JP3118031B2 - Molding method of synthetic resin molded article having female fitting part - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a synthetic resin molded product having a female fitting portion which is fitted and connected to a male fitting portion of another molded product.

[0002]

2. Description of the Related Art FIG. 1 shows that a male fitting portion 1 of one synthetic resin molded product A and a female fitting portion 2 of another synthetic resin molded product B are fitted to each other. It is sectional drawing which shows the state which connected B. Molded product B having such a female fitting portion 2
In particular, when the inside diameter is larger than the diameter of the opening of the female fitting portion or when the shape of the molded product B is complicated, a slash molding method, a rotation molding method or a blow molding method is adopted.

FIG. 2 is a perspective view typically showing a slush molding method. In this molding method, a sol (hot water of a high-temperature synthetic resin material) is injected into the cavity of the mold 3, and when the resin on the outer peripheral surface side in contact with the inner wall of the cavity is gelled due to a temperature drop, the resin in the sol state is removed. The molded product formed by curing the remaining resin is ejected from the mold, and as shown in FIG. 3, the burr 4 attached to the female fitting portion 2 and molded by the runner portion of the mold. Was cut off to form a molded product B having the female fitting portion 2. Also in the rotation molding method and the blow molding method, a molded product having a female fitting portion is obtained by removing burrs in substantially the same manner.

[0004]

Therefore, as is apparent from FIG. 1, since the fitting strength of the two molded products A and B is weak, the two molded products are easily separated by an external force. For example, when a player applies an external force to the head of a doll body, which is one molded product, and the neck of the doll head, which is another molded product, is fitted and connected to the neck hole of the doll body. However, there were problems such as the head coming off the torso.

[0005] This invention is a <br/> made in view of the above, by utilizing the characteristics such as slush molding, a variation characteristic of the physical properties in the molding process of synthetic resin, it is folded inwardly By molding a female fitting portion, after the male fitting portion is fitted, it is possible to provide a method of molding a molded article having a female fitting portion that prevents the male fitting portion from coming off and separating well. Aim.

[0006]

In order to achieve the above-mentioned object, a molding method according to the present invention uses a mold having an additional cavity for forming a fitting margin with an original cavity for molding a molded product. , Slush molding, rotation molding or blow molding , at least one of the openings
Molding the intermediate molded article having a recess, excising burr formed into opening edge of the recess of the intermediate <br/> molded article, before the intermediate molded article is cured, the intermediate molded article
After being removed from the mold, the part molded by the additional cavity is folded inside the part molded by the original cavity, and cooling and hardening are performed in this order.

[0007]

The injection of the resin into the mold is the same as in the prior art. In addition to the part formed by the cavity, the part formed by the additional cavity and the burr formed by the runner are formed integrally. When the burr is cut between the additional cavities, the portion formed by the additional cavities can be easily turned inward. The folded portion becomes a female fitting portion into which the male fitting portion of another molded product is screwed or pushed. Since the female fitting portion has elasticity and is folded inward, it exerts a large clamping force or a retaining force against the male fitting portion that is screwed or pushed in.

[0008]

Next, an embodiment of the present invention will be described with reference to FIGS.

FIG. 4 is a sectional view of a mold 3N used when using the first embodiment of the present invention. As can be seen from the figure, an additional cavity 12 for forming a female fitting portion, that is, a fitting margin for the molded product A, is provided above the cavity 11 for forming the main part of the molded product B of the mold 3N. Is provided. In the example shown in FIG. 4, a female screw is cut in the additional cavity portion. This mold 3N
As shown in FIG. 2, the cavities 12,
It is attached to the position where hot water is poured toward 11, and is used for slash molding, rotation molding or blow molding by a method similar to the conventional method.

FIG. 5A shows an intermediate molded product formed by using the above-mentioned mold 3N and having a concave portion which is opened on one side. The main portion 2a of the molded product B is followed by a female fitting portion. Is formed integrally, and a burr 4 similar to the conventional one is formed at the tip of the additional formed portion. A male screw is formed on the outer peripheral surface of the additional forming part 2b. Further, in the present invention, after molding by the die, the burr 4 is cut along the line L at the tip end of the additional molded product 2b as a second step.

Next, as shown in FIG. 2 (b), when the additional molded portion 2b is folded back inside the concave portion, the portion which has been a male thread is changed to a female fitting portion having a female thread. The annular groove 2c provided at the upper end of the additional molded part facilitates the inside folded of the additional molded part.

The folding of the additional molded portion 2b can be easily performed when the molded product B is taken out of the mold 3N and is still in a soft state.

Subsequently, the molded product B having the female fitting portion molded as described above is screwed into the male fitting portion 1 of the second molded product A into the female fitting portion (2b). As shown in FIG. 3C, they are firmly fitted and fixed.

FIG. 6 shows a case in which the present invention is applied to a case where the male fitting portion is connected to the female fitting portion by simply pushing it into the female fitting portion, and is similar to the metal mold 3N in FIG. Using a mold, an intermediate molded product B having a concave portion opened on one side and an additional molded portion 2b 'is molded, and after the burr 4 is cut along the line L, the intermediate molded product is taken out from the mold. an additional molding unit 2b' return Ri folded inwardly of the recess to form an inward flange-shaped female fitting portion 2b', the tip of the other of the molded article a is a large diameter into the female fitting part The male fitting portion 1a is pushed in, fitted and connected so as not to come off.

[0015]

As described above, according to the present invention, a slush, rotation or blow molding method is used in the same manner as in the prior art using a mold having an additional cavity for forming a female fitting portion on the gate side of the cavity. By forming an intermediate molded product having a concave portion that opens on one side, and after burr cutting, before the molded product is hardened, the additional molded portion is folded inside the concave portion to form the female fitting portion, so that screwing is performed. any of the female fitting part of the expression or closet type can also be made easier, this can be combined connecting fitting the Ohamago portion so as not to pull-out.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which two molded products are fitted and connected by male and female.

FIG. 2 is a perspective view showing an example of a slush molding method.

FIG. 3 is a cross-sectional view showing a molded product obtained by a conventional slush molding method and a cutting position of a burr.

FIG. 4 is a sectional view showing an example of a mold used for using the method according to the present invention.

FIG. 5 is a schematic view illustrating the fitting of each step of the first embodiment of the present invention to another molded product.

FIG. 6 is a schematic view for explaining each step of the second embodiment of the present invention and fitting with other molded products.

[Explanation of symbols]

 A Molded product having a male fitting portion 1a Male fitting portion 1b Male fitting portion B Molded product having a female fitting portion 2b 'Additional molding portion (female fitting portion) 2b Additional molding portion (female fitting portion) 3N Mold 11 Cavity 12 Additional Cavity 4 Burr

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI // B29L 31:00

Claims (1)

(57) [Claims] (1) A mold provided with an additional cavity for forming a margin for fitting into an original cavity for molding a molded product is formed by at least one of a slash molding method, a rotation molding method and a blow molding method. Has a recess that opens
To form an intermediate molded product . (B) A bar formed on the periphery of the opening of the recess of the intermediate molded product.
Remove the ri . (C) before the intermediate molded product is cured, the intermediate molded product
Is taken out of the mold, the part formed by the additional cavity is folded inside the part formed by the original cavity, and cooled and hardened. Above (a)
(B) A method for molding a synthetic resin molded article having a female fitting portion, wherein (c) is performed in this order.