ground G.

[0018] As shown in Fig. 2, the protective cover 1 is cylindrical and has a length L in the axial direction (see the dashed line in Fig. 2). From the viewpoint of ease of handling during transportation and installation, the length L is, for example, 500 mm or more and 2000 mm or less. However, the length L can be freely set according to the installation conditions of the protective cover 1, the dimensions of the utility pole T, and the like.

[0019] The protective cover 1 comprises a cylindrical main body 2, a first enlarged diameter portion 4 connected to the main body 2, and a second enlarged diameter portion 6 connected to the first enlarged diameter portion 4.

[0020] The main body 2 is cylindrical and has an outer diameter φ1 and an inner diameter φ2 smaller than the outer diameter φ1. The dimensions of the main body 2 need only be such that the ground wire C can be passed through it, and the outer diameter φ1 and inner diameter φ2 can be freely set. The outer diameter φ1 is, for example, 15 mm or more and 30 mm or less. The inner diameter φ2 is, for example, 10 mm or more and 20 mm or less.

[0021] The main body 2 has a first end 21 and a second end 22 opposite the first end 21 .

[0022] The first expanded diameter portion 4 is provided at the second end portion 22 of the main body portion 2, and has an axial length L1 and a first inner diameter φ3. The length L1 of the first expanded diameter portion 4 in this embodiment is equal to or greater than 10 mm and equal to or less than 20 mm.

[0023] The first enlarged diameter portion 4 has a connection portion 41 and a tubular portion 42 continuous with the connection portion 41 .

[0024] The connecting portion 41 is provided at the second end 22 of the main body 2. The connecting portion 41 has a so-called tapered shape, which increases in diameter as it moves away from the main body 2 in the axial direction. The connecting portion 41 increases in diameter at a first taper angle θ1. The first taper angle θ1 in this embodiment is approximately 15° to 45°.

[0025] The tubular portion 42 is connected to the connecting portion 41 and has a cylindrical shape extending from the end opposite to the main body portion 2. The tubular portion 42 has a length L11 in the axial direction. The tubular portion 42 further has a first inner diameter φ3 larger than the inner diameter φ2 of the main body portion 2 and a first outer diameter φ5 larger than the first inner diameter φ3. The length L11 may be half or more of the first outer diameter φ5. The length L11 is, for example, 5 mm or more and 10 mm or less. The first inner diameter φ3 is, for example, 10 mm or more and 25 mm or less. The first inner diameter φ3 of the tubular portion 42 is, for example, larger than the inner diameter φ2 of the main body portion 2 in a range of 0.3 mm or more and 1 mm or less. The first inner diameter φ3 of the tubular portion 42 may be approximately the same size as the outer diameter φ1 of the main body portion 2 within the range of dimensional tolerance. However, the dimensions of the length L11, the first inner diameter φ3, and the first outer diameter φ5 of the cylindrical portion 42 are not limited to this, and can be freely set.

[0026] The second enlarged diameter portion 6 is connected to the first enlarged diameter portion 4 and is provided at the end opposite to the main body portion 2. The second enlarged diameter portion 6 is tapered in that the diameter increases as it moves away from the main body portion 2 along the axial direction. The second enlarged diameter portion 6 is enlarged at a second taper angle θ2 smaller than the first taper angle θ1 of the first enlarged diameter portion 4. The second taper angle θ2 in this embodiment is 2° or more and 10° or less. That is, the protective cover 1 in this embodiment is enlarged in two stages, at the first enlarged diameter portion 4 and the second enlarged diameter portion 6.

[0027] The axial length L2 of the second expanded diameter portion 6 is longer than the length L1 of the first expanded diameter portion 4, and more preferably, is longer than twice the length L1 of the first expanded diameter portion 4. The length L2 of the second expanded diameter portion 6 is also longer than the first inner diameter φ3. The length L2 of the second expanded diameter portion 6 is, for example, 10 mm or more and 40 mm or less. The length L2 of the second expanded diameter portion 6 is not limited to this and can be freely set.

[0028] The second expanded diameter portion 6 has a second inner diameter φ4 at an end portion of the second expanded diameter portion 6 opposite to the first expanded diameter portion 4. The second inner diameter φ4 is, for example, larger than the first inner diameter φ3 by 1 mm or more and 3 mm or less. For example, the second inner diameter φ4 is 11 mm or more and 30 mm or less. The dimension of the second inner diameter φ4 is not limited to this and can be freely set.

[0029] The manufacturing method of the protective cover 1 of this embodiment will be briefly described below. The manufacturing method of the protective cover 1 includes a step S1 of forming the main body portion 2, a step S2 of forming the first enlarged diameter portion 4, and a step S3 of forming the second enlarged diameter portion 6.

[0030] First, in step S1, a cylinder having an outer diameter φ1 and an inner diameter φ2 is formed. In step S1 of this embodiment, the thermoplastic resin, modified polyphenylene ether, or flame-retardant polyvinyl chloride that forms the protective cover 1 is heated and extruded to a desired size. In step S1, the cylinder may be formed using various processing methods, without being limited thereto.

[0031] Next, in step S2, one end of the cylinder formed in step S1 is heated and softened. In step S2 of this embodiment, the cylinder is heated to a temperature of approximately 75° C. or higher and 220° C. or lower. Furthermore, a first metallic insert corresponding to the shape of the first enlarged diameter portion 4 is press-fitted into the softened cylinder. The first insert is press-fitted while expanding the cylinder outward. As a result, the first enlarged diameter portion 4 is formed at one end of the cylinder.

[0032] Furthermore, in step S3, a second metallic insert corresponding to the shape of the second expanded diameter portion 6 is press-fitted into the location where the first expanded diameter portion 4 was formed in step S2. At this time, the cylinder may be heated again to soften it. The outer diameter of the second insert is formed to be larger than that of the first insert. The second insert is press-fitted while further expanding the cylinder outward. As a result, the second expanded diameter portion 6 connected to the first expanded diameter portion 4 is formed, and the protective cover 1 is thereby formed.

[0033] As described above, the protective cover 1 of this embodiment is formed of a thermoplastic resin, modified polyphenylene ether, or flame-retardant polyvinyl chloride, whose heat softening temperature is approximately 75°C to 220°C and whose bending modulus is approximately 900 MPa to 3000 MPa. As a result, the manufacturing method of the protective cover 1 of this embodiment can precisely process the heated and softened resin material into a desired shape. As a result, the manufacturing method of the protective cover 1 can precisely and easily form the first enlarged diameter portion 4 and the second enlarged diameter portion 6.

[0034] Although the first enlarged diameter portion 4 and the second enlarged diameter portion 6 are formed using different first and second nests in steps S2 and S3, the present disclosure is not limited thereto. That is, the first enlarged diameter portion 4 and the second enlarged diameter portion 6 of the protective cover 1 may be formed simultaneously using a single nest.

[0035] Next, a method for installing the protective cover 1 of this embodiment will be described with reference to Figs. 3 to 6. As shown in Fig. 3(a), a ground wire C covered by an existing pipe 10 extends to the ground G along a utility pole T on which the protective cover 1 is installed. A part of the existing pipe 10 is buried in the ground G together with the ground wire C, while the other part is exposed to the outside air and is affected by ultraviolet rays and wind and rain and changes over time. The existing pipe 10 that has changed over time may, for example, have a brittle surface, causing cracks, or may deform from its cylindrical shape, such as a perfect circle, at the time of installation to an elliptical shape. The protective cover 1 protects the ground wire C in place of the existing pipe 10 that has changed over time.

[0036] In the method of installing the protective cover 1 of this embodiment, as shown in FIG. 3(b), first, the soil at the base of the utility pole T is dug up to expose the existing pipe 10 buried in the ground G. Next, the existing pipe 10 is cut at the cutting position (see the black dashed line in FIG. 3(b)). It is preferable that the existing pipe 10 is cut at the location where it was buried in the ground G before construction. This allows the existing pipe 10 to be selected and removed from the location exposed to the outside air and deteriorated over time. In addition, it is possible to continue using the location of the existing pipe 10 that has deteriorated relatively little over time, and to reduce the amount of excavation. As a result, the replacement with the protective cover 1 can be performed at low cost. The ground wire C may be removed from the existing pipe 10 before cutting the existing pipe 10.

[0037] 3(c), the cut surface 101 of the cut existing pipe 10 is exposed above the ground with a portion of the cut existing pipe 10 remaining underground G. Next, the protective cover 1 is pushed into the cut existing pipe 10 from above, and the protective cover 1 and the existing pipe 10 are connected.

[0038] 4 is a cross-sectional view showing a connection state between the protective cover 1 and the existing pipe 10. The protective cover 1 is attached while pressing the existing pipe 10. The protective cover 1 is pressed down toward the existing pipe 10 to a position where the inner peripheral surface of the second enlarged diameter portion 6 and the outer peripheral surface of the existing pipe 10 cannot be displaced from each other. Accordingly, the second enlarged diameter portion 6 of the protective cover 1 is deformed so as to be pressed and expanded by the outer peripheral surface of the existing pipe 10. This makes it possible to restrict the movement of the protective cover 1 along the axial direction relative to the existing pipe 10. As a result, the protective cover 1 is fixed and connected to the existing pipe 10.

[0039] The cross-sectional shape of the existing pipe 10 may change from a circular shape to an elliptical shape depending on the manner of use. The protective cover 1 of this embodiment can contact the outer peripheral surface of the existing pipe 10 at at least one point on the inner peripheral surface of the second enlarged diameter portion 6 regardless of the shape of the existing pipe 10, and restrict the movement of the existing pipe 10, and therefore can be applied to the existing pipe 10 whose cross-sectional shape has changed to an elliptical shape.

[0040] Furthermore, as shown in Fig. 5(a), another protective cover 1 may be connected to the protective cover 1 connected to the existing pipe 10. Any number of protective covers 1 can be connected depending on the lengths of the utility pole T and the ground wire C. Finally, as shown in Fig. 5(b), after the installation of the multiple protective covers 1 is completed, the existing pipe 10 and a part of the protective covers are backfilled in the ground G.

[0041] 6 is a cross-sectional view showing the connection state of the protective cover 1 and another protective cover 1. The protective cover 1 is attached while pressing the other protective cover 1. The protective cover 1 is pressed down to a position where the inner circumferential surface of the first enlarged diameter portion 4 and the outer circumferential surface of the main body portion 2 of the other protective cover 1 cannot be displaced.

[0042] As described above, the outer diameter φ1 of the main body portion 2 of the protective cover 1 and the first inner diameter φ3 of the tubular portion 42 of the first enlarged diameter portion 4 are formed to be approximately the same size. Therefore, the outer peripheral surface of the protective cover 1 near the first end portion 21 comes into surface contact with the inner peripheral surface of the tubular portion 42 of another protective cover 1. This allows the protective cover 1 to be connected to another protective cover 1.

[0043] The protective cover 1 of the present disclosure includes a first enlarged diameter portion 4 that is connected to the first end 21 of another protective cover 1, and a second enlarged diameter portion 6 that is connected to the end of the existing pipe 10. The length L2 of the second enlarged diameter portion 6 is longer than the length L1 of the first enlarged diameter portion 4, and is preferably more than twice as long. As a result, the second enlarged diameter portion 6 is fixed to the existing pipe 10, whose surface shape varies due to deformation caused by aging, at any point on its inner circumferential surface. Therefore, the protective cover 1 can be connected to the existing pipe 10. On the other hand, the first enlarged diameter portion 4 is connected to another protective cover 1 that is not affected by wind, rain, or ultraviolet rays and has a small variation in the outer diameter φ1 and surface shape. As a result, the protective cover 1 can be connected to both the other protective cover 1 with a small variation in the surface shape and the existing pipe 10 with a large variation in the surface shape.

[0044] Additionally, the length L2 of the second expanded diameter portion 6 of the protective cover 1 is longer than the first inner diameter φ3 of the first expanded diameter portion 4. Furthermore, the second taper angle θ2 of the second expanded diameter portion 6 may be formed in the range of 2° to 10°. This allows the protective cover 1 to suppress abrupt expansion of the second expanded diameter portion 6 while preventing the connected existing pipe 10 from being displaced in a direction that would cause it to fall off.

[0045] As described above, according to the protective cover of the present disclosure, a new protective cover can be provided that can easily replace an existing synthetic resin pipe that has deteriorated over time.

[0046] Although the present disclosure has been described above with reference to the embodiment, the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. In particular, the multiple modifications described in this specification can be arbitrarily combined as necessary. [Explanation of symbols]

[0047] 1: Protective cover 2: Main body 4: First enlarged diameter section 6: Second enlarged diameter section φ1: Outer diameter φ2: Inner diameter φ3: 1st inner diameter φ4: 2nd inner diameter L; length L1; length L2: length T: Utility pole C: Ground wire G: Underground 10: Existing pipe

Claims

1. A protective cover for a cable, comprising: A cylindrical main body portion; a first enlarged diameter portion provided at an end of the main body portion and having a first inner diameter larger than a main body inner diameter of the main body portion; a second enlarged diameter portion provided at an end portion of the first enlarged diameter portion opposite the main body portion, the second enlarged diameter portion having a second inner diameter larger than the first inner diameter, the second inner diameter increasing with increasing distance from the main body portion; Equipped with Protective cover.

2. The second enlarged diameter portion is longer than the first enlarged diameter portion in the axial direction of the main body portion. The protective cover of claim 1 .

3. The length of the second expanded diameter portion in the axial direction is more than twice the length of the first expanded diameter portion in the axial direction. The protective cover of claim 2.

4. The length of the second expanded diameter portion in the axial direction is longer than the first inner diameter. The protective cover of claim 1 .

5. The second expansion portion is tapered, and the taper angle of the second expansion portion is in the range of 2° to 10°. The protective cover of claim 1 .

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