JP3022799B2 - Pipe unit used for cable buried pipeline, and its pipeline connection structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power cable, a communication cable, and the like (hereinafter, simply referred to as "power cable, etc.").
The present invention relates to a cable buried conduit for burying a cable in the ground, and in particular, a pipe unit used in the cable buried pipe, and connection between the pipe units, or circumferential projections at a predetermined pitch with the pipe unit. The present invention relates to a conduit connection structure with a formed cable protection tube.

[0002]

2. Description of the Related Art In recent years, power cables and the like have been replaced with conventional overhead systems in order to ensure the safety of pedestrians and the like and to ensure smooth traffic, from the viewpoint of landscape, and to realize a highly information-oriented society. There is an increasing demand for conversion from underground to underground.

[0003] As a conduit material used for a cable buried conduit to meet this demand, there are wire permeability, strength, water tightness, and the like.
Various functions such as impact resistance, durability, earthquake resistance, flame resistance and heat resistance are required, and in consideration of these, various materials such as resin, ceramic, metal, and concrete are proposed. Have been.

[0004] As the most general pipe material, for example, one power cable or the like is basically passed through a single wire section, and the contact area with the power cable or the like is reduced so that the wire connection is improved. In order to improve the quality, a corrugated cable protection tube made of synthetic resin and having circumferential projections formed at a predetermined pitch has been proposed. Further, in order to enable a plurality of power cables and the like to be buried at the same time, a pipeline structure has been proposed in which a plurality of the above cable protection tubes are bundled and buried in a state where a gap is provided by a spacer or a connector at both ends.

Further, the above-mentioned corrugated cable protection tube is weak in the impact property of equipment such as a pickaxe or the like, or when backfilling, it is difficult for backfill soil such as earth and sand to enter gaps between a plurality of cable protection tubes. The pipe unit is formed with a plurality of semi-circular cross-sectional grooves formed vertically and arranged in a plurality of stages, thereby forming a pipe unit for covering a plurality of cable protection tubes. A technique of arranging a corrugated cable protection tube in the insertion hole has been proposed.

However, in any of the techniques using these cable protection tubes, it is necessary to arrange a long cable protection tube, so that there is a problem that the length of excavation at one time becomes long. As a means for solving this problem, there is also a technique of sequentially connecting pipe units having the same length (about 1 m) as the above-mentioned pipe unit in the pipe axis direction without using a cable protection pipe to form a cable buried conduit. Proposed.

A plurality of inner pipes are integrally formed in the pipe unit, and the pipe units are connected to each other in a pipe axis direction through a watertight packing to form a pipe.
A power cable or the like is inserted directly into the inner tube. The materials used for these tube units include:
There are plastic, ceramic, metal and concrete products. However, ceramic, metal and concrete products can be molded only to a length of about 60 cm due to their heavy weight. The number of locations increased, and this was a problem in terms of workability.

In addition, in connection with all the materials, it is necessary to connect these pipe units firmly in the pipe axis direction with bolts and nuts from both sides of the pipe unit in order to maintain the performance of the watertight packing. In addition, the tightening work becomes complicated, and the side surface is tightened, so that the excavation width becomes larger than the width of the pipe unit.

Further, since the pipe units are firmly connected to each other by tightening the bolts and nuts, there is a problem in the earthquake resistance, and in some cases, the tube units are damaged due to an earthquake or the like and watertightness cannot be maintained. Furthermore, since the wall surface of the inner tube portion of these tube units is formed to be a smooth surface, the contact area with the outer sheath of the power cable or the like becomes large, and there is a problem in the lineability.

[0010] In order to solve these problems such as the lineability, earthquake resistance, workability, etc. at once, a resin-made cable protection tube with an independent wave corresponding to the length of the tube unit is placed in a resin tube. A tube unit in which the space between the tubular body and the corrugated cable protection tube is filled with a filler such as foamed polyurethane has also been proposed (see JP-A-8-170762).

In this tube unit, one end and the other end of the corrugated cable protection tube are formed so as to be in a male-female fitting state. The female unit is made to protrude by the length inserted into the tube end, so that the female side cutout and the male side protrusion are fitted together, and when both fit together, the tube unit is connected to each other. It has become.

[0012]

However, in the above tube unit with the cable protection tube, the formation of the cylindrical body,
There is a problem that the number of molding steps, such as processing of a cable protection tube and injection of a filler, increases, and the cost increases, and the appearance of a tube unit that is easy to manufacture is desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tube unit which is easy to manufacture and has excellent lineability. Also,
The present invention provides a pipe connection that can easily perform connection between pipe units or connection between a pipe unit and a cable protection pipe as compared with conventional pipe units made of ceramic, metal, concrete, or the like. It is intended to provide structure. further,
It also aims to provide a pipeline connection structure suitable for earthquake resistance or curved installation.

[0014]

Means for Solving the Problems [Structure and Manufacturing Method of Tubular Unit] In order to achieve the above object, the present inventor has proposed a conventional independent circumferential projection in order to easily and quickly mold the tubular unit. Instead, we focused on the method of forming a corrugated insertion hole that can secure the same wire permeability as this at the same time as forming the tube unit using the mold, and as a result of intensive research, we used a male threaded core. It has been found that if the core is removed from the mold while rotating, a tube unit with an insertion hole having a spiral projection on the hole wall can be easily formed .

If such a rotary core release method is adopted, compared with split mold molding using a similar core, molding burrs do not occur in the insertion holes, and power cables and the like inserted inside are damaged. There is an advantageous effect in that there is no.

In this molding, since the core is released while rotating, the material to be injected is resin, metal, or the like.
It is possible to use either ceramic or concrete, but especially in the case of resin molding, the unit body is lighter and the length of the pipe that can be transported and installed by one person can be longer than that of ceramic, metal, concrete, etc. It is advantageous . Special
Then, if polyethylene is adopted as the resin to be injected,
In addition to a small contact area between the internal spiral projection and the power cable or the like, a friction coefficient is reduced due to its physical properties, and the lineability is further improved.

The use of recycled plastic, for example, one of recycled polyethylene and recycled polypropylene or a mixture thereof as the molding resin is advantageous in that the plastic can be recycled and can be produced at low cost .

If necessary, a flame retardant, a filler and a foaming agent can be added to these recycled plastics. Flame retardancy can be achieved by adding, for example, antimony trioxide as the flame retardant. As a filler, an inorganic substance such as calcium carbonate or glass fiber can be added . The incorporation of the filler is advantageous in that the recycled plastic has a reduced shrinkage ratio during molding, improved dimensional stability, reduced warpage and deformation, and increased rigidity. The compounding weight of the filler is desirably 5 to 30% by weight. The filler is
If the content is more than 30% by weight, the viscosity becomes too high and molding becomes difficult. If the content is less than 5%, the effect of reducing the product shrinkage is not exhibited.

Further, as the filler material, if a scrap material trimmed at the time of forming and finishing a glass fiber reinforced plastic (FRP) molded product or a material obtained by crushing waste of the FRP molded product into chips is used, the FRP molded product can be used. It can also be recycled. Further, a pyrolytic foaming agent is added as a foaming agent, and the specific gravity is reduced to 0.8, so that the weight can be reduced while maintaining the allowable strength.

In the case of this molding, a casting method, an injection molding method, a transfer molding method and the like can be adopted.
If the low-pressure casting method is used, recycled plastic can be used, so that it can be manufactured at low cost. Furthermore, if the casting method is adopted, it is possible to easily produce a thick molded product,
It is also strong in that it can maintain sufficient strength against impacts such as pickaxes, and does not break due to an earthquake or the like unlike a ceramic tube . Furthermore , in such a molding method, in order to shorten the molding cycle, it is possible to adopt a measure in which the core itself is hollow and cooling water is circulated through the hollow portion.

In the case of this molding, the outer shape is
By processing the inner surface of the cavity of the mold, tube units of various shapes can be formed.In particular, if the outer shape is formed into a square shape, especially a rectangular parallelepiped shape, even if the cable protection tubes are arranged in multiple stages and multiple rows, they can be filled. At the time of returning, since there is no gap between the tube units, the work of backfilling the earth and sand can be easily performed. Even in the case of this rectangular tube unit, a configuration in which four corners are cut out can be adopted in consideration of weight reduction. In the case of this four-corner notched tubular unit, when filling and burying it in a multi-stage double row, if a filler such as a square bar is inserted into a space generated at the cut corner, the The backfill operation can be easily performed.

The number of through-holes of the tube unit to be molded can be appropriately selected according to the use mode.
Embodiments formed in a single row or multiple rows, such as two rows, three rows, etc., and
It is also possible to adopt an embodiment in which a plurality of stages such as two stages and three stages are formed. Of course, in this case, it is necessary to use the number of cores used for molding in accordance with the number of insertion holes.

Further, on the upper and lower surfaces of the tube unit, at least one of the projections for positioning is formed, and the other is formed with a corresponding concave portion. The fitting of the concave and convex portions facilitates positioning in the tube axis direction and the direction orthogonal thereto when the tube units are arranged in multiple stages. This uneven portion can be formed not only in one place but also in a plurality of places.

As a further development, the uneven portion may be formed as a ridge and a groove continuous in the tube axis direction of the unit body. That is, on one of the upper and lower surfaces of the unit main body, ridges for positioning continuous in the tube axis direction are formed at a predetermined pitch over the entire surface in the left-right width direction orthogonal to the tube axis direction, and are formed on the other surface. Further, it is possible to adopt a configuration in which the concave grooves engageable with the ridges are formed at a predetermined pitch over the entire surface in the left-right width direction of the unit main body .

By adopting such a configuration, when the tube units are stacked, the opposed upper and lower convex ridges and grooves are engaged without any gap, and the positioning in the left-right direction is facilitated. Not only that, there is no gap on the stacking surface, and backfilling becomes easy. In this regard, even when the number of insertion holes, the left-right width, and the length in the tube axis direction of the tube unit are different, the same effect can be expected if the ridges and grooves are formed in the same manner. That is, in the case where the tube units having different lengths are stacked and the connection points in the tube axis direction are changed at each stage to increase the strength of the pipe, the tube units to be stacked are easily guided in the tube axis direction. In addition, no gap is formed on the stacking surface of the tube unit. In addition, even when pipe units having different widths are placed in the left-right direction, there is an advantage that no gap is formed on the stacking surface.

Since the above-mentioned tube units are used in such a manner that a plurality of tube units are connected in the tube axis direction and a power cable or the like is inserted thereinto, the tube units are attached to both ends of the tube unit. A connecting portion to be connected or a connecting portion to be connected to a corrugated cable protection tube or the like is required. Therefore, the present invention employs a configuration in which a connecting portion is formed at the end of the unit main body .

As the structure of the connecting portion, for example, a male / female type structure in which the ends of the unit main body are fitted to each other, that is, a large-diameter connecting hole communicating with the insertion hole is formed at one end of the tube, and the other is formed. A structure in which a small-diameter portion that fits into this connection hole is formed at the pipe end (see FIG. 27). Further, as another aspect, various structures such as a structure in which an end face is formed in a sloped shape, a structure in which a stepped shape is cut out, and the like can be adopted. In any of these structures, if a core corresponding to the connecting portion structure is integrated on the base end side of the core, the core can be released at the same time as the core is released, and the core can be easily manufactured. In addition, if the connecting part mold structure is detachable from the core also on the tip side of the core, the connecting part can be formed simultaneously with the molding.

[Connection Structure between Tube Units] The present inventor has invented the above-mentioned tube unit. Further, the present inventor has also conducted intensive research on the connecting portion structure and devised the following configuration. That is, as an optimal connection structure between the tube units, the tube unit communicates with a cable insertion hole formed in the tube axis direction, and at the end of each tube unit, a diameter larger than the inner diameter of the insertion hole. Form a connection hole, make the connection holes of each tube unit face each other, interpose a short tube inside it,
A pipe connection structure in which an annular watertight packing is externally fitted to both ends of the short pipe is adopted .

If such a structure is adopted, the short tube is a separate member from the tube unit, but only by inserting the short tube into the connection hole of the tube unit, the watertight packing comes into close contact with the hole wall of the connection hole. In addition, the connection work can be easily performed while ensuring watertightness.

The material of the short tube is not particularly limited, such as resin and metal, but is preferably made of polyethylene which can reduce the coefficient of friction with an electric power cable or the like in consideration of the lineability. Also, as the structure of the short tube,
The inner and outer surfaces of the pipe may be smooth or corrugated, but those having corrugated irregularities formed inside reduce the contact area with a power cable or the like passing therethrough, and are also preferable in terms of lineability. .

In particular, in the case of a short tube having an irregular corrugated shape in which circumferential concave portions and circumferential convex portions are alternately formed on the inner and outer surfaces at predetermined pitches alternately in the tube axis direction, a groove into which an annular watertight packing can be fitted. Since the (circumferential concave portion) is formed in advance, there is an advantage that mounting of watertight packing or the like can be easily performed.

Further, if the short tube is formed of a flexible material, even if stress is generated between the tube units due to an earthquake or the like, the stress can be absorbed by the flexible short tube and the watertightness can be improved. This is advantageous in that it can be handled while maintaining it . In addition , since the flexible short tube bends against the force in the bending direction, it can cope with this without damaging the tube unit. In addition, as the short tube, a cable protection tube with an independent wave as a conventional hard synthetic resin tube is used as long as a gap between tube units is minimized when the connection holes are opposed to each other. It can be cut into pieces and used.

As the watertight packing, not only rubber but also any material that can maintain watertightness can be used. In particular, the present invention adopts a configuration in which the watertight packing is interposed between the outer surface of the short tube and the hole wall of the connection hole of the tube unit in consideration of the lineability. This is advantageous in that bolts and nuts tightening each other in the pipe axis direction are not required in order to ensure watertightness as in the case where a watertight packing is interposed between opposing surfaces.

The reason why the connecting hole formed at the end of the tube unit is formed larger in diameter than the insertion hole is that the inner wall of the insertion hole and the inner wall of the short tube have the same diameter so that they are flush with each other. do it,
This is for improving the lineability, and particularly when a short tube with an independent wave is used, it is advantageous in that the two can be flush with each other with respect to the lineability.

Further, in the case of a short tube with an independent wave, it is desirable to use a tube whose end is cut into a mountain cut. This is because if the end of the short pipe is cut to the valley, the cut portion faces the wire portion, which may damage the power cable and the like.

The connection structure between the tube units may be constituted only by the connection holes of the tube units, a short tube, and watertight packing. However, in order to make the connection between the tube units more firm, It is desirable to provide a connecting means for connecting the two. As the connecting means, an engaging hole is formed in the outer surface of the end of the tube unit, and the tip of the cap is engaged between the engaging holes to connect the two. By tightening the nut in the tube axis direction, or by fitting the end of the tube unit with a male / female structure, piercing the insertion hole in this overlapping surface, and inserting the insertion pin in this part Various measures, such as a connection structure, can be adopted.

Among these connecting means, the following configuration is particularly preferable as a structure which is advantageous in that connection can be performed from above and which can cope with earthquake resistance or curved installation described later. That is, as the connecting means, of the opposing tube units, an upper stepped portion formed by cutting out from the upper surface of the end of one tube unit to the tube edge, and the tube end from the lower surface of the end of the other tube unit It is configured to include a lower stepped portion formed by cutting out to an edge, a pin hole formed through the corresponding upper and lower matching wall surfaces of both stepped portions, and an insertion pin that can be fitted into the pin hole from above .

By adopting such a configuration, the upper and lower matching wall surfaces of the stepped portion can be formed as pin hole forming surfaces, and the pin holes are formed to penetrate in the vertical direction. Can be performed, and the connection workability is greatly improved.

In this case, the position of the pin hole may be set at any position in the left-right direction of the upper and lower matching walls of the step portion. For example, in the case of a tube unit having a single row of insertion holes, the left and right mating walls are arranged on both sides, and the two rows of insertion holes are formed on the upper and lower mating walls of the center portion.
It can be formed on the upper and lower wall surfaces of the partition wall of each insertion hole. Also, the size of the pin hole may be any diameter as long as the insertion pin can be fitted. In particular, if the pin hole is formed long in the pipe axis direction, the pipe unit will not fit in the pipe axis direction in the event of an earthquake or the like. Even if tensile stress acts on the tube unit, the tube units can be displaced in the tube axis direction in cooperation with the absorption of the stress by the short tube, preventing damage to the tube unit and improving earthquake resistance. An excellent connection structure can be provided.

Here, the upper step portion is formed by cutting off from the upper surface of the end of the tube unit to the end of the tube, and the lower end of the tube unit projects outward in the tube axis direction. The stepped portion refers to a form in which the end of the tube unit is cut from the lower surface of the end to the end of the tube, and the upper end of the tube unit projects outward in the tube axis direction. And when both step parts are mutually matched in the up-down direction, it means the form which joins without an up-down gap. Therefore, the upper and lower mating wall surfaces at the stepped portion are not limited to those formed at the center of the tube axis, but include those formed to be offset to either one in the vertical direction. Further, the upper and lower mating wall surfaces are not limited to the horizontal plane, but may be inclined surfaces, and thus may have a tube end structure which is notched like a slope. Since the upper step and the lower step are simply formed at the ends of the tube unit, the step can be formed at the same time as the tube unit is formed by processing in a mold, and can be easily formed.

In this connection structure between the tube units, the connection structure between the end portions of two opposed tube units has been described. However, the tube units are connected in multiples in the tube axis direction to embed the cable buried pipe. Considering the configuration of the road, an optimal configuration is such that one tubular unit has an upper step at one end and a lower step at the other end.

Further, the present inventors have invented a pipeline connection structure that can easily cope with curved installation in addition to the above-mentioned connection structure. That is, on at least one of the surfaces of the upper and lower steps that face each other in the tube axis direction, in a direction orthogonal to the tube axis direction,
A pipe connection with a tapered surface projecting toward the tube unit side at the center, and a pin hole with a long hole in the pipe axis direction longer than the short diameter side slightly larger than the diameter of the insertion pin. The structure can be adopted .

By adopting such a structure, the two pipe units can be moved in either the left or right direction with respect to one of the pipe units by the two tapered surfaces inclined in the left and right directions from the center of the pipe end of the pipe unit. Can also be swung, and can respond to curved installations. In addition, since the pin hole is formed long in the pipe axis direction, it is possible to cope with a lateral shift due to an earthquake. The tapered surface may be formed not only on one of the ends of the upper and lower steps of the tubular unit but also on both opposed tubular units. The taper angle of the tapered surface is desirably set to 2 to 10 degrees in order to cope with a curved installation of a power cable or the like.

As the tube unit having the above-mentioned connection structure, it is most suitable to apply to the tube unit having the above-mentioned helical projection and having an insertion hole. However, the present invention is not limited to this. It goes without saying that the present invention may be applied to a tube unit having an insertion hole with an independent wave. Therefore, the connection structure of the present invention can be adopted also in the connection between the tube unit according to any one of claims 1 to 5 having a spiral protrusion and the tube unit having an insertion hole with an independent wave. .

[Connection Structure between Tube Unit and Cable Protection Tube] The present inventor has also invented a connection structure between the tube unit and the cable protection tube. That is, in the present invention, a pipe unit having a cable insertion hole formed in the pipe axis direction and a cable protection tube with independent waves in which circumferential concave portions and convex portions are alternately formed at a predetermined pitch are fastened. The pipe connection structure is connected to the end of the tube unit, the connection hole having a diameter larger than the inner diameter of the insertion hole, is formed in communication with the cable insertion hole, at the end of the cable protection tube The watertight packing is externally fitted, the end of the cable protection tube is internally fitted into the connection hole, and the fastener has a plurality of split pieces in which corrugated uneven portions corresponding to the circumferential unevenness of the cable protection tube are formed. A structure is adopted in which these pieces are connected and fixed to each other and externally fitted and fixed to the end of the cable protection tube, and further, from the top surface to the edge of one end of the fastener and the tube body unit. Cut out to form the upper step and the other end Forming a lower step portion cut from the surface to the edge, a pin hole formed through the corresponding upper and lower alignment wall of the stepped portions of both upper and lower,
A pipe connection structure in which an insertion pin is fitted into the pin hole from above is adopted .

By adopting such a configuration, it is possible to adopt a structure similar to the connection structure between the above-mentioned tube units, and the connection can be achieved simply by inserting the cable protection tube and the insertion pin from above. There is an advantage that it can be easily performed, and that the watertightness by the watertight packing can be sufficiently ensured.

Here, the cable protection tube is a hard synthetic resin tube having an independently corrugated concavo-convex shape in which circumferential concave portions and circumferential convex portions are alternately and repeatedly formed in the tube axis direction on the inner and outer surfaces at a predetermined pitch. And a flexible pipe (FEP: corrugated hard polyethylene pipe shown in JIS C3653) interposed at the time of connection between the pipe unit and the handhole.

As the fastener structure in this case, a plurality of split-type structures can be adopted in addition to the splitting. In this case, the connecting and fixing of the split pieces is not only screw connection by a thumb screw, but also a fixing pin and a fixing hole. Can be adopted.

The concept of the upper step portion and the lower step portion is the same as the concept of the connection structure between the tube units. Therefore, the upper and lower mating wall surfaces at the step portion are formed at the center of the tube axis. However, the present invention is not limited to this, and includes a case where it is formed so as to be offset in one of the vertical directions. Also,
The upper and lower mating wall surfaces are not limited to the horizontal plane, but may be inclined surfaces, and therefore may have a tube end structure cut off in an inclined shape. In particular, in the case where the fastener has a split structure, if the split piece is composed of a long fastener and a short fastener, these fasteners are joined up and down to provide a difference in length between the two fasteners. Thereby, a step can be formed at the end of the fastener in the tube axis direction.

[0050]

BEST MODE FOR CARRYING OUT THE INVENTION

[Overall Configuration of Cable Buried Pipeline] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded view of a cable buried conduit showing an embodiment of the present invention, and FIG. 2 is a view showing a connection state of the cable buried conduit. First, the overall configuration of the cable buried pipeline will be described based on these drawings.

Cable buried pipeline 1 shown in this embodiment
1 is an electric wire common groove used for laying power cables such as power lines, telephone lines, communication lines, and signal lines at a depth of 30 cm to 40 cm underground such as a sidewalk.
To make it easier to insert power cables,
A tube unit 3 having a weight that can be carried by one person between hand holes 2 installed every 7 to 20 m, a short tube 4 for connecting the tube units, and a hand at an end of the tube unit 3 It is combined with a cable protection tube 6 for connection with the connection portion 5 of the hole 2.

Therefore, the structure of the tube unit 3, the connection structure between the tube units including the short tube 4, the connection structure between the tube unit 3 and the cable protection tube 6, the method of manufacturing the tube unit, and the like will be described in order below. Will be described later.

[Structure of Tube Unit] FIG. 3 is a plan view of the tube unit of the present embodiment, FIG.
FIG. 5 is a front view of the same, and FIG. 6 is a cross-sectional view showing a stacked state of the tube unit. As shown, the tube unit 3
In the unit main body 10, two rows of cable insertion holes 11 are formed in the tube axis direction via a center partition 10a, and a spiral projection 12 is formed on the wall surface of the insertion hole 11 in the tube axis direction. At both ends of the unit main body 10, connecting portions 13 for connecting to another tube unit 3 or the cable protection tube 6 are formed.

The unit body 10 is formed in a substantially rectangular parallelepiped shape in consideration of workability at the time of backfilling. That is, the side wall of the unit main body 10 is a smooth vertical wall, and the upper and lower surfaces of the unit main body 10 are formed with the ridge 21 and the groove 22 as described later. It is set so that no gap is formed on the mating surface (laminated surface) when the layers are stacked. The length of the tube unit 3 is 30 cm to 2 in consideration of the weight that can be carried by one person.
It is set between 00 cm. In this case, the length of the tube unit 3 can be appropriately selected, but 1 m is adopted as a standard length.

As a material of the tube unit 3, a lightweight resin is adopted in consideration of portability. Specifically, polyethylene or polypropylene, particularly, a friction coefficient and cost are reduced. Recycled polyethylene is used for its meaning. Also, if necessary, flame retardants,
Fillers and blowing agents are added. For example, flame retardancy can be achieved by adding antimony trioxide or the like as a flame retardant, and an inorganic substance such as calcium carbonate or glass fiber can be added as a filler. Further, a pyrolytic foaming agent is added as a foaming agent, and the specific gravity is reduced to 0.8, so that the weight can be reduced while maintaining the allowable strength.

Each of the insertion holes 11 is formed to have the same diameter in the tube axis direction.
Is in communication with The hole diameter of the insertion hole 11 is, for example, 5
0 mm, 80 mm, 100 mm, 150 mm, and the like can be appropriately selected as required. As the inner wall structure of the insertion hole 11, a continuous spiral convex portion 12 is formed instead of the conventional inner wall structure with independent waves in order to reduce the contact area with a power cable or the like. This spiral convex part 1
2 has a corrugated inner wall structure in which independent circumferential protrusions are formed at a predetermined pitch as in the related art, except that the protrusions can be formed simultaneously with the molding of the tube unit, and that the protrusions 12 are helical. Functionally unchanged. The height of the convex portion 12 is 3
mm, and the protrusion pitch is formed in the range of 15 to 50 mm.

The connecting portion 13 communicates with the cable insertion hole 11 and has a diameter larger than the inner diameter of the insertion hole 11 (inner diameter of the convex portion 12) and larger than the outer diameter of the short tube 4 or the cable protection tube 6 to be connected. A slightly larger circular connection hole 14 is formed. This is to make the inner diameter of the short tube 4 fitted into the connection hole 14 and the inner diameter of the insertion hole 11 the same. The length of the connection hole 14 in the pipe axis direction is 5 in two or more pitches in terms of the ridge pitch of the short pipe 4 and the protection pipe 6 so that the short pipe 4 or the cable protection pipe 6 to be connected can be sufficiently fitted.
The length is less than the pitch.

One end of the connecting portion 13 is cut off from the upper surface thereof to a half in the height direction of the pipe edge to form a half-cylindrical portion to form an L-shaped upper step portion 15 in a side view.
The other end of the tube unit 3 has a semi-cylindrical portion cut out from the lower surface to half the height of the tube end to form an inverted L-shaped lower step 16 in a side view. Part 1
The upper and lower mating walls 15a, 16a of 5 and 16 are horizontal surfaces, and the vertical walls are vertical walls 15b perpendicular to the pipe axis direction.
16b.

The relationship between the step portions 15 and 16 and the connection hole 14 in the length in the tube axis direction is as follows.
“a” is set to a length that can fit at least two pitches of the peak of the short tube 4 and the protection tube 6. Therefore, the upper and lower steps 15 and 16 are symmetrical steps which are displaced in the tube axis direction and can be fitted to each other. These steps 15, 16
Is formed to facilitate connection between the tube units 3 and 3 and to facilitate insertion of the insertion pin 17 from above.

Further, in order to cope with the curved installation of the tube unit 3, the tube end surfaces of the two stepped portions 15 and 16 are formed such that the right and left central portions in the direction (left and right direction) orthogonal to the tube axis direction are opposed to each other. Tapered surface 19 protruding to the side and inclined to the left and right sides
Are formed. The taper angle θ of the tapered surface 19 is
When the standard length of the tube unit 3 is 1 m, an appropriate angle can be selected from 2 to 10 degrees. These angle ranges correspond to the allowable installation range of the curved power cable and the like, and indicate that the power cable and the like can be curvedly installed with a radius of approximately 2.5 m or more. Therefore, the range of the taper angle θ of the tapered surface 19 differs depending on the length of the tube unit 3 in relation to the allowable installation range of a curve such as a power cable.

The pin holes 18 are provided on the upper and lower wall surfaces 15a, 16a so that the tube unit 3 can be rotated symmetrically.
a is formed through the central partition wall in the vertical direction, and its hole shape is slightly larger than the diameter of the insertion pin 17 in order to cope with a displacement of the pipe unit 3 in the pipe axis direction due to an earthquake or the like. Larger diameter in the tube axis direction than the shorter diameter (1.5 to
3 times).

Further, of the upper and lower surfaces of the unit body 10,
At least on the upper surface, positioning ridges 21 for positioning that are continuous in the tube axis direction are formed at a predetermined pitch over the entire surface in the left-right width direction orthogonal to the tube axis direction. The matable concave grooves 22 are formed at a predetermined pitch over the entire surface of the unit body 10 in the left-right width direction.

In this embodiment, on each of the upper and lower surfaces of the unit body 10, a ridge 21 and a groove 22 formed in a triangular shape and an inverted triangular shape having the same cross-sectional shape are alternately continuous in the left-right direction. As shown in FIG. 6, when the tube units 3 are stacked in multiple stages as shown in FIG. 6, the opposed upper and lower convex ridges 21 and groove ridges 22 are set so as to be engaged without any gap. The height of the ridge 21 and the depth of the groove 22 are set to, for example, 5 mm, and the bottom length is set to 20 mm. Therefore, the ridges 21 formed on the upper surface and the ridges 21 formed on the lower surface of the unit body 10 are formed with a phase difference of 1/2 pitch from each other in the left-right direction.
The groove 22 on the upper surface and the groove 22 on the lower surface are also formed with a phase difference of 1/2 pitch in the left-right direction.

The ridges 21 and the grooves 22 are set to be formed in the same manner even when the number, the width, and the length of the insertion holes 11 of the tube unit 3 are different. Then, the tube units 3 having different lengths can be
Alternatively, even when the pipe units are shifted in the pipe axis direction and stacked, and the connection points in the pipe axis direction are changed in each stage to increase the strength of the pipe line, the pipe unit 3 to be stacked may be stacked in the pipe axis direction. There is an advantage that guidance is facilitated and a gap is not formed on the upper and lower mating surfaces (laminated surfaces) of the unit body 10.
Furthermore, even when the unit main bodies 10 having different widths in the left-right direction are placed, there is an advantage that there is no gap between the upper and lower surfaces.

The relationship between the ridges 21 and the grooves 22 on the upper and lower surfaces of the unit body 10 and the pin holes 18 is as follows.
The groove 22 is formed on the entire upper and lower surfaces of the unit main body 10 except for the portion where the pin hole 18 is formed. Further, when the insertion pin 17 is inserted into the pin hole 18, the insertion pin tip Of the retaining head 17a of the projection 21 and the groove 2
A step 18a having a depth corresponding to the height of the insertion pin head 17a is formed in the portion of the pin hole 18 facing the upper and lower surfaces of the unit body 10 so as not to interfere with the unit 2.

The protrusions 21 and the grooves 22 are shown only in FIGS. 5 to 8 and are not shown in FIGS. 1 to 4.

[Connection Structure between Tube Units] Next, the connection structure between the tube units will be described with reference to FIGS. 1, 2, 7 to 10. FIG. 7 is an exploded perspective view showing a connection structure between the tube units, FIG. 8 is an assembled perspective view thereof, FIG. 9 is a sectional view showing a connection structure between the tube units,
FIG. 10 is a sectional view of the watertight packing.

As shown in the figure, the connection structure between the tube units 3 is characterized in that a short tube 4 is used separately from the tube unit 3. That is, the end connection holes 14 of the tube unit 3 are arranged so as to face each other, the short tube 4 is interposed in the opposing connection hole 14, and annular watertight packing is provided at both ends of the short tube 4. 25 is externally fitted to maintain watertightness, and an insertion pin 17 is inserted from above into a pin hole 18 located on the upper and lower mating wall surfaces 15a, 16a of the stepped portions 15, 16 to be joined to connect the pipeline. ing.

As shown in FIG. 9, the short tube 4 is an independent corrugated tube having a predetermined wall thickness and a plurality of circumferential concave portions 4a and circumferential convex portions 4b alternately and repeatedly formed in the tube axis direction on the inner and outer surfaces. In addition, it has flexibility in order to bendable in response to an earthquake or the like. The length of the short tube 4 is 3 to 10 pitches in accordance with the peak pitch of the cable protection tube 6 described later. One pitch is in a range of 10 mm to 50 mm, and can be appropriately selected in this range in consideration of flexibility and the like.
Among these lengths, the length of the short pipe 4 is preferably 4 to 6 pitches in consideration of minimizing the length of the connection hole 14 and the gap between the pipe units 3 as much as possible.

The inner diameter of the short tube 4 is formed to match the inner diameter of the insertion hole 11 in consideration of the lineability, and the outer diameter of the short tube 4 is larger than the inner diameter of the connection hole 14 of the tube unit 3. Is also slightly smaller. Further, the end of the short tube 4 is formed as a mountain cut for cutting the central part of the convex part 4b so as not to damage the power cable or the like at the time of connection, and the end edge is retracted from the wire part.

The short tube 4 has a thickness of 1.5 to 4 mm in consideration of its flexibility and durability, and is manufactured by blow molding using a thermoplastic resin such as polyethylene or polypropylene. Alternatively, the existing cable protection tube 6 with independent waves may be formed by cutting. Further, a styrene-based or olefin-based thermoplastic elastomer (TPE) may be used. In this case, an elastomer having a rubber hardness of 80 or more is preferable in order to ensure a low friction coefficient. Specifically, "Sumitomo TPE" manufactured by Sumitomo Chemical Co., Ltd. and "Clayton G" and "Califlex TR" manufactured by Shell Chemical Co., Ltd. can be used.

As shown in FIG. 10, each of the watertight packings 25 is made of rubber which is fitted into one of the concave portions 4a at both ends of the short tube 4. Is slightly smaller than the inner diameter of the connection hole 14 of the tube unit 3 (about 1 to
2 mm). The cross-sectional shape of the watertight packing 25 is such that the short tube 4 is easily inserted into the connection hole 14 from the tube axis direction and is difficult to be removed. A blade portion 25b that spreads in a blade shape in two stages from the inner end side to the outer end side in the pipe axis direction. While being reduced in diameter, it exhibits a watertightness of approximately 1 kg / cm2 with respect to the external water pressure.

In this case, the watertight packing 25 is
The power cable and the like do not get caught in the watertight packing unlike the conventional case where the end face watertight structure is adopted. In this embodiment, a watertight packing having a form as shown in FIG. 10 is used. However, the present invention is not limited to this.

The insertion pin 17 has a shaft portion 17b and a head portion 17a for retaining the shaft portion 17b formed on the shaft portion 17b, and is formed of a non-corrosive metal, polypropylene, FRP, or the like. The diameter of the shaft portion 17b of the insertion pin 17 may be any diameter that allows the pin portion 18 to be loosely fitted so that the pin portion 18 can be easily inserted into the pin hole 18 from above. It can be set appropriately according to the minor axis. In addition, the length of the shaft portion 17b of the insertion pin 17 is a length that penetrates between the pin holes of the tube unit 3 to be joined, and is set shorter than the height of the tube unit 3.

In the connection structure described above, a gap is formed between the pipe ends of the tube units 3 by the tapered surface 19. However, even if this gap is formed, the presence of the short pipe 4 and the watertight packing 25 may cause a gap. The watertightness of the line section of the pipeline is sufficiently ensured. In addition, when the gap due to the tapered surface 19 becomes a problem at the time of backfilling, for example, in the curved installation of the tube unit, a gap is generated outside the tube unit in the bending direction. Filling with a filler such as flexible foamed polyethylene can solve the problem of backfilling.

[Connection Structure between Tube Unit and Cable Protection Tube] Next, a connection structure between the tube unit 3 and the cable protection tube 6 will be described with reference to FIGS. 1, 2, 11 to 16. 11 is an exploded view showing a connection state between the tube unit 3 and the cable protection tube 6, FIG. 12 is an exploded perspective view of the same fastener, FIG. 13 is a bottom view of the elongated fastener, and FIG. FIG. 15 is a front view of the body, FIG. 15 is a plan view of the short fastening body, and FIG. 16 is a perspective view showing a connection fixing portion of the fastening.

As shown in FIG. 11, the connection structure between the tube unit 3 and the cable protection tube 6 is such that the cable protection tube 6 in which the watertight packing 25 is externally fitted is inserted into the connection hole 14 at the end of the tube unit 3. The cable protection tube 6 is fitted and a fastener 26 is externally fitted and fixed.

The cable protection tube 6 is made of flexible hard polyethylene in which circumferential convex portions 6a and concave portions 6b are alternately formed in the tube axis direction.
Is set in the range of 10 mm to 50 mm similarly to the short tube 4.

The fastener 26 has a split structure comprising a long fastener 27 and a short fastener 28, and a corrugated uneven portion 29 corresponding to the waveform of the cable protection tube 6 is formed therein. I have. As shown in FIG. 16, the long fastening body 27 has a rectangular outer shape, and when fitted into the step portion 15 or 16 of the tubular unit 3, the outer dimensions are such that it becomes flush with the outer surface of the tubular unit 3. Is formed, the inner surface is formed in a semi-cylindrical shape, and the circumferential protrusions 29a to be fitted into the concave portions 6b of the cable protection tube 6 are formed for three pitches. An elongated pin hole 30 into which the insertion pin 17 can be inserted is formed through the center of the end of the elongated fastening member 27, and when a tensile stress in the pipe axis direction due to an earthquake or the like acts on the elongated pin body 30, the pin hole 30 is formed. It can be adapted to.

As shown in FIG. 15, the short fastening member 28 has a rectangular shape so as to correspond to the long fastening member 27.
The inner surface is formed in a semi-cylindrical shape, and a circumferential projection 29b that fits into the concave portion 6a of the cable protection tube 6 is formed for two pitches.

The length of the long fastening member 27 is set to three pitches, and the length of the short fastening member 28 is set to two pitches.
However, the present invention is not limited thereto, and the end surface of the elongated fastening body 27 may be formed in accordance with the length of the upper and lower steps 15 and 16 of the pipe unit 3 to be connected in the pipe axis direction.
It is preferable that the length is set to such a length as to contact the inner vertical walls 15b, 16b.

Then, the long fastening member 27 and the short fastening member 28
The connection means adopts a pin connection method in consideration of ease of connection. That is, a fixing pin 31 is formed on one of upper and lower mating surfaces of the long fixing body 27 and the short fixing body 28, and a fixing hole 32 for fitting the fixing pin 31 is formed on the other. The fixing pin 31 has, for example, a pin shape of a circular section having a diameter of 6 mm, and the fixing hole 32 has a diameter of 5 m.
As shown in FIG. 11, the m-shaped square hole is used to sandwich the cable protection tube 6 from both the upper and lower sides and forcefully fit them together. The fixing holes 32
13 and 15, the upper and lower fastening members 27, 2
8, four fixing pins 31 may be inserted into both fixing holes 32 at the time of on-site construction.

When the watertight packing 25 is the same as that used for joining the tube units, it is possible to ensure sufficient watertightness between the cable protection tube 6 and the tube unit 3. Become.

The handhole 2 and the cable protection tube 6
Connection 5 is usually a concrete handhole 2
Although a through hole for a protection tube is formed in this embodiment, in the present embodiment, as shown in FIG.
As No. 3, a connecting plate 33 formed integrally with the concrete handhole body 2 is employed.

The connection plate 33 is integrally formed with a connection tube 34 having an inside diameter into which the cable protection tube 6 can be fitted. The connection tube 34 has a watertight packing 25 and a bell-shaped edge cover. The protection tube 6 fitted with 35 is fitted.

The connection tube 34 of the connection plate 33 is formed in consideration of the presence of an unused connection tube 34.
At the time of molding, a lid portion 36 having a thin portion formed on the periphery is integrally formed, and the lid portion 36 of only the connection tube 34 to be used is configured to be opened with a tool such as a screwdriver at the site. Is also good.

[Connection method of cable buried pipeline] Next, the connection work of the cable buried pipeline 1 will be described. First, the connection operation between the pipe units will be described. After excavating a pipe buried portion such as a sidewalk, the handhole 2 and the pipe unit 3 are arranged in the excavation groove portion, and the short pipe 4 with the watertight packing 25 is provided. Is inserted into the end connection hole 14 of the tube unit 3, and then the facing tube unit 3 is inserted into the other end of the short tube 4 from the tube axis direction. At this time, the steps 15, 16 of the tube units 3 are engaged with each other, and the steps 15,
The 16 pin holes 18 are aligned with each other, and the insertion pin 17 is inserted from above to complete the connection operation between the tube units.
This operation is sequentially repeated to install and connect a desired number of tube units 3 between the handholes 2.

Next, a method of connecting the handhole 2 and the tube unit 3 will be described. Since the handhole 2 and the tube unit 3 cannot be directly connected, a cable protection tube 6 with independent waves is connected between them. This connection operation may be performed from the handhole side or from the tube unit 3 side. When the operation is performed from the handhole 2 side, the cable protection tube 6 is inserted in the tube axis direction from the inside of the handhole 2 so that the distal end portion protrudes toward the tube unit 3 side. At this time, if the watertight packing 25 is attached to the end of the cable protection tube 6 in advance, the watertightness on the handhole 2 side can be ensured only by inserting the cable protection tube 6 into the handhole 2.

A watertight packing 25 is fitted to the end of the cable protection tube 6 protruding from the handhole 2 toward the tube unit 3 in accordance with the pitch of the fastener 26 in advance. The short clasp 27 and the short clasp 28 are joined with the fixing pin 31, and then the end of the cable protection tube 6 is fitted into the connection hole 14 of the tubular unit 3. Then, the long fastening member 27 is engaged with the step portion 15 of the tube unit 3, so that the watertightness is ensured only by aligning the two pin holes and inserting the insertion pin 17 from above. The established connection work can be secured.

When these connection operations are completed, the excavated earth and sand is buried in the buried conduit. In this case, since the outer shape of the tubular body unit 3 is square, there is no gap at the time of backfilling, and the backfilling operation can be easily performed. When the backfilling operation is completed, a power cable or the like is passed from the handhole 2 to the cable protection tube 6, the short tube 4, and the insertion hole 11 of the tube unit, and then guided to the handhole 2. In these wiring operations, corrugated projections are formed on all of the communication lines, and the contact area with the power cable or the like is reduced, so that the wiring operation can be easily performed.

[Manufacturing Method of Tube Unit] Next, a method of manufacturing the tube unit 3 will be described with reference to FIGS. 17 is a front view of a mold of the tube unit, FIG. 18 is a sectional view taken along line AA of FIG. 17, FIG. 19 is a sectional view taken along line BB of FIG.
FIG. 20 is an overall view of the mold, and FIG. 21 is a side view of the core.

The tube unit 3 can be manufactured by any of injection molding, transfer molding and cast molding. In the present embodiment, however, in order to manufacture the tube unit 3 at low cost using recycled polyethylene, which will be described later, Adopts low pressure casting method. In this low-pressure casting method, as shown in FIG. 20, a molding die 42 is put into a water tank 41 on a lower platen 40, and is pressed between an upper platen 43 and a lower platen 40.
And a method of injecting a molten resin into the mold cavity from the heating pipe 45 and molding, and employing a water cooling method to shorten the molding cycle.

As shown in FIG. 17, the molding die 42 is
A split mold is used in which 6 is １ ／ of the height of the molded product, and is composed of an upper mold 47, a lower mold 48, side molds 49 and 50, and a core 51.

The core 51 is, as shown in FIGS. 18 and 21,
It is for forming the insertion hole 11 and the connection hole 14 and is continuous with the large diameter portion 52 for forming the connection hole on the base end side,
A male screw portion 53 for forming the spiral convex portion 12 of the insertion hole 11 is formed, and the tip thereof is detachably fitted to a large-diameter core receiver 54 for forming a connection hole. Also,
The core 51 has a hollow portion 55 through which cooling water flows in order to shorten the molding cycle of the tube unit. The external thread portion 53 can be appropriately selected and set within a range of a peak height of about 3 mm and a pitch of 15 to 50 mm. Therefore, the convex portion 12 of the insertion hole 11 formed by this is also formed with a height and a pitch corresponding to the male screw portion 53.

The upper mold 47, the lower mold 48 and the side mold 49,
By 50, a cavity 56 is formed in which a thick molded product can be formed. The cavity shape can be appropriately selected according to the required outer shape of the tubular body unit 3. For example, the molding portions 57 of the step portions 15, 16 can be easily set.

When the tube unit 3 is formed using the mold 42 having the above structure, the molten resin is heated by the extruder 44 under the pressing of the upper and lower stools 40 and 43.
5 is injected into the mold cavity 56 from the injection nozzle 45a, cooled after completion of the injection, and then removed from the mold while rotating the core 51, whereby the tube unit 3 can be molded, and the molding cycle is greatly shortened. I was able to.

[Examples] Hereinafter, using resins having different compounding ratios, an outer shape of 145 mm (height in the vertical direction) × 290 mm
(Left and right width) x 600mm (length in tube axis direction), inner diameter 100
An example in which a tube unit 3 having two rows of insertion holes 11 of mm is formed will be described. Tube unit 3 in this case
Is under a 70-ton press by the upper and lower stools 40 and 43 shown in FIG.
This is obtained by injecting a molten resin at 220 ° C. from the injection nozzle 45a into the mold cavity 56, cooling it for 12 minutes after completion of the injection, and removing the mold while rotating the core 51.

Table 1 shows comparative evaluations of product specific gravity, shrinkage, sink mark depth, appearance, amount of flexure, and flexure ratio when molded with synthetic resins having different compositions. The first embodiment is an example using only recycled polyethylene (100% by weight of recycled PE). In the second example, low-density type recycled PE was blended at a ratio of 80% by weight, and calcium carbonate (charcoal) (trade name "Princeton B", manufactured by Shiraishi Calcium Co., Ltd.) as a filler at a ratio of 20% by weight. Here is an example. The third embodiment shows an example in which 80% by weight of low-density type recycled PE and 20% by weight of recycled FRP obtained by chipping waste material of an FRP molded product into a chip having a diameter of 5 mm or less as a filler. In Table 1, the deflection amount and the deflection rate are as follows:
It is the result of measuring the deflection in the height direction when a force of 3380 kgf was applied to a test piece obtained by cutting the tube unit 3 to a length of 250 mm in the tube axis direction.

[0099]

[Table 1]

As shown in Table 1, as in the first embodiment,
The tube unit 3 can be molded using 100% by weight of recycled PE. However, in terms of product evaluation, the second embodiment and the third embodiment can suppress the product shrinkage rate, have a small sink mark depth, and have an external appearance. Was also good. It has a sufficient compressive strength in terms of the amount of deflection and the degree of deflection of the product. Further, in the pipe unit 3, even in the picking test (JIS C3801), dents were formed at the hit points, but no deformation damage was recognized in the insertion hole 11.

Therefore, the product strength can be improved by mixing calcium carbonate or recycled FRP chips as a filler into recycled polyethylene, and when recycled FRP is used, the use of waste materials of FRP molded products is important. The significance is significant.

[Another Embodiment] Next, another embodiment will be described. The outer shape of the tube unit 3 is not limited to a rectangular parallelepiped shape as described above, but as shown in FIG. 22 (a), a recessed portion 66 for squeezing is formed on the upper and lower surfaces and a flange portion 67 is formed on a side portion, and a pin hole is formed on this portion. In this case, the shape is such that the four corners are obliquely cut off as shown in FIG. 3B, and the shape in which the step portion 15 is arranged on the upper side in the height direction as shown in FIG. Good.

As shown in FIG. 22 (a), when the tubular body units 3 having the concave portions 66 are stacked in parallel in multiple stages and multiple rows,
As shown in FIG. 3, a space 68 is formed inside the laminate due to the concave portion 66 and the flange portion 67. If the space 68 is filled with a square member (not shown) corresponding to this cross-sectional shape, a gap is formed inside the laminate structure. And the backfilling operation can be easily performed.

Further, the number of insertion holes 11 formed in the tube unit 3 is not limited to two as in the above-described embodiment.
One row, three rows, or two or more rows in the horizontal direction can be appropriately selected and formed. Similarly, one, two, three, or more rows in the height direction can be formed. can do. FIG. 24A shows a tube unit having one insertion hole, and FIG. 24B shows three rows of tube units. When the insertion holes are formed in multiple stages and multiple rows, it is also possible to arrange those having different diameters.

FIG. 25 shows a state in which pipe units 3 of the same hole diameter type and different hole diameter types are stacked in multiple stages and multiple rows. In this way, by stacking the pipe units 3 of the same hole diameter type and different hole diameter types in parallel in multiple stages and multiple rows, a pipe structure having an arbitrary number of holes can be obtained. In this case, if the ridges 21 and the grooves 22 of the same mode are formed on the upper and lower surfaces of the tube unit 3, even when the tube units 3 are stacked, they can be stacked without gaps.

The position of the pin hole 18 is determined by the insertion hole 1
When 1 is in two rows, as in the above embodiment, it is preferable to dispose it on the central partition 10a of the unit body 10, but in three rows, as shown in FIG. 26, the partitions 10c, 10d between the insertion holes are provided. It is preferable to dispose it at the tip portion. In the case of a single row of insertion holes 11, it cannot be formed at the center in the left-right direction.

In the above-described embodiment, the spiral insertion hole 11 is formed in consideration of ease of molding and connection.
And the tube unit 3 having the step portions 15 and 16 at the ends, but when only the ease of molding is considered, the tube unit 3 may have a form as shown in FIGS. 27 and 28. That is, the shape of one end portion of the tube unit 3 is a large-diameter connection hole 14 communicating with the spiral insertion hole 11,
Is formed in a small-diameter portion 69 that can be fitted in the connection hole 14 so as to form a so-called male-female fitting type connection portion structure.

In this case, a watertight packing (rubber ring) 71 is brought into contact with the step 70 between the connecting hole 14 and the insertion hole 11,
As shown in FIG. 28, the watertightness is maintained by clamping the watertight packing 71 by engaging the watertight packing 74 with the engaging portions 72 and 73 formed on the outer surface of the end of the tube unit 3. It is also possible.

[0109]

[0110]

As is apparent from the above description, the present invention
According to this , as a connection structure between the tube units, a short tube and a watertight packing fitted on the short tube are used separately from the tube unit, so that there is an effect that the connection in the tube axis direction can be easily performed.

In addition, a step portion is formed at the end of the tube unit at the connection portion, and a plug-in connection method using this step portion is adopted, so that the tube unit connection operation can be performed entirely from above. This has the advantage that the workability is improved and the underground excavation area can be reduced.

Further, tapered surfaces are formed at the ends of the tube units so as to be able to cope with curved installation.
In addition, since the pin hole of the insertion pin is a long hole extending in the pipe axis direction, there is an excellent effect that the earthquake resistance against an earthquake or the like is improved.

Furthermore, the connection between the tube unit and the cable protection tube is also made by using a split-type fastener with independent waves corresponding to the circumferential projection of the cable protection tube inside, and connecting the insertion pin from above. Since the system is adopted, there is an excellent effect that the connection operation can be easily performed.

[Brief description of the drawings]

FIG. 1 is an exploded view of a cable buried conduit showing one embodiment of the present invention.

FIG. 2 is a diagram showing a connection state of a cable buried pipeline;

FIG. 3 is a plan view of a tube unit.

FIG. 4 is a side view of the same.

FIG. 5 is a front view of the same.

FIG. 6 is a cross-sectional view showing a laminated structure of a tube unit.

FIG. 7 is an exploded perspective view showing a connection structure between tube units.

FIG. 8 is an assembled perspective view of the same.

FIG. 9 is a cross-sectional view showing a connection structure between tube units.

FIG. 10 is a sectional view of a watertight packing.

FIG. 11 is an exploded view showing a connection state between the tube unit and the cable protection tube.

FIG. 12 is an exploded perspective view of the fastener.

FIG. 13 is a bottom view of the long fastening body.

FIG. 14 is a front view of a long clasp.

FIG. 15 is a plan view of a short fastening body.

FIG. 16 is a perspective view showing a connection fixing portion of the fastener.

FIG. 17 is a front view of a mold of the tube unit.

18 is a sectional view taken along line AA of FIG.

19 is a sectional view taken along line BB of FIG.

FIG. 20 is an overall view of the mold.

FIG. 21 is a side view of the core.

FIGS. 22 (a), (b) and (c) are front views each showing another embodiment of the outer shape of the tubular body unit.

FIG. 23 is a front view showing a state in which the tube units of FIG. 22 (a) are stacked.

24A and 24B are cross-sectional views of a tube unit, wherein FIG. 24A is a cross-sectional view of a single-row insertion hole, and FIG.

FIG. 25 is a front view showing a state in which pipe units having different diameters are stacked in a multi-stage double row.

FIG. 26 is a partial plan view of a tube unit having three rows of insertion holes.

FIG. 27 is a sectional view showing another connecting portion structure of the tubular body unit.

FIG. 28 is a sectional view showing the connecting means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cable embedding pipe 2 Hand hole 3 Tube unit 4 Short pipe 10 Unit main body 11 Insertion hole 12 Spiral convex part 13 Connection part 14 Connection hole 15, 16 Step part 17 Insertion pin 18 Pin hole 19 Tapered surface 25 Watertight packing 26 Fastener 27 Long fastening body 28 Short fastening body

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ichiro Nakai 1-17-18 Edobori, Nishi-ku, Osaka-shi, Osaka Toyo Tire & Rubber Co., Ltd. (72) Inventor Tadayoshi Ohira 1-17-18 Edobori, Nishi-ku, Osaka, Osaka No. Toyo Tire & Rubber Co., Ltd. (56) References JP-A-61-180507 (JP, A) JP-A-8-240288 (JP, A) JP-A 7-1542 (JP, A) JP-A-6-205 288867 (JP, A) JP-A-7-31031 (JP, A) JP-A-8-90138 (JP, A) Japanese Utility Model Laid-Open No. 64-20314 (JP, U) (58) Fields investigated (Int. ⁷ , DB name) F16L 9/19 F16L 19/00 F16L 37/12

Claims (5)

(57) [Claims] In a cable buried conduit for burying a power cable or the like in the ground, a connection structure between pipe units having a cable insertion hole formed in a pipe axis direction, wherein an end of each pipe unit is provided. In the portion, a connection hole communicating with the cable insertion hole and having a diameter larger than the inner diameter of the insertion hole is formed, the connection holes of each tube unit are opposed to each other, a short pipe is interposed therein, and the short A pipe connection structure in which an annular watertight packing is fitted on both ends of the pipe. 2. A connecting means for connecting the ends of the tubular units to each other, wherein the connecting means includes a pipe end extending from an upper surface of an end of one of the opposed tubular units. The upper step portion formed by cutting out to the edge, the lower step portion formed by cutting off from the lower surface of the end of the other tube unit to the tube end edge, and the corresponding upper and lower mating wall surfaces of both step portions in the vertical direction. Claims: A configuration including a pin hole formed through and an insertion pin that can be fitted into the pin hole from above.
Item 4. The pipe connection structure according to Item 1 . 3. A tapered surface is formed on at least one of the surfaces of the step portions facing in the tube axis direction, the center portion of the step portion projecting toward the facing tube unit in the left-right direction orthogonal to the tube axis direction. The pin hole is a long hole having a longer diameter in the pipe axis direction than a shorter diameter slightly larger than the diameter of the insertion pin.
The pipe connection structure according to claim 2 . 4. A cable buried conduit for burying a power cable or the like in the ground, wherein a tube unit having a cable insertion hole formed in a pipe axis direction and circumferential concave and convex portions are alternately formed at a predetermined pitch. A pipe connection structure for connecting a cable protection tube with an independent wave formed repeatedly to a pipe connection structure, wherein the end of the pipe unit communicates with the cable insertion hole, and the inner diameter of the insertion hole is A large diameter connection hole is also formed, and a watertight packing is externally fitted to an end of the cable protection tube, and an end of the cable protection tube is internally fitted to the connection hole. A plurality of pieces each having a corrugated portion corresponding to a circumferential protrusion of the cable protection tube; and these pieces are connected and fixed to each other and externally fitted and fixed to an end of the cable protection tube. Fasteners and tube units An upper step is formed by cutting from the upper surface of one end to the edge, and a lower step is formed by cutting from the lower surface of the other end to the edge. A pipe connection structure in which a pin hole is formed through, and an insertion pin is fitted into the pin hole from above. 5. The tubular unit according to claim 1,
And the upper and lower surfaces of the unit body
Ridges and grooves for positioning in the direction
Form alternately and continuously over the entire surface in the right and left width directions
Made, formed ridge and a lower surface which is formed on the upper surface of the unit body
The projected ridges have a phase of 1/2 pitch in the left-right width direction.
When the tube unit is formed with a difference,
In this case, the upper and lower ridges and grooves facing each other
Set pipe unit.