JPH0698678B2 - Continuous blow molding method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a split mold that moves a parison extruded from a die head of an extruder in synchronism with the extrusion speed, like a rotary blow molding device. Sequentially insert with the device,
Continuously blow mold desired hollow molded products such as bottles,
The present invention relates to a continuous blow molding method and apparatus for sequentially opening the divided mold apparatuses to take out hollow molded articles in the form of strands in which the parts between the divided mold apparatuses are connected by burrs.

[Conventional technology]

In the blow molding method, when the mold is opened, it is always temporarily held in the split molds on the same direction side, and then released from this, the molded product after being released in a strand shape is treated. It is desirable to do.

By the way, as an apparatus used in the blow molding method of continuously performing blow molding, a parallel movement in which one mold of one of the facing molds is relatively parallel to the other mold in the opposite direction. Mold or one mold, the other mold is rotated in a direction orthogonal to the moving direction to mold-clamp and open the mold. There is a so-called double-door type in which the molds are clamped by cooperating symmetrically with respect to the position to open the molds.

In the conventional one-sided single-door type, as shown in Japanese Utility Model Laid-Open No. 61-47619, a hollow hollow molded product at the time of mold opening is held in a fixed-side split mold, and then fixed. The hollow molded article is released by pushing up with a pushing-up member provided in the divided mold on the side.

Further, in the double-door type, the one split mold is provided with a recess for temporarily holding a molded product in the split mold together with a knock pin in the mold clamping direction of the mold, or protrudes into the molded product. A holding rod is provided so that the molded product when the mold is opened engages with the above-mentioned recess, or is retained by the holding rod to temporarily hold it in one of the divided molds, and then each is protruded with a knock pin to be hollow. It is designed to release the molded product.

[Problems to be Solved by the Invention]

Among the conventional blow molding methods and devices thereof, in the case of the single-open type, the device becomes large because a push-up member has to be provided in each of the divided molds of a plurality of sets provided by connecting them together. However, there is a problem that the operation process of the push-up member becomes complicated and the timing tends to shift. Further, when the mold is opened, the molded product is not always held on the non-moving side split mold side provided with the lifting member, and the molding process may be disturbed.

On the other hand, in the case of the parallel movement type or the double-door type, in which one of the split molds is provided with a recess along with a knock pin in the mold clamping direction (for example, Japanese Examined Patent Publication No. 47-42932), the recess In order to give the hollow molded article a function to temporarily hold the hollow molded product, this recess must be formed into a so-called undercut shape with a large back side. The part becomes thin, and when this ear part is pushed out with a knockout pin when it is not completely hardened and partitioned, this ear part is pierced by the knockout pin, which causes a trouble in releasing the molded product. There was an occasion.

The present invention has been made in view of the above, and in any of the continuous blow molding methods of the double-sided opening type, the double-sided opening type, and the parallel movement type, one split mold that is always determined at the mold opening position. The hollow molded product is temporarily held in the mold, and the subsequent mold release is easily performed, and the mold opening process and the mold release process are smoothly performed without timing deviation, and further, molding defects such as air leakage may occur. It is an object of the present invention to provide a continuous blow molding method which does not include a continuous blow molding method.

In addition, there is no movable member for releasing the push-up member, knock pin, etc. as a device for carrying out the above continuous blow molding method,
It is an object of the present invention to provide a continuous blow molding device which has an extremely simple structure, does not change molding conditions for a long time, and does not require repair.

[Means for Solving the Problems]

In order to achieve the above object, the continuous blow molding method according to the present invention, a parison extruded from a die head of an extruder is moved in synchronism with the extrusion speed, and a large number of pairs of split molds are provided. With the split mold unit, the desired hollow molded products are blow-molded continuously, and then the split mold units are opened one after another to form a continuous strand at the part between the split mold units. In the continuous blow molding method in which the hollow molded product is taken out, the hollow molded product at the time of opening the mold is one of the split molds of the split mold device, and is formed on the side surface of the cavity of the split mold that performs the mold clamping operation. The hollow mold product was engaged with a recess provided in a direction perpendicular to the mold clamping direction of the split mold and temporarily held in this split mold, and then the hollow molded product was pulled and continuously released from the mold.

Further, the apparatus for carrying out the continuous blow molding method is provided with a large number of split mold apparatuses each consisting of a pair of split molds so as to be continuously movable at a predetermined speed, and mold clamping, blow molding with the movement. In a continuous blow molding device configured to perform mold opening, in one split mold of the split mold device and on the side surface of the cavity of the split mold that performs the mold clamping operation, in a direction orthogonal to the mold clamping direction. It is configured to have a recess.

[Action]

Hollow molded products molded by each split mold device that moves continuously are temporarily held on one split mold side that opens during mold opening of the split mold device, and then the hollow molded product can be pulled. Thus, the mold is released from the temporarily held split mold.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a rotary blow molding machine 1. This rotary blow molding machine 1 comprises a plurality of sets of split mold devices.
2,2 ... are connected in a radial shape at equal intervals and are connected in an arc shape so as to rotate in a vertical plane. With this movement, mold clamping is performed in a part of the circumferential direction and the split metal The parison 3 extruded from the die head A is sandwiched in the mold device 2,
Further, the mold is opened at the other portion, and the molded product 4 blow-molded while being clamped at the mold clamping position and moving on the arc is taken out at this portion. .

Each installment device 2 in the rotary blow molding machine 1
Is a fixed-side split mold 2a fixed to the disk-shaped rotary base 5 side, and is rotated relative to the fixed-side split mold 2a in a direction orthogonal to the moving direction of the mold. It is composed of a split mold 2b on the moving side which is adapted to be closed and opened.

The split mold device 2 is as shown in FIG.
The cavities 5, 6 for the body of the bottle and the cavities 7, 8 for the burr are respectively provided on both the fixed side and the moving side split molds 2a, 2b.
The burr cavities 7 and 8 are provided with concave grooves 7a and 8a for holes into which blow injection needles are inserted. In addition,
In this embodiment, the main body cavities 5 and 6 are separated from the burr cavities 7 and 8, and the burr cavities 7 and 8 are the heads of the body cavities 5 and 6 of the subsequent split mold 2. It is designed to be connected via Paris 3.

A concave portion 9 is formed on a side surface of the burr cavity 8 of the split mold 2b on the moving side of each split mold device 2, 2, ... In a direction orthogonal to the mold clamping direction.

A continuous blow molding method using the apparatus configured as described above will be described below with reference to FIGS. 3 to 5.

.. are moved in synchronism with the extrusion speed of the parison 3 extruded from the die head A, and the split mold 2b on the moving side rotates at the mold clamping position to move the parison 3 above. The sandwiched mold is clamped. After that, a blow injection needle is inserted into the hole formed by the concave grooves 7a and 8a to inject a pressure fluid to expand the parison 3 in the split mold device 2 and blow molding. At this time, the body 10 of the hollow molded product is continuously formed in a strand shape with the preceding burrs cavities 7, 8 of the split mold 2. At this time, in the burr cavity 8 on the side of the movable die 2b, a burr hollow portion 12 having a protrusion 11 formed along a recess 9 provided on the side surface of the cavity 8 is formed. It

Next, the split mold 2b on the moving side is sequentially opened at the mold open position, whereby the hollow molded product is pulled out in a strand shape.

At this time, the appearance in parts 7 and 8 of the cavity for burr is the third
From the figure to Figure 5, the cavities for burr 7,8
The side surface in the direction orthogonal to the mold clamping direction of the hollow portion 12 for burr formed by is engaged with the split mold 2b side on the moving side by the protrusion 11 (FIG. 3). Therefore, during the mold opening operation, the burr hollow portion 12 moves together with the burr cavity 8 on the moving side (FIG. 4). As a result, the main body 10 of the hollow molded product, which is connected to the burr hollow portion 12 by the burr, is released from the fixed side split mold 2a together with the burr hollow portion 12 and the moving side split mold 2b side. Temporarily held.

When the moving-side split mold 2b moves and opens at a certain angle, the hollow molded product is connected in the form of a strand and sequentially pulled, so that it is also released from the moving-side split mold 2b ( (Fig. 5).

In the above-mentioned embodiment, the concave portion 9 is provided on the side surface of the movable split die 2b on the side of the rotating hinge. However, the concave portion 9 is provided on the side surface on the opposite side, the side surface on the side of the main body cavity 6 and the opposite side. It may be provided on the side surface of.

Further, in the above-described embodiment, an example is shown in which the movable split mold 2b is rotated with respect to the fixed split mold 2a. However, this movable split mold is used as the fixed split mold. It may be applied to a parallel movement type in which it moves in parallel with respect to.

Further, in the above-mentioned embodiment, the case of the single-open type in which one of the pair of split molds constituting the split mold device 2 is the fixed side and the other is the moving side is shown. It may be a double-door type that moves from the state in a symmetrical direction. In this case, a concave portion 9 is provided in the hollow portion of one of the split molds in a direction orthogonal to the mold clamping direction.

〔The invention's effect〕

According to the continuous blow molding method of the present invention, at the mold open position, the hollow molded product and one of the split molds are locked by the protrusion projecting from the hollow molded product side, so that the double-ended double-sided mold is provided. In any of the continuous blow molding methods for both the double-door type and the parallel movement type, the hollow molded product is always temporarily held in one of the divided molds that is set at the mold opening position, and the subsequent mold release is performed. It is performed easily and smoothly without timing deviation from the mold opening process to the releasing process, and further, molding defects such as air leakage do not occur.

Further, according to the apparatus of the present invention for carrying out the continuous blow molding method according to the present invention, there is no push-up member or knock pin for releasing the hollow molded product, and the structure is extremely simple, and over a long period of time. The molding conditions remain unchanged and there is no need for additional training.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a schematic configuration explanatory view of a rotary blow molding machine, FIG. 2 is a perspective view showing a split mold device, FIG. 3, FIG. FIG. 5 is a cross-sectional view showing the operation explanation. 1 is a rotary blow molding machine, 2 is a split mold device, 2a, 2
b is a split mold, 3 is a parison, 9 is a concave portion, and 12 is a hollow portion for burr.

Claims (2)

[Claims] 1. A parison extruded from a die head of an extruder is moved in synchronism with the extrusion speed, and is sandwiched by a plurality of sets of split mold devices each consisting of a pair of split molds to obtain a desired shape. In a continuous blow molding method in which a hollow molded product is continuously blow-molded, and then the split mold units are sequentially opened to take out the hollow molded product in a continuous strand at a portion between the respective split mold units. The hollow molded product at the time of opening the mold is one of the divided molds of the divided mold device, and is provided on the side surface of the cavity of the divided mold that performs the mold clamping operation in a direction perpendicular to the mold clamping direction of the divided mold. The continuous blow molding method is characterized in that the hollow molded product is engaged with the concave portion and temporarily held in one of the split molds, and then the hollow molded product is pulled to continuously release the mold. 2. A plurality of sets of split mold devices each consisting of a pair of split molds are provided so as to be continuously movable at a predetermined speed, and mold clamping, blow molding, and mold opening are performed in accordance with the movement. In the continuous blow molding device, one of the divided molds of the divided mold device, and a concave portion is provided on the side surface of the cavity of the divided mold that is clamped in a direction orthogonal to the mold clamping direction. Characteristic continuous blow molding equipment.