JPH0623152Y2 - Underground electric wire burying protection tube - Google Patents

Description

[Detailed Description of the Invention] <Industrial field of application> This invention is a protective tube for embedding an underground electric wire, which is used to protect an electric wire cable such as a power line buried in the earth from earth and sand, water, etc. It is about.

<Prior Art> The underground electric wire burying protection tube is buried in the ground in a state where the electric wire cable is housed therein in order to protect the electric wire cable as described above.

This kind of protective tube is usually made of hard synthetic resin, and generally, for example, three kinds of straight tubes with a predetermined length of 1 m, 2 m, 4 m and a radius of curvature of 5, 10, 15, 25 m and Eight types of curved pipes with a predetermined length of 1 m and 2 m, respectively, are combined appropriately,
It is a protective tube with the required length and curvature.

By the way, since the curvature of the curved pipe is fixed in advance as described above, this may not match the curvature required at the site, and in this case, a curved pipe having a suitable curvature may be made at the site, or Since it is necessary to heat and soften the straight pipe and bend it to the required angle, it takes time and effort.

Also, for example, a protection pipe may be piped from a flat land to a slope, or a protection pipe may be connected along a curved road in a three-dimensionally bent state while avoiding other underground buried facilities such as water and sewerage. In this case, it is necessary to pipe the adjacent pipes in a twisted state, and the pipe itself may be impossible.

Therefore, the applicant of the present invention rotatably fits a plurality of pipes to the spherical projections and the insertion opening in which the spherical projections are formed on at least a part of the outer peripheral surface of the adjacent tubes. A protective tube for embedding an underground electric wire, which is connected by a receiving port having an inner peripheral surface and is provided with packing on both sides of the maximum bulging portion of the spherical convex portion, has been previously proposed (actual opening 3-50922). issue).

With this configuration, since the spherical convex portion on the outer peripheral surface of the outlet freely rotates along the inner peripheral surface of the receptacle, the connecting pipes connected to the receptacle and the receptacle or connected to each other. The pipe and the end pipe can be flexibly bent according to the curvature of the site, and the connection part that exists linearly continuously can be bent independently according to the inclination of each embedded part, so it is a universal protection tube. It becomes possible to bend the three-dimensionally freely.

In addition, the packing provided on both sides of the maximum bulge of the spherical convex portion will force one of the packings to be pushed strongly into the receiving port even when a force such as axial pulling or pushing is applied to the protective tube. The pressure contact with the mouth ensures a reliable seal at the connection.

<Problems to be Solved by the Invention> However, even if the inlet and the receptacle are flexibly connected as described above, the bendable curvature naturally has a structural limit. When the outlet and the receiving end are bent beyond this limit or deformed due to pressure when working or buried in the ground, the sealing property between them is impaired, and therefore the connection part In this case, there is a risk that it will not be possible to prevent the intrusion of earth and sand or water from the outside, and if it is in an excessively bent state, there is a problem that the outlet and the receiving end may come off at the connecting portion.

This invention provides a protective tube for embedding an underground electric wire, which can enhance reliable protection of an electric wire cable without a possibility of deterioration of sealing property or disconnection at the connecting portion between the outlet and the receiving socket as described above. The purpose is to

<Means for Solving the Problems> The universal protective tube for burying an underground electric wire according to the present invention has one of the connecting portions for connecting a plurality of pipes as an outlet formed by a spherical bulging portion, and the other of the connecting portions. Is a receptacle having a spherical inner peripheral surface rotatably fitted in the spherical deodorant portion, and an underground packing is embedded to seal by providing annular packings on both sides of the maximum bulging portion of the spherical bulging portion. In the universal protective tube, a concave groove is formed in the spherical bulging portion between the both packings, and a stopper projection loosely fitted in the concave groove is provided on the spherical inner peripheral surface. It is a thing.

The concave groove or the stopper projection may be provided continuously over the entire circumference of the spherical bulge or the inner peripheral surface, or may be intermittently provided at an appropriate interval.

Further, instead of the stopper portion composed of the groove and the stopper protrusion, a stopper protrusion is formed on the spherical bulging portion of the outlet, and a stopper protrusion engaged with the stopper protrusion is formed. It may be provided on the spherical inner peripheral surface of the receiving port.

These locking projections and stopper projections are also the same as above.
It may be continuous over the entire circumference of the outlet or the receiving opening, or may be provided intermittently at an appropriate interval.

<Operation> By providing the stopper portion composed of the concave groove or the locking projection and the stopper projection, the relative movable range of the insertion port and the receiving port is reliably fixed within a certain range,
It is not bent to a curvature beyond the movable range, and therefore it is possible to prevent the above-mentioned deterioration of the sealing property and the occurrence of disconnection due to excessive bending.

<Example> An example of the present invention will be described below.

Example 1 The electric wire burying free protective tube of the example shown in FIGS. 1 (A) and (B) is formed by connecting a plurality of straight tubes made of hard synthetic resin, and more specifically, A plurality of connecting pipes 1 each having a socket 11 and a socket 12 at both ends are connected by fitting the socket 11 and the socket 12 together, and a socket tube 2 having sockets 22 on both sides thereof is provided. The receiving pipes 3 having the ports 31 are connected by similar fittings.

The insertion port 11 and the receiving port 12 in the fitting portion are shown in FIG.
As shown in (A). The structures of the outlet 31 and the receptacle 22 are similar.

That is, a part of the outer peripheral surface of the spigot 11 bulges to form a spherical bulging portion 11a. On the inner peripheral side of the receiving port 12, there is formed a spherical inner peripheral surface 12a which is loosely fitted to the spherical bulging portion 11a, and the end portion of the inner peripheral surface 12a has a predetermined inclination. It is a spreading surface 12b.

When the protective tube is bent, the end of the unspread surface 12b is locked on the outer peripheral surface of the spigot 11, so the relative rotatable range between the spigot 12 and spigot 11 is It will be temporarily regulated within the range of the solid angle θ formed by the unspread surface 12b in the entire circumferential portion.

In addition, in the spout 11, annular grooves 11b formed on both sides of a substantially central portion of the spherical bulging portion 11a where the spherical surface is maximum,
Annular packings 4 and 5 made of an elastic material such as rubber are fitted into the inside of 11c. These packing 4,
In the separated state of the outlet 11 and the receiving port 12 shown in FIG. 2, 5 has an outer peripheral surface projecting from the annular grooves 11b and 11c, and as shown in FIG. Socket 12
In the connected state, it functions to press-contact the inner peripheral surface 12a of the receiving port 12 and seal the connected portion.

Further, a concave groove 11d is formed in the spherical bulging portion 11a of the insertion port 11, and the concave groove 11d of the inner peripheral surface 12a of the receiving port 12 is formed.
A stopper projection 12d is formed at a location corresponding to d. The stopper projection 12d is narrower than the concave groove 11d, and when the insertion opening 11 and the receiving opening 12 are straightly connected as shown in FIG.
d is in a state in which it is loosely fitted in the substantially central portion of the concave groove 11d so as to be movable in the left-right direction in the drawing.

As for the shapes of the concave groove 11d and the stopper projection 12d, the shapes shown in the drawings have substantially right-angled end portions, but an appropriate shape such as a concave groove for ensuring the locking state described below can be more reliably achieved. 11d and the stopper projection 12d may each be formed in a trapezoidal shape in the drawing.

Fig. 2 (C) shows the connection state of the outlet 11 and the receptacle 12 when the flexible protective tube for burying the electric wire is bent as shown in Fig. 1 (B). A certain stopper projection 12d is locked by the end of the concave groove 11d of the outlet 11.

This locking makes it practically impossible to bend the outlet 11 with respect to the receptacle 12, and thus the relative movable range of the receptacle 11 and the receptacle 12 is reliably limited within this range. Since it becomes impossible to bend to a curvature beyond this movable range, excessive bending can be prevented when an excessive force is applied.

In the above description, the annular groove is used as the concave groove and the stopper projection, respectively. However, as shown in FIG. 2 (D), for example, along the outer circumference of the spherical bulging portion 13a of the insertion port 13. A combination of a plurality of recessed grooves 13d intermittently provided at an appropriate interval and a plurality of stopper projections 14d intermittently provided at an appropriate interval at a location corresponding to the recessed groove 13d of the inner peripheral surface 14a of the receiving port 14 may be used. . Alternatively, the concave groove may be formed in a continuous annular shape, and only the stopper projection may be provided intermittently.

Embodiment 2 FIGS. 3 (A) to (C) show an outlet 15 in another embodiment of the present invention.
The receptacle 16 has a spherical bulging portion 15a formed on the outer peripheral surface thereof, and the receptacle 16 has a spherical inner peripheral surface 16a fitted therein. In addition, the end of the inner peripheral surface 16a is an unexpanded surface 16b, and the annular packings 4 and 5 are fitted in the annular grooves 15b and 15c formed in the spherical bulging portion 15a. Is the same as in the first embodiment.

In this embodiment, a locking projection 15d is formed on the spherical bulging portion 15a of the spigot 15 side by side with the annular groove 15b, while the inner peripheral surface 16a of the receiving opening 16 is engaged with the locking projection 15d. A stopper protrusion 16d to be fitted is provided.

The locking projections 15d and the stopper projections 16d may have substantially right-angled end surfaces as shown in the figure, or in order to make the locked state more reliable, for example, the end surfaces of the locking projections 15d and stoppers The end faces of the protrusions 16d may be inclined to the lower left in the figure.

Then, as shown in FIG. 3 (B), when the insertion port 15 and the receiving port 16 are straightly connected, these locking protrusions
The gap 6 shown in the figure is present between the projection 15d and the stopper projection 16d in substantially the same width over the entire circumference of the pipe, so that they do not engage with each other.

However, when these are bent in the connected state as shown in FIG. 3 (C), the stopper projection 16d on the inner peripheral surface of the receiving opening 16 and the locking projection 15d of the insertion opening 15 are engaged,
Both are locked, and it becomes substantially impossible to further bend the outlet 15 with respect to the receptacle 16.

FIG. 4 (A) shows another example of the stopper portion composed of the above-mentioned locking projection and stopper projection.
17d is a protrusion for stopper in the middle of packings 4 and 5.
The example of FIGS. 3 (A) to 3 (C) has the same structure except that 18d is formed at the corresponding position.

And in this example as well, as shown in FIG.
In the state where 7 and the receiving opening 18 are connected in a straight line, there is a gap 7 between the locking projection 17d and the stopper projection 18d, so that they are not locked, but as shown in FIG. 4 (C). When the connection projection is bent, the stopper projection 18d and the locking projection 17d are engaged with each other, so that both are locked and it becomes impossible to further bend the insertion opening 17 with respect to the receiving opening 18.

The above description is for a case where a straight pipe is used as the connecting pipe, the outlet pipe or the receiving pipe, and a plurality of these pipes are connected. However, curved pipes are used for these connecting pipes, etc. Of course, the present invention can also be applied to the case where pipes and curved pipes or curved pipes are connected to each other.

<Effects of the Invention> As described above, according to the underground electric wire burying protection tube of the present invention, the relative engagement between the insertion opening and the receiving opening is achieved by the stopper portion including the concave groove or the locking projection and the stopper projection. The movable range is reliably limited within a certain range.

As a result, it will not be bent to a curvature beyond the movable range, and it is possible to reliably prevent the deterioration of the sealing property at the connection part and the occurrence of disconnection due to excessive bending, so protect the wire cable securely. Is possible.

[Brief description of drawings]

1 (A) is a sectional view showing a straight state of a protective tube for embedding an underground wire according to an embodiment of the present invention, and FIG. 1 (B) is a sectional view showing the same bent state, Figures (A) to (C) are explanatory views of a connecting portion in the embodiment, FIG. 2 (D) is an explanatory view of a modified example thereof, and FIGS. 3 (A) to (C) are connecting portions in other embodiments. And FIGS. 4 (A) to 4 (C) are explanatory views of the modification. 1 ... Connection pipe, 2 ... Outlet pipe, 3 ... Receiving pipe, 11, 13, 1
5, 17, 31 ... outlet, 12, 14, 16, 18, 22 ... receptacle,
4,5 ... Packing.

Claims (2)

[Scope of utility model registration request] Claim: What is claimed is: 1. One of the connecting portions for connecting a plurality of pipes is an opening formed by a spherical bulging portion, and the other of the connecting portions is a spherical shape rotatably fitted to the spherical bulging portion. In a protective tube for embedding an underground wire in which a receiving opening having an inner peripheral surface is provided and annular packings are respectively provided on both sides of the maximum bulging portion of the spherical bulging portion to seal the spherical bulging portion between both packings. A protective tube for embedding an underground wire in which a recess groove is formed, and a stopper projection that is loosely fitted in the recess groove is provided on the spherical inner peripheral surface. 2. A spherical surface in which one of the connecting portions for connecting a plurality of pipes has an opening formed by a spherical bulging portion and the other of the connecting portions is rotatably fitted to the spherical bulging portion. In a protective tube for embedding an underground electric wire in which a ring-shaped inner peripheral surface is provided and an annular packing is provided on both sides of the maximum bulging portion of the spherical bulging portion, the outer surface of the spherical bulging portion is engaged. A protective tube for embedding an underground wire, wherein a stop projection is formed and a stopper projection engaged with the locking projection is provided on the spherical inner peripheral surface.