JPH0449430Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a flexible joint used when connecting concrete pipes.

[Conventional technology]

At present, joint structures such as those shown in FIGS. 1 to 6 are used to connect concrete pipes such as humid pipes.

Figure 1 shows the joint structure of the most popular concrete pipe called B-type pipe.
The rubber ring a attempts to stop water, but
If the accuracy of the inner surface finish of the socket b is poor, the water-stopping performance will be reduced and there will be a drawback that it will not be able to follow displacement due to uneven settlement or the like.

Figure 2 shows the joint structure of a concrete pipe called a C-shaped pipe, but it has the disadvantage that even slight deformation reduces water-stopping performance and that it cannot follow displacement due to uneven settlement.

The joint structures shown in Figures 3 and 4 show the joint structure of the propulsion tube, but not only do they have the disadvantage of not being able to follow displacement due to uneven settlement, etc., but the structure shown in Figure 3 also When manufacturing the propulsion tube, there is a drawback that it cannot be manufactured at a low price because it cannot be punched and molded using split molding, and the structure shown in Fig. 4 also has the drawback that the embedded collar d is easily damaged during transportation. .

Improvements to the joint structure mentioned above have been proposed, such as improving the structure of the joint or changing the material or shape of the sealing material. We have not yet reached the point where we are satisfied in terms of cost, etc.

In addition, due to uneven settlement of the buried ground, bending or shear stress is generated at the joint of the pipe, causing the joint to deform, reducing the water-stopping properties of the joint, and causing the pipe to collapse. Phenomena such as cracking have been observed.

In order to improve these problems, structures have been proposed that can follow deformation by providing flexibility when bending or shear stress occurs.

Figures 5 and 6 show an example of this, and the one shown in Figure 5 has a rubber ring e with a T-shaped cross section in the center of the tube to give it flexibility. Since a mold must be set and molded during manufacturing, there is a drawback that mass productivity is poor.

In addition, f in FIG. 5 is a steel plate, and g is an anchor reinforcement.

The method shown in FIG.
However, the structure of the flexible joint h is complicated and expensive.

In FIG. 6, i is a metal band, j is a soft rubber ring, and k is a sponge ring.

[The problem that the idea aims to solve]

Therefore, the object of this invention is to provide a flexible joint that has a simple structure, can be provided at low cost, and has excellent watertightness.

[Means to solve the problem]

The present invention has been made to solve the above problems, and includes an outer ring fitted on the outer periphery of both ends of a rubber cylinder, and a water-swellable member that swells when the inner side of the outer ring comes into contact with water. It has a structure in which a plurality of circumferential protrusions are provided on the inner surface of the water-swellable member.

[Effect]

By making the inner diameter of the ridges slightly smaller than the outer circumference of the concrete pipe, the water-swellable member swells when it comes into contact with water, and its multiple ridges come into close surface contact with the outer surface of the concrete pipe. This results in a joint structure with excellent water-tightness and water-stopping effects.

〔Example〕

Example 1 Figure 7 shows an example of implementing the present invention.
is a hard rubber cylinder (main body); 2, 2 is an outer ring made of a rigid material such as metal, plastic, or vinyl chloride, which is fitted into the recesses 1a, 1a on the outer periphery of both ends;
3, 3 is a water-swellable member that swells in contact with water (for example, foamed urethane, water-swellable rubber, etc.) forming the inner side of the cylindrical body of the rigid outer peripheral rings 2, 2; ) is a circumferential protrusion made slightly smaller than the outside diameter of the concrete pipe.

As described above, the outer circumferential rings 2, 2 are provided on the outer periphery of both sides of the rubber cylinder 1, and the inner part thereof is composed of the water-swellable members 3, 3 that swell when in contact with water, and the inner surface of the water-swellable member is provided with a plurality of outer rings 2, 2. Since the structure is provided with the protrusions 4, 4, there are the following advantages.

When laying a concrete pipe, insertion and fitting between the concrete pipe and a flexible joint can be performed reliably and easily.

The watertightness of the joint can be improved.

When shearing or bending stress occurs in a concrete pipe due to uneven ground subsidence, the flexible joint can follow the deformation and prevent damage such as cracking of the concrete pipe.

Embodiment 2 FIG. 8 shows a modification of the one shown in Embodiment 1, in which a concrete pipe P ₁ , which is inserted and fitted at both ends.
For positioning _P2 , there is a protrusion B on the inner surface of the center part A.
was formed.

Embodiment 3 Figure 9 shows a different embodiment of the present invention.
In contrast to the ridges shown in Figures 7 and 8, which had serrated ridges, the ridges 4' have a tail-like cross section, making it easier to insert and fit the concrete pipe. It has the effect of

In the embodiment of the present invention, the outer rings 2, 2 are attached to the outer periphery of both ends to prevent the composite rubber body from turning over when the pipes are joined, and to prevent the water-swellable member from swelling after the pipes are joined. This enhances the adhesion effect to the concrete pipe and improves the water-stopping properties of the joint.

In particular, the feature of this invention is that, unlike the conventional "line" water stopping method using a rubber ring, the "surface" water stopping method is achieved by contacting the entire inner circumference of the composite rubber body with the outer circumference of the pipe end. Water-swelling members 3, 3, which are water-stop type and swell when the inner circumferential portion of the outer ring comes into contact with water, are attached to the outer circumferential surface of the concrete pipe,
Since the outer ring and the cylinder are restrained from three directions, when the water-swellable member performs a swelling action, the compaction property becomes greater.
This makes it possible to extremely effectively improve the water-stopping properties of the joint.

[Effect of idea]

Compared to the conventional structure shown in Fig. 6, the present invention has the following features:
It has a simple structure, can be provided at low cost, and has the effect of improving workability, watertightness, and flexibility when laying concrete pipes.

[Brief explanation of the drawing]

1 to 6 are sectional views showing a conventional concrete pipe joint structure, and FIGS. 7 to 9 are sectional views of embodiments of the present invention, respectively. 1...Rubber cylinder, 2...Outer ring, 3...
Water-swellable member, 4...Protrusion.

Claims (1)

[Scope of utility model registration request] Outer rings 2, 2 are fitted to the outer periphery of both ends of the rubber cylinder 1, and the inner side of the cylinder of the outer rings 2, 2 is composed of water swelling members 3, 3 that swell when in contact with water. A flexible joint characterized in that a plurality of circumferential protrusions are provided on the inner surfaces of the members 3, 3.