JPS6025725A - Method of blow molding and apparatus therefor - Google Patents

Abstract

PURPOSE:To obviate that a piece is separated from a parison and remains in a container, by forming a hole in a parison by a solid needle capable of being moved in a hollow needle, and inserting the hollow needle into the hole to blow air into the parison. CONSTITUTION:A solid needle 31 is projected from a hollow needle 35 to form a hole in a parison 25, and then is retracted to be moved away from the hollow needle 35. With this state, air is blown into the parison 25 to inflate the parison 25 so that the parison 25 may be brought in firm contact with the cavity 24 defined by molds 21, 22 thereby producing a hollow container. A piece would not be separated from the parison and would not remain in the container.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a hollow molding method J3 for producing hollow containers, etc.
In particular, a hollow needle is inserted into a parison housed in a mold, and air is introduced into the parison through the hollow part of this 11 to perform molding, and a blow molding method thereof. Regarding equipment.

By using hollow-molded synthetic resin containers to supply various foods, packaging costs can be reduced. Therefore, along with advances in plastic molding technology, containers formed by blow molding have become widely used. When performing such hollow molding with high efficiency, a zero-tally type molding machine is used.

A rotary molding machine places a mold on a rotary table, and blows air into the mold with an air blowing device after it has been moved to a predetermined position to perform hollow molding, and continuously blow molds. It becomes possible to do this.

In such a blow molding apparatus, a hollow needle is inserted into a parison held in a mold, and air is introduced into the parison through the hollow portion of the needle to perform molding. For example, as shown in FIG. 1, a conventional air blowing device has a cylinder 1 and a piston 2 disposed within the cylinder 1.
Then, by supplying air from the air supply boat 3, the piston 2 is moved forward against the spring 4, and the hollow needle 5, which has been cut at the tip of the piston 2, is inserted into the parison 6. C8 After that, air is supplied into the parison 6 through the air supply hole 7 formed in the center of the piston 2 in the axial direction and the hollow needle 5, and the parison 6 is expanded to perform hollow molding. It was like that.

The drawback of such a conventional device is that the parison 6 must first be punctured with a hollow needle 5, and even if the tip is inclined as shown in FIG. The problem was that it would separate from the parison 6. In other words, if a hole [-] was made in the hollow 115, the parison 6 would look like it had been punched out, and the polygon piece 8 would be separated from 11;
It was supposed to be dropped and remain in a hollow container. Therefore, if such a hollow-molded container is filled with various foods, the plastic pieces 8 will be mixed into the foods.

FIG. 2 shows another conventional air blowing device, in which a hollow nail 1 is attached to the tip of the holder 10.
1 is being held, and when the air in the space between the holder 10 and the sleeve 12 is sucked from the air suction boat 13, the parison 15 is suctioned by the suction hole 14 formed at the tip of the sleeve 12, and the hollow needle It is designed to be crimped onto the tip of 11. Then, a hole is made in the parison 15 by this crimping, and by blowing air into the parison 15 through the air supply hole 16 of the holder 10 and the hollow sword 11, the parison 15 is expanded to form a hollow container. It has become.

Even in a device in which the hollow i+ 11 is inserted into the parison 15 by such a vacuum suction method, a part of the parison 15 is punched out by the hollow needle 11, and the poly piece 17 is removed. Sometimes it separated from parison 15.

Therefore, this plastic piece 17 would also remain in the molded container, and there was a risk that it would be mixed in with the food stuffed into the container.

The present invention was made in view of these problems, and when a hollow button for introducing air for blow molding is inserted into a parison, a piece of plastic separates from the parison and falls into the container. It is an object of the present invention to provide a blow molding method and an apparatus for the same in which no residue remains.

The present invention will be explained below with reference to an illustrated embodiment.

FIG. 3 schematically shows the entire apparatus according to this embodiment, and this apparatus is equipped with a rotary table 20. As shown in FIG. On the rotary table 20, molds 21 and 22 are arranged at a predetermined pitch in the circumferential direction. Further, an air blowing device 23 is arranged at a position corresponding to a predetermined rotational position of the rotary table 20. The molds 21 and 22 are separably joined to each other as shown in FIG. is held in a state C in which both ends 5 are sandwiched.

Next, the air blowing device 23 for blowing air into the parison 25 in this mold 21 and 22 will be explained as follows.
As shown in FIG. 5', this device includes a cylinder 26 in which a piston 27 is disposed. The piston 27 is pushed to the right by a spring 28 as shown in FIG. Therefore, the right side of the piston 27 is pushed by the air supplied from the air supply boat 29.
This causes the piston 28 to move to the left. The piston 27 has screws and rods 30 marked with mounting numbers, and a blank needle 31 is fixed to the piston radial 330. - A sleeve 32 is fixed to the outer periphery of the distal end of the cylinder 26, and a protrusion 3 is attached to the distal end of the sleeve 32.
3 is formed. A needle insertion hole 34 is formed in the center of the protrusion 33. A hollow hole 135 is inserted into the insertion hole 34. Note that the hollow needle 35 is fixed to the tip of the cylinder 26. Further, a plurality of air suction holes 36 are formed along the circumferential direction outside the side insertion hole 34 of the protrusion 33 . Further, an air suction boat 37 is formed on the upper side of the sleeve 32.

In the above configuration, when the molds 21 and 22 reach the position facing the air blowing device 23 as the rotary table 20 shown in FIG.
An air blowing device 23 is inserted into the mold 21 as shown by the arrow.
is connected. This air blowing device 23 is connected to the molds 21 and 2.
A hole is provided on the side surface of the parison 25 housed in the recess 24 of No. 2, and air is blown into the parison 25 to perform blow molding.

To explain this operation in more detail, the air blowing device 2
Prior to connection with the mold 21 of No. 3, air is inserted through the air supply boat 29 of the cylinder 26 shown in FIG. 5, and the piston 27 is moved to the left within the cylinder 26.
The empty 1131 fixed to the piston 27 via the rod 30 is protruded from the tip of the hollow 135. In this state, the blowing device 23 is connected to the mold 21, and air suction is performed. Po 1-37 and J, three 132
The air in the space between the cylinder 26 and the cylinder 26 is exhausted. Then, the parison 2 in the mold 21 and 22 is removed by the air suction hole 36.
5 is sucked, and due to this suction force, the empty cap 31 and the hollow button 35 are relatively inserted into the parison 25.

As is clear from Fig. 5, the hollow forceps 31 have a sharp tip and protrude more than the hollow forceps 1135.
It does not look like it has been punched out, and no poly pieces separate from the parison 25 as in the prior art. Therefore, if such a device is used, the plastic pieces will be hollow-molded and will not remain in the container, thus preventing the plastic pieces from being mixed into the food filled in the container. becomes possible.

When the hollow 135, together with the blank button 31, is completely inserted into the parison 25, the supply of air from the boat 29 of the cylinder 26 is cut off, and the air in the cylinder 26 is discharged through this boat 29.

Then, the piston 27 is moved to the sea urchin spring 2 as shown in FIG.
Pushed by 8 to move to the right. Therefore piston 2
The hollow needle 31 connected to the hollow sword 35 via the rod 30 also moves in the same direction, and moves 11tllQ from the hollow sword 35. In this state, the air supply boat 3B formed in the cylinder 38, the cylinder 26, and the hollow! 1
Air is blown into the C parison 25 through 35. Then, the parison 25 is inflated by the air pressure and inflated 11 so as to come into close contact with the four parts 24 formed inside the molds 21 and 22, and is formed into a hollow container 39 by blow molding.
will be formed.

As described above, according to this embodiment, since the hole is made in the parison 25 by the hollow needle 31 movably disposed inside the hollow needle 35, the hole is made in the parison 25. Occurrence can be prevented.

Furthermore, since the parison 25 is made to have a hole by the blank 1131 with a sharp tip, it is possible to easily break through the hole even if the parison 25 has a large wall thickness. ] Becomes Noh. Another sharp void 11
31 is used so that it exceeds the C parison 2, so it is possible to set the inner diameter of the hollow chime 35 to a large value. Therefore, in order to speed up the blowing of air and to quickly remove the residual internal pressure, the time required for blow molding from 1 to 1 cycle is reduced. Can be shortened. Therefore, a highly productive blow molding method and apparatus for the same are provided.

As described above, the present invention makes a hole in the parison by means of a blank button arranged movably with respect to the needle inside the hollow 11, and inserts the hollow button into the hole. This invention relates to a blow molding method in which air is blown into the parison through this needle, and to the apparatus of (a). According to the invention, therefore, the hole is punched by a hollow needle! At the same time, plastic pieces separated from the parison/J't
It is possible to reliably prevent this from happening. Furthermore, since it becomes possible to increase the inner diameter of the hollow button, the productivity of hollow molding can be improved.

[Brief explanation of the drawing]

Figure 1 shows the air blowing stations of conventional hollow molding. l[
2 is a sectional view of another conventional air blowing device, FIG. 3 is a plan view showing the entire blow molding device according to an embodiment of the present invention, and FIG. 4 is a diagram showing the same components. FIG. 5 is an enlarged sectional view taken along the line V--V in FIG. 4, and FIG. 6 is a sectional view similar to FIG. 5 showing the air blowing operation. In No. 11 used in the drawings, 21.22...Mold 25...Parison 31...Empty needle 35...Hollow button. Agent Osamu Matsutoshi

Claims (1)

[Claims] 1. A method in which a hollow needle is inserted into a parison housed in a mold, and air is introduced into the parison through the hollow part of the needle to perform molding. A blow molding method characterized in that a hole is made in the parison using a hollow needle, the hollow needle is inserted into the hole, and air is blown into the parison through the needle. 2. A mold that holds a parison and a hollow needle that is movable relative to the mold and is connected to an air supply device, and the hollow needle is inserted into the parison. In a device that performs molding by introducing air into the parison through the needle, an empty needle is provided inside the hollow nail so as to be movable relative to the needle, and the empty needle is A hole is made in the parison in a state where the tip protrudes beyond the hollow button, and then the empty needle is retreated and air is blown through the hollow needle. Hollow molding method.