JPH0122520B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a plastic tube socket.

As shown in Fig. 1, the plastic tube socket has a groove 1' for attaching a rubber ring, and a reversely tapered pocket 2' is provided behind the groove 1'. It is known that the tip end 11' of the bottom surface of the ring mounting groove is locally recessed.

At the socket of this plastic pipe, even if an external bending force M' is applied to the plastic pipe as shown in Fig. 1 due to ground subsidence, etc., the socket 3' of the plastic pipe will not reach the socket of the plastic pipe. ,
Since it is tiltable due to the presence of the pocket 2', the above-mentioned external bending force can be absorbed by the joint of the plastic tube.

In addition, when inserting the plastic tube socket into the plastic tube socket, the rubber ring is locked in the local recess of the rubber ring mounting groove, so the rubber ring does not come out and the plastic pipe socket does not slip out. The insertion work can be carried out smoothly.

As mentioned above, in the socket shown in Figure 1,
Although the bending force acting on the plastic tube can be absorbed by allowing the insertion port 3' to tilt, the compressed state of the rubber ring 4' changes as the insertion port 3' tilts.

In FIG. 1, the maximum strain rate of the tail portion 40' of the rubber ring 4' is Δh/h, with the upper side A being a compressive strain and the lower side B being an extensional strain. However, over the long term, rubber rings are subject to repeated compression and extensional strains due to ground movement, but when the strain rate is large, there is concern that the elasticity of the rubber ring may decrease. be done.

The plastic tube socket according to the present invention was invented in view of the above-mentioned points, and has a groove for attaching a rubber ring, and has an inverted tapered pocket behind the groove, Moreover, in the plastic tube socket in which the tip of the bottom surface of the rubber ring mounting groove is locally recessed, the bottom surface of the rubber ring mounting groove behind the local recess is formed into an inverted tapered surface. It is.

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

In Figure 2, 1 is a groove for attaching a rubber ring, 2 is a groove for attaching a rubber ring;
is the reversely tapered pocket behind the groove for attaching the rubber ring.

Reference numeral 11 denotes a local recess provided at the tip of the groove surface for attaching a rubber ring. The rubber ring mounting groove bottom portion 12 at the rear of the local recess 11 is an inverted tapered surface in the same direction as the inverted tapered surface constituting the pocket portion 2.

In FIG. 1, reference numeral 4 indicates a rubber ring, which is provided with a tail portion 40.

FIG. 3 shows a plastic tube joint with a spout inserted into the socket of the present invention, with the spout tilted relative to the socket.

In FIG. 3, ΔT is the maximum strain of the rubber ring tail due to the tilting of the insertion port. The dashed line indicates the state when the insertion port is not tilted, and T is the thickness of the maximum thickness portion of the rubber ring tail in this state. Therefore, the maximum strain rate of the rubber ring tail due to the tilting of the socket is ΔT/T.

In FIG. 3, the dotted line hypothetically indicates a conventional socket in which the bottom surface of the rubber ring mounting groove 11 is a flat surface. Even in this conventional socket, the maximum strain of the rubber ring tail due to the tilting of the socket is ΔT, which is the same as in the case of the socket of the present invention. However, in the conventional socket, the thickness T' of the maximum thickness portion of the rubber ring tail when the socket is not tilted is smaller than the thickness T in the case of the socket of the present invention described above.

Therefore, according to the socket of the present invention, the maximum strain rate ΔT/T of the rubber ring tail when the socket is tilted is lower than the maximum strain rate ΔT/T' of the rubber ring tail in the conventional socket. can also be made smaller.

As described above, in a socket that can absorb external bending force of a plastic pipe, the present invention reduces the strain rate of the rubber ring that occurs due to the tilting of the socket within the socket to absorb the external bending force. Since the rubber ring can be made smaller than the socket, the initial elasticity of the rubber ring can be maintained well. Furthermore, since the strain rate is small, the insertion force can be made smaller than in the past.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a plastic pipe joint using a conventional socket, FIG. 2 is an explanatory diagram showing a plastic pipe socket according to the present invention, and FIG. 3 is an explanatory diagram showing a plastic pipe joint according to the present invention. FIG. 3 is an explanatory diagram showing a plastic tube joint using a spout. In the figure, 1 is a rubber ring mounting groove, 11 is a recess, 12 is a reverse tapered surface, and 2 is a pocket.

Claims (1)

[Claims] 1. A plastic tube socket having a groove for attaching a rubber ring, an inverted tapered pocket behind the groove, and a locally recessed tip at the bottom of the groove for attaching the rubber ring. . A socket for a plastic pipe, characterized in that the bottom surface of the groove for attaching a rubber ring at the rear of the local recess is an inverted tapered surface.