JPH0214714Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a corrugated pipe whose connecting portion is required to have high watertightness.

[Conventional technology]

Corrugated pipes are strong, light, and highly flexible, so they are used for underground drainage pipes such as culvert drainage pipes, and protection pipes for laying and accommodating electrical cables. For example, when a corrugated pipe is used as an underdrain drainage pipe, strict watertightness is not required at the connection part. However, when a corrugated pipe is used as a protection pipe for electric wires, water is not allowed to enter the pipe, so strict watertightness is required at the connecting portion.

Conventionally, in order to ensure watertightness at the connection part, the ends of two corrugated pipes to be connected to each other were inserted into a cylindrical collar, butted together, and a sealing material was loaded between the collar and the corrugated pipe. It was hot.

[Problem that the invention attempts to solve]

As is well known, since the outer wall of a corrugated pipe has peaks and valleys, there is a problem in maintaining high watertightness over a long period of time using the above-mentioned conventional means.

In addition, according to the conventional means, when an external force in the direction of separating the two corrugated pipes is applied, the connecting portions tend to separate and create gaps, resulting in a lack of reliability in maintaining watertightness. It was hot too.

The purpose of this invention is to solve these conventional problems, and to provide a corrugated pipe that can firmly connect two corrugated pipes and also reliably maintain the watertightness of the connected part. do.

[Means for solving problems]

In order to solve the above problems, the corrugated pipe of the present invention has one to three peaks of the tube body, in which the valleys of the outer wall, in which peaks and valleys are formed alternately, are heat-sealed to the inner wall. A cylindrical body having a threaded groove, which is heat-sealed to the end and simultaneously injection molded with one to three of the ridges of the end crushed, is extended to the end including the end. It has a summary.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 indicates a corrugated pipe. The corrugated pipe 1 includes a pipe main body 5 having an outer wall 4 in which peaks 2 and valleys 3 are alternately formed, and a cylinder 6 extending from an end of the pipe main body 5.

As shown in FIG. 2, the tube body 5 of the illustrated example has the valley portion 3 of the outer wall 4 heat-sealed to the inner wall 7 having a smooth inner surface. Further, the cylindrical body 6 is provided with a spiral thread groove 8 on its outer periphery, and the inner surface of the cylindrical body 6 is formed on the inner wall 7.
It is smoothly continuous with the inner surface of the and,
The cylindrical body 6 is formed by injection molding, and at the same time as the injection molding, one end of the tube body 5 including one to three peaks 2 is attached as shown in FIG.
The three peaks 2 are crushed and heat-sealed to the end.

An example of a method for extending the cylindrical body 6 to the end of the tube body 5 will be described with reference to FIG. 3. As shown in FIG. After inserting the end portion A, a predetermined amount of molten resin is injected into the cylinder molding space S to injection mold the cylinder 6. At the same time, the end portion A of the tube body 5 and the cylindrical body 6 are heat-sealed together.

The mold 100 shown in FIG. 3 consists of a core 110 and an outer mold (split shape) 120. The core 110 has a neck 111 into which the end A of the tube body 5 is externally fitted, and the outer mold 120 has an uneven surface 121 that engages with the peaks 2 and troughs 3 of the tube body 5. Above molding space S
is configured to have a size such that a space _S1 is formed around the peak portion 2 inserted into the molding space S. Injection of the molten resin into the cylindrical molding space S of the mold 100 is performed, for example, through a resin injection port 122 provided in the outer mold 120. The molten resin injected into the cylindrical body molding space S flows due to the injection pressure at that time and fills the space S, and also
It wraps around the two peaks 2 and valleys 3. In that case, the end A of the tube body 5 is heated to a softening temperature within the mold 100, and the injection pressure acts on the end A, so that one to three peaks of the end A are heated to a softening temperature. 2 and the valley portion 3 are crushed and deformed by the molten resin, and are compatible with the molten resin and thermally fused. The synthetic resin used for injection molding of the tube body 6 must be the same as the synthetic resin constituting the tube body 5, or must be compatible with it. Note that if an uneven surface 121 is formed on the outer mold 120 as in the mold 100 shown in FIG. Since the portion 2a is backed up, the peak portion 2 is prevented from being crushed by the molten resin indefinitely. Therefore, in the heat-sealed portion between the tube body 5 and the cylindrical body 6, the above-mentioned rising portion 2a retains its original shape, which has the advantage that the appearance does not become unsightly.

Next, when connecting the corrugated pipe 1 described above, the socket 10 shown in FIG. 1 is used. This socket 10 is made of a cylindrical molded product having a spiral protrusion 11 on its inner surface, and as shown in FIG. Screw in the cylinders 6, 6. In this way, the two corrugated pipes 1, 1
The cylindrical bodies 6, 6 engage with the protrusion 11 of the socket 10 and are firmly connected. Furthermore, when screwing the socket 10 into the cylinders 6, 6, if a sealant or adhesive is applied to the outer surface of the cylinders 6, 6 or the inner surface of the socket 10, the connection between the cylinders 6, 6 and the socket 10 will be secured. The gaps in between are reliably closed and high watertightness is maintained.

In the above case, the helical directions of the protrusions 11 of the socket 10 are reversed between the right half and the left half of the socket 10, and the thread groove 8 of the cylinder 6 in one corrugated pipe 1 and the other corrugated pipe If the helical direction of the thread groove 8 of the cylindrical body 6 in 1 is reversed, the cylindrical bodies 6, 6 of the corrugated pipes 1, 1 are applied to each end of the socket 10, respectively, and then the socket 10 is rotated. As a result, the cylindrical bodies 6, 6 are screwed into the socket 10 and connected at the same time, so that the workability at the time of connection is improved. Therefore,
It is desirable that the corrugate 1 has a cylindrical body 6 having a right-handed helical thread groove 8 extending at one end thereof, and a cylindrical body 6 having a left-handed helical thread groove 8 extending from the other end thereof.

According to the corrugated pipe 1, FIGS. 4 and 5
As is clear from the figure, the heat-sealed area becomes a large area corresponding to the entire outer surface of two to three peaks 2 and the outer surface of the valley 3 between those peaks 2, and at the same time,
The heat-sealed part becomes thick and the strength of this part becomes extremely high. In FIG. 5, imaginary lines indicate the state of the peak portion 2 before the cylinder 6 is formed.

[Effect of idea]

The present invention can be carried out as described above, and two corrugated pipes can be connected by threading the thread groove of the cylinder into the protrusion of the socket.
A strong connection is made. Moreover, if a sealing material or adhesive is interposed between the cylindrical body and the cylindrical body at the same time as the cylindrical body is screwed into the socket, high watertightness can be reliably maintained after the connection. In particular, according to the present invention, the cylindrical body is heat-sealed to the end portion of the tube body including one to three peaks with the peaks crushed, so the heat-sealing area is considerably wide. As the thickness increases, the heat-sealed portion becomes thicker. Therefore, the strength of the heat-sealed part between the tube body and the cylindrical body is extremely high, and even when a large force is applied to the heat-sealed part when screwing the cylinder into a joint such as a socket, the heat-sealed part easily closes. It has the effect of not coming off.

[Brief explanation of drawings]

FIGS. 1 and 2 are partially cutaway side views showing the procedure for connecting corrugated pipes according to an embodiment of the present invention, and FIG. 3 is a sectional view of essential parts showing an example of the method for manufacturing the above-mentioned corrugated pipes. , FIG. 4 is a partially cutaway side view showing the main parts of a corrugated pipe according to another embodiment,
FIG. 5 is an enlarged sectional view of section A in FIG. 4. DESCRIPTION OF SYMBOLS 1... Corrugated pipe, 2... Peak, 3... Valley, 4... Outer wall, 5... Pipe body, 6... Cylindrical body, 8
... Thread groove on the cylinder body, A ... End of corrugated pipe.

Claims (1)

[Scope of utility model registration request] The troughs of the outer wall, in which ridges and troughs are alternately formed, are heat-sealed to the inner wall, and one to three of the ridges are attached to the end of the tube body including one to three of the ridges. A corrugated pipe formed by extending a cylindrical body having a screw groove that is heat-sealed to the end portion with the portion crushed and simultaneously injection molded.