JPS6153597B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a universal joint for plastic pipes, which is used for constructing bent portions of pipes.

Conventionally, bent pipe fittings are used when constructing curved sections of pipes, but with these bent pipe joints, the bending angle is fixed, and the bending angle varies depending on the bending angle of the pipe bend to be constructed. The disadvantage is that many types of bent pipe joints must be prepared.

For this purpose, as shown in FIG. 5, the ends of the plastic joint pipes 1', 10' are bulged into spherical shell shapes 2', 3', and the inside of the bulge 2' of one joint pipe 1' is Then, attach the bulge 3' of the other joint pipe 10' to the rubber ring 12'.
A flexible bendable tube rotatably fitted via a flexure tube has been proposed.

In this freely bendable pipe, the mutual angle between the joint pipes 1' and 10' can be changed over a fairly wide range by the relative rotation of the spherical shell-like bulges 2' and 3', and the bending part of the pipe can be changed over a fairly wide range. , it can be constructed at any bending angle within a fairly wide range of bending angles.

However, when the freely bendable tube is at its maximum bending angle, that is, as shown in FIG.
When an external rotational force M' is applied to the flexible bending pipe while it is in contact with the base of the tube at point P', the tip of the inner bulge 3' is compressed by the contact pressure indicated by f', The tip of the outer bulge 2' is expanded by the same contact pressure f', and due to the cooperation of this compression and expansion, the spherical shell-like bulges 2' and 3' are finally separated. Arrive. Of course, it is effective to increase the thickness of the spherical shell-like bulges 2' and 3' to prevent separation of the spherical shell-like bulges, but in this case, it is necessary to increase the thickness of the spherical shell-like bulges 2' and 3'. This makes it extremely difficult to insert the bulged portion 3', which is disadvantageous for assembling the freely bendable pipe.

The universal joint for plastic pipes according to the present invention has a structure that is more advantageous than the above-mentioned flexible pipes in terms of both pull-out resistance and assembly. The fitting bulge is formed with a shell-like fitting bulge, has a spherical outer surface approximately equal to the inner diameter of the spherical shell-like bulge, and has a shape in which both sides of a spherical body are cut out. A more rigid adapter is rotatably fitted into the spherical shell-shaped bulge via a rubber ring, and a tube insertion port is provided through the adapter.

The present invention will be explained below with reference to the drawings.

In Fig. 1, 1 is a plastic tube;
As shown in the figure, a fitting bulge 2 having a maximum bulging inner diameter larger than the opening diameter is formed at one end. The rigidity of this fitting bulge 2 is rather small, and the bulge 2 can be formed by a method such as blow molding the end of the plastic tube 1. Of course, the tube portion 1 and the bulging portion 2 can also be integrally injection molded, and in this case, the wall thickness of the bulging portion 2 is made slightly thinner than that of the tube portion 1.

Reference numeral 3 designates a plastic pipe insertion adapter, the outer surface of which is spherical, and the outer peripheral surface has a rubber ring mounting groove 4, and the inner peripheral surface has a rubber ring mounting groove 5 on the tube insertion port side. It is provided.

This adapter 3 has a rigidity greater than that of the above-mentioned bulging portion 2, and is usually molded by injection molding. During this injection molding, in order to eliminate thermal stress distortion as much as possible, it is preferable to perform thinning 6, 7, and 7 on the tube insertion surface and the outer circumferential surface, as shown in FIG. In this case, it is desirable that ribs be provided at predetermined intervals in the circumferential direction at the portion where there is excess thickness. In Fig. 2, 8 and 8 indicate ribs provided in the grooves 7 and 7 on the outer circumferential surface, and Fig. 3 shows an example in which the removed flesh portion 6 is provided only on the inner circumferential surface and a rib 9 is formed. ing.

In FIG. 1, numeral 10 is a plastic tube having an insertion opening 11. As shown in FIG. 12 and 13 are rubber rings.

In the universal joint for plastic pipes of the present invention, it is preferable that the bulge be formed at one end of the hard vinyl chloride pipe by blow molding, and the adapter be molded by injection molding of the hard vinyl chloride.

The universal joint for plastic pipes of the present invention is assembled in the following manner.

That is, as shown in FIG. 4A, the adapter 3 is made so that its hollow axis a-a (see FIG. 4C) is substantially perpendicular to the central axis b-b of the spherical shell-shaped bulge 2. In this state, the adapter 3 is forcibly press-fitted into the spherical shell-like bulge 2 as shown in FIG. 4B. The outer shape of the adapter 3 at the time of this press-fitting is a shape in which both sides of a sphere are cut out, and the amount by which the entrance of the spherical shell-like bulging portion 2 must be deformed by pushing and expanding for this press-fitting becomes smaller accordingly. This means that when the adapter 3 is press-fitted by aligning the hollow axis a-a of the adapter 3 with the central axis b-b of the spherical shell-shaped bulge 2, the outer shape of the adapter 3 will be shaped like a spherical shell. This can be easily understood by assuming that the diameter is significantly larger than the inner shape of the entrance of the bulging portion 2.

In this way, the amount of deformation of the inlet of the spherical shell-shaped bulge 2 when the adapter is press-fitted can be reduced to a small amount, and the rigidity of the spherical shell-shaped bulge 2 is relatively small. Spherical shell-like bulge 2 shown in FIG. 4B
It is easy to press fit the adapter 3 inside.

As shown in FIG. 4B, after the adapter 3 is press-fitted into the spherical shell-like bulge 2, the adapter 3 is rotated so that the hollow axis a-a of the adapter 3 is aligned as shown in FIG. 4C. , the central axis bb of the spherical shell-like bulge 2
1, and then insert the insertion part 11 of the tube 10 into the adapter 3 as shown in FIG.

FIG. 1 shows the universal joint according to the present invention at its maximum bending angle, that is, with the tip 20 of the spherical shell-like bulge 2 in contact with the pipe insertion port 11 at point P. The situation is shown when an external rotational force M is applied to the . Spherical shell-like bulge 2 and adapter 3
A contact pressure f acts as a reaction force of the rotational moment centered on the point P mentioned above.
The compressive deformation of the adapter 3 due to this contact pressure f is kept to a small extent because the adapter 3 has high rigidity and the tube insertion port 11 inserted into the adapter 3 resists this deformation.
Therefore, only the spherical shell-like bulge 2 is substantially expanded, and the diameter of the adapter 3 is not reduced, so that escape of the adapter 3 from the spherical shell-like bulge 2 is sufficiently prevented. can.

In the universal joint shown in Fig. 1, even if a tensile force F is applied, this tensile force F is absorbed by the sliding of the tube inlet 11 within the adapter 3, and the adapter 3 expands into a spherical shell shape due to the tensile force F. Escape from exit 2 is not a problem.

As described above, the universal joint for plastic pipes according to the present invention is easy to assemble and has sufficient resistance to separation due to external rotational force.

Therefore, according to the present invention, it is possible to eliminate all of the disadvantages of conventional flexible tubes, such as difficulty in assembly and insufficient separation resistance against external rotational forces.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing a universal joint according to the present invention, FIGS. 2 and 3 are vertical cross-sectional views showing various examples of adapters used in the present invention, and FIG.
Figures A, 4B, and 4C are explanatory diagrams showing the assembly procedure of the universal joint of the present invention, Figure 5 is an explanatory diagram showing a known flexible tube, and Figure 6 is the flexible tube of Figure 5. It is an explanatory view showing the maximum bending state of. In the figure, 1 is a plastic tube, 2 is a spherical shell fitting bulge, 3 is a tube insertion adapter, 11 is a tube insertion opening, and 12 and 13 are rubber rings.

Claims (1)

[Claims] 1 At one end of the plastic tube, the maximum bulging inner diameter is
A spherical shell-shaped fitting bulge larger than the opening diameter is formed, has a spherical outer surface approximately equal to the inner diameter of the spherical shell-shaped bulge, and has a shape in which both sides of the spherical body are cut out; An adapter having greater rigidity than the spherical shell-like bulge is rotatably fitted into the spherical shell-like bulge via a rubber ring, and the adapter further includes:
A universal joint for plastic pipes characterized by having a pipe insertion port provided through the joints.