JPS6021276B2 - Expanded diameter socket for synthetic resin pipe - Google Patents

Description

[Detailed description of the invention] The present invention relates to a receiving box formed by expanding one end of a synthetic resin pipe.
Regarding the configuration, in particular, a groove for loading the rubber ring is formed on the inner circumferential surface of the socket to stably hold the rubber ring, and the rubber ring seals and holds the insertion pipe and connects the insertion pipe and the socket. This relates to the shape of the socket configured to allow slight bending with □.

As a pipe socket for buried resin pipes, especially for low pressure, the first
The one shown in the figure (partially sectional side view) is known.

That is, the socket 2 formed at one end of the pipe is the insertion pipe 3.
The diameter is enlarged to form a slight gap between the two, and a groove 4 is formed in the gap to stably hold the rubber roller 5. The insertion pipe 3 is held in the socket 2 while being sealed by a rubber ring 5, and a gap 7 is formed on the open side of the socket 2, and a gap 6 is formed on the back side. Therefore, the insertion pipe 3 and the socket 2 have a structure that allows them to bend slightly with respect to each other. It is possible to perform insertion joints, and even if the pipe joint bends due to external force such as a tonosho after being buried, it can adapt to this, and the joint can be easily bent due to concentrated stress. Prevents damage to nearby areas. However, since the buried resin pipe as described above generally has a property of being easily flattened, there is a risk that an accident such as the rubber ring 5 coming off due to the action of external force may occur especially when it is used as a buried pipe.

That is, FIGS. 2 and 3 show the left side of FIG.
The figure shows a state in which the insertion pipe 3 is correctly held in the receiving part 2 via the rubber ring 5, and the gap 7 is formed evenly around the entire circumference. In this state, even if the soil as shown by arrow A in FIG. 1 acts, the entire socket will only be displaced along with the ground, and accidents such as the rubber slipping out of the socket 2 will not occur. However, when the receiving part 2 and the insertion pipe are bent with respect to each other, if the pressure force exclusively pressurizes the insertion pipe 3, the gap 7 will be 7' above as shown in FIG. The receiving part 2 is often made thicker overall than the main pipe part for the purpose of improving water pressure resistance. As can be seen in the figure, since it has a curved structure along the pipe axis direction, it has considerably higher rigidity than the insertion pipe 3.

Therefore, for the state shown in Figure 3, the receiving part 2 and the insertion pipe 3
Even if a larger external force is applied to flatten the insertion pipe 3, as shown in Fig. 4, the flattening of the receiving part 2 will not be that much. does not proceed. In other words, an excessively large gap as shown by 8 is formed, and the rubber ring 5 is likely to escape, leading to a water leakage accident. If you want to avoid this situation and create an ideal flattened situation as shown in Figure 5, the gap 6 shown in Figure 1 will be
, 7, it is not unthinkable to create a dense structure that does not cause the bending of the socket 2 and the insertion pipe, and to improve the followability of the socket 2 and the insertion pipe so that the flattening behavior of both is the same. Therefore, it falls outside the scope of the flexible joint that is the aim of the present invention. However, the socket part 2
There are many problems in reducing the overall wall thickness from the viewpoint of improving water pressure resistance. The present invention has been made with attention to these circumstances, and it has been developed to separate parts that particularly require water pressure resistance from those that do not. This was completed with the aim of reducing the rigidity as much as possible by improving the bending structure within the limits that can prevent the escape of the rubber theory. Therefore, the gist of the present invention is that a groove for loading rubber and a gap for allowing insertion pipe to be inserted are formed on the inner peripheral side of a socket portion formed by expanding one end of a synthetic resin pipe. In the enlarged diameter receiver □, which is formed to allow bending by supporting the pipe with a rubber ring loaded in the rubber ring loading groove, the receiver □ has a slight gap between its closed end green and the inserted pipe. The expansion socket is formed with a parallel insertion port that maintains a gap, and the stool movement allowing gap is formed with a diameter that forms a larger gap than the gap in the parallel insertion port, and the wall thickness of the expansion socket is Form the back side of the socket from the rubber loading part to be thicker than the receiving opening side, and also make the rubber bearing groove slope formed at the receiving entrance side of the rubber loading groove at least 300 to 600 with respect to the pipe axis. It exists at a point formed with an angle of inclination within

The present invention will be explained in detail below based on the drawings. The drawings show a case where the present invention is applied to a conventionally known extension socket as an example of a specific implementation. It is not limited to the shape of the socket, and the design of the flange shape, stepped portion, etc. can be freely changed and implemented. Expanding the diameter refers to a state in which a part of the pipe wall is expanded, and is inserted into the end of a core-shaped pipe, or is formed by wrapping a pipe forming material around a core. The expansion socket □ of the present invention can also be applied to blow molding when a means for regulating the wall thickness is used in advance. The figure shows a molding method that uses commonly used inner and outer molds and expands while increasing the thickness. FIG. 6 is an enlarged view of a part of the expansion socket 2 according to the present invention. In other words, the ○ line part of the socket part 2 serves as a fulcrum, and the sockets are formed at a distance of C on the open side and a distance of D on the back side of the socket, and generally C<D.
There is a relationship between Further, since the joint is constructed to allow slight bending as described above, the gap 7 and cavity 6 as described above are formed on both sides of the fulcrum. The gap 6 is formed to have a larger diameter than the outer diameter of the insertion pipe and communicates with the inside of the pipe, and the water pressure inside the pipe acts on the peripheral wall of the socket 2 as shown by arrow B from these gaps. The water pressure also directly acts on the front surface of the rubber tube 5, as shown by 8, and tries to move the rubber tube 5 in the direction shown by the arrow. In other words, pressure is applied in the escape direction. However, the slope formed in Rubber Theory 5,
The slanted surface formed in the receiving part 2 joins together to support the above-mentioned pressure, and is supported by a thrust that moves the holding part 5' of the rubber ring 5 into the gap 7. That is, if the angle 8 formed by the sloped surface on the receiving port side with the tube axis becomes an acute angle, the thrust will increase, promoting entrapment, making it easier to escape, or impairing the sealing performance. On the other hand, in push molding or cover molding, it is difficult to increase the angle 8 of the inclined surface. According to experiments conducted by the present inventors, it has been found that when the inclination angle 8 is made smaller than 300, the rubber wheel 5 becomes easier to escape due to the bending of the joint. Therefore, it is necessary to set the inclination angle to 30 degrees or more. In addition, if the inclination angle is increased as described above, it will be difficult for the resin material to conform to the mold for forming the undercut portion, and if you try to force the resin material to conform to the mold forcibly, a large amount of pressure will be applied by the outer mold, resulting in a decrease in wall thickness. Can't hold it. In addition, in a method of manufacturing a tube body by winding a molding material around the outer periphery of a core mold to form the inclination angle, the retainability of the wrapped molding material deteriorates as the inclination angle becomes large. From these points, it was learned that the oblique angle must be within 60 degrees. By setting the angle within the above range, the holding ability of the rubber ring 5 is increased and escape is prevented, and it becomes possible to suppress the rigidity of the receiver 2 from becoming high. On the other hand, in diameter-expanding socket molding by secondary forming, the pipe wall of the socket part is reduced, so a method of increasing the wall thickness while expanding the diameter is known.

The mainstream of these methods is to press-fit resin material into the wide hollow space, but these thickenings are generally performed on the entire receiving area, so it is absolutely essential. Unfortunately, it must be said that the ideas regarding whether or not this is the case are insufficient. Therefore, the inventors of the present invention investigated which part of the receiving part 2 actually requires an increase in thickness. As a result, as shown in Figure 6, it was found that the socket part D, which is subject to the water pressure B, requires the most thickening, while the part C, which supports the rubber theory 5, does not require as much wall thickness as the above-mentioned part D. Ta. In addition, this C portion is a part that has many difficulties in molding. Therefore, as shown in FIG. 7, the entire enlarged portion is formed to be thicker than the wall of the receiving tube 1, but we thought that it would be sufficient to make only the portion D particularly thick. That is, the present invention accepts □
If the wall thickness of the tube body is T3, the wall thickness of the C portion is T1, T.
I′, TI″, TI′″ are formed by increasing the thickness from T3,
T2, T2', T2'', T2 river of D part is further T1, T
The thickness is increased from the I′ and TI″ parts (T2...>T
1...>T3). In this way, it has been found that the TI only needs to be thick enough to prevent the rubber ring 5 from coming off due to water pressure, and can be sufficiently utilized even if it is formed thinner than the T2 portion. Under such wall thickness conditions, it is easy to perform thickening molding, and it has become possible to achieve a beautiful striped finish by thickening molding in areas that were difficult to mold. FIG. 8 shows an example of a mold for forming the expanded socket portion of the present invention by a push-molding means, and the mold 9 includes an inner mold (core mold) 1.
0 and an outer mold 11, a core mold 101 is configured such that a slide piece forming the groove for attaching the rubber member protrudes and retracts, and the inner surface of the outer mold 11 composed of a split mold and a core. A sky striped portion 12 meeting the above-mentioned conditions is formed between the mold 10 and the mold 10 . A suitably heated socket tube 1 is then pushed into these molds 9, filling the hollow portion 12 and forming the mold. If necessary, a sleeve may be provided at the rear end of the hollow portion 12 and moved in the direction opposite to the pushing direction to increase the thickness. As mentioned above, the synthetic resin pipe of the present invention can be widely used.
The closed end of the section is formed by a parallel insertion port with a slight gap between the seeding pipe and the insertion pipe, and the insertion tip of the insertion pipe is formed with a larger inner diameter than the parallel insertion port. The part C on the closed side from the support part of the included pipe is formed to be thicker than the wall of the receiving pipe, and the part D on the far side from the support part is formed to be thicker than the part C on the closed side. Since it is formed so that it is between 30o and 60o from the pipe axis, there is no accident of rubber escape even if considerable bending is applied to the joint.
Moreover, when molding the receiving part, unnecessary parts are not increased in thickness, making the molding operation simple and easy, and saving materials.
In addition, it has become possible to reduce the weight and provide a joint pipe with excellent performance at a low cost.

[Brief explanation of the drawing]

Fig. 1 is a partially cross-sectional side view illustrating an expanded diameter joint of a resin pipe, Figs. 2 and 3 are explanatory left side views of Fig. 1 showing a deformed state, and Figs. 4 and 5. The figures are Figures 2 and 3.
An explanatory diagram vaguely showing the changes in the figure, FIG. 6 is a partial cross-sectional explanatory diagram of the socket part according to the present invention, and FIG. 7 is a configuration of the present invention shown with the insertion pipe of FIG. 6 removed. The explanatory diagram, FIG. 8, is a partially cutaway side view showing an example of a mold. 1...Socket pipe, 2...Socket part, 3...
...Insertion pipe, 4...Stepped groove, 5...
・Rubber wheel, 6...Gap, 7, 8...
-Gap, 9...Mold, 10...Inner mold, 11...Outer mold, 12...Void. Figure 1 Figure 2 Figure 3 Figure 5 Figure 6 Figure 8

Claims (1)

[Claims] 1 A rubber ring loading groove and an insertion pipe tilting allowance space are formed on the inner peripheral side of the socket portion formed by expanding the diameter of one end of the synthetic resin pipe, and the insertion pipe is inserted into the rubber ring loading groove. In an enlarged-diameter socket formed to allow bending by being supported by a rubber ring loaded in the socket, the opening edge of the socket can be inserted parallel to the insertion pipe so that a slight gap is maintained between the opening edge and the insertion pipe. At the same time, the tilting allowable gap is formed with a diameter that forms a larger gap than the gap in the parallel insertion port, and the wall thickness of the enlarged diameter socket is from the rubber ring loading part to the back of the socket. The side is thicker than the socket opening side, and the rubber ring contacting slope formed on the socket opening side of the rubber ring loading groove is formed at an angle of inclination of at least 30° to 60° with respect to the pipe axis. An enlarged diameter socket for synthetic resin pipes featuring: