JP3124640B2 - Injection stretch 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 an injection stretch blow molding apparatus for performing one stage from injection molding of a preform to blow molding of a hollow container.

[0002]

2. Description of the Related Art Conventionally, a typical apparatus of this type has been disclosed in Japanese Patent Publication No. 53-22096. This apparatus supports a neck plate for a neck mold for holding a neck portion of a preform or a bottle at four positions of a rotating disk, and intermittently drives the rotating disk to move the neck mold to an injection molding station. It is rotated and transported to a conditioning station, a blow molding station and an unloading station.

[0003] This kind of rotating disk has a neck plate of four.
It has a considerable diameter because it is located opposite one of the stations, and its weight is considerable. Therefore,
At the present time, when the neck mold is rotated and conveyed to each station, the rotational driving force is also required more than necessary.

Japanese Patent Publication No. 4-9128 discloses a blow molding machine that rotatably supports a rotating disk on an upper substrate, drives the rotating disk to rotate, and moves the rotating disk up and down together with the upper substrate in conjunction with opening and closing of a mold. It has been disclosed. In this case,
In addition to the driving force for rotationally driving the rotating disk, a driving force for the upper substrate and the rotating disk having a considerable weight is required even when the upper substrate and the rotating disk are vertically moved.

On the other hand, Japanese Patent Publication Nos. 64-3657, 64-40316 and 3-159726 disclose a system in which a neck plate is linearly conveyed and circulated to each station. .

[0006]

In the type in which the neck plate itself is transported linearly, since the neck plate is relatively lightweight, the driving force required for transporting the neck plate can be reduced, and energy can be saved. Further, by conveying the neck plate itself, the conveying speed can be increased, and the molding cycle can be shortened.

However, when the neck plate itself is transported in a straight line, the following new problem arises particularly in an injection molding station.

For example, consider a case in which an injection cavity mold is fixed and the injection core mold and the neck mold are driven up and down in a region above the mold to perform mold clamping and mold opening. When the neck plate is linearly conveyed to the injection molding station having this configuration, a guide rail or the like for receiving and supporting the neck plate is used in the injection molding station. The guide rail is supported between the tie bars like other dies.

[0009] It has been found that a problem arises when the injection core mold is released from the preform in the above structure. That is, the preform immediately after injection molding and the injection core mold are in close contact with each other, and when the injection core mold is driven upward with respect to this preform, FIG.
An upward load F acts on the preform 100 as shown in FIGS. This upward load F is
It also acts on the neck plate via the preform and the neck mold.

Incidentally, as described above, the neck plate and the guide rail supporting the neck plate constitute a simple support beam supported between two tie bars.
As a result of the application of the upward load F as shown in FIG. 7, as shown in FIG. 8, the neck plate and its guide rail are subjected to upwardly convex bending deformation. In a rotary transfer type blow molding machine, this kind of bending deformation is prevented by a rotating disk and an upper base having considerable strength.However, in the case of a type in which a neck plate is transferred linearly, a neck plate and its guide rails are used. I have to rely on strength. If the above-described bending deformation is prevented by increasing the strength of the neck plate, the advantage of the linear transport method of directly transporting the lightened member is impaired.

On the other hand, in the rotary transfer type blow molding machine described above, even if the rigidity of the neck plate is low, the deformation of the neck plate at the time of release of the injection core mold is such that the rotating disk and the upper base have sufficient strength. Can be prevented. On the other hand, since the rotating disk has a considerable weight, a large rotating energy is required, and it is difficult to achieve high-speed transport of the neck plate. Furthermore, when the upper base moves up and down together with the rotating disk, the vertical movement energy is enormous, and it is impossible to realize high-speed mold clamping.

Accordingly, it is an object of the present invention to shorten the molding cycle by increasing the conveying speed of the neck plate, and to prevent bending deformation of the neck plate and the like at the time of mold release at the injection molding station. It is an object of the present invention to provide an injection stretch blow molding apparatus capable of performing the above.

[0013]

According to the present invention, there is provided an injection molding station for injection molding a preform, and a blow molding station for blow molding the preform holding heat during injection molding to form a hollow container. A neck cavity mold comprising at least a pair of split molds for forming a neck portion of the preform, supported by a neck plate, and an injection stretch blow molding device for circulating and transporting the neck plate to each station; Wherein the neck plate itself that supports the split mold in an openable and closable manner is circulated and conveyed to each of the stations, wherein the injection molding station mold-clamps an injection cavity mold, an injection core mold and the neck cavity mold, and Injecting a preform, and releasing the injection core mold from the preform When that is characterized in that a means for pressing the split or the neck plates in the direction to prevent the bending of the neck plate by releasing force.

[0014]

According to the present invention, the pressing means is driven when the injection core mold is released from the preform. The pressing means presses the pair of split molds or the neck plate constituting the injection cavity mold in a direction to prevent the neck plate from bending due to the release force of the injection core mold. Therefore, even if the rigidity of the neck plate is reduced by reducing its weight, no bending deformation occurs at the time of mold release at the injection molding station. Further, the rigidity of the member holding the neck plate can be reduced, and the weight of the holding member can be reduced. This holding member, in the case of a linear transport type,
It is a guide rail or the like located at the injection molding station. In the case of a rotary transfer type, it serves as a rotating disk and an upper base. When the present invention is applied to the rotary transport type, not only the neck plate but also the rotating disk and the upper base supporting the neck plate can be reduced in weight, so that the neck plate can be transported at a high speed. In the linear transport type, both when the neck plate itself is transported and when the neck plate is transported together with its holding member, both the neck plate and its holding member can be reduced in weight, so that high-speed transport is possible. Therefore, the molding cycle can be shortened in any case.

The pressing means preferably has a pressing ring which can move up and down around the injection core mold. Then, the pressing ring may be driven to protrude by a short stroke during the time including the time when the maximum load acts on the preform at the time of releasing the mold.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment to which the present invention is applied will be specifically described below with reference to the drawings.

First, the overall configuration of the injection stretch blow molding apparatus according to the embodiment will be described with reference to FIG. FIG. 2 is a plan view of the molding apparatus, in which a conveying path of a preform or a final molded product is formed along each side of a rectangular area of the bed 20. An injection molding station 10, a temperature control station 12, a blow molding station 14, and an unloading station 16 are arranged on the transport path.

In this embodiment, the injection molding station 10
Only two of them are juxtaposed, and preform injection molding is performed at the first and second injection molding stations 10a and 10b, respectively. Then, the first and second injection molding stations 10 requiring the longest processing time among the above-mentioned stations.
In (a) and (10b), the preform is molded with a time difference of (injection molding cycle time T / 2), whereby the operation rate of the blow mold is doubled to improve the throughput.

A two-row injection molding station 1 shown in FIG.
Details of the mold clamping mechanisms 0a and 10b will be described with reference to FIGS.

On the bed 20 of the molding machine, a total of eight tie bars 22 are set up vertically upward, four each corresponding to each area of the first and second injection molding stations 10a and 10b. Have been. As shown in FIG. 3, a hot runner block 26 capable of touching the injection nozzle 24 with a nozzle and an injection cavity 28 laminated thereon are provided in a region surrounded by the four tie bars 22. Above the injection cavity 28, a neck cavity mold 30 including a pair of split molds 32a and 32b and an injection core mold 34 are provided so as to be able to move up and down. And
The preform 100 can be injection-molded by clamping each mold as shown in FIG. 2, and then, as shown in FIG.
Can be taken out.

In order to clamp the molds, a tie bar 2 is used.
An upper mold clamping plate 40 that can be moved up and down is provided on the upper end side of 2. An injection core mold 34 is provided on the lower surface of the upper mold clamping plate 40.
Is fixed to the core-type fixing plate 42. The injection core mold 34 has a base end portion 36a fixed to the core mold fixing plate 42, a lower end having a tapered portion 36b fitted in a tapered hole of the pair of split dies 32a, 32b, and a lower end provided with a core pin. It has a portion 36c. This upper clamping plate 40
Is configured to be able to move up and down along the tie bar 22 by the high-speed cylinder 44 for opening and closing the mold, and to be pressed toward the injection cavity mold 28 by the high-pressure cylinder 46 for clamping at the lower end position.

A neck cavity mold 30 including a pair of split molds 32a and 32b is supported by a neck plate 50. In the present embodiment, the neck cavity mold 30 is integrated with the neck plate 50 and each of the stations 10 to 10
16 and circulates. In the injection molding station 10, as shown in FIG. 3, the neck plate 50 is carried in from the direction of arrow A, and is discharged in the direction of arrow B after injection molding of the preform 100. In order to support the neck plate 50 at the injection molding station 10, a neck type elevating plate 70 that can be raised and lowered along the tie bar 22 and a guide rail 72 fixed to the lower surface thereof are provided. The thin plate-shaped neck plate 50 is supported in a groove space formed between the neck-type elevating plate 70 and the guide rail 72, and its vertical and width directions are regulated. Neck type lifting plate 70
Is a neck-type lifting cylinder 7 fixed on a bed 20.
4 is connected to the fourth cylinder rod 74a. By driving the cylinder 74, mold clamping and mold opening of the neck cavity mold 30 with respect to the injection cavity mold 28 are possible.

The neck plate 50 is formed in a rectangular shape having a long side and a short side as shown in FIG. 5, and has a thickness that can be inserted into a space formed between the neck type elevating plate 70 and the guide rail 72. Have. The neck plate 50 has a parting surface 5 extending along the longitudinal side.
0a, and a pair of divided plates 52a, 52
b. Each split plate 52a, 52b
Are provided with semi-circular neck-type mounting openings 54 facing the parting surface 50a, for example, the same number as the number of simultaneous moldings, for example, eight. Around the neck-type mounting opening 54, holes 56 for fixing the pair of split dies 32a and 32b with bolts are provided.
have. Further, in order to reduce the weight of the neck plate 50 that is circulated and conveyed toward each of the stations 10 to 16, a large number of cutouts 58 penetrating from the front surface to the back surface of the neck plate 50 are formed. Neck plate 5
The pair of split plates 52a and 52b constituting the pair 0 have built-in coil springs that constantly contact the parting surfaces 50a. The coil springs are formed in spring receiving holes 6 formed at both ends in the longitudinal direction of the neck plate 50.
2 housed. Also, a pair of split plates 52a, 5
2b to release each split plate 52a, 52b
A wedge-shaped notch 64 is formed in the rim.

The neck plate 50 has a notch 58 to reinforce the reduced bending strength.
It has a rod accommodation hole 60 for accommodating a reinforcing rod (not shown). Further, at both ends in the longitudinal direction of the neck plate 50, grooves 65 used for driving the plate are formed. And, in this groove 65, the first and second
A positioning hole 66a for positioning the neck plate 50 is formed in the injection molding stations 10a and 10b. Further, positioning holes 66b for positioning the neck plate 50 at the blow molding station 14 are provided at, for example, two places of the neck plate 50.

In this embodiment, the neck plate 50 and the pair of split dies 32a, 32 are also provided in order to prevent the neck plate 50 from being bent when the injection core mold 34 is released.
A pressing means 80 for pressing b downward is provided.
The pressing means 80 has a pressing ring 82 arranged concentrically with the base end portion 36a of the injection core mold 34 and surrounding the same. In order to drive the pressing ring 82 up and down, an eject cylinder 84 is fixed to the upper mold clamping plate 40, and an elevating plate 86 is fixed to the cylinder rod 84a. A first eject pin 88 having an upper end fixed to the elevating plate 86 and a lower end inserted into a pin insertion hole 40 a penetrating from the front surface to the back surface of the upper mold clamping plate 40 is provided. This first eject pin 88
Can be protruded and retracted from the lower end opening of the pin insertion hole 40a by driving the eject cylinder 84. Further, a stepped hole 42a for pin insertion is provided at a position facing the pin insertion hole 40a of the upper mold clamping plate 40 and communicates from the upper end to the lower end of the core mold fixing plate 42. Eject pin 90 is accommodated. This second eject pin 90 has a flange 90a at its upper end,
A compression coil spring 92 is accommodated between the lower surface of the flange 90a and the step surface 42b of the pin insertion hole 42a. A pressing ring 82 is fixed to a portion where the second eject pin 90 protrudes from the lower end opening of the pin insertion hole 42a.

Next, the injection molding stations 10a and 10b
Will be described.

FIG. 2 shows a mold clamping state of the injection cavity mold 28, the neck cavity mold 30, and the injection core mold 34. After this mold clamping state, the hot runner block 2
Through 6, the cavity formed by each mold is filled with the molten resin. The resin filled in the cavity is supplied to the injection cavity mold 28 and the injection core mold 34.
After being cooled by the cooling medium circulating in the inside, a release operation for removing the preform 100 is started after a predetermined cooling time has elapsed.

In this embodiment, the injection cavity mold 28 is fixed on the bed 20 and the neck cavity mold 30
The preform 100 can be taken out by releasing the injection core mold 34 upward. For this purpose, the mold opening and closing high-speed cylinder 4
4 and the neck type lifting cylinder 74 is operated. Then, the upper mold clamping plate 40 and the neck mold elevating plate 70
Moves upwardly and integrally along the tie bar 22, and the releasing operation of the neck cavity mold 30 and the injection core mold 34 is started. Injection cavity mold 28
The integral release of the injection core mold 34 is performed until the neck plate 50 reaches the upper limit height position of the neck type elevating plate 74 shown in FIG.

After the neck plate 50 reaches this height position, the driving of the mold opening / closing high-speed cylinder 44 is continued, and the neck portion is held by the pair of split dies 32a and 32b as shown in FIG. Withdrawal of the core pin portion 36c of the injection core mold 34 from the preform 100 thus started is started. Then, before the pull-out drive of at least the core pin portion 36c is started, the drive of the eject cylinder 84 for driving down the pressing ring 82 is started. FIG. 1 shows a state in which the pressing ring 82 is driven to descend. That is, the eject cylinder 84
The lifting plate 86 is driven downward by the driving of the first ejecting pin 88 so that the first eject pin 88 is
0a will protrude from the lower end opening. For this reason,
The flange 90a of the second eject pin 90, which has been constantly urged upward by the compression coil spring 92, is pressed downward, and the pressing ring 82 is driven to move down around the base end 36a of the injection core mold 34. Will be. FIG.
This will be described with reference to FIG.

FIG. 7 shows the tie bar 2 when the core pin portion 36c of the injection core mold 34 is pulled out from the preform 100.
2 shows a load acting on the neck-type elevating plate 70 supported by the lifter 2 and the like. That is, when the core pin 36c is pulled out, the preform 100 has a considerable amount of heat during injection molding, and the inner wall of the preform 100 and the outer wall of the core pin 36c are in close contact with each other. When the core pin portion 36c is forcibly pulled out and driven in such a close contact state, the upward load F is applied to the neck plate 50 and the neck type elevating plate 72 via the preform 100 and the pair of split dies 32a and 32b. Will work. Since the neck-type lifting plate 70 constitutes a simple support beam whose both ends are supported by the tie bar 22, the upward movement of the load F causes the neck-type lifting plate 70 to act as shown in FIG. In addition, the neck plate 50 is subjected to bending deformation of the upward projection. Further, as shown in FIG. 8B, since the neck cavity is constituted by a pair of split dies 32a and 32b, a bending moment M acts on each of the split dies 32a and 32b as shown in FIG. Will be.

Such an upward load F is a repetitive load acting on the neck-type elevating plate 70 and the like each time the mold is released after injection molding. Therefore, there is a possibility that breakage may occur when the fatigue limit of each member is reached. . Also, a pair of split dies 32
a and 32b are acted on by bending moment M,
In particular, the neck portion of the preform 100 is deformed.

Therefore, in the present embodiment, at the initial timing when the core pin portion 36c is pulled out of the preform 100, the neck plate 50 due to the releasing force is used.
The pair of split dies 32a, 32b and the neck plate 50 are pressed by the pressing means 80 in a direction to prevent such bending (in this embodiment, a direction directed vertically downward). That is, when the neck type elevating plate 70 reaches the upper limit position, the eject cylinder 84 is driven, preferably at a timing before the upper limit position. As a result, the pressing ring 82 is driven to move down around the base end portion 36a of the injection core mold 34 by the above-described operation. This pressing ring 8
The lower end surface of 2 abuts on the upper surfaces of the pair of split dies 32a and 32b, and presses the lower portions downward, whereby bending of the neck plate 50 and the like can be prevented. The upward load F described above becomes the maximum when the core pin portion 36c starts to be pulled out. Therefore, the pressing of the pair of split dies 32a and 32b by the pressing ring 82 is performed for a relatively short time until at least a predetermined time elapses from a state before the core pin portion 36c is pulled out of the preform 100, that is, a short circuit. It is sufficient to perform the stroke drive. Therefore, it is not necessary to perform the downward drive by the pressing ring 82 while the core pin portion 36c is completely pulled out from the upper end opening of the preform 100.

As described above, according to the present embodiment, the neck plate 50 itself supporting the pair of split dies 32a and 32b is transported to each of the stations 10 to 16, and the cutout 58 is formed in the neck plate 50 by lightening. By reducing the weight of the transport mechanism, the load on the transport mechanism can be reduced and the size of the apparatus can be reduced. Further, while reducing the weight of the neck plate 50, the injection molding stations 10a, 1
When the mold is released from the mold at 0b, the neck plate 50 can be prevented from bending and deforming, and the deformation of the preform 100 can be prevented, so that molding with a high yield can be realized.
Further, by providing the pressing means 80, the strengths of the neck type elevating plate 70 and the guide rail 72 can be reduced.

Since the strengths of the neck type elevating plate 70 and the guide rail 72 can be reduced, one or both of them can be made thinner. The opening / closing stroke of the injection core mold 34 can be shortened, and the length of the core pin portion 36c can be shortened, because the neck-type lifting plate 70 or the guide rail 72 can be made thinner. As a result, the height of the blow molding machine can be made lower than before, the size of the apparatus can be reduced, and the cost and weight of the mold can be reduced.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

For example, the present invention can be applied to a rotary transfer type blow molding machine as described above. In this case, the strength of the rotating disk and the upper base can be reduced and the weight thereof can be reduced. Transport is achieved. Further, the pressing means 80 is not limited to the one having the configuration of the above-described embodiment, but the point is that when the injection core mold 34 is released from the preform, the bending force generated in the neck plate 50 due to the release force. Any method can be used as long as it presses the split mold 32 or the neck plate 50 in the direction to prevent the cracking.

[0037]

As described above, according to the present invention,
By circulating and transporting the neck plate itself supporting the pair of split dies to each molding station, it is possible to reduce the weight of the means for transporting the molded product. Therefore, the driving force of the transfer actuator can be reduced, and the molding cycle can be shortened by the high-speed transfer. Further, when the injection core mold is released from the preform at the injection molding station, the bending generated in the neck plate due to the release force can be prevented by providing the pressing means for pressing the split mold or the neck plate. In addition, it is possible to prevent the member from being damaged and to prolong the service life, and to reduce the load acting on the split mold, thereby preventing the deformation of the preform.
Also, since the rigidity of the holding member for holding the neck plate at the injection molding station can be reduced, the thickness in the mold opening / closing direction can be reduced. In this case, the opening / closing stroke of the injection core mold can be shortened, and the in-core Since the length of the part can be shortened, it is possible to reduce the size of the apparatus and reduce the cost and weight of the mold.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view for explaining a release operation at an injection molding station in a biaxial stretch blow molding apparatus to which the present invention is applied.

FIG. 2 is a schematic sectional view showing a mold clamping state in the injection molding station shown in FIG.

FIG. 3 is a side view in which a part of the injection molding station shown in FIG. 1 is cut away.

FIG. 4 is a partially cutaway front view of the injection molding station shown in FIG. 1;

FIG. 5 is a plan view of a neck plate circulated and conveyed to an injection molding station.

FIG. 6 is a schematic plan view of a biaxial stretch blow molding apparatus to which the present invention is applied.

FIGS. 7A and 7B are schematic explanatory diagrams for explaining upward loads acting on a neck plate when the injection core mold is released. FIGS.

8 (A) and 8 (B) are schematic illustrations for explaining a bending deformation generated in a neck plate as a result of the upward load shown in FIG. 7, respectively.

[Explanation of symbols]

 10a, 10b Injection molding station 28 Injection cavity mold 30 Neck cavity mold 32a, 32b A pair of split molds 34 Injection core mold 36c Core pin part 50 Neck plate 52a, 52b Split plate 58 Cutout part 70 Neck mold elevating plate 80 Pressing means 82 Press ring

Continuation of the front page (72) Inventor Shuichi Ogiwara 4586-3 Komoro-shi, Nagano Pref. Nissei ASB Machine Co., Ltd. (56) References JP-A-3-159726 (JP, A) Japanese Patent Publication No. 53- 22096 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 49/00-49/80

Claims (2)

(57) [Claims] 1. An injection molding station for injection molding a preform, and a blow molding station for molding a hollow container by blow molding the preform holding heat during injection molding, wherein the preform A neck cavity mold consisting of a pair of split molds for molding a neck part is supported on a neck plate, and the neck plate is circulated and conveyed to each station. The injection core mold and the neck cavity mold are clamped to perform injection molding of the preform, and when the injection core mold is released from the preform, the neck plate is released by a releasing force. Means for pressing the split mold or the neck plate in a direction to prevent bending is provided. Injection stretch blow molding apparatus. 2. The pressing unit according to claim 1, wherein the pressing unit includes a pressing ring that can move up and down around a base end of the injection core mold, and a start time of releasing the injection core mold from the preform. And a driving means for driving the pressing ring to protrude with a short stroke for a predetermined period of time.