JPH0852793A - Mold for hollow molded product - Google Patents

Abstract

PURPOSE:To easily obtain a hollow molded product having uniform wall thickness up to the corner parts of both molds by attaching a shaft so that the outer surface of the shaft connecting a side wall member and a bottom surface member passes the abutting contact ridgeline of a cavity forming position. CONSTITUTION:The outer surfaces of the shafts 12a, 12b connecting the upper and lower side wall members 10a, 10b of a female mold 8b and a bottom surface member 9 are passed a closed position forming the abutting contact ridgeline of a cavity forming position while male and female molds 8a, 8b are allowed to gradually approach a parison P and the parison P is allowed to follow the cavities 3a, 3b of the male and female molds between the fixed side wall members on the lateral side of the parison P while the side wall members on the lateral side of the parison P are allowed to gradually advance. At the time of the completion of mold clamping, the preblow due to a preblow pin 18 is changed over to the main blow due to blow pins 17a, 17b to shape the parison P from the inside thereof toward the cavities 3a, 3b at a stroke.

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]

9 and 10 are explanatory views showing the procedure of blow molding using a conventional hollow molding die. Of the male and female molds 8a and 8b for blow molding, the female mold 8b
Is a bottom member 9 and side wall members 10 constituting the peripheral portions of the four sides of the female mold 8b are pivotally supported by a pivot 12 provided on the bottom member 9 to form a substantially right angle with a closed leg position. The legs can be freely opened and closed between the opened positions.

Reference numeral 14 is a hydraulic cylinder, one end of which is tiltably provided via brackets 5a which are erected on the upper and lower portions of the mounting plate 5 to which the female mold 8b is mounted.

The tip end portion of the piston rod of the hydraulic cylinder 14 is pivotally supported by the side wall member 10 to expand and contract the piston rod, so that the side wall members 10 on the four sides form up and down, left and right legs. There is.

Reference numeral 2 is a die, 3a and 3b are cavities, 18 is a pre-blow pin, and 21 is a pinch device.

[0006]

However, before hanging the parison P from the die 2, each side wall member 10 on four sides is suspended.
10 is opened, and the upper and lower side wall members 10 are closed while the hanging parison P is asymptotically moved by both molds 8.
As shown in FIG. 11, the parison P is inserted into the gap 30 between the bottom member 9 and the upper and lower side wall members 10 to locally expand and become thin, which not only weakens the strength of the molded product but also reduces the strength of the parison during molding. However, there is a problem that it cannot be molded due to bursting.

The present invention has been made in view of the above-mentioned problems, and provides a hollow molding die in which there is no local extension and a hollow molded product having a uniform wall thickness at the corners is easy to manufacture. It is a thing.

[0008]

In order to achieve the above object, in the present invention, a female mold of a hollow molding mold is formed by a bottom member and a side wall member, and the side wall member is not formed with a cavity forming position. In a hollow molding die pivotally attached to the bottom member so as to be tiltable via a pivot, the outer surface of the pivot connecting the side wall member and the bottom member passes through the butt contact ridge line at the cavity forming position. The above-mentioned axis is attached to.

[0009]

[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 (cavity non-forming position). 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 outer side of the pivot connecting the upper and lower side wall members and the bottom member of the female dies forms a butt contact ridge line at the cavity forming position. While the cavity forming position) and the side wall member on the side of the parison are gradually advanced, the parison is made to follow the male and female mold cavities on four sides between the side wall members fixed on the side of the parison.

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. For this reason, the parison does not locally expand during molding into 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.

[0012]

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 vertical sectional view of a hollow molding die according to an embodiment of the present invention, FIG. 2 is a front view seen from AA of FIG. 1, and FIGS. 3 to 6 show a molding process of a hollow molded product. FIGS. 7 and 8 are explanatory vertical cross-sectional views, and FIG. 7 and FIG. 8 are explanatory views showing a state in which the parison follows the corners of the female mold.

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 and 2, the female die 8b has a quadrangular bottom member 9 and four side wall members 1.
It consists of zero.

A closed leg position (cavity forming position) which is located above and below the bottom member 9 and forms a ridge line at a right angle to the bottom member 9 and a position where the legs are tilted and opened in a V shape (cavity non-forming position). ) Between the upper and lower side wall members 10a, which can be freely tilted,
10b is 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 mounting positions of the pivots 12a and 12b are such that the outer surfaces of the pivots 12a and 12b connecting the upper and lower side wall members 10a and 10b and the bottom member 9 pass through the butt contact ridge line 32 at the cavity 3b forming position. Has been done.

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. 2, the right side wall member 10c of the bottom member 9 having a rectangular shape is of a slide type.
The slide type side wall member 10c is fixed to the tips of a pair of upper and lower side hydraulic cylinders 16a and 16b on support legs (not shown) provided on the mounting plate 5b.
By the operation of a and 16b, 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. 2, 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.

Explaining the state before hanging the parison P from the die 2, 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 are opened in a V shape (see FIG. 7) In addition, the slide-type side wall member 10c is set to the retreat limit apart from the bottom member 9. The pinch device 21 is open.

First, the parison P is hung from the die 2 to a length below the pinch device 21, and then the suspension of the parison P is temporarily stopped. Then, the pinch device 21 is operated to close the parison P, and the parison P is closed. The lower part is pinched to form a bag (Fig. 3).

Next, the pinch device 21 is opened, and compressed air of ² to 3 kg / cm ² is introduced into the parison P from the pre-blow pin 18 to pre-blow the parison P while the parison P is again male and female. Mold 8a, 8b
Hang it all the way to the bottom (Fig. 4). Next, the left and right male and female metal molds 8a and 8b are brought close to each other at a high speed, and the parison P is gradually brought close to the cavities 3a and 3b of the male and female metal molds 8a and 8b.

When a little time has passed while performing mold clamping, pressure oil is introduced into the hydraulic cylinders 14a, 14b to tilt the upper and lower side wall members 10a, 10b to a position where a ridge line at a right angle to the bottom member 9 is formed. And let the legs close (Fig. 5,
(Figure 8).

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 die 8b having complicated irregularities (FIG. 6).

In this way, both dies 8a and 8b are kept closed for a certain cooling time, and the parison P is cooled. When the mold is opened after a certain time has passed, the parison P is obtained as a panel-shaped molded product having a desired unevenness, for example.

[0033]

As is apparent from the above description, the female mold of the hollow molding mold is formed by the bottom member and the side wall member, and the side wall member is pivoted between the cavity forming position and the cavity forming position. In a hollow molding die pivotally attached to the bottom member so as to be tiltable via the, the outer surface of the pivot connecting the side wall member and the bottom member passes through the butt contact ridge line at the cavity forming position. By mounting the parison, the parison will not be inserted between the bottom member and the side wall member due to the closed legs of the upper and lower side wall members when the parison follows the female die, so that the parison is inserted and locally stretches to reduce the wall thickness. As a result, 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 front view seen from AA of FIG.

FIG. 3 is an abbreviated vertical sectional view for explaining a molding process of a hollow molded product.

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 explanatory view showing a state in which the parison follows the corner portion of the female die.

FIG. 8 is an explanatory diagram showing a continuation of the operation shown in FIG. 7.

FIG. 9 is an explanatory view showing a procedure of blow molding using a conventional hollow molding die.

10 is an explanatory diagram showing a continuation of the operation shown in FIG.

FIG. 11 is an explanatory diagram showing a state in which the parison is inserted.

[Explanation of symbols]

 2 dies 3a, 3b cavity 4 tuck-off molding projections 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 30 Gap 32 Contact ridge P Parison

Claims (1)

[Claims] 1. A female mold of a hollow molding die is formed of a bottom member and a side wall member, and the side wall member is tilted on the bottom member between a cavity forming position and a cavity forming position via a pivot. In a hollow molding die formed by pivoting, the hollow shaft is attached such that an outer surface of the shaft connecting the side wall member and the bottom member passes through a butt contact ridge line at a cavity forming position. Type.