JPH0213888B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a synthetic resin pipe with a socket.

(Prior Art) As a manufacturing method for this type of synthetic resin pipe, conventionally, as shown in Fig. 1A, a molded synthetic resin pipe 1
A rod-shaped heater, such as a far-infrared heater 20', is inserted into the tube end 11' of 0' to uniformly heat the tube end 11', and the tube end 11' softened by heating is heated as shown in FIG. There is a method of forming the socket 12' by inserting the socket into a mold 30' for molding a socket and expanding the diameter thereof.

(Problem to be solved by the invention) However, in the case of the above conventional method,
As the synthetic resin pipe 10' is extrapolated into the mold 30', the resistance between them increases. Phenomenon (A) such as buckling or buckling occurs near the socket shoulder 13' of the resin pipe 10', resulting in a defective product.

(Means for Solving the Problems) In view of the above-mentioned conventional problems, the present invention is capable of extrapolating a synthetic resin pipe into a socket molding die without causing phenomena such as buckling or buckling. The purpose of this invention is to provide a method for manufacturing a synthetic resin pipe with a socket that can be used to soften the pipe by inserting a rod-shaped heater into the end of the synthetic resin pipe, and then In a method for manufacturing a synthetic resin pipe with a socket, in which the diameter of the pipe is expanded by pushing the end of the pipe into a mold for molding the socket, a predetermined length on the tip side of the rod-shaped heater is set as a low wattage region, and the end of the synthetic resin pipe is set as an axis. The present invention resides in a method for manufacturing a synthetic resin pipe with a socket, which is characterized by non-uniform heating in the direction.

(Function) As mentioned above, since the predetermined length on the tip side of the rod-shaped heater is the low wattage region, the portion including the portion that becomes the socket shoulder corresponding to this low wattage region is
The hardness is higher when heated and softened than the part that becomes the socket. For this reason, even when the heated and softened tube end is force-fitted into a mold for molding a socket, the phenomenon of bending or buckling does not occur.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 2, a rod-shaped heater 40 is configured so that a predetermined length from its tip side is a low wattage region 41, and a high wattage region 42 is a portion 12a of the synthetic resin pipe 10 that is approximately the socket 12. The low wattage region 41 contributes to the heating of the shoulder 1 of the socket 12.
It is inserted into the pipe end 11 of the synthetic resin pipe 10 so as to contribute to the heating of the part 13a including the part 3.

Therefore, the pipe end 11 of the synthetic resin pipe 10 is heated to the conventional temperature by the high wattage region 42 of the rod-shaped heater 40 on the side 12a that will become the socket 12.
The portion 13a side including the portion that will become the socket shoulder portion 13 is heated to a lower temperature than before by the low wattage region 41 of the rod-shaped heater 40, creating a temperature gradient that slopes downward toward the inner part of the synthetic resin pipe 10. Since the hardness increases toward the center in the longitudinal direction, even when the tube end 11 is pressed into the mold 30, the phenomenon of buckling or buckling does not occur as in the conventional case, and as shown in FIG. As shown, the tube end 1
1 is smoothly extrapolated to the mold 30 until the end.

(Effects of the Invention) As described above, according to the present invention, by making a part of the rod-shaped heater into a low wattage region and heating the end portion of the synthetic resin pipe unevenly, the socket of the synthetic resin pipe is heated. Since it is possible to press-fit the area near the back of the part that will become the socket shoulder part, that is, the part that will become the shoulder part of the socket, with higher rigidity than before, it eliminates the above-mentioned buckling and buckling, and reduces the occurrence of defective products. can be significantly reduced compared to conventional methods.

[Brief explanation of drawings]

Figures 1A and 2B are partial cross-sectional side views for explaining the conventional manufacturing method, Figure 1C is a diagram for explaining the problems of the conventional manufacturing method, and Figure 2A and 2B are the invention of the present invention. FIG. 2 is a partially sectional side view for explaining a method of manufacturing a synthetic resin pipe with a socket. 10: Synthetic resin pipe, 11: Pipe end, 12: Socket, 13: Socket shoulder, 30: Socket mold, 4
0: rod-shaped heater, 41: low wattage region, 42: high wattage region.

Claims (1)

[Claims] 1. A method for manufacturing a synthetic resin pipe with a socket, in which a rod-shaped heater is inserted into the end of the synthetic resin pipe to soften it by heating, and then the pipe end is pushed into a socket molding die to expand the diameter. A method for manufacturing a synthetic resin pipe with a socket, characterized in that a predetermined length on the tip side of the rod-shaped heater is set in a low wattage region, and the end portion of the synthetic resin pipe is heated unevenly in the axial direction.