JP3255497B2 - Blow molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molding apparatus, and more particularly to a blow molding apparatus having a blow mold opening prevention mechanism.

[0002]

2. Description of the Related Art Conventionally, as a method of molding a thin packaging container made of synthetic resin, a preform obtained by injection or extrusion molding is positioned in a blow mold, and a gas is blown into the inside of the preform and stretched. There is a method in which the rod is driven longitudinally to expand the preform in the longitudinal direction and the lateral direction, and is subjected to biaxial stretching blow to obtain a final container.

[0003] In the biaxial stretching blow step, the preform is stretched at a considerably high blowing pressure, and the stretched preform is pressed against the cavity surface of the blow mold, whereby the cavity surface of the blow mold is pressed. A final container having a shape corresponding to the shape can be obtained. Therefore, a blow mold composed of a pair of split molds used for blow molding must be held so as not to open due to blow pressure. This prevents the parting surface of the blow mold from opening during blowing and preventing the capacity of the final container from becoming larger than desired, and preventing the final container from protruding and generating burrs on the surface of the final container. It is necessary for.

Therefore, conventionally, when the parting surfaces of the split molds are joined, a force against the blow pressure is applied to the parting surfaces to clamp the molds, thereby preventing the blow molds from opening. Was. In particular, among the apparatuses for performing the biaxial stretching blow step, there is a type that horizontally transports a preform and a blow-molded product. As a blow mold clamping structure in this type of apparatus, a hydraulic actuator uses a blow mold. Some open / close and mold-clamp.
This structure is an effective structure in a horizontal transfer type molding machine so that when a preform or a blow-molded product is transferred, there is no obstacle between the blow dies that hinders the transfer. .

FIG. 10 is a view showing a blow type opening / closing structure using the hydraulic actuator. In the figure, a hydraulic actuator 110 is provided outside the split mold 100a of the blow mold 100 in the opening and closing direction.
The split mold 100a is supported by a mold clamping plate 114 attached to the tip of a piston rod 112 provided on the 10, and the blow mold 100 is opened and closed and the mold is clamped.

[0006]

However, in the above-mentioned mold clamping structure, when the parting surfaces of the split molds 100a are joined and blow pressure is applied, the blow pressure and the rod 112 are used to separate the split molds 100a. And the mold clamping force applied to the split mold 100a may act in the direction of lifting the split mold 100a.

For example, especially when the height of the final container is low and the content is large, the blow cavity is formed at the upper part of the blow mold 100, so that the blow pressure acts on the upper part of the blow mold 100 as an eccentric load, and Is applied as a force to open the split mold 100a outward. And each split mold 100a
There is a problem in that, while rising, the split mold 100a opens outward with the lower end of the parting surface as a fulcrum.

In order to avoid this problem, it is conceivable to reduce the blow pressure. However, for example, when molding a final container having a special shape, the blow pressure cannot be reduced.

The present invention has been made in order to eliminate the above-mentioned disadvantages of the prior art, and has as its object the following.
An object of the present invention is to provide a blow molding apparatus that prevents the blow mold from rising and opening the blow mold, and stabilizes the quality of the final container.

[0010]

In order to achieve this object, the invention according to claim 1 is based on a blow mold having a pair of split dies and a mold clamping portion provided outside the split dies. In a blow molding apparatus which is provided on the base and has a driving means for driving the blow mold in the opening and closing direction on the base, the blow mold has a guided portion along the opening and closing direction,
On the base, and providing a guide portion slidably engaged the said opening and closing direction with the guided portion.

According to a second aspect of the present invention, in the first aspect, the guided portion is formed only in the mold clamping portion of the blow mold.

According to a third aspect of the present invention, in the first or second aspect, when the blow mold is driven to close, the parting surface of the split mold is positioned at the center of the preform housed in the cavity of the blow mold. It is characterized in that a stopper for stopping the mold clamping movement of the blow mold when the shaft position is reached is provided.

[0013]

According to the first aspect of the present invention, when the blow mold is closed and driven by the driving means, the guide portion and the guided portion are engaged with each other, so that the upward movement of the blow mold can be restricted.

Therefore, when the parting surfaces come into contact with each other and are pressurized, it is possible to prevent the blow mold from opening while being raised. Further, the guide portion and the guided <br/> part, because those which permit the movement of the blow mold opening and closing direction, does not interfere with clamping of the blow mold.

According to the second aspect of the present invention, since the guided portion is formed only in the mold clamping portion, the formation of the guided portion can be omitted in the split mold exchanged corresponding to the final container. .

In addition to these functions, the invention according to claim 3 is characterized in that, when the split mold is closed, when the parting surface comes to the position of the center axis of the preform, the blow mold is further closed by the stopper. Does not move in the direction. Therefore,
The blow mold split mold does not hit the lip mold or the upper bottom mold and damages them, and the pair of split molds do not hit each other to damage the parting surface or the like. In particular, in a device in which the blow-type drive on both sides is not mechanically synchronized with a tie bar or the like, it is difficult to tune the blow-type drive on both sides. It is possible to prevent the lip mold from being pressed first to damage the mold.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing a blow molding apparatus 200 according to the first embodiment. In the figure, a rotating disk 220 is provided above a machine 210 of the blow molding apparatus 200, and the rotating machine 220 can intermittently rotate with respect to the machine 210 in a direction indicated by an arrow. Then, the preform (not shown) injection-molded at the injection molding station 202 is held by the lip mold 300 and rotated by the rotating plate 220 to perform the temperature control of the preform. A blow station 206 for executing a biaxial stretching blow molding step of reforming and an eject station 208 for executing a step of taking out a molded product pass through the respective stations.

Here, an enlarged side view of the structure of the blow station 206 is shown in FIG. This blow station 2
06 is a pair of split mold 10 and mold clamping plate 20 on machine stand 210.
And an actuator 30 and a guide means 40.

The split mold 10 has a cavity surface 14 corresponding to the final container on the parting surface 12 side (see FIG. 3). A blow cavity for blow molding a reform (not shown) into a predetermined shape can be formed. A slide metal 16 as an oil-containing material is attached to the bottom of the split mold 10.

The mold clamping plate 20 needs to be replaced with the split mold 10 depending on the shape of the final container.
0, the driving force from the actuator 30 is split
To facilitate the exchange of the split mold 10. The mold clamping plate 20 is mounted on the opposite side of the parting surface 12 of the split mold 10, and a slide metal 26 as an oil-impregnated material is mounted on the bottom thereof. It is designed to move smoothly.

The actuator 30 linearly moves the rod 32 by hydraulic pressure such as hydraulic pressure, and drives the split mold 10 in the opening and closing direction via the mold clamping plate 20 attached to the tip of the rod 32, thereby causing the split mold 10 to move. At the time of closing, the split mold 10 is further pressurized at a predetermined pressure. In addition, the magnitude of this pressure is set to a magnitude that can prevent mold opening in accordance with the blow pressure.

The guide means 40 includes a guide groove 42 as a guided portion and a guide projection 44 as a guide portion (see FIG. 3). The guide groove 42 is a concave rail formed on both sides of the split mold 10 and the mold clamping plate 20 so as to be continuous in the opening and closing direction of the split mold 10.

On the other hand, as shown in FIG. 3, which is a sectional view taken along line AA of FIG. 2, the guide projections 44 are formed on a pair of guide plates 46 provided on both side surfaces of the split mold 10 and the mold clamping plate 20. , And are convex rails formed so as to be continuous in the opening and closing direction of the split mold 10.

The guide grooves 42 and the guide projections 44 have corresponding shapes. Then, as shown in FIG. 4 which is a partially cutaway plan view of the blow station 206, the guide groove 42 and the guide projection 44 always engage partially regardless of the open / closed state of the split mold 10. I have. In this way, since both are engaged, the split mold 10
Even if is pressed, the upward movement of the split mold 10 can be restricted, and the split mold 10 can be prevented from opening while rising. Note that the guide groove 42 and the guide protrusion 44 do not always have to be engaged with each other.
0 from the middle of the closing drive to the completion of closing, and the split mold 10
May not be engaged when fully opened.

The first embodiment is constructed as described above, and its operation will be described below.

Injection molded preform (not shown)
Is transported to the blow station 206 while being held by the lip mold 300 shown in FIG. Next, the split mold 10 is driven in the closing direction via the mold clamping plate 20 by the actuator 30 shown in FIG. Since the slide metals 16 and 26 are provided on the bottoms of the split mold 10 and the mold clamping plate 20, smooth driving is possible. Then, even if the parting surfaces 12 of the pair of split dies 10 come into contact with each other, a driving force is further applied to the split dies 10, and the split dies 10 are pressed and clamped.

At this time, the guide groove 42 and the guide projection 44
However, since both are formed along the opening and closing direction of the split mold 10, the movement of the split mold 10 in the opening and closing direction is not hindered. On the other hand, since both are always engaged in the up-down direction, the upward movement of the split mold 10 is restricted, and it is possible to prevent the split mold 10 from opening while rising.

Next, a second embodiment will be described with reference to FIGS. FIG. 5 is a side view of a blow station according to the second embodiment, and FIG. 6 is a sectional view taken along line BB in FIG.

The feature of the second embodiment is that, compared to the first embodiment, the length of the split mold 50 in the height direction is shortened, the slide metal is omitted, and the guide groove 52 is formed only by the mold clamping plate 20. 5 is that the width of the guide plate 56 is increased to lengthen the rail of the guide projection 54 in FIG. 5, and the split mold 50 is disposed above the guide projection 56. Also,
The bottom surface of the cavity of the split mold 50 is formed by the upper bottom mold 80. Other configurations are the same as in the first embodiment.

As described above, since the guide groove 52 is provided only in the mold clamping plate 20, it is possible to omit the formation of the guide groove in the split mold 50 to be exchanged according to the shape of the final container. In addition,
By disposing the split mold 50 at a position above the guide projection 54, the split mold 50 is arranged so as to avoid the guide projection 54.
Can be opened and closed.

Next, a third embodiment will be described with reference to FIGS. FIG. 7 is a side view of a blow station according to the third embodiment, and FIG.
FIG. 9 is a sectional view taken along line C of FIG. 9, and FIG. 9 is a partially cutaway plan view of the blow station of the third embodiment.

The feature of the third embodiment is that a stopper 60 is provided as compared with the first embodiment, and the other configuration is the same as that of the first embodiment.

The stopper 60 is, as shown in FIG.
It comprises a positioning recess 62 and a positioning pin 64. The positioning recesses 62 are formed on the parting surfaces 72 of the pair of split molds 70.
And is formed at a position corresponding to each parting surface 72.

On the other hand, the positioning pin 64 is provided on the machine base 210 at the position of the center axis of the preform (not shown) when the blow cavity is stored, as shown in FIG.

As shown in FIG. 9, the parting surfaces 72 are in contact with each other so that the corresponding pair of positioning recesses 62 sandwich the positioning pin 64.

In the third embodiment, since the structure is configured as described above, when the split mold 70 is closed, if the driving of one and the other split molds 70 is not synchronized, one split mold 70 is not synchronized. Even if only the first reaches the closed position, the positioning recesses 62 come into contact with the positioning pins 64, so that the split mold 70 does not advance any further. Therefore, the split mold 70 does not hit the lip mold 300 (see FIG. 1) or the upper bottom mold 80 (see FIG. 5) and break them.

When the driving is synchronized, the parting surfaces 72 do not collide with each other due to excessive driving force, and the parting surfaces 72 are not damaged.

The present invention is not limited to the above embodiment,
Various modifications are possible within the scope of the invention. For example, the above-described embodiment is a so-called hot parison type four-station blow molding apparatus. However, the present invention is not limited thereto. The same hot parison type three-station molding apparatus may be used, or a cold parison type molding apparatus may be used. It may be a blow molding device.

Further, the present invention is not limited to the one in which the guide groove 42 is formed in the split mold 10 and the mold clamping plate 20 and the guide projection is provided for engaging with the guide groove 42. It may be formed and provided with a rail engaging with this guide projection.

Further, a hole is made to penetrate the split mold 10 and the mold clamping plate 20 in the opening and closing direction, and a guide rod is inserted into the hole, thereby guiding the split mold 10 and the mold clamping plate 20. There may be.

[0042]

According to the claim 1, wherein as described above the invention according to the present invention, the engagement between the guide portion and the guided portion, the effect of the mold opening of the blow mold can improve the quality of the final container can be prevented There is.

According to the second aspect of the present invention, the split mold has an effect that the formation of the guided portion can be omitted.

Further, according to the third aspect of the invention, there is an effect that the stopper can prevent breakage of the lip type, the upper bottom type, the parting surface and the like.

[Brief description of the drawings]

FIG. 1 is a plan view showing a blow molding apparatus according to a first embodiment.

FIG. 2 is an enlarged side view showing the structure of the blow station in FIG. 1;

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a partially cutaway plan view of the blow station of FIG. 2;

FIG. 5 is a side view of a blow station according to a second embodiment.

6 is a sectional view taken along line BB in FIG.

FIG. 7 is a side view of a blow station according to a third embodiment.

FIG. 8 is a sectional view taken along line BB in FIG. 7;

FIG. 9 is a partially cutaway plan view of a blow station according to a third embodiment.

FIG. 10 is a side view of a blow station in a conventional blow molding apparatus.

[Explanation of symbols]

100 split mold 12 parting surface 20 mold clamping plate 30 actuator 40 guide means 42 guide groove 44 guide protrusion

Continuation of the front page (56) References JP-A-5-31795 (JP, A) JP-A-63-116830 (JP, A) JP-A-5-38750 (JP, A) JP-A-4-344220 (JP) JP-A-3-203622 (JP, A) JP-A-6-226826 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 49/00-49/80

Claims (3)

(57) [Claims] 1. A blow mold having a pair of split molds and a mold clamping portion provided outside the split mold is disposed on a base,
In the blow molding apparatus comprising a drive means for driving the blow mold with the base surface plate in the closing direction, wherein the blow mold, the provided guided portion along the opening and closing direction, on the foundation, the guided portion And a guide portion slidably engaged in the opening / closing direction. 2. The blow molding apparatus according to claim 1, wherein the guided portion is formed only on the mold clamping portion of the blow mold. 3. The blow mold according to claim 1, wherein a parting surface of the split mold comes to a center axis position of a preform housed in a cavity of the blow mold during the closing drive of the blow mold. And a stopper for stopping the mold clamping movement of the blow mold.