JPH0623153Y2 - 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 of 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 fits a plurality of pipes in adjacent portions thereof with a spherical projection formed on at least a part of the outer peripheral surface, and rotatably fitted to the spherical projection. A protective tube which can be embedded in an underground electric wire, which is connected by a receiving port having an inner peripheral surface and which is provided with packing on both sides of the maximum bulging portion of the spherical convex portion, has been previously proposed (actual opening flat 3- No. 50922).

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 underground electric wire-embedded protective tube of the present invention has a connecting portion for connecting a plurality of pipes, one of which is formed by a spherical bulging portion and the other of the connecting portions. An underground cable embedded with a receptacle having a spherical inner peripheral surface rotatably fitted to the spherical bulging portion, and annular packings provided on both sides of the maximum bulging portion of the spherical bulging portion for sealing. In the universal tube, an outer peripheral groove is formed in the spherical portion bulging portion between the both packings, an inner peripheral groove overlapping the outer peripheral groove is provided on the spherical inner peripheral surface, and the outer peripheral groove and the inner peripheral groove are combined. The gist is that a stopper piece having a width smaller than the width of the annular space is provided in the annular space formed in the overlapping portion.

The outer peripheral groove or the inner peripheral groove may be an annular one continuously formed over the entire circumference of the outlet or the receiving opening, or may be intermittently formed in this annular space at an appropriate interval. .

When the outer peripheral groove and the inner peripheral groove are continuously formed over the entire circumference of the insertion opening or the receiving opening, the stopper piece may be formed into, for example, a ring shape. In a state where the receiving port and the receiving port are directly joined, the overlapping portion may be loosely fitted.

In order to achieve this loose fitting state, the inner diameter of the ring-shaped stopper piece is larger than the inner diameter of the inner peripheral groove and smaller than the outer diameter, and the outer diameter thereof is larger than the inner diameter of the outer peripheral groove and smaller than the outer diameter. .

Further, as the stopper piece, a ball-shaped piece having a diameter smaller than the width of the overlapping portion may be used, and a plurality of the stopper pieces may be provided at appropriate intervals in the overlapping portion.

Further, when the outer peripheral groove and the inner peripheral groove are provided intermittently as described above, a strip-shaped stopper piece is used,
It may be provided in each of these intermittent spaces.

<Operation> By using the stopper portion configured by providing the stopper piece in the overlapping portion of the outer peripheral groove and the inner peripheral groove as described above, the relative movable range of the outlet and the receiving port is limited within a certain range. To be done.

For this reason, the protective tube is not bent to a curvature exceeding the movable range at the connecting portion, and therefore it is possible to prevent the occurrence of leakage or disconnection at the connecting portion due to excessive bending.

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

The universal protective tube for burying electric wires of the embodiment shown in FIGS. 1 (A) and (B) is formed by connecting a plurality of straight pipes made of hard synthetic resin, and more specifically, inserted at both ends. A plurality of connecting pipes 1 each having a port 11 and a receiving port 12 are connected to each other by fitting the inlet port 11 and the receiving port 12 together, and the outlet port tube 2 having a receiving port 22 and the outlet port 31 are provided on both sides thereof. The socket pipes 3 provided 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 divergent end having a predetermined inclination. It is the surface 12b.

When the protective tube is bent, the end of the diverging surface 12b is locked on the outer peripheral surface of the spigot 11, so that the relative rotatable range between the spigot 12 and the spigot 11 is the whole of the spigot. It is temporarily regulated within the range of the solid angle θ formed by the divergent surface 12b in the peripheral 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, an outer peripheral groove 11d is formed in the spherical bulging portion 11a of the outlet 11, while the receiving opening 12 corresponding to the outer peripheral groove 11d.
An inner peripheral groove 12d is formed on the inner peripheral surface 12a. The outer peripheral groove 11d and the inner peripheral groove 12d are annular grooves having substantially the same width,
Further, as shown in FIG. 2 (B), the insertion port 11 and the receiving port 12 are provided at positions where they overlap each other when they are connected in a straight line.

On the other hand, in the annular space 7 formed in the overlapping portion of the outer peripheral groove 11d and the inner peripheral groove 12d in the state where the outlet 11 and the receiving opening 12 are connected straight, a ring shape made of metal or hard synthetic resin is formed. The stopper piece 6 is provided.

The outer diameter of the stopper piece 6 is substantially the same as the diameter of the bottom surface of the inner peripheral groove 12d, the inner diameter thereof is substantially the same as the diameter of the bottom surface of the outer peripheral groove 11d, and the width thereof is the annular space 7 described above. Therefore, the stopper piece 6 is loosely fitted in the annular space 7 so as to be movable in the left-right direction in the drawing.

2 (A) and 2 (B) show an example in which the stopper piece 6 is temporarily fixed in the inner peripheral groove 12d of the receiving opening 12 and the insertion opening 11 and the receiving opening 12 are fitted to each other. However, in addition to this, the stopper piece 6 is temporarily fixed in the outer peripheral groove 11d of the insertion port 11 and
Of course, the stopper piece 6 may be loosely fitted in the annular space 7 by fitting the receiving piece 11 and the receiving opening 12.

FIG. 2 (C) shows a connection state of the insertion port 11 and the receiving port 12 when the free electric wire burying protection tube of this embodiment is bent as shown in FIG. 1 (B). 11d and inner groove
The stopper pieces 6 provided in the overlapping portion with 12d abut on the right end of the outer peripheral groove 11d and the left end of the inner peripheral groove 12d, respectively.
It will be locked between these.

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.

<Effect of the Invention> As described above, according to the underground electric wire burying protection tube of the present invention, the outer peripheral groove is formed in the spherical bulging portion between both packings, and the inner peripheral groove overlapping the outer peripheral groove is formed. In addition to being provided on the spherical inner peripheral surface, a stopper piece having a width smaller than the width of the annular space is provided in the annular space formed in the overlapping portion of the outer peripheral groove and the inner peripheral groove. The relative movable range between the and the receiving port 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 the connecting portion in the embodiment. DESCRIPTION OF SYMBOLS 1 ... Connection pipe, 2 ... Outlet pipe, 3 ... Receiving pipe, 11,31 ... Outlet, 12,22 ... Receiving port, 4, 5 ... Packing, 6 ... Stopper piece.

Claims (1)

[Scope of utility model registration request] 1. A spout formed by a spherical bulging portion on one side of a connecting portion for connecting a plurality of pipes, and a spherical shape rotatably fitting the other side of the connecting portion on the spherical bulging portion. In a protective tube for embedding an underground wire in which an annular packing is provided on both sides of a maximum bulging portion of the spherical bulging portion as a receiving port having an inner peripheral surface, the spherical bulging portion between the packings is sealed. An outer peripheral groove is formed on the inner peripheral groove, and an inner peripheral groove that overlaps the outer peripheral groove is provided on the spherical inner peripheral surface, and the inner peripheral groove is formed in an overlapping portion of the outer peripheral groove and the inner peripheral groove. A protective tube for embedding underground electric wires, characterized in that a stopper piece having a width smaller than the width is provided.