JPH06233442A - Protection case for power cable connection and manufacture thereof and resin pipe mold therefor - Google Patents

Abstract

PURPOSE:To provide a protection case for power cable connections, more excellent in workability and productivity than and equal in strength to concrete protection cases. CONSTITUTION:This protection case has an opening 11 at both ends which can receive a power cable C, and a housing section 12 in the center which is larger in inside diameter than the openings 11. The case also has a cylindrical body 1 of thermoplastic resin, the outside surface of which is provided with an FRP layer 13. The cylindrical body 1 has two cuts at positions where the circumference of the body is equally divided into two. Opening the cuts 14 to separate the cylindrical body 1 into two halves allows a connection between power cables C to be housed in the housing section 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective box into which a connecting portion of a power cable is inserted.

[0002]

2. Description of the Related Art There are two types of power cable wiring systems: a conduit system in which a power cable is passed through a conduit that has been previously piped in the ground, and a power cable is directly buried in the ground without passing through the conduit. There is a direct buried type. By the way, when connecting a power cable, connect a battledore formed of a copper plate etc. to the tip of the power cable, connect the battledores to each other, and then wrap the insulation tape over the insulated piles in multiple layers for insulation. It is done by. Therefore, the connection part is considerably thicker than the other parts. In the case of the former pipe type, the entire power cable is protected by the pipe, so there is no problem in terms of insulation and strength, but in the latter direct buried type, only the connection part is partially protected. It was stored in a box to protect it from rainwater and loads.

By the way, heretofore, the protective box formed by combining concrete plates has been used.

[0004]

However, the conventional protection box made of concrete is difficult to carry because of its heavy weight, and the workability is poor, and the productivity is high because the concrete board is assembled in a box shape. Was also bad. Furthermore, due to its heavy weight, great care must be taken to ensure safety during production and construction.

Japanese Patent Publication No. 56-31243 discloses a method in which a connecting portion of a power cable is covered with a plastic sleeve and both ends thereof are heat-sealed to the power cable. However, the plastic sleeve is superior in productivity and workability to the concrete protection box, and because it is lightweight, it is very easy to ensure safety during production and construction, but it is significantly inferior in terms of strength. There is a new problem of being lost.

Focusing on the above problems, the present invention provides a protective box for a power cable connection portion which is superior in workability and productivity to a concrete protective box and is not inferior in strength. The second purpose is to provide a manufacturing method capable of efficiently and inexpensively manufacturing the protective box for connecting the power cable, and the third purpose is to provide a resin pipe processing mold that can be used in the manufacturing method. The purpose is.

[0007]

In order to achieve the first object, the protective box for the power cable connecting portion according to claim 1 of the present invention has an open end through which the power cable can be inserted. At the same time, a thermoplastic resin tube having a storage part having a larger inner diameter than the opening end in the center and an FRP layer provided on the outer surface is provided, and the power cable to be inserted from the opening end into the tube. A crack is provided so that the connection portion between them can be stored in the storage portion.

Further, in order to achieve the second object, in the method for manufacturing the protective box for the electric power cable connection portion according to the second aspect of the present invention, the central portion of the thermoplastic resin tube is heated until it is softened and the softened state is obtained. After inflating by pressurizing in, the FRP layer is provided on the outer surface of the thermoplastic resin tube so that both ends have open ends through which the power cable can be inserted, and the central part is thicker than this open end. A tubular body having a storage portion and provided with an FRP layer on the outer surface is formed, and a crack is provided in the tubular body so that the connection portion of the power cables inserted through the opening end can be stored in the storage portion.

Further, in order to achieve the third object, in the resin pipe working die according to the third aspect of the present invention, the thermoplastic resin pipe is used in the working die used when the central portion of the thermoplastic resin pipe is inflated. It has a hollow part that can be inserted, and includes a main body that can be disassembled so that the thermoplastic resin tube can be inserted into and taken out of the hollow part, and the main body of the thermoplastic resin tube inserted into the hollow part. Holding portions capable of holding the end portions are formed at both end portions, and a forming portion having an inner diameter larger than that of the holding portion is formed in the central portion, and the holding portion and the forming portion allow the steel pipe to have a predetermined length. It is formed of a cut short tube and is connected through a short tube formed by winding a steel plate in a trumpet shape.

[0010]

In the power cable connection part protection box according to claim 1 of the present invention, the connection part of the power cable to be inserted into the open end is
Open the crevice of the cylinder, insert between the crevices, and store in the storage part. Since the tubular body is made of a thermoplastic resin that is lighter in weight than concrete, it is easy to carry and work in the above construction. Further, since the thermoplastic resin cylindrical body can be mechanically produced in a factory, it is possible to improve productivity. Furthermore, since the FRP layer is provided on the outer surface of the cylindrical body, it is possible to secure the strength which is not different from that made of concrete while achieving weight reduction.

The method of manufacturing the protective box for the electric power cable connection portion according to the second aspect of the present invention can be applied when manufacturing the protective box for the electric power cable connection portion. In this manufacturing method, since the tubular body is formed using the thermoplastic resin tube, that is, the existing product, the tubular body can be formed in a short time, and the central portion of the thermoplastic resin tube is bulged. A relatively simple processing mold can be used for the purpose.

The resin pipe working die according to the third aspect of the present invention can be used in the process of expanding the central portion of the thermoplastic resin pipe in the above manufacturing method. Explaining the processing method, first, a thermoplastic resin tube whose central portion is heated to a predetermined softening temperature is inserted into the hollow portion of the main body. Then, the central portion of the thermoplastic resin tube inserted into the hollow portion is pressed in the softened state. Both ends of the thermoplastic resin pipe are held by the holding portion of the main body, but since a gap is formed between the central portion of the thermoplastic resin pipe and the molded portion of the main body, the central portion of the thermoplastic resin pipe is When pressed, it swells until it comes into close contact with the inner surface of the molded part and becomes thicker than both ends. When the thermoplastic resin tube has cooled and solidified, the main body is divided and the thermoplastic resin tube is taken out from the hollow portion. In this way, the central portion of the thermoplastic resin tube can be inflated.

In the main body, the holding portion and the forming portion are formed by a short pipe obtained by cutting a steel pipe into a predetermined length, and are connected through a short pipe formed by winding a steel plate in a trumpet shape.
Compared with a working die formed by cutting a steel block with a machine tool, it can be produced in a shorter time and at a lower cost. Further, since the weight can be significantly reduced as compared with a machining die formed by cutting a steel block with a machine tool, it is easy to perform work such as opening and closing the die.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of a protective box for a power cable connecting portion according to claim 1 will be described with reference to FIGS. FIG. 1 shows a state in which the protective box for the power cable connection portion of this embodiment is opened, and FIG. 2 shows a state in which the protective box is closed.

The protective box B of this embodiment comprises a cylindrical body 1 made of thermoplastic resin and formed in a cylindrical shape. This cylinder 1
Has an open end 11 through which the power cable C can be inserted, a storage part 12 having a larger inner diameter than the open end 11 at the center, and an FRP layer reinforced with, for example, glass fiber on the outer surface. 13 are provided. In addition, this cylindrical body 1 has two cracks 1 at positions where the outer circumference of the cylindrical body 1 is divided into two equal parts.
4 is provided and is divided into two. By opening the split 14 and disassembling the tubular body 1 into two, the connecting portion between the electric power cables C and C can be stored in the storage portion 12 from that interval. The reinforcing fiber of the FRP layer 13 is
In addition to glass fibers, organic fibers such as aromatic polyamide and carbon fibers can be used.

Although not shown, the cylindrical body 1
When the connection portion of the power cable C is stored in the storage portion 12 of, the rubber wire is caught in the crack 14 of the tubular body 1, and
It is desirable to provide a rubber ring between the power cable C and the open end 11 of the tubular body 1 to prevent the intrusion of earth and sand or water. The rubber wire may be embedded in advance on the end surface of one of the parts to be disassembled so as to partially project. Also,
The sectional shape of the rubber wire or the rubber ring used here is not particularly limited.

After the connecting portion of the power cable C is stored in the tubular body 1, the band 2 is wound around the tubular body 1 to prevent the crack 14 of the tubular body 1 from opening. Band 2
Can be made of polypropylene or nylon, which is used for packaging, and cloth or leather. Alternatively, the steel plate may be rounded with a flange and fastened with screws. Further, the band 2 may not be used, and the band 2 may be used for tightening.

As described above, in the power cable connecting portion protection box B of this embodiment, since the tubular body 1 is made of a thermoplastic resin which is lighter in weight than concrete, it is stored in the housing portion 12 of the tubular body 1. It is easy to carry and work when storing the connection portion of the power cable C. Further, since the thermoplastic resin cylinder 1 can be mechanically produced in a factory, it has good productivity. Further, since the FRP layer 13 is provided on the outer surface of the cylindrical body 1, it is possible to secure the strength which is not different from that made of concrete while reducing the weight. That is, the power cable connection part protection box B of this embodiment
Is superior in terms of workability and productivity and is not inferior in strength as compared to a concrete protection box.

Next, a description will be given of an embodiment of the method for manufacturing the power cable connection portion protection box B according to claim 2 and an embodiment of the resin pipe processing mold K according to claim 3.

First, the construction of the resin pipe processing mold K of this embodiment will be described with reference to FIGS. FIG. 3 shows a state in which the working die K is disassembled, and FIG. 4 shows a state in which the working die K is fastened, and 3 in the drawing is a main body.

The main body 3 has a hollow portion 31 into which the thermoplastic resin pipe P can be inserted, and at the position where the outer periphery is bisected so that the thermoplastic resin pipe P can be taken in and out. It can be disassembled into one. Further, the main body 3 is formed with holding portions 32 capable of holding the end portions of the thermoplastic resin pipe P inserted in the hollow portion 31 at both end portions, and has a larger inner diameter than the holding portion 32. Part 33
Is formed in the central part, and the holding part 32 and the molding part 33 are
It is formed of a short pipe obtained by cutting a steel pipe into a predetermined length, and is connected through a short pipe formed by winding a steel plate in a trumpet shape.

5 to 7 show the procedure for manufacturing the main body 3. That is, first, as shown in FIG. 5, two types of short pipes p1 and p2 having different diameters are replaced by a trumpet-like short pipe p3.
Via welding to complete one tube p as shown in FIG. Then, the main body 3 is completed by cutting the pipe p as shown in FIG. That is, the steel block can be manufactured in a short time and the material can be inexpensive as compared with the case where the steel block is formed by cutting with a machine tool. In addition, the weight can be significantly reduced compared to the processing die K formed by cutting a steel block with a machine tool,
Work such as disassembling the processing die K is easy to perform.

Further, in this machining die K, a flange 35 having a through hole 34 for a bolt is fixed to each of the two parts to be disassembled. When the two parts are combined, the flanges of both parts are combined. 35 are overlapped with each other, and the bolt 4 is passed through the through hole 34 of each flange 35 and the nut 5
The two parts can be fastened by screwing. The flanges 35 are provided on both sides of the molding portion 33, and two flanges 35 are provided on each side.

Next, a method of manufacturing the power cable connection portion protection box B will be described with reference to FIGS.

When manufacturing the protective box B, first, referring to FIG.
As shown in FIG. 3, the air inlet 6 is provided at one end of the thermoplastic resin pipe P.
A rubber stopper 6 having 1 is attached, and a blind rubber stopper 7 is attached to the other end. Then, the central portion of the thermoplastic resin pipe P is heated to a predetermined softening temperature. A silicon rubber heater is used for heating, but a gas burner, a far infrared heater, or a heated paraffin oil tank can also be used. In addition, when it is desired to strictly limit the heating area, a silicon rubber heater is preferable. The heating temperature is 1 when the thermoplastic resin pipe P is made of vinyl chloride.
10 to 150 degrees is preferable.

Next, as shown in FIG. 9, the thermoplastic resin pipe P in the heat-softened state is inserted into the hollow portion 31 formed in the main body 3 of the working die K, and one end of the thermoplastic resin pipe P is inserted. The compressed air is sent from the air inlet 61 of the stopper 6 provided in the inside to pressurize the inside of the thermoplastic resin pipe P,
Inflate the center of the. Both ends of the thermoplastic resin pipe P are held by the holding portions 32 of the main body 3, but a gap is formed between the center portion of the thermoplastic resin pipe P and the molding portion 33 of the main body 3, so By pressing, the central portion of the plastic resin pipe P swells until it comes into close contact with the inner surface of the molding portion 33, and becomes thicker than both end portions.

When the thermoplastic resin pipe P has cooled and solidified, the pressurized air is stopped, and as shown in FIG. 11, the stoppers 6 and 7 are removed, and the main body 3 is divided so that the thermoplastic resin pipe P is hollow 3
Take out from 1.

Next, for example, a glass mat in which glass fibers are impregnated with a polyester resin and a glass cloth are alternately wound around the outer surface of the thermoplastic resin pipe P, and cured in a furnace at about 90 ° C. for 1 hour. As a result of the work up to this point, as shown in FIG. 12, both ends have an open end 11 through which the power cable C can be inserted, and a central portion has a storage part 12 thicker than the open end 11 and has an outer surface. The cylindrical body 1 in which the FRP layer 13 is provided is formed.

Finally, as shown in FIG. 13, the cylindrical body 1
Is cut at a position where the outer circumference is bisected. By these procedures, the protection box B is completed.

In this manufacturing method, since the tubular body 1 is formed by using the thermoplastic resin pipe P, that is, the existing product,
The cylinder 1 can be formed in a short time. Further, when the central portion of the thermoplastic resin pipe P is bulged, a relatively simple and inexpensive processing die K formed of a steel pipe or a steel plate is used, so that the manufacturing cost can be reduced. it can. That is, the power cable connection part protection box B can be provided at low cost.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific structure is not limited to this embodiment, and there are design changes and the like within the scope not departing from the gist of the present invention. Also included in the present invention. For example, in the embodiment, two cracks 14 are formed at a position that divides the outer circumference of the tubular body 1 into two equal parts.
The protection box B provided with is shown, but the crack 14 is
It may be made into a book and the crack 14 may be expanded by elastic deformation. Further, the split 14 may be provided at a position that divides the length of the tubular body 1 into two equal parts.

[0032]

The protective box for the electric power cable connection portion according to the first aspect of the present invention is made of concrete because it can be made of thermoplastic resin and yet can have the same strength as that of concrete. The workability and productivity can be improved as compared with the protective box of 1 above, and the strength can be maintained.

In the method of manufacturing the protective box for the electric power cable connection portion according to claim 2 of the present invention, the manufacturing cost can be reduced by using a relatively simple working die when forming the cylindrical body. Therefore, the effect that the power cable connection part protection box according to claim 1 can be manufactured at low cost is obtained.

In the resin pipe working die according to the third aspect of the present invention, since the main body is made of the steel pipe and the steel plate, compared with the working die formed by cutting the steel block with the machine tool. Can be produced in a short time,
It can be produced at low cost. Further, since the weight can be significantly reduced as compared with a machining die formed by cutting a steel block with a machine tool, there is an effect that work such as mold opening can be easily performed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a power cable connection portion protection box of the present embodiment is opened.

FIG. 2 is a perspective view showing a state in which a power cable connection portion protection box of this embodiment is closed.

FIG. 3 is a perspective view showing a disassembled state of the resin pipe processing mold of the present embodiment.

FIG. 4 is a perspective view showing a state in which the resin pipe processing die according to the present embodiment is fastened.

FIG. 5 is a perspective view showing a method for manufacturing the working die.

FIG. 6 is a perspective view showing a method for manufacturing the working die.

FIG. 7 is a perspective view showing a method for manufacturing the working die.

FIG. 8 is a perspective view showing a method for manufacturing the power cable connection part protection box of the present embodiment.

FIG. 9 is a perspective view showing a method for manufacturing the power cable connection part protection box of the present embodiment.

FIG. 10 is a perspective view showing a method of manufacturing the power cable connection part protection box of the present embodiment.

FIG. 11 is a perspective view showing a method for manufacturing the power cable connection part protection box of the present embodiment.

FIG. 12 is a perspective view showing a method of manufacturing the power cable connection part protection box of the present embodiment.

FIG. 13 is a perspective view showing a method for manufacturing the power cable connection part protection box of the present embodiment.

[Explanation of symbols]

 B power cable connection part protection box 1 cylinder 11 open end 12 storage part 13 FRP layer 14 crack C power cable P thermoplastic resin pipe K resin pipe processing type 3 main body 31 hollow part 32 holding part 33 molding part p1, p2, p3 Short pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // B29D 22/00 7344-4F B29L 31:26 4F

Claims (3)

[Claims] 1. A thermoplastic resin having an open end through which a power cable can be inserted at both ends, a storage part having an inner diameter larger than the open end at a central part, and an FRP layer provided on an outer surface. A protective box for a power cable connection part, characterized in that the power cable connection part is provided with a crack so that the connection part of the power cables to be inserted from the opening end can be stored in the storage part. 2. A power cable is provided at both ends by heating the central part of the thermoplastic resin tube until it is softened and applying pressure in the softened state to expand the FRP layer on the outer surface of the thermoplastic resin tube. A cylindrical body having an opening end through which the FRP layer is provided and having a storage portion thicker than the opening end in the center and having an FRP layer on the outer surface is formed in the cylindrical body. A method of manufacturing a protective box for a power cable connection part, characterized in that a crack is provided so that a connection part between power cables inserted from the ends can be stored in a storage part. 3. A processing die used to inflate the central part of a thermoplastic resin tube, having a hollow part into which the thermoplastic resin tube can be inserted, and allowing the thermoplastic resin tube to be taken in and out. The main body is configured to be disassembled so that the main body is formed with holding portions at both ends capable of holding the ends of the thermoplastic resin tube inserted into the hollow portion, A forming part having a large inner diameter is formed in the central part, the holding part and the forming part are formed by a short tube obtained by cutting a steel pipe into a predetermined length, and a short tube formed by winding a steel plate in a trumpet shape is interposed. Resin pipe processing type characterized by being connected.