JPS5944208B2 - Manufacturing method for synthetic resin branch joints - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a method of manufacturing a synthetic resin branch joint in which the diameter of the branch part is the same as that of the main pipe.

A branch joint can be manufactured by drilling a hole in the peripheral wall of a synthetic resin pipe, heating and softening the peripheral edge of the hole, and pulling out a mold having a diameter larger than the hole from inside the tube to raise the peripheral edge of the hole. well known.

However, since this method involves pulling out the mold placed inside the pipe, the size of the mold is limited, and the diameter of the rising part is smaller than the diameter of the synthetic resin pipe, and the diameter of the branching part is the same as the diameter of the synthetic resin pipe. It has been difficult to manufacture similar branch joints (same diameter cheeses). In view of the above points, this invention was completed as a result of intensive research with the aim of forming a branch part with the same diameter as the pipe in a synthetic resin pipe. The peripheral edge of the hole is heated and softened, and a substantially spherical mold is inserted into the tube, and the spherical mold is pulled outward from the hole to raise the peripheral edge and touch the rising part. In this state, a cylindrical mold having an outer diameter approximately equal to the outer diameter of the spherical mold is pushed into the tube from the outside while aligning the outer peripheral surface of the cylindrical mold with the inner surface of the rising part, and then the rising part is cooled. The method of manufacturing a synthetic resin branch joint is characterized in that the cylindrical mold and the spherical mold are then removed and a branch pipe is connected to the rising portion.

Next, the method of the invention will be further explained with reference to embodiments shown in the drawings.

4 is a synthetic resin pipe such as a hard vinyl chloride pipe, and a hole 11 can be bored in the center of this synthetic resin pipe 1.

The diameter of this hole 11 is of course smaller than the diameter of the resin tube 1, and may be an elliptical hole or an elongated hole that is long in the tube axis direction. The peripheral edge of this hole 44 is heated to soften it. The range to be softened by heating is preferably a width approximately equal to the radius of the synthetic resin tube 1 from the center of the hole 11. Next, a spherical mold 2 is inserted into the synthetic resin tube 1 (FIGS. 1 and 2). The chain 3 is locked to the hook hook 21 of the spherical mold 2 through the hole 11, and the chain 3 is pulled up and the spherical mold 2 is pulled outward, and the heated and softened peripheral edge of the hole 11 is connected to the outer periphery of the spherical mold 2. (Figure 2). Although the spherical mold 2 is not a perfect sphere in order to provide the hook hook 21, it is made of a substantially spherical metal hollow body whose diameter is approximately equal to the inner diameter of the synthetic resin tube 1. If only the periphery of the hole 11 is raised with the spherical mold 2, the rising part 12 will recover along the spherical surface of the spherical mold 2, and the inner diameter of the rising part 12 will cover the entire surface, since the rising part 12 has the property of restoring in a softened state. It is not equal to the outer diameter of the spherical mold 2 (Fig. 3). Therefore, while the spherical mold 2 remains in contact with the rising portion 12, a cylindrical mold 4 made of a metal cylinder is pushed in from the outside while aligning its outer peripheral surface with the inner surface of the rising portion 12 (Fig. 3). , Figure 4).

After the cylindrical mold 4 is pushed in and the rising portion 12 is in contact with its outer peripheral surface, the cylindrical mold 4 and the spherical mold 2 are pulled out after the rising portion 12 is cooled and solidified. An end portion of a synthetic resin branch pipe 5 having the same diameter as the synthetic resin pipe 1 is inserted into this rising portion 12 and bonded.

In this way, a so-called equal-diameter branch joint in which the diameter of the branch pipe portion 5 is equal to the diameter of the main synthetic resin pipe 1 is obtained. In this embodiment, the outer circumferential surface of the synthetic resin branch pipe 5 is
2, the outer diameter of the tubular mold 4 is slightly larger than the outer diameter of the spherical mold 2 and equal to the outer diameter of the synthetic resin branch pipe 5. It is also possible to connect the synthetic resin branch pipe 5 by bonding its inner circumferential surface to the outer circumferential surface of the rising portion 12, in which case the tubular mold 4
The outer diameter of the spherical mold 2 is slightly smaller than that of the rising part 1.
The dimensions are such that the outer diameter of the pipe 2 is equal to the inner diameter of the synthetic resin branch pipe 5. As described above, the method of this invention involves inserting a substantially spherical mold into a synthetic resin pipe and pulling it outward to raise the peripheral edge of the hole. Furthermore, since a cylindrical mold having an outer diameter approximately equal to the outer diameter of the spherical mold is pushed into the pipe from the outside while aligning its outer circumferential surface with the inner surface of the rising part, the dimensions of the rising part can be formed. , the shape becomes the desired one.

Therefore, by connecting a branch pipe here, it is possible to obtain a synthetic resin branch joint having a branch part with the same diameter or nearly the same diameter as the main pipe.

[Brief explanation of drawings]

1 to 4 are longitudinal sectional views showing an embodiment of the method of this invention in the order of its steps, FIG. 5 is a longitudinal sectional view of an example of a synthetic resin branch joint manufactured by the method of this invention, and FIG. 6 is a sectional view in FIG. 1... Synthetic resin pipe, 11... Hole, 2...
... Spherical mold, 4 ... Cylindrical mold, 5 ...
...Synthetic resin branch pipe.

Claims (1)

[Claims] 1. A hole is bored in the peripheral wall of a synthetic resin pipe, the peripheral edge of the hole is heated and softened, a substantially spherical mold is inserted into the tube, and the spherical mold is pulled outward from the hole to make the peripheral edge stand up. A cylindrical mold having an outer diameter approximately equal to the outer diameter of the spherical mold is inserted into the pipe from the outside while the outer peripheral surface of the cylindrical mold is aligned with the inner surface of the rising part. 1. A method for manufacturing a synthetic resin branch joint, which comprises pressing, then cooling the rising portion, removing the cylindrical mold and the spherical mold, and connecting a branch pipe to the rising portion.