JPH08168153A - Conduit for wire - Google Patents

Abstract

PURPOSE: To reduce the volume of backfilling earth while enhancing the strength against impact from a pick or the like and the workability by a structure wherein holes formed by the bottom face of a trough and a synthetic resin board, as well as holes formed by the synthetic resin boards are employed as conduits. CONSTITUTION: A concrete or lightweight concrete trough 1, having a semicircular groove 4 in the bottom face thereof, is laid in a trench dug from the ground surface. A synthetic resin board 2 having semicircular grooves 5 in the opposite sides thereof is then set at the bottom face of the trough 1 to form a circular hole. One or a plurality of synthetic resin board 2 is then stacked thereon and integrated by inserting bolts into holes 21 made through the board 2 and tightening nuts thus assembling them fixedly and forming many holes in multistage. When the synthetic resin boards 2 are stacked equal to the depth of the trough 1, a cover 3 is set watertightly on the trough 1 thus completing a wire conduit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric wire conduit for burying an electric wire or cable in the ground.

[0002]

2. Description of the Related Art Generally, in a conduit for electric wires, a conduit system in which a cable is pulled into the conduit after the conduit is buried, or a concrete trough for storing the cable is buried in the ground, and the cable is placed in the conduit. The underdrain method of arranging is implemented.
Further, in recent years, since it is necessary to arrange a plurality of cables in the electric line, the pipes are often embedded in multiple rows and multiple stages in the pipeline system.

[0003]

In such a case, the excavation width is determined in consideration of the outer diameter of the pipe and the distance between the pipes from the ground surface, and after the pipes are arranged, backfilling is performed. At this time, the narrower the excavation width is, the more economical it is. However, since it becomes difficult to backfill the sand or the soil between the pipes, an extra excavation width must be taken to some extent, and workability is deteriorated. Also, due to the ease of construction work, synthetic resin pipes are being used more often, but there is also the potential for external damage such as a pickaxe during other road works,
Marking tapes and protectors indicating the embedding of pipes are embedded together on the upper surface of the pipeline to notify the danger.
Further, although the pipes have been stored in the underdrain, the workability is deteriorated because the pipes must be filled with sand or the like in order to prevent feeding damage due to invasion of mice and the like. On the other hand, in the underdrain type called a cab, the trough tends to increase in size with the increase in the number of cables, which inevitably increases the cost required for the construction, and the reality is that it is not widely used even though public capital maintenance is being called for. The present invention solves the above-mentioned problems of the conduit type and the underdrain type, and provides a conduit for electric wires which has strength against impact from a pickaxe and the like and has improved workability.

[0004]

That is, according to the present invention, a trough made of concrete or lightweight concrete having a plurality of grooves having a semicircular cross section at the bottom has a plurality of grooves having a semicircular cross section on both sides. A synthetic resin plate is arranged so as to form a plurality of circular holes together with a plurality of semicircular grooves provided in the trough, and further, a plurality of semicircular grooves in cross section are formed on both sides of the holes. After arranging a synthetic resin plate having the above so as to form a plurality of holes by the upper and lower synthetic resin plates and forming a multi-row multi-stage hole, a concrete lid is provided in a watertight state. It is a conduit for electric wires.

Further, according to the present invention, among the plurality of semicircular grooves provided on the trough bottom surface and the plate made of synthetic resin, at least the groove corresponding to the lower surface of the circular holes formed in combination has the top portion. Since it is a groove having a shape having a plurality of continuous or discontinuous convex peaks having a height of 1/10 or less of the radius of a circle which is smooth and at intervals of 5 times or less the height of the peaks The conduit for electric wire according to claims 1 and 2 is also included. Further, according to the present invention, among the plurality of semicircular grooves provided on the trough bottom surface and the synthetic resin plate, at least the groove corresponding to the lower surface of the circular hole formed in combination has a smooth top. Also included is a groove having a shape having a plurality of continuous or discontinuous convex peaks having a height of 1/10 or less of the radius of a circle at intervals of 5 times or less the height of the peaks. are doing.

Further, the present invention is a synthetic resin plate having a plurality of grooves having a semicircular cross section and a plurality of grooves having a semicircular cross section on one or both sides provided on the bottom surface of a trough made of concrete or lightweight concrete. Circular holes formed,
And, at least one of a plurality of circular holes formed by plates made of synthetic resin having a plurality of grooves having a semicircular cross section on one or both sides is accommodated in a groove corresponding to the lower surface of the hole more than half. It may be a conduit for electric wires, in which the electric conduit is housed and a concrete lid is provided in the trough in a watertight state.

[0007]

In the electric wire conduit according to the present invention, the electric wire and the cable are provided with the trough bottom surface and the synthetic resin plates and the holes formed by the synthetic resin plates as conduits, and are drawn in for practical use. . Also, in another method of arranging the conduit in the hole formed by the trough bottom surface and the plate made of synthetic resin and the plates made of synthetic resin, this conduit becomes the conduit and the cable is drawn in at a later date. Be put to practical use. The electric wire conduit of the present invention needs to be excavated by the outer width formed by the trough and the widths of the spaces on both sides to some extent, and the amount of backfill earth and sand can be small. Also, by using an electric line with such a configuration, the cable will be stored in a concrete or lightweight concrete trough, so that the trough itself will be damaged even when subjected to mechanical shock such as a pickaxe. It is durable and can be used for a long time.

[0008]

1 and 6, reference numeral 1 denotes a trough made of concrete or lightweight concrete having a semicircular groove 4 on the bottom, which is installed by being housed in a groove excavated from the surface of the earth. Since the trough is usually about 1 m long due to its weight and transportation problems, it is installed every 1 m so that there is no step and is connected by mortar or the like to form a long groove.
Reference numeral 2 is a synthetic resin plate having a plurality of grooves 5, and has semicircular grooves 5 on both sides as shown in FIG. The plate 2 has a circular hole. Board made of synthetic resin 2
When the is installed on the bottom surface of the trough 1, a circular hole is formed, and one or more synthetic resin plates 2 are stacked on the circular hole, and through the holes 21 provided in the synthetic resin plate 2,
Although not shown in the figure, they are assembled using bolts and nuts so that they cannot move relative to each other. Thus, the holes are formed in multiple rows and multiple stages. When the synthetic resin plates 2 are stacked to the depth of the trough 1, the trough lid 3 is installed in a watertight state to complete the electric wire conduit. Although not shown in the drawing, a plurality of similar holes can be formed by using a synthetic resin plate having a plurality of grooves on one surface.

Further, in a trough having a groove having a semicircular cross section on the bottom surface, a synthetic resin plate having a plurality of grooves having a semicircular cross section on one side is placed at the bottom, and one or both surfaces are placed on the plate. Similarly, a plurality of holes can be formed by stacking synthetic resin plates having a plurality of grooves having a semicircular cross section. The length of these synthetic resin plates is preferably longer than the length of the trough, but is 4 m or less from the viewpoint of transportation such as trucks.

The synthetic resin used for the synthetic resin plate is not particularly limited, but polyethylene, polypropylene, polyvinyl chloride resin or the like is usually used. Particularly, in recent years, the use of synthetic resin industrial wastes has been actively studied, and it is possible to use these plates.

Although the holes are formed in three rows and three stages in FIGS. 1 and 6, the number of rows and the number of steps can be easily changed to other numbers. The cable can be used as an electric line by pulling the cable into the hole of the conduit for electric wire.
In the above, it was stated that construction should be done so that there is no step at the connection part of the trough, but in reality, due to the condition of the ground, there is a step, so the connection of the synthetic resin plate stored in it Even in a part, a step may occur due to a step due to it or a manufacturing variation of the synthetic resin plate itself. If the cable is pulled in in such a state, the cable may be caught at a step, and the cable may be damaged, resulting in a serious situation. Therefore, as shown in FIG. 6, if the conduit is installed in the hole formed as described above, the step is absorbed by the conduit, so that the cable is not caught.

Further, the electric conduit may be only a hole formed by the bottom surface of the trough and the plate made of synthetic resin. Increase the semicircular shape of the trough and the groove at both ends of the plate made of synthetic resin by a step difference that is larger than the semicircular shape of other places,
It will be possible by making a smooth transition. Normally, the step difference can be considered to be about 1 cm, so the diameter of the semicircle in the shape of the grooves at both ends of the trough and the plate made of synthetic resin should be 1 cm larger than the other places, and usually 5
Smoothly reduce the diameter over cm and make it the same as the central part.

Here, the conduit used in the present invention is
Meaning of corrugated synthetic resin pipes such as metal pipes, polyvinyl chloride electric conduit pipes, FRP pipes, straight pipes such as polycon pipes, corrugated hard polyethylene pipes, corrugated polyvinyl chloride pipes, corrugated polypropylene pipes, etc. The corrugated synthetic resin pipe is preferable because the step portion has a large absorbing effect.

When the cable is pulled in, even if the influence of the step is reduced as described above, the pulling-in tension may increase due to the resistance force due to the friction between the cable and the wall of the conduit. If the pull-in tension exceeds the allowable tension of the cable, the cable loses its reliability and cannot be used for a long time. In such a case, the groove as shown in FIG. 3, FIG. 4 and FIG.
Providing a continuous or discontinuous convex crest portion 22 having a height of 10 or less at a distance of 5 times or less the height of the crest portion 22 on the lower surface of at least a groove having a groove shape. Is effective. 3 shows that the convex ridges 22 are formed in parallel with the groove, FIG. 4 shows that the convex ridges 22 intersect diagonally with the groove cross section, and FIG. 5 shows a meandering spiral convex shape. The thing which has the mountain part 22 is shown. Other than this, although not shown in the figure, a semi-circular convex mountain portion parallel to the groove cross section may be used. Here, the reason why the convex ridge portion is 1/10 or less of the radius of the semicircle is that if it is too large, not only the cable passage is narrowed, but also the effect of reducing the pull-in tension is not increased. / 20 or less. In addition, the interval between the convex crests is set to 5 times the height or less, because if it is more than that, the cable may fall between the convex crests depending on the size of the cable. As shown in FIGS. 4 and 5, when the convex ridge portion is inclined or spiral with respect to the axial direction of the groove, the effect of reducing the pull-in tension is large.

[0015]

Since the electric wire conduit of the present invention is constructed as described above, the electric wire and the cable have a trough bottom surface, a synthetic resin plate, and a hole formed between the synthetic resin plates. It becomes a road and is drawn in for practical use. Also, in another method of arranging the conduit in the hole formed by the trough bottom surface and the plate made of synthetic resin and the plates made of synthetic resin, this conduit becomes the conduit and the cable is drawn in at a later date. Be put to practical use. Further, the conduit for electric wire of the present invention may be excavated by the outer width formed by the trough and the widths of the spaces on both sides to some extent, and the amount of backfill earth and sand may be small. Also,
Since the cable is stored in the trough made of concrete or lightweight concrete by using the electric line of such a structure, the trough itself is durable even if it receives a mechanical shock such as a pickaxe. Therefore, it can be used for a long period of time. Therefore, according to the present invention, it is possible to provide a conduit for electric wire that has strength against impact from a pickaxe and the like and has improved workability.

[Brief description of drawings]

FIG. 1 is a front view of an electric wire conduit according to the present invention.

FIG. 2 is a synthetic resin plate having a plurality of semicircular smooth grooves on both sides used in the present invention.

FIG. 3 shows another example of the shape of a synthetic resin plate having a plurality of semicircular grooves on both sides used in the present invention, and an enlarged view of one having convex ridges parallel to the grooves.

FIG. 4 shows another example of the shape of a synthetic resin plate having a plurality of semicircular grooves on both sides used in the present invention, which has a convex mountain portion obliquely intersecting the groove cross section. Enlarged view.

FIG. 5 shows another example of the shape of a synthetic resin plate having a plurality of semicircular grooves on both sides used in the present invention, and is an enlarged view of a groove having spiral convex ridges.

FIG. 6 is a front view showing an electric wire conduit according to another embodiment of the present invention.

FIG. 7 is a front view showing an example of a conventional electric line.

FIG. 8 is a cross-sectional view of a conventional electric line.

[Explanation of symbols]

 1 Trough 2 Synthetic Resin Plate 21 Connection Hole 22 Convex Mountain Part 3 Trough Lid 4 Trough Bottom Groove 5 Synthetic Resin Plate Groove 6 Conduit 7 Pipe Head or Pipe Pillow 71 Connection Hole 8 sand

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Ono 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (4)

[Claims] 1. A synthetic resin plate having a plurality of semicircular cross-section grooves on one or both sides in a trough made of concrete or lightweight concrete having a plurality of semicircular cross-section grooves on the bottom surface, Made of synthetic resin having a plurality of semicircular grooves formed in the trough and a plurality of circular holes, and further having a plurality of semicircular grooves on one or both sides thereof. The plates are made of synthetic resin and are placed one on top of the other to form a plurality of holes, and after forming a multi-row, multi-step hole, a concrete lid is provided in a watertight state. Pipe line for electric wires. 2. A synthetic resin plate having a plurality of grooves having a semicircular cross section on one or both sides in a trough made of concrete or lightweight concrete, and having a plurality of circular shapes by combining the semicircular grooves. A conduit for electric wire, characterized in that it is arranged so as to form a hole, and after forming a multi-row, multi-stage hole, a concrete lid is provided in a watertight state. 3. Among the plurality of semicircular grooves provided on the trough bottom surface and the synthetic resin plate, at least the groove corresponding to the lower surface of the circular hole formed by combining is a circle having a smooth top. Is a groove having a shape having a plurality of continuous or discontinuous convex ridges having a height of 1/10 or less of the radius of the ridges at intervals of 5 times or less the height of the ridges. The conduit for electric wire according to claim 1 or 2. 4. A synthetic resin plate having a plurality of grooves having a semicircular cross section and a plurality of grooves having a semicircular cross section on one or both sides provided on the bottom surface of a trough made of concrete or lightweight concrete. At least one of the circular holes formed by a plurality of circular holes and a plurality of synthetic resin plates having a plurality of grooves having a semicircular cross section on one or both sides, the lower surface of the hole A conduit for electric wires, characterized in that more than half of the electric conduits are accommodated in the corresponding groove, and a concrete lid is installed in a watertight state on the trough.