JP3520187B2 - Fitting for soft synthetic resin pipe - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint used for a soft synthetic resin pipe, for example, a polyethylene pipe for water supply. 2. Description of the Prior Art FIG. 2 shows a conventional joint comprising a metal connection socket 21 and an outer ring 22 and a polyethylene pipe 1.
0 is connected between the connection socket 21 and the outer ring 22. In addition, irregularities are formed on the outer surface of the connection socket 21 to prevent the connection socket 21 from coming off. However, the joint shown in FIG. 2 has sufficient connection strength in normal times, but has a problem in the earthquake resistance when an earthquake occurs. Because, in this joint, when a tensile load is applied at a speed of 50 mm / min after pipe connection, stress concentrates on the joint between the connection socket and the polyethylene pipe, and local elongation occurs near point P in FIG. Eventually, the polyethylene tube will break at this location. For seismic resistance, polyethylene pipes must be full length and not stretched locally, but entirely stretched. As described above, the conventional joint has strength against a load acting slowly, but is weak against a sudden load and does not have earthquake resistance. An object of the present invention is to solve this problem and to provide a joint for a soft synthetic resin pipe which does not cause local elongation even under a sudden load and has excellent earthquake resistance. [0005] The technical means of the joint for a soft synthetic resin pipe of the present invention is to fit the end of the soft synthetic resin pipe.
A connection socket and an outer ring fitted on the outside of the pipe .
A tapered diameter area is formed, and further, an inclined area serving as a relief surface is formed on the distal end side, and the slope of the inclined area is gentle, and the surface is subjected to surface processing to increase a slip resistance value. Is to be. An embodiment of a joint according to the present invention will be described with reference to an embodiment shown in the drawings. The joint of the present invention is made of metal such as stainless steel, and has a connection socket 1.
And an outer ring 2. FIG. 1 shows a state in which a polyethylene pipe 10 for water supply is connected. The present invention can be used by being assembled to a pipe connection part of a device such as a valve in addition to a joint as an independent member. In this case, the connection socket 1 becomes a part of the device. The tube connection surface 3 of the connection socket 1 is divided into three sections in the longitudinal direction. Among them, the area A on the proximal end side is the same diameter area, and the outer diameter dimension in this area is the same. The middle B area is a gradually reducing diameter area, and its outer diameter is gradually narrowed toward the distal end side with a gradient θ of 1 to 2 °. Tip C
The area is an inclined area serving as a relief surface, and is inclined toward the tip at a gentle inclination angle of about 10 to 30 °. The slope of this C area is extremely important, and if this is steep,
Since the stress concentration occurs and local elongation occurs, the slope must be gentle enough. Besides, this C
On the surface of the area, surface treatment 4 to increase the slip resistance
is necessary. As surface treatment to increase this resistance value,
The formation of small irregularities, labyrinth processing, knurl processing, sand plast processing, etc. are suitable. If the surface of the area C is smooth, stress cannot be dispersed and local elongation is caused. It is preferable to form ring-shaped irregularities 5 on the surfaces of both the areas A and B for retaining and dispersing stress. Particularly, in the area B, providing a gradient of about 1 to 2 degrees and forming irregularities is effective in dispersing stress. The method of connecting the joint to the polyethylene pipe according to the present invention is the same as the conventional one. First, the end of the polyethylene pipe 10 is fitted into the connection socket 1 and then the outer ring 2 is fitted outside. An appropriate tool is used for this fitting. When the outer ring 2 is fitted, the polyethylene tube 10 is strongly tightened from the outside, and bites into the irregularities on the outer surface of the socket 1, so that the bonding strength is increased and the polyethylene tube 10 does not easily come off. In addition, even when subjected to sudden tension, since the stress at the joint is dispersed, local elongation does not occur, and the polyethylene pipe is extended entirely, so that the pipe does not break. The present invention is not limited to the above embodiment, but can be freely modified and implemented within the scope of the claims. In particular, the type of surface processing in the C area is free. Further, the present invention can be used by assembling it to a device such as a water valve. According to the joint for a soft synthetic resin pipe of the present invention, the pipe connecting surface of the connection socket has a tapered diameter section having a gradient of 1 to 2 °.
And the slope area where the slope is gentle and the relief surface
And increase the sliding resistance on the surface of the sloped area
Since surface treatment is applied, even if a sudden tensile load is applied after pipe connection, the stress acting on the joint will not be concentrated but will be dispersed, local elongation will not occur, and soft synthetic The entire length of the resin tube is extended, and therefore, the resin tube has high earthquake resistance and does not break due to local elongation unlike the conventional product. [0013]

[Brief description of the drawings] FIG. 1 is a sectional view of a main part of a joint of the present invention in a pipe-connected state. FIG. 2 is a sectional view of a conventional joint. [Explanation of symbols] 1 Connection socket 2 outer ring 3 Pipe connection surface 4 Surface processing 5 Ring-shaped irregularities A area of the same diameter B Reducing diameter area C slope area

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16L 21/00-25/02 F16L 47/06

Claims (1)

(57) [Claims 1] A connecting socket for fitting an end of a soft synthetic resin tube, and an outer ring fitted on the outside of the tube, and a connecting surface of the connecting socket is 1 mm. Reducing diameter of ~ 2 ° gradient
An area is formed, and an inclined area serving as a relief surface is formed on the tip side of the area. The slope of the inclined area is gentle, and the surface is subjected to a surface treatment to increase a slip resistance value. Joint for resin pipe.