JPS62199424A - Apparatus for molding screw part of plastic molding - Google Patents

Abstract

PURPOSE:To easily prepare a molding having a screw part, by mounting the screw part forming core of a split mold to a bottom force in a freely assembling manner. CONSTITUTION:Grasping cores 3 split into two, inner screw cores 40 split into four and a ring-shaped air nozzle 25 are mounted to the central part of a bottom force 20 opposed to a die 10 for supplying a plastic material. The bottom force 20 is allowed to approach the die 10 to be stopped temporarily so as to keep a proper clearance therebetween. Subsequently, a molten resin is extruded from a die nozzle 11. After a predetermined amount of the resin is accumulated in the bottom force 20, it is contacted with the die 10 under pressure to form the top plate and screw part of the molding. Not only the bottom force 20 is fallen but also the resin is injected from the die to be fallen to a predetermined position and the bottom force 20 is fallen to take out the molding. Then, the grasping cores 30 and the inner screw cores 40 are detached from the molded product. By this method, the cores 30, 40 for molding the screw part can be easily detached from the molding and the molding can be obtained without damaging the thread of a screw.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molding device for a threaded portion when blow molding a plastic container.

[Technical Background and Prior Art] For example, when producing a plastic container such as a large drum by blow molding, the top plate of the drum and the threaded neck formed at the center of the top plate are attached to the bottom mold of the mold. A side molding device is utilized.

FIGS. 10 to 13 show an outline of the molding process for this type of plastic drum, which was proposed by the applicant in Japanese Patent Application No. 59-207101. In order to better understand the present invention, the proposed technique will first be explained.

In the figure, 1 is a die for extruding molten resin, 2 is a lower mold having a predetermined shape and a recess 2a of a predetermined width and depth for molding the top of a plastic container having a chime, and 3
is a lifting cylinder for lifting and lowering the lower mold 2; 4 is an air nozzle provided on the lifting cylinder 3; 5A and 5B are a pair of left and right side molds for molding the sides and bottom of a plastic container; 6A; 6B is a cylinder for moving the same, 7 is a heated steam or cooling water hole formed in the lower mold 2, 8 is a cooling water hole formed in the side mold, and each mold 2.5
The inner surfaces of A and 5B and the lower surface of the die 1 are coated with fluororesin. Note that a notch 1a is formed around the die 1, and the lower mold 2 is fitted into this notch 1a. In this way, as will be described later, the resin accumulated in the central recess 2b of the lower mold 2 can be extruded and the formation of cavities can be prevented.

Moreover, the thickness can be controlled by the amount of movement of the lower mold.

Next, a description will be given of how a plastic container is formed using the aforementioned mold.

The lower die 2 is raised by the lifting cylinder 3, and the lower die 2 is brought close to the die 1 to a predetermined clearance. The clearance between die 1 and lower mold 2 is the required resin l.
Adjust by. In this state, the molten resin is measured (using a timer, for example) and extruded from the die 1 (Fig. 10). Next, when the necessary resin m has been measured, the lower mold is molded again using the lifting cylinder 3. 2 is raised to press the die 1 and the lower mold 2 together. This forms the top of the container with the chime (FIG. 11).

Next, the molten resin in the accumulator is extruded from the die 1 with a ring piston, and at the same time, a small amount of air is blown from the pre-blow air nozzle 9 to prevent the parison from being in a vacuum state, and the air is moved up and down according to the speed of the parison. The lower mold 2 is lowered by the cylinder 3. Then, a parison P having a chime 4a at its lower end is formed in a swollen state (FIG. 12). When the lower mold 2 is lowered to a predetermined position, the pair of left and right side molds 5A and 5B are closed, and pressurized air is injected from the nozzle 4 to perform blowing (first
Figure 3). During the molding process, the container is processed upside down.
This is used upside down. As a result, a plastic container having a chime a formed on the top of the container can be obtained.

In order to manufacture containers with internal threads using such blow molding equipment, a jig for the internal threads was attached to the center of the lower mold. Although it is easy to form external threads, it is difficult to remove the internal thread jig. When removing the internal screw jig from the product, it was removed by rotating it in the opposite direction. This is relatively quick if the internal screw has a small number of threads, but it takes time if there are many threads. Furthermore, since the resin contracts after molding, the method using rotation has the problem of frequently damaging the internal threaded portion formed of the resin.

[Object of the Invention] Therefore, an object of the present invention is to provide an apparatus for forming an internal threaded part of a plastic molded product, which facilitates molding of the internal threaded part and facilitates attachment and detachment of an internal thread forming jig.

[Structure of the Invention] According to the present invention, an apparatus for molding a plastic molded product provided with an internal thread in the injection port includes a die for supplying a plastic material and a lower die facing the die, and a A thread forming mold consisting of a clamping core divided into two, an internal screw core divided into four, and a ring-shaped air nozzle is attached.

[Operations and Effects of the Invention] Therefore, the separable clamping core and internal thread core allow these cores and the air nozzle to be easily attached and detached, and can be easily attached to and detached from the mold.

Therefore, even if there are many internal threads, the film can be easily deposited, and the internal threads will not be damaged after molding.

[Preferred Embodiment] When carrying out the present invention, it is preferable to form an external thread in addition to an internal thread. In this way, both the blind plug that engages with the internal thread and the cap that engages with the external thread can be used as appropriate.

[Example] The present invention will be described in detail below based on the drawings.

FIG. 1 is a cross-sectional side view of a thread molding mold according to the present invention, in which a die 10 is formed with a nozzle 11 for parison injection, and an air nozzle 12 is provided in the center. The lower mold 20 facing the die 10 is designated by the reference numeral 30 as a whole.
and a clamping core forming an external screw thread indicated by 40 as a whole.
An internal thread core 40 shown in is attached, and a gap 35 filled with a resin layer is provided between both cores.

An air nozzle 2 is installed inside this internal screw core 40.
5 is loaded.

FIG. 2 shows the planar shape of the screw core part,
The clamping core is divided into two parts 30a and 30b. The internal thread core is divided into four parts, two large internal thread molds 40a and 40b and a small internal thread mold 40c and 4Qd inserted between them.

A ring-shaped air nozzle 25 is installed inside this internal screw core.
is inserted, but two dovetail groove mechanisms 43a are inserted between the two.
, 43b are formed to ensure engagement.

3 to 9 show each part of the screw molded member, and as shown in FIGS. 3 and 4, the clamping core 30
a and 30b are divided into two parts, and there are screw threads 31a on the inside,
31b. FIGS. 5 and 6 show two-split screw types 40a and 40b, which are larger of the internal screw types, and have screw threads 41a and 41b formed on the outside. 7 and 8 show the smaller internally threaded molds 40c and 40d, both sides 44 of these threaded molds are tapered to ensure secure engagement with the larger internally threaded molds 40a and 40b. However, it can withstand resin pressure during molding.

FIG. 9 shows the air nozzle 25.
has a ring shape and can be reliably engaged with the internal thread core using the dovetail groove 43a143b.

Next, a process of blow-molding a drum having a threaded neck using this thread-forming mold will be described.

The blow molding process is substantially the same as the conventional molding shown in FIG. 10 and subsequent figures.

(1) The mold is divided into three parts: the die, the lower mold, and the side mold. (2) The lower mold 20 is brought close to the die 10 and temporarily stopped while maintaining an appropriate clearance.

(3) Extrude the molten resin from the nozzle 11 of the die.

(4) After a predetermined amount of resin has accumulated in the lower mold 2o, the lower mold is pressed onto the die 10 to form the top plate and threaded portion of the drum.

(5) Thereafter, the lower mold 20 is lowered and the resin is injected from the die and lowered to a predetermined position.The left and right molds are closed and blow molding is performed to form a drum shape.

(6) After cooling, open the left and right molds, lower the lower mold, and take out the molded product.

(7) Remove the clamping core 30 and the internal screw core 40.

Next, the process of attaching and detaching the screw core to the lower die is as follows.

(1) Attach the clamping parts 730a, 30b to the lower die 20.

(2) Large split cores 40a and 40b for internal screw cores
Then, attach the small split cores 40G and 40d161.

(3) When removing the product from the molded product, the clamping core will come off when the product is released from the mold, and if the internally threaded cores 40c and 40d are removed, then the inner screw cores 40a and 40b will also come off easily.

[Summary] As described above, in the present invention, when a drum with a threaded portion is produced by blow molding, a split type screw core is attached to the lower mold so that it can be assembled freely. You can easily produce the product by removing it from the screw jig! #No damage to the threads in case.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a die and a lower mold according to an embodiment of the present invention, Fig. 2 is a plan view of a screw core, Fig. 3 is a plan view of a clamping core, and Fig. 4 is a x of Fig. 3. -X arrow view, Fig. 5 is a plan view of the large part of the internal thread type, Fig. 6 is a front view, Fig. 7 is a plan view of the small part Iα of the internal thread type, and Fig. 8 is a front view, FIG. 9 is a plan view of the air nozzle, and FIGS.
Figure 2 shows the conventional plastic container molding process used in carrying out the present invention, and Figure 10 shows a state in which the lower mold is brought close to the die and molten resin is extruded from the die.
Fig. 11 shows the state in which the lower mold is crimped to the die to form the top of the palanquin with a chime, Fig. 12 shows the lower mold lowered and does not show the part, and Fig. 13 shows It is a figure which shows the state which lowered a lower mold to a predetermined position, and blowing is carried out using a pair of left and right side molds. 1.10...Die 2.20...Lower mold 3
... Cylinder for lifting and lowering the lower mold 4 ... Air nozzle 5A, 5B ... Pair of left and right side molds 6A
16B... Cylinder for moving the side mold 7... Hole for heated steam or cooling water in the lower mold 8... Hole for cooling water in the side mold 9.12... Air nozzle for pre-blow 25... Air nozzle 30... Core for clamping 40... Core for internal screw Fig. 1 Fig. 2 Fig. 4 δd 1d Fig. 12 Fig. 13 Procedure correction teeth 7゜March 28, 1986 (Director of the Patent Office Uga Michibu-dono
8゜1, Indication of the incident Patent application No. 61-4196
No. 3, No. 2, Title of the invention: Apparatus for forming threaded parts of plastic molded products 4, Relationship with the case of the person making the amendment Applicant's address: 3-2-5 Kasumigaseki, Chiyoda-ku, Tokyo, C'
”3*4Q. 4. Agent〒105
Address: 2-13 Nishi-Shinbashi, Minato-ku, Tokyo
No. 3, -Pa] E 5, Date of amendment order Voluntary amendment 6, Target of amendment Contents of drawing amendment 1) Drawing No. 5 will be amended as shown in the attached drawing. List of attached documents

Claims (1)

[Claims] An apparatus for molding a plastic molded product having an internal thread in the injection port, which includes a die for supplying plastic material and a lower die facing the die, and a clamping core divided into two parts in the center of the lower die, and four A device for molding a threaded part of a plastic molded product, characterized by mounting a mold for molding a threaded part consisting of a divided internal threaded core and a ring-shaped air nozzle.