JPH0425849B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a blow molding apparatus used for molding a hollow body having a tubular portion communicating with the outside.

An example of the above-mentioned hollow body is the cuff band of a blood pressure monitor.In the case of this cuff band, in order to introduce air into the hollow body, a tubular part that communicates with the outside is formed in the hollow body, and this tubular part includes a rubber tube, etc. However, in the case of hollow molding (blow molding), the inner diameter of the tubular part that is integrally molded with the hollow body is not regulated, so a notch-shaped groove is formed on the inner diameter surface along the parting line. This creates a problem with the airtightness between the tube and the tube inserted into it.

BACKGROUND TECHNOLOGY Based on the above, conventional technology has
When a hollow body b having a tubular portion a communicating with the outside is molded by a blow molding method, a core c is used to regulate the inner diameter of the tubular portion a.

Problems to be Solved by the Invention The above conventional technology has the following problems.
That is, (1) the core is not always in the center.

(2) The core may be bent.

(3) A tubular part with uniform wall thickness cannot be obtained.

(4) When inserting and gluing rubber tubes, etc., the adhesive leaks and the appearance is unsightly.

(5) Difficult to insert rubber tubes, etc.

Means and Effects for Solving the Problems The present invention has been made in consideration of the above-mentioned problems, and includes regulating the inner diameter of the tubular part at the outer diameter part of the core located in the cavity for the tubular part of the split mold. It has a structure that includes a right cylindrical part, a tapered part that restricts the opening end of the tubular part into a tapered shape, and a guide cylinder part that tightly fits into the cavity for the tubular part in the mold clamped state. When the mold is in a closed state, the guide cylinder part of the core is tightly held in the cavity, and the core is positioned at the center of the cavity, and the right cylinder and tapered part of the core form a tubular part formed in the cavity for the tubular part. The inner diameter of the portion is formed into a cylindrical shape, and the inner surface of the opening end thereof is formed into a tapered shape.

Example An explanation will be given based on an example of the present invention.

In the figure, 1 and 2 are left and right split molds, 3a and 4a are cavities for the hollow body, and 3b and 4b are cavities for the tubular part that are integrally molded with the hollow body. 5
is an extrusion head for extruding parison arranged above the opposing parts of the split molds 1 and 2.

Reference numeral 6 denotes a core disposed oppositely between the cavities 3b and 4b for the tubular portion. This core 6 is tightly fitted into a right cylindrical part 6a that regulates the inner diameter of the tubular part, a tapered part 6b that regulates the open end of the tubular part into a tapered shape, and cavities 3b and 4b for the tubular part in a clamped state. It consists of a guide cylinder part 6c that fits.

In the above configuration, the parison 7 is arranged hanging down from the extrusion head 5 between the opposing left and right split molds 1 and 2, and the core 6 is arranged between the cavities 3b and 4b for the tubular parts of the split molds 1 and 2. , In this state, both split molds 1 and 2 are closed. Next, air is injected through the air inlet provided in the core 6 to expand the parison 7 along the hollow body cavities 3a and 4a of the split molds 1 and 2, thereby forming a hollow body.

When the split molds 1 and 2 are in a clamped state, the guide cylinder part 6c of the core 6 is tightly held between the cavities 3b and 4b, and the core 6 is positioned at the center of the cavities 3b and 4b, and the tapered part 6b Tsute parison 7
The compressive force gradually increases toward the open end. The right cylindrical portion 6a and the tapered portion 6b of the core 6 form the inner diameter of the tubular portion formed by the cavities 3b and 4b for the tubular portion into a cylindrical shape, and the inner surface of the open end thereof into a tapered shape. be done.

Effects of the Invention According to the present invention, the core 6 is always connected to the cavities 3b and 4b for the tubular part by the clamping of the split molds 1 and 2.
located in the center of the cavity 3b, 4b
The thick guide tube portion 6c having the same diameter as the cavities 3b, 4
By being supported at point b, the core 6 will not bend. Further, from the above, a tubular portion having a uniform wall thickness can be obtained. Furthermore, the opening end of the tubular part is tapered, making it easy to insert a rubber tube, etc., and even if the adhesive leaks when inserting a rubber tube and gluing it with adhesive, the adhesive will not leak. It does not overflow to the outside and does not deteriorate the appearance.

[Brief explanation of drawings]

Figures 1 to 3 show examples of the present invention, with Figure 1 being a sectional view, Figure 2 being a sectional view showing the main parts of the molded product in a clamped state, and Figure 3 showing the main parts of the molded product. The perspective view shown in FIG. 4 is a cross-sectional view showing the main parts of the conventional device. 1 and 2 are divided molds, 3a, 4a, 3b, and 4b are cavities, 6 is a core, 6a is a right cylindrical portion, 6b is a tapered portion, and 6c is a guide cylindrical portion.

Claims (1)

[Claims] 1 Split mold 1 having cavities 3a and 4a for hollow bodies and cavities 3b and 4b for tubular parts,
2, and a core 6 located at the axial center of the cavities 3b, 4b for the tubular portion to regulate the inner diameter of the tubular portion.
A blow molding device comprising: a right cylindrical portion 6a on the outer diameter portion of the core 6 for regulating the inner diameter of the tubular portion;
A tapered part 6b that regulates the opening end of the tubular part into a tapered shape, a cavity 3b for the tubular part in a clamped state,
4b and a guide cylinder part 6c that tightly fits into the hollow molding apparatus.