JPH06126820A - Mold clamping device of blow mold - Google Patents

Abstract

PURPOSE:To provide a mold clamping device provided with structure which reduces a time necessary for clamping of a mold due to a fact that breaking or clamping of a blow mild is performed swiftly and, moreover, maintenance operation such as an exchange of blow molds also is performed simply without causing growing larger of the device. CONSTITUTION:The title device is provided with a mold supporting rest 32 capable of performing breaking and clamping in the opposite directions and a locking user 36 locking a mold clamping member 30 integrated with the mold supporting rest 32 and the mold supporting rest 32 on the closed position. The molding member 30 is clamped at a shorter moving stroke than that of the mold supporting rest by a noncompressible fluid after closure of the mold supporting rest having the longer stroke than that of the mold clamping member 30, through which miniaturization of a mechanism to which the noncompressible fluid is used can be performed. Therefore, securing of transporting properties and securing of a space at the time of an exchange of the molds can be simplified by miniaturizing the device and a time necessary for mold clamping can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow mold clamping device.

[0002]

2. Description of the Related Art Generally, a synthetic resin thin-walled packaging container called a biaxially stretched blow container has a preform obtained by injection or extrusion molding, which is placed in a blow mold and stretched in the longitudinal direction of the container. At the same time, the pressure of the gas blown into the interior causes lateral expansion.

In such biaxial stretch blow molding, for example, as shown in FIG. 5, a blow mold 100A is used.
There may be used a structure in which the hydraulic actuator 110 is provided on the back surface of the mold clamping plate 100 supporting the. In this structure, the opening / closing operation and the mold clamping operation of the blow mold 100A are performed by the same hydraulic actuator 110.

Further, as a structure for locking the mold at the closed position in order to prevent the mold from being opened during blow molding, as shown in FIG. There may be a case where concave engaging portions are provided at both ends in the longitudinal direction, and for example, a locking device 120 having an engaging member having a U-shape in plan view is provided facing the concave engaging portions.

[0005]

By the way, in the biaxial stretch blow molding, the blow pressure during molding is considerably increased.

Therefore, it is necessary to prevent the blow mold from opening against the blow pressure. Therefore, when the mold clamping force for preventing the mold opening is obtained by the hydraulic actuator, the diameter of the piston inserted in the cylinder of the hydraulic actuator can be increased to increase the mold clamping force. .

However, in the case of such a large diameter cylinder, a considerably large amount of oil is required in order to open and close the mold quickly.

Further, since the hydraulic pressure obtained when a large-diameter cylinder is used is considerably large, the impact force when the molds collide with each other is also large, and if this collision is repeated during molding, the mold will be fatigued. It will be noticeable.

On the other hand, when a lock device is used, for example, when a blow-molded product is suspended and held on a rotary disk for blow molding, a narrow space between the rotary disk and the machine base is avoided to avoid blow-molding. Locking devices will be provided at both ends in the longitudinal direction.

Therefore, for example, when the product area is very large and a pressure higher than the set mold clamping pressure is required, or when it is a container in which shape molding is difficult, the blow pressure is the mold clamping pressure. You may beat your strength. And
If such a phenomenon occurs when the number of products taken out is increased, the distance in the longitudinal direction of the blow mold also becomes longer, as shown in FIG.
As shown by the chain double-dashed line in (B), bending may occur at the center of the blow mold. Therefore, even with the structure using the locking device, it may not be possible to reliably prevent the closed mold from opening.

Moreover, when such mold opening occurs,
The molded product protrudes from the parting surface of the blow mold, and burrs are generated on the surface of the final molded product.

Further, when such a protrusion of the molded product occurs, the capacity of the container which is the final molded product also changes. That is, the protrusion of the molded product due to the stretching in the lateral direction results in an increase in the inner area in the lateral direction,
There is a possibility that the capacity of the final molded product may vary from molding to molding.

Therefore, it is desired to prevent flexural deformation of the blow mold in the longitudinal direction during mold clamping.

When the same hydraulic actuator is used for opening and closing the mold and for closing the mold in the above-described mold clamping structure, the hydraulic plunger is fixed to the machine base. However, when such a hydraulic actuator is equipped, the movement stroke of the hydraulic actuator may be set to a large value, which may make it impossible to quickly open and close the mold. In other words, when performing mold clamping on a molded product held on a turntable, if the number of molded products taken out is large, the length of the molded product in the arrangement direction also becomes long.
The open / close stroke of the blow type is also enlarged. This requires a stroke in order to prevent the blow mold from colliding with those at both ends in the arrangement direction of the molded product, which also lengthens the opening / closing time of the mold.

Further, when the mold opening and closing and the mold clamping are operated by the same hydraulic actuator, the hydraulic actuator is often fixed to the machine base. Therefore,
When removing the blow type, a set of hydraulic actuators must be taken out of the machine, but it is almost difficult to take out a large hydraulic actuator out of the machine.

Therefore, conventionally, only the blow mold 110A is removed from the mold clamping plate 110 attached to the plunger of the hydraulic actuator, and the blow mold 110A is pulled out of the machine while traversing the space facing the plunger. There is.

However, in this type of take-out method, the take-in / take-out operation is extremely difficult because the take-out operation cannot be performed within the narrow space where the plungers face each other.

Therefore, in view of the problems in the mold clamping device in the conventional biaxial stretch blow molding, the object of the present invention is to quickly open and close the mold and to reliably maintain the mold open state. It is an object of the present invention to provide a blow-type mold clamping device having a structure capable of controlling.

[0019]

In a mold clamping device for clamping a blow mold composed of a pair of split molds, two mold supporting bases which are provided on the machine base so as to face each other and can be opened and closed in opposite directions. A base, a high-speed actuator that drives the mold support base to open and close, and a lock member that is locked in the vertical direction of the mold support base after closing the mold support base to lock the mold support base in the closed position. , A drive rod that is provided integrally with the die support base and is capable of reciprocating with a stroke smaller than the opening / closing movement amount of the die support base by an incompressible fluid, and the split die is provided at the tip of the drive rod. Two mold clamping members that are fixed and that clamp the mold half after locking the lock member, wherein the lock member closes the mold support base when the mold mold is clamped by the mold clamping member. To keep the lock at It is characterized in.

According to a second aspect of the present invention, a rotary plate for rotating and conveying the intermediate molded product to the blow mold is provided above the machine frame, and the lock member is locked to the rotary plate and the machine frame. It is characterized by that.

[0021]

According to the present invention, the mold support base is opened and closed by the high speed actuator, and the movement of the mold clamping member is performed with a stroke shorter than the opening and closing stroke of the mold support base. Therefore, when a hydraulic mechanism that uses one of the incompressible fluids to move the mold clamping member is used, the hydraulic mechanism becomes larger than when both the mold opening and closing operations and the mold clamping operation are performed by the hydraulic mechanism. And the amount of oil required for high-speed opening and closing of the mold is small.

Further, since the hydraulic mechanism does not have to be upsized, labor for transportation can be reduced.

Furthermore, according to the present invention, after the mold support base is closed, the mold support base is locked in the vertical direction to lock the mold support base in the closed position, so that the entire length direction of the mold is covered. It becomes possible to lock at. Therefore, with a simple lock structure, the bending of the mold in the entire length direction can be prevented, and the mold can be reliably opened.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings.

FIG. 1 shows a molded product to which the blow mold clamping device according to the present invention is applied. This molded product is, for example, before the secondary blow molding of the biaxial stretch blow molding. It is obtained by oven blow molding, which allows a primary blow-molded product to be heat-shrinked in a heating furnace to obtain a heat-resistant molded product.

That is, the details of the oven blow molding are described in detail in, for example, Japanese Patent Application Laid-Open No. Hei.
No. 205124 and Japanese Patent Application Laid-Open No. 3-234520, for example, a preform 60 injection- or extrusion-molded using poly-ethylene terephthalate (hereinafter abbreviated as PET) is temperature-controlled. After that, each step for obtaining the primary blow molded product 70, the heat shrinkable molded product 80, and the secondary blow molded product 90 is included.

The primary blow-molded product 70 is extended in the longitudinal direction while the center is guided by a stretchable stretch rod (not shown) inserted from the neck portion of the preform 60, and the container is extended to the inside. Expansion molding in the lateral direction is performed by blowing a pressurized fluid, for example, air.

The heat-shrinkable molded product 80 is composed of 180-22
By heating the primary blow-molded product 70 in an atmosphere of 0 ° C., the primary blow-molded product 70 is thermally shrunk in the longitudinal direction and the lateral direction. The heat-shrinkable molded product 80 is molded so that its height is substantially the same as or slightly higher than that of the final molded product, and the size in the lateral direction is smaller than that of the final molded product.

In the secondary blow-molded product 90, the heat-shrinkable molded product 80 is positioned in the cavity of the blow mold formed to the dimensions of the final molded product, and the heat-shrinkable molded product 80 is introduced by introducing air.
Is stretched in the transverse direction.

On the other hand, FIG. 2 is a plan view showing an oven blow stage 20 which is a part of the oven blow molding apparatus 10 to which the mold clamping apparatus of the present invention is applied. Molding device 1
A turntable 22 is provided on the machine base of 0. Turntable 22
Is provided by a machine base so as to be intermittently rotatable in the direction of the arrow in the drawing, and has a transfer station 12 having a loading path for the primary blow-molded product 70 along the rotation direction of the turntable 22 and a secondary blow-molded product 90 discharged. A take-off station 14 having a path is located between these stations
First to fifth heating stations 24A to 24E are arranged. A secondary blow molding station is provided behind the fifth heating station, and the blow mold clamping device 30 according to the present invention is arranged in the secondary blow molding station.

The turntable 22 is provided with a structure for holding a molded product while it is moved to each station. This structure is described in, for example, Japanese Patent Laid-Open No. 3-234520. Is provided. In the case of the present embodiment, for example, four sandwiching members are provided as one block along the circumferential direction of the turntable 22.

Further, the transfer station 14 and the take-out station 14 are respectively provided with a supply device 16 and a take-out device 18 which are capable of reciprocating with respect to the turntable 22.

On the other hand, the blow mold clamping device 30 is arranged at the secondary blow molding station and is equipped with a blow mold composed of a pair of split molds which can be opened and closed in the radial direction of the rotary table 22. 3 and FIG.

That is, the mold clamping device 30 comprises a mold support base 32, an air cylinder 34, a mold clamping member 36 and a locking member 38.

The mold support base 32 faces the primary blow-molded product 70 suspended on the rotary disk 22 and is openable and closable in opposite directions. In the present embodiment, the structure for opening and closing the mold support base 32 in opposite directions includes a pair of racks 40 and 42 and a pinion 44, and the racks 40 and 42 are the machines of the oven blow molding apparatus 10. It can be guided and slid by the platform,
In addition, a pinion 44 is provided between the racks 40 and 42.
Are in mesh.

In order to move the racks 40 and 42, in this embodiment, an air cylinder 34, which constitutes a high speed actuator, is connected to one of the die support bases 32. The air cylinder 34 is a piston. The state in which 34A is stored is set as the initial state. Therefore,
When the initial position of the air cylinder 34 is set, the mold supporting bases 32 are placed at positions separated from each other, and the blow mold 50 is opened. The speed of the high speed actuator in this embodiment is set to be higher than that of the plunger 36A of the mold clamping member 36, which will be described later.

On the other hand, the mold clamping member 36 is the mold support base 32.
It is fixed to the upper surface of the
A plunger 36A that constitutes a drive rod for performing the mold clamping and a lock member 38 for locking the position of the mold clamping member 36 to the locking position are provided. Note that FIG.
In the figure, for convenience, the configuration of the plunger 36A in the left mold clamping member 36 and the lock member 38 in the right mold clamping member 36 are shown.

For example, the plunger 36A has a tip protruding from the inside of the mold clamping member 36 at a plurality of positions in the longitudinal direction of the blow mold 50 or at both end positions, and the base portion is inside a chamber formed inside the mold clamping member 36. It is fixed to the piston 36B that is inserted into. A mold substrate 52 to which the blow mold 50 is fixed is attached to the tip of the plunger 36A. Further, in the chamber, a space facing the piston 36B is filled with an incompressible fluid such as oil, and the piston is controlled by the supply / discharge control of the incompressible fluid between the spaces. 36
B can reciprocate.

The supply / discharge control of the non-compressible fluid is performed by, for example, a drive control unit (not shown) between the setting state of the die support base 32 by the air cylinder 34 and the locking state of the lock member 38 described later. It is set according to the result. In the present embodiment, the mold support base 32 is set to a closed state in which the parting surface of the blow mold 50 can be lightly butted, and the piston 36B is projected when the lock member 38 is locked. . Therefore, when the piston 36B protrudes, the split surfaces of the blow mold 50 are pressed against each other, whereby the mold is clamped. The pressing force used for mold clamping in this embodiment is set to have a lower limit of at least 40 kg / cm ² .
Further, in the present embodiment, the movement stroke of the piston 36A is set as the rod 38B of the lock member 38 described later.
Is set to a value approximately equal to the total of the fitting gaps generated between the rotating table 22 and the fitting portion on the base side.
It is an extremely small stroke of about 0.4 mm.

On the other hand, the lock member 38 is the mold clamping member 36.
It has a rod 38B fixed to a piston 38A inserted into a chamber formed inside.
The rods 38B are arranged at positions facing each other in the vertical direction of the mold clamping member 36, and are capable of projecting and retracting with respect to the machine base and the turntable 22 in conjunction with the forward / backward movement of the piston 38A. This lock member 38 is
It has a function of locking the die support base 32 in the closed position of the blow die 50 by engaging with the fitting portion 26 formed in the. By this function, the mold support base 32
When the blow pressure generated after the mold clamping is loaded, is held so as not to be opened by the blow pressure.

The chamber in which the piston 38A is inserted is filled with air in a space facing the piston 38A, and air is supplied and discharged between the spaces to control the rod. 38B can be vertically sunk.

Therefore, the air supply / discharge control is performed on the basis of causing the rod portion 38B to enter the fitting portion 26 when the mold support bases 32 are closed in the drive control portion described above. .

Further, the fitting portion 26 is composed of a bush attached to a hole formed in the turntable 22,
The rotary plate 22 is prevented from being damaged when the rod 38B hits.

In the figure, reference numeral 54 is a rod having a function as a contraction restriction and centering during the heat shrinking step of the primary blow molded product 70, a reference numeral 56 is a bottom mold of the blow mold 50, and a reference numeral 58 is 3 shows blow cores each having a built-in check valve that is connected to a holding member and opens in a direction in which a pressurized fluid for blowing is supplied.

Next, the operation will be described.

The mechanism using hydraulic pressure in this embodiment is only the mold clamping member 36.

That is, as shown in FIG. 4, the mold support base 32 is placed at a position where the air cylinder 34 connected to one side provides a closed state where the parting surface of the blow mold 50 is lightly abutted. It can move at a high speed, and when the die support base 32 moves to the closed position, the rod 38B of the lock member 38 moves to the turntable 22.
The fitting portion 26 and the machine base are locked by the air supply / discharge control. Therefore, when it is detected that the mold support base 32 has moved to a predetermined position and that the lock member 38 is engaged, the mold clamping member 36 blows by controlling the supply and discharge of an incompressible fluid such as oil. The blow mold 50 is moved with a stroke smaller than the opening / closing stroke of the mold 50 to press the parting surfaces of the blow mold 50 against each other. Then, in this state, when the secondary blow molding is performed on the heat-shrinkable molded article 80 located in the blow mold 50, the blow pressure acts on the blow mold 50. This pressure causes the lock member 38 to rotate the turntable 22. It is received by the fitting part 26 of the
The mold clamping member 36 is held at the position for clamping the mold. Therefore, part of the structure related to mold clamping is the turntable 2
2 and the lock member 38.
Since the lock member 38 engages with the turntable 22 and the machine base in the vertical direction of the mold support base 32, the blow mold 50
The blow mold 50 is prevented from opening not only at its both ends in the entire length direction, but also between the both ends.

On the other hand, when the secondary blow molding is completed, first, the pressurization of the blow mold 50 is released by the supply / discharge control of the incompressible fluid in the mold clamping member 36, and then the rod 38B of the lock member 38 is released. Locked and
The air cylinder 34 returns to the initial position. The pressure release to the blow mold 50 by the mold clamping member 36 may be performed after the engagement of the lock member 38 is released, or may be performed when the air cylinder 34 is returned to the initial position. Good.

According to the embodiment described above, the locking member 38
Since the mold clamping members 36 are provided at the upper and lower positions facing each other, the mold support base 3 is attached to the rack when blow pressure is applied.
It is possible to prevent 6 from tilting. Therefore, when the die support base 36 moves, the sliding portion of the die support base is prevented from biting into the rack, and smooth sliding can be performed.

Further, according to the present embodiment, the blow mold is moved to the closed position by driving the air cylinder which is a high speed actuator, and further, the moving stroke of the mold clamping member using the incompressible fluid. Is smaller than the stroke of moving the blow type to the closed position, so that the enlargement of the device when an incompressible fluid is used can be suppressed.

In the above-mentioned embodiment, the case where the step of heat-treating the primary blow-molded article by heat-shrinking is set before the secondary blow-molding is set. However, the present invention has such a structure. The present invention is not limited to the above, and various modifications can be made within the scope of the gist of the present invention. For example, it is possible to target a mold clamping device when manufacturing a biaxially stretched blow container without a heat treatment step.

Further, according to the present embodiment, the mold clamping member, which is set to have a small movement stroke, is operated by using the incompressible fluid, and the blow mold is moved to the closed position as a rack and rack structure. Since the pinion system is used, the structure of the mechanism that uses non-compressible fluid is downsized to reduce the labor required for transportation, and by removing one of the racks, the space for taking out the blow mold can be easily made. Can be secured.

The structure for moving the blow mold to the open / close position is not limited to the structure in which the air cylinder and the rack and pinion connected to one of the mold support bases are combined, and the air cylinders are used for both mold support bases. It is also possible to use a structure other than rack and pinion as a structure for connecting or moving in opposite directions.

[0054]

As described above, according to the present invention,
Speeding up the opening and closing drive of the mold support base used for mold opening and closing,
Since the mold clamping member, which moves with a stroke smaller than the moving stroke of the mold support base, is driven by the incompressible fluid, the mold can be opened and closed quickly. Moreover, since the moving stroke using the incompressible fluid is reduced, the mechanism using the fluid can be downsized.

Therefore, since the mechanism using the non-compressible fluid can be miniaturized, the labor required for transporting the mechanism can be reduced and the space for taking out the die at the time of exchanging the die can be easily secured.

Further, since the rotary table and the machine base can be locked in the vertical direction of the mold support base, the mold is prevented from bending when the blow pressure is applied in the mold opening direction to open the mold. It can be surely prevented.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a molded product obtained in a manufacturing process of a biaxially stretched blow container to which a mold clamping device according to the present invention is applied.

FIG. 2 is a plan view for explaining an overall configuration of an oven blow stage of an oven blow molding machine to which the mold clamping device according to the present invention is applied.

FIG. 3 is a schematic diagram for explaining the configuration of a blow mold clamping device according to the present invention.

FIG. 4 is a schematic view for explaining one position of the blow mold clamping device shown in FIG.

FIG. 5 is a schematic view showing a conventional example of a mold clamping device.

FIG. 6A is a plan view showing an example of a mold locking member;
FIG. 7B is a plan view showing the operation of the lock member shown in FIG.

[Explanation of symbols]

 10 Oven Blow Molding Machine 20 Oven Blow Stage 22 Rotating Plate 26 Fitting Part 30 Blow Mold Clamping Device 32 Mold Support Base 34 Air Cylinder 36 Mold Clamping Member 38 Lock Member 50 Blow Mold 70 Primary Molded Product

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Saburo Suzuki 4586 Ko Komoro-shi, Nagano 3 Nissei ASB Machinery Co., Ltd.

Claims (2)

[Claims] 1. A mold clamping device for clamping a blow mold composed of a pair of split molds, wherein two mold support bases are provided facing each other on the machine base and can be opened and closed in opposite directions, A high-speed actuator that drives the mold support base to open and close, a lock member that is locked in the vertical direction of the mold support base after the mold support base is closed, and locks the mold support base in the closed position; A drive rod that is provided integrally with the support base and is capable of reciprocating with a stroke smaller than the opening / closing movement amount of the mold support base by an incompressible fluid, and the split mold is fixed to the tip of this drive rod; Two mold clamping members for clamping the split mold after locking the lock member, wherein the lock member locks the mold support base at a closed position when the split mold is clamped by the mold clamping member. Characterized by maintaining Blow type of mold clamping device. 2. The blow mold tightening device according to claim 1, wherein a rotary plate for rotating and conveying the intermediate molded product to the blow mold is provided above the machine base, and the lock member is the rotary plate. Blow type clamping device characterized by being locked to the machine base.