JPH0852792A - Mold for hollow molded product - Google Patents

Abstract

PURPOSE:To obtain a hollow molded product holding squareness produce no gap or inclination between adjacent panels at the time of connection use by providing the upper and lower side wall members positioned in the axial direction of a parison between a closed position almost right-angled to a bottom surface member and a truncated chevron-shaped open position. CONSTITUTION:The upper and lower side wall members 10a, 10b of a female mold 8b are opened in a truncated chevron shape. Subsequently, a molten parison P is suspended from a die 2 and pinched at the lower part thereof to be continuously suspended to the gap between mutually separated male and female molds 8a, 8b. Low pressure air is blown into the parison from a preblow pin 18 to be preparatorily inflated while the parison is held between the upper and lower side wall members 10a, 10b. At the same time, the upper and lower side wall members of the female mold are closed while the male and female molds are allowed to gradually approach the parison and the parison is allowed to follow the cavity formed by the male and female molds between the fixed side wall members on the lateral side of the parison while the side wall members on the side of the parison are gradually advanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when used as a combination panel formed by combining hollow flat plates, is a hollow molding die which is required to have a flatness and a squareness without gaps or inclinations between the joint surfaces of adjacent panels when connected and used. It is about.

[0002]

2. Description of the Related Art FIG. 8 shows a sectional view of a conventional hollow molding die. In blow molding, which produces a hollow resin product from a parison injected or extruded into a cylinder from a die head,
The parison is injected or extruded from the die head, the parison formed into a bag shape by the parison pinch is pre-blown to be slightly inflated, and the parison is put into the opened mold and both molds 8a and 8b are closed, and the molds 8a and 8b After degassing the gas in the cavity formed by the parison P and the parison P, the air is sucked through the vacuum pump device from the small air vent hole that communicates with the mold surface, and high-pressure air is blown into the parison. Is formed into a predetermined shape based on the cavity and then cooled by a mold to complete the molding. In this way, the molded product 25 (resin product) molded is taken out by opening the mold.

On the other hand, as shown in FIG. 9, a resin is molded into a panel shape having a bag-shaped air space therein, and used as a building material such as a door (gate) or a simple wall material (partition wall). However, it has come to be considered to use it on the floor surface of a simple pier such as a formwork for concrete pouring, but these molded products have considerable structural strength despite their light weight and are resistant to deformation. It has the feature of being strong.

[0004]

However, when a panel-shaped molded product having such a bag-shaped space inside is manufactured by blow molding, the parison hanging from the die is clamped with both molds. After that, when the parison is imitated by the cavity, there is a problem that the deep portion of the concave portion of the cavity locally expands and becomes thin, which not only weakens the strength of the molded product but also causes the parison to burst during molding and cannot be molded.

Further, when the parison is clamped between both molds after the mold is clamped and the mold is cooled and solidified to take out a hollow molded product, it is difficult to take out the molded product from the female mold unless there is a draft. Therefore, if such a draft is provided, there is a problem in that when the molded products are connected and used, the perpendicularity of the joint surfaces cannot be maintained, and a gap is generated to cause a joint failure.

The present invention has been made in view of the above problems, and provides a hollow molding die which is free from local extension and is easy to manufacture a hollow molded product having a perpendicularity of a joint surface. .

[0007]

In order to achieve the above object, according to the present invention, there is provided a male and female metal mold for hollow molding which is provided so as to freely come into contact with and separate from a parison suspended from a die,
The female mold is composed of a side wall member and a bottom member, and upper and lower side wall members positioned in the axial direction of the parison have a closed leg position and a V-shaped open leg position that are substantially perpendicular to the bottom member. The side wall member is movably provided between a tangential position that is located laterally in the radial direction of the parison and forms a ridge between the bottom members and a position retracted outside the bottom member. The other side wall member is fixed so that it cannot move.

[0008]

[Operation] A pair of male and female metal molds are attached so as to be separated from each other.
At this time, the side wall members at the upper and lower portions of the female mold are opened in a V shape. Next, the molten parison is drooped from the die, the lower part of the parison is pinched, and subsequently, the molten parison is drooped between the male and female molds that are reciprocally separated from each other. Then, while sandwiching the parison between the upper and lower side wall members, low-pressure air is blown into the parison from the pre-blow pin to pre-expand it.

At the same time, while the male and female dies are gradually approaching the parison, the closed legs of the upper and lower side wall members of the female die and the side wall members on the side of the parison are gradually advanced, and the side wall members fixed on the side of the parison. The parison is imitated by the male and female mold cavities on the four sides.

Upon completion of the mold clamping, the pre-blow is switched to the blow air to mold from the inside of the parison toward the cavity all at once. For this reason, the parison does not locally expand midway when it is formed in the cavity, and a hollow molded product having no draft can be easily obtained only by moving the side wall member forward and backward with the opening and closing legs.

[0011]

EXAMPLES Specific examples of the hollow molding die according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a hollow molding die according to an embodiment of the present invention, FIG. 2 is a perspective view of an upper side wall member, FIG. 3 is a front view seen from AA of FIG. 1, and FIGS. FIG. 7 is an abbreviated vertical sectional view for explaining a molding process of a hollow molded product.

As shown in FIG. 1, the parison P ejected from the die 2 is suspended between the pair of left and right metal molds 8 and 8b.

Unlike the conventional structure, the mold structure of the present invention comprises a male mold 8a having a smooth surface of the cavity 3a and a female mold 8b having a plurality of tack-off molding protrusions 4 on the surface of the cavity 3b. Are formed from.

The male die 8a is mounted on a substrate 7a which is arranged via a plurality of support columns 6a which are erected on the mounting plate 5a. The female die 8b also has the same structure as the male die 8a.

As shown in FIGS. 1 to 3, the female die 8b has a quadrangular bottom member 9 and four side wall members 1.
It consists of zero.

Upper and lower side walls which can be tilted between a closed leg position which is located above and below the bottom member 9 and forms a ridge line substantially perpendicular to the bottom member 9 and a position where the leg member is tilted and opened in a V shape. Members 10a and 10b are provided.

The upper and lower side wall members 10a, 10b and the bottom member 9 are pivotally supported on the bottom member 9 by pivots 12a, 12b.
The upper and lower side wall members 10a, 10b are hydraulic cylinders 14a,
It is possible to tilt between the above-mentioned positions by the operation of 14b.

The pivots 12a and 12b are rotatably supported by the upper and lower corners 15a and 15b of the bottom member 9 and are rotatable together with the upper and lower side wall members 10a and 10b.

Further, as shown in FIG. 1, blow pins 17a and 17b are formed at the upper and lower portions of the female mold 8b so as to be able to move in and out from the surface of the cavity 3b, so as to fit the male and female molds 8a and 8b. The blow pins 17a and 17b are pierced into the parison P to feed blow air compressed to 5 to 7 kg / cm ² .

As shown in FIG. 3, the right side wall member 10c of the bottom member 9 having a rectangular shape is of a slide type.
Side wall members 10c are fixed to the tips of a pair of upper and lower side hydraulic cylinders 16a, 16b on support legs (not shown) provided on the mounting plate 5b, and the side hydraulic cylinders 16a, 16b are provided.
By the operation of (1), it is provided so as to be movable back and forth within a range indicated by a solid line and a two-dot chain line.

Further, as shown in FIG. 3, the side wall member 10d on the left side of the bottom member 9 having a rectangular shape is a fixed type which cannot be moved.

Reference numeral 20 is a cooling water passage for cooling the parison P provided in the male and female dies 8a and 8b, 18 is a pre-blow pin, and 21 is a pinch device.

The operation of the hollow molding die constructed as described above will be described.

The state before hanging the parison P from the die 2 will be described. The male and female dies 8a and 8b are reciprocally separated from each other, and the upper and lower side wall members 10a and 10b open in a V-shape, and The slide-type side wall member 10c is set to the retreat limit separated from the bottom surface member 9. The pinch device 21
Is open.

First, the parison P is hung down from the die 2 to a length below the pinch device 21 and then the pinch device 2 is moved.
1 is actuated to the closed state, and the lower part of the parison P is pinched to form a bag (FIG. 4).

Next, while the pinch device 21 is opened, compressed air of ² to 3 kg / cm ² is introduced into the parison P from the pre-blow pin 18, and the parison P is pre-blown while the parison P is male and female again. Mold 8a, 8b
Hang it all the way to the bottom (Fig. 5). Next, the left and right male and female molds 8a and 8b are brought close to each other at a high speed, and the parison P is made to gradually approach the cavities 3a and 3b of the male and female molds 8a and 8b (FIG. 6). At the same time, the hydraulic cylinders 14a, 14
The pressure oil is introduced into b and the upper and lower side wall members 10a and 10b are tilted to the position where a ridge line substantially perpendicular to the bottom member 9 is formed and the legs are closed (FIG. 7).

At the same time, the side hydraulic cylinders 16a, 16b
Pressure oil is introduced to gradually move the slide-type side wall member 10c, and finally the upper and lower side wall members 10a and 10b are closed.
After forming the female mold 8b in a state where the four side wall members, the slide side wall member 10c and the fixed side wall member 10d, which have moved to the forward limit, are adjacent to each other, the parison P is molded into the cavities 3a and 3b. Of.

Under this condition, the supply of pre-blow air from the pre-blow pin 18 is stopped and the blow pin 1
7a and 17b are advanced to pierce the parison P, and blow air of 5 to 7 kg / cm ² is introduced from the blow pins 17a and 17b. By introducing this high-pressure blow air, the parison P is deformed substantially along the cavity 3b of the female mold 8b having complicated irregularities. Under such a condition that the parison P sandwiched between the male and female dies 8a and 8b is substantially deformed, the pressure inside the parison P is adjusted via the blow pins 17a and 17b.

In the present invention, when the side wall members 10a and 10b at the upper and lower portions of the female die 8b are opened, the parison P hanging from the die 2 is copied and deformed. The side wall members 10a, 10b are deformed so as to follow the closed leg movements. In particular, in the present invention, the upper and lower corners 15a, 15 of the bottom member 9 of the female mold 8b are deformed.
The parison P of the pivots 12a and 12b is exposed between the bottom side members 9 and the upper and lower side wall members 10a and 10b which are closed legs.
Since it follows the open circle portion of 12b, it is possible to manufacture a hollow molded product having a uniform thickness without causing local extension at the corner (deep portion of the recess).

[0031]

As is apparent from the above description, according to the present invention, there is provided a hollow-molding male / female mold provided so as to be freely contactable / separable with respect to a parison suspended from a die. The mold includes a side wall member and a bottom member,
The upper and lower side wall members positioned in the axial direction of the parison are tiltably provided between a closed leg position and a C-shaped open leg position that are substantially at right angles to the bottom member, and are located laterally in the radial direction of the parison. A side wall member is movably provided between a tangential position where a ridge line is formed between the bottom surface members and a position retracted to the outside of the bottom surface member, and one side of the other side wall member is immovably fixed. By doing so, since no draft is provided, a squareness can be maintained, and a hollow molded product can be obtained in which no gap or inclination is generated between adjacent panels when connected and used.

Further, since the parison is not locally stretched, a hollow molded product having a uniform thickness up to the corners of both molds can be easily obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a hollow molding die according to an embodiment of the present invention.

FIG. 2 is a perspective view of an upper side wall member.

FIG. 3 is a front view as seen from AA of FIG.

FIG. 4 is an abbreviated vertical cross-sectional view illustrating a molding process of a hollow molded product.

FIG. 5 is an abbreviated vertical sectional view for explaining a molding process of a hollow molded product.

FIG. 6 is an abbreviated vertical sectional view for explaining a molding process of a hollow molded product.

FIG. 7 is an abbreviated vertical cross-sectional view illustrating a molding process of a hollow molded product.

FIG. 8 is a cross-sectional view of a conventional hollow molding die.

FIG. 9 is a perspective view of a panel-shaped molded product.

[Explanation of symbols]

 2 dies 3a, 3b cavity 4 tuck-off molding protrusions 7a, 7b substrate 8a male mold 8b female mold 9 bottom member 10 side wall member 10a upper side wall member 10b lower side wall member 10c sliding side wall member 10d fixed side wall member 12a, 12b Axis 14a, 14b Hydraulic cylinder 15a, 15b Corner part 16a, 16b of bottom member Side hydraulic cylinder 17a, 17b Blow pin 18 Pre-blow pin 20 Cooling water channel 21 Pinch device 25 Molded product

Claims (1)

[Claims] 1. A male / female mold for hollow molding, which is provided so as to be capable of coming into contact with and separating from a parison suspended from a die,
The female mold is composed of a side wall member and a bottom member, and upper and lower side wall members positioned in the axial direction of the parison have a closed leg position and a V-shaped open leg position that are substantially perpendicular to the bottom member. The side wall member is movably provided between a tangential position that is located laterally in the radial direction of the parison and forms a ridge between the bottom members and a position retracted outside the bottom member. A hollow molding die, wherein one side of the other side wall member is immovably fixed.