JP2835284B2 - Corrugated pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corrugated pipe made of a thermoplastic plastic, into which, for example, optical fibers, electric wires, communication lines and the like are inserted and buried in the soil.

[0002]

BACKGROUND OF THE INVENTION Optical fibers, electric wires,
The tubes used to protect communication lines and the like are corrugated to provide flexibility. The corrugated pipe is made of a thermoplastic material such as polyvinyl chloride, polyethylene, or polypropylene, and is provided with a metal core embedded to withstand the earth pressure.

[0003]

2. Description of the Related Art Conventionally, as shown in FIG.
A corrugated pipe (1) having (2) and a valley (3) and having a metal core (4) embedded therein is provided.

[0004]

The above conventional corrugated pipes (1) are connected to each other by a collar (5) as shown in FIG. 5, for example. It is necessary to fit a packing ring to the connection end of the corrugated pipe (1). But the corrugated tube
Since the peak (2) and the valley (3) in (1) are spiral, there is a problem that an annular packing ring cannot be fitted.

[0005]

According to the present invention, there is provided, as a means for solving the above-mentioned conventional problems, a thermoplastic resin having an annular crest (12) and a valley having a metal core (14) embedded therein. Corrugated pipe (11) made of plastic (15), said corrugated pipe
(11) is divided into a predetermined number of units (11A) at the positions of the peaks (12), and the units (11A) provide a corrugated pipe (11) that is electromagnetically bonded to each other.

[0006]

According to the present invention, the corrugated pipe (11) is divided into a predetermined number of units (11A) at the positions of the peaks (12), so that the corrugated metal core (14) can be easily manufactured by sheet metal working. Become. Further, since the connection of the unit (11A) is made at the peak (12), the thermoplastic layer (1) of the peak (12) is connected.
It is easy to partially soften 5) by electromagnetic induction. The corrugated pipe (11) of the present invention has an annular valley (13).
Therefore, it is possible to fit the packing ring (16) into the valley (13), and it is possible to enhance the airtightness of the connection portion by the collar (17) or the like.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to an embodiment shown in FIGS. 1 to 4. The corrugated pipe (11) shown in FIG.
(12) and a valley (13). The corrugated pipe (11) is divided into units (11A) at the center of each ridge (12) as shown in FIG. Each unit (11A) has a peripheral wall having a structure in which a metal core (14) is embedded in a thermoplastic layer (15) such as polyvinyl chloride, polyethylene, or polypropylene.

The units (11A) are joined in a predetermined number. To join the units (11A) together, as shown in FIG. 3, the heating coils (18) are joined by abutting the units (11A). The heating coil (18)
Then, the thermoplastic resin layer (15) at the butt portion is heated and softened by the electromagnetic induction by electromagnetic induction so as to adhere to each other. In this case, since the units (11A) are butted at the position of the peak (12), only the thermoplastic plastic layer (15) substantially at the butted portion is heated by electromagnetic induction.

Thus, as shown in FIG. 1, a corrugated pipe (11) in which a predetermined number of units (11A) are electromagnetically bonded at the positions of the ridges (12) is manufactured. )
For interconnection, a collar (17) is used as shown in FIG. In order to improve the airtightness of the connection part, a packing ring (1) is provided at the valley (13) at the connection end of the corrugated pipe (11).
6) is fitted.

In this embodiment, the unit (11A) of the corrugated pipe (11) uses the smallest unit divided at each peak (12), but two units (11A) of the smallest unit are used. Alternatively, three or more units may be used. However, if the unit is too long, sheet metal processing of the metal core (14) becomes difficult. Therefore, in the present invention, it is desirable to use a unit having three or less of the minimum unit.

[0011]

Thus, according to the present invention, a corrugated pipe made of a thermoplastic plastic having an annular crest and a valley and having a metal core embedded therein can be easily manufactured. A packing ring can be fitted to the connection end, and thus the airtightness of the connection portion can be improved.

[Brief description of the drawings]

 1 to 4 show one embodiment of the present invention.

FIG. 1 is a perspective view

FIG. 2 is a sectional view of a unit.

FIG. 3 is a sectional view of a unit connection state.

FIG. 4 is an explanatory view of a connection portion.

FIG. 5 is a conventional explanatory view.

[Explanation of symbols]

 11 Corrugated pipe 11A unit 12 Peak 13 Valley 14 Metal core 15 Thermoplastic layer 18 Heating coil

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-272535 (JP, A) JP-A-2-33990 (JP, U) Japanese Patent Publication No. 4-78875 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) H02G 9/06 F16L 11/11

Claims (1)

(57) [Claims] 1. A corrugated pipe made of thermoplastic plastic having an annular crest and a valley and having a metal core embedded therein, wherein the corrugated pipe is divided into a predetermined number of units at a position of the crest. Characterized in that the units are mutually electromagnetically bonded to each other.