DE102017102838A1 - Apparatus and method for forming plastic preforms to plastic containers with blown by moving bottom part - Google Patents

Abstract

Forming device (1) for forming plastic preforms (10) into plastic bottles, wherein the forming device (1) has a blow mold with a first side part (4), a second side part (6) and a bottom part (2), these side parts (4, 6) as well as the bottom part (2) form a cavity (15) within which the plastic preforms (10) can be formed into the plastic bottles, and wherein the forming device (1) carrying means (14, 16) for supporting the side parts (4, 6) and between at least one support means (14, 16, 24, 26) and at least indirectly on this support means (14, 16) arranged side part (4, 6) is arranged acted upon by a flowable medium pressure pad means (12), wherein by the application this pressure pad assembly (12) with the flowable medium which is arranged on this support means (14, 16) side part (4, 6) in the direction of the other side part is urged. According to the invention, the bottom part (2) is movable relative to the side parts (4, 6) in a closed state of the blow mold, and the forming device (1) has a drive device (30) to move the bottom part (2) in relation to the side parts (4, 6). to move.

Description

The present invention relates to an apparatus and a method for forming plastic preforms into plastic containers. Such devices and methods have long been known in the art. In this case, heated plastic preforms are usually introduced into blow molds and then expanded by applying compressed air to containers, in particular bottles. In the prior art so-called blow molds are usually used, which have two side parts and a bottom part, which together form a cavity within which the plastic preforms are expanded to the plastic bottles.

It is also known in the art that during the blowing process, the bottom part of this blow mold is delivered to the plastic preform, in particular to produce a kink in the container to be produced. Such conversion stations are also referred to as Active Base units. Usually, the bottom parts are also pneumatically moved, that is, a piston is delivered by applying compressed air to the plastic preform during the blow molding process. However, this sometimes requires a relatively complicated valve technology, since additional 3/2 -way valves must be maintained.

The present invention is therefore based on the object to simplify such devices for producing plastic containers. This object is achieved by the subjects of the independent claims. Advantageous embodiments and further developments are the subject of the dependent claims.

A forming device according to the invention for forming plastic preforms to plastic bottles has a blow mold, which in turn has a first side part, a second side part and a bottom part, said side parts and the bottom part form a cavity within which the plastic preforms are deformable to the plastic bottles and wherein the Forming device carrying means for supporting the side parts and arranged between at least one support means and a least indirectly arranged on this support means side member is acted upon by a flowable medium pressure pad device, wherein by applying (this pressure pad means) with the flowable medium arranged on this support means side part in Direction of the other side part is urged.

According to the invention, the bottom part is movable relative to the side parts in a closed state of the blow mold, the forming device having a drive device in order to move the bottom part relative to the side parts. Thus, the pressure pad device is generally an urging device which is suitable and intended to urge one side part (in particular by the effect of air pressure) in the direction of the other side part, in particular so as to form a forming gap which arises between the two side parts out.

It is therefore proposed that a forming device is provided which, in addition to the movable bottom part, also has a so-called pressure pad, which serves to deliver the side parts of the blow mold to one another. Through a combination of these approaches, the manufacture of the containers can be improved in terms of bottle quality.

In a preferred embodiment, the bottom part is movable in a closed state of the blow mold and can be delivered in particular to the plastic preform in the longitudinal direction thereof. The closed state of the blow mold is, in particular, the state in which the parts of the blow mold form the cavity which serves to expand the plastic preforms. Preferably, the blow mold is in this closed state, while the plastic preforms are expanded.

Preferably, the flowable medium is compressed air. The pressure pad assembly can be acted upon with compressed air to deliver the two blow moldings each other. Advantageously, the forming device also so-called carrier shells on which the side parts of the blow mold are arranged. These carrier shells in turn are arranged on the above-mentioned carrying means, that is, the blow mold carriers. The pressure pad is advantageously arranged between the carrier shell and the side part arranged on this carrier shell. Advantageously, the device also only (exactly) a so-called pressure pad, that is, only one of the two side parts can be delivered to the other, whereas the other side part is fixedly arranged on the carrier shell associated therewith.

In a further advantageous embodiment, the forming station has a plurality of valves to control the loading of the plastic preforms with different pressures. It is preferred that the plastic preforms are first subjected to a Vorblasdruck, then with a so-called Zwischenblasdruck and finally with a Final blowing. In this case, the intermediate blowing pressure is preferably higher than the pre-blowing pressure and the finished blowing pressure is again preferably higher than the intermediate blowing pressure.

In a further advantageous embodiment, the device has at least one reservoir for holding the air at a predetermined air pressure. Preferably, the device has a plurality of such reservoirs, each serving to hold air at different pressures. Preferably, at least one of these reservoirs is designed as an annular channel, which is suitable and intended to supply several transformation stations with air pressure.

In a further advantageous embodiment, the device has a unit for recycling compressed air. So it is possible that compressed air after the expansion of the container in turn is passed back into a compressed air reservoir. In a further advantageous embodiment, each forming station has a rod-like body, which can be inserted through an opening of the containers in this, in order to stretch them in the longitudinal direction. Furthermore, the forming station also preferably has a loading device in order to supply the plastic preforms with a flowable and in particular a gaseous medium, in particular in order to expand them. This loading device may in particular be a so-called. Blasdüse, which can be applied to the mouth of the plastic preforms.

In a further advantageous embodiment, the drive device is also acted upon by a flowable medium drive means. In particular, this is a pneumatic drive device which serves to move the bottom part. In a preferred embodiment, the drive device can be acted upon by the same flowable medium as the pressure pad arrangement. By this is meant that in particular a part of the air required for operating the pressure pad arrangement is also used to control the drive device for moving the bottom part.

It is suggested that the Active Base unit does not require a separate compressed air supply.

In a further advantageous embodiment, the shaping device has a feed device and in particular a feed line for feeding the flowable medium, wherein both the pressure pad device and the drive device can be supplied by means of this feed device.

In a particularly preferred embodiment, the forming device has a valve device in order to supply the drive device with compressed air. Thus, for example, a portion of the air can be diverted, which serves to actuate the pressure pad assembly. By means of this branched air, the drive means for moving the bottom part can be supplied.

In a further advantageous embodiment, this valve device is designed as a 2/2 way valve.

This can be saved by using this 2/2-way valve is a much more expensive in itself 3/3 high pressure valve with separate vent. In addition, the existing air recycling system can already be used by the procedure described here. In this case, a control device is preferably provided, which also controls this valve device. For example, during the start of the supply of the pressure pad arrangement with the required pressure, this valve may be closed. Only at a desired time, for example, during the loading of the plastic preform with the Fertigblasdruck this valve can be activated and thus control the bottom mold or the bottom part.

Thus, the forming device particularly preferably has a control device for controlling the valve device, and this control device is preferably designed such that a switching time point at which the valve device is switched can be changed. In this way, in particular it can also be determined at what time should be started with the delivery of the bottom part in the direction of the plastic preforms.

In addition, a valve may be provided which allows the provision of the bottom part in a starting position.

The present invention is further directed to a method of forming plastic preforms into plastic bottles. In this case, a plastic preform is introduced into a blow mold, this blow mold having at least two side parts and a bottom part, which form a cavity in a closed state of the blow mold, within which the plastic preform is expanded by applying a flowable medium to a plastic bottle. In a further method step, a pressurized cushion arrangement is subjected to a flowable medium in order to force one of the two side parts onto the other side part.

According to the invention, the bottom part is delivered to the plastic preform at least once in a closed state of the blow molding device.

It is therefore also proposed on the method side to combine the application of the side part with the pressure, that is, as a pressure pad, with the movement of the bottom part in a blow molding process. In this way, an overall simplification of the method can be achieved. Also in this way the quality of the containers and in particular the uniformity of this quality can be improved.

In a further preferred method, the bottom part is delivered to the plastic preform by application of the gaseous medium. It is therefore also proposed that the drive of the bottom part also takes place pneumatically.

In a further advantageous embodiment, the movements of the bottom part and the movements of the pressure pad assembly from the same source for the flowable medium are fed. It is therefore also proposed on the method side, that the source, which is already provided for the application of the pressure pad, also serves to pressurize the bottom part with compressed air.

In a particularly preferred procedure of the method, a specific pressure p is first applied to the pressure pad. In this case, a compressed air supply line preferably has a connection element which, in addition to the pressure pad arrangement, also supplies the active base unit, that is to say the drive device for moving the bottom part, with compressed air. It is advantageous, as mentioned above, for this purpose, a valve device and in particular a 2/2 way valve provided.

This valve is preferably closed at the beginning of supply of the pressure pad assembly with the required pressure and is opened only at a later selectable time. Preferably, the plastic preform is subjected to several pressures as part of its forming, as mentioned above. These different pressures can be provided by different reservoirs or by switching different valves available.

As mentioned, first the container can be subjected to a Vorblasdruck, then with a so-called Zwischenblasdruck and finally with a Fertigblasdruck. Preferably, this Fertigblasdruck is the highest pressure that is applied. From this pressure, the drive for the bottom part is preferably fed. This is particularly advantageous because the bottom part must be raised against a possible pressure within the blow mold.

Since, as mentioned above, preferably the bottom part and the actuation of the pressure pad arrangement are fed from the same source, this can be made possible. Advantageously, this source is a reservoir which is suitable and intended for receiving compressed air. This reservoir can be switched with different valves, so that the above-mentioned pressures can be made available. Advantageously, a point in time of the active switching of this valve and thus also a time in which the movement of the bottom part is initiated, freely selectable or parameterizable.

Overall, a cost reduction is achieved by the procedure described here, since in particular a so-called 3/2 high-pressure valve with a separate vent can be dispensed with.

Advantageously, the device also has a further valve, which can be switched to a reset of the bottom part. This second valve device may also be a 2/2 way valve.

• 1 eine schematische Darstellung einer erfindungsgemäßen Vorrichtung;
• 2 eine schematische Darstellung der erfindungsgemäßen Vorrichtung in einem ersten Zustand;
• 3 eine Darstellung der erfindungsgemäßen Vorrichtung in einem zweiten Zustand;
• 4 eine Darstellung der erfindungsgemäßen Vorrichtung in einem dritten Zustand;
• 5 Eine weitere Darstellung der erfindungsgemäßen Vorrichtung in einem vierten Zustand.

Further advantages and embodiments will be apparent from the attached drawings:
Show:

• 1 a schematic representation of a device according to the invention;
• 2 a schematic representation of the device according to the invention in a first state;
• 3 a representation of the device according to the invention in a second state;
• 4 a representation of the device according to the invention in a third state;
• 5 A further illustration of the device according to the invention in a fourth state.

1 shows a schematic representation of a forming device 1 for forming plastic preforms into plastic containers. This forming device has a blow mold, which two side parts 4 . 6 and a bottom part 2 having. This bottom part 2 is opposite the side panels 4 and 6 in the longitudinal direction L the plastic preforms to be expanded 10 movable. These side parts 4 and 6 are each on carrier dishes 14 and 16 arranged. Between the side part 6 and the carrier cup 16 , at this side part 6 is arranged, is a pressure pad 12 available. During the expansion process can this are pressurized with compressed air and so the side part 6 closer to the side panel 4 press.

The reference numerals 24 and 26 schematically illustrate blow mold carrier parts to which the carrier shells 14 and 16 and thus also the blow-molded parts 4 and 6 are arranged.

The reference number 18 denotes a stretch rod, which is used to stretch the plastic preforms 10 in the longitudinal direction L serves and is preferably introduced through an opening of the plastic preforms in this.

2 shows a more detailed representation of the drive means 30 that is the actual lifting mechanism for moving the bottom part 2 , The reference number 40 indicates a pressure reservoir, which via lines 42 and 44 and 46 Air pressure on the one hand to the pressure pad 12 and on the other hand via a valve 50 and a line connection 48 to a pressure room 54 , The feed line 42 thus serves to supply both the pressure pad assembly and the drive device 30 with compressed air. The reference number 62 indicates a Einstellraum, within which the designated in its entirety with 38 piston, on which also the bottom part 2 is arranged, is movable. If necessary, the lifting height of the piston element 38 can also be set within this setting space.

The reference number 58 indicates an outlet conduit, which also upon an upward movement of the piston member 38 Compressed air is applied. The reference number 60 indicates a further valve device, which is preferably designed here as an outlet valve.

The reference number 32 indicates a carrier on which also the bottom part 2 is movably arranged and with which this can be delivered upwards. Preferably, the bottom part in the longitudinal direction of the plastic preforms relative to this carrier 32 be moved.

The reference number 15 indicates the cavity that the blow mold forms to mold the plastic containers.

At the in 2 shown situation is initially on the plastic preform still no pressure, but already the pressure pad is pressurized to the blow moldings 4 and 6 to push each other. The reference number 52 indicates a carrier in which both the pressure space 54 as well as the adjustment space are formed. The adjustment space is preferably separated from the pressure chamber. The reference numeral 34 denotes a holding device which faces the side parts 6 , 4 is stationary, and by means of which the bottom part is held on the side parts during the forming process.

3 shows another situation during a manufacturing process. For clarity, some reference numbers have been omitted here. Now on the plastic preform was a Vorblasdruck P1 applied, which causes the plastic preform expands. In this situation is also in the pressure pad 12 Pressure built and on the other hand, however, the bottom part 2 not yet delivered. It can be seen that this bottom part is still in a lower position.

At the in 4 shown situation is now on the plastic container a pressure P2 applied, that is the so-called Fertigblasdruck. In this situation, the container 10 is already fully formed and pressed against the inner wall of the blow mold. At the same time the valve 50 unlocked or opened and by the also applied blowing pressure P2 The bottom part is also delivered in the direction of the plastic container and thus shapes its bottom and / or creates a kink in this bottom. Also the valve 60 is unlocked to over the line 58 be able to record according to compressed air.

At the in 5 As shown, the blow mold is vented and again relieved the pressure pad. At the same time, the bottom part is reset by air pressure, and here too the valve 50 as well as the valve 60 are open. It can be seen that the bottom part has arrived here again in a retracted position. You can also see that this is an air flow back into a reservoir to recycle air.

The Applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided that they are novel individually or in combination with respect to the prior art. It is further pointed out that features have also been described in the individual figures, which in themselves can be advantageous. The person skilled in the art immediately recognizes that a particular feature described in one figure can also be advantageous without taking over further features from this figure. Furthermore, the person skilled in the art recognizes that advantages can also result from a combination of several features shown in individual or in different figures.

LIST OF REFERENCE NUMBERS

1

shaping device

2

the bottom part

4.6

side panel

10

Plastic preform, plastic container

12

caul

14.16

support tray

15

cavity

16

support tray

18

stretching rod

24, 24

Blasformträgerteil

32

carrier

38

piston

40

pressure reservoir

42.44

management

46

management

48

line connection

50

Valve

52

carrier

54

pressure chamber

58

outlet pipe

60

valve means

62

configuration area

L

longitudinal direction

P1

pre-blowing pressure

P2

final blowing

Claims (10)

Forming device (1) for forming plastic preforms (10) into plastic bottles, wherein the forming device (1) has a blow mold with a first side part (4), a second side part (6) and a bottom part (2), these side parts (4, 6) as well as the bottom part (2) form a cavity (15) within which the plastic preforms (10) can be formed into the plastic bottles, and wherein the forming device (1) carrying means (14, 16) for supporting the side parts (4, 6) and between at least one support means (14, 16, 24, 26) and at least indirectly on this support means (14, 16) arranged side part (4, 6) is arranged acted upon by a flowable medium pressure pad means (12), wherein by the application this pressure pad assembly (12) with the flowable medium, the on this supporting means (14, 16) disposed side part (4, 6) can be forced toward the other side part, dadurc h characterized in that the bottom part (2) is movable relative to the side parts (4, 6) in a closed state of the blow mold, and wherein the forming device (1) has a drive device (30) to move the bottom part in relation to the side parts (4, 6). to move. Forming device (1) after Claim 1 , characterized in that the drive device (30) is acted upon by a flowable medium drive means. Forming device (1) according to at least one of the preceding claims, characterized in that the drive device (30) can be acted upon by the same flowable medium as the pressure pad device. Forming device (1) according to at least one of the preceding claims, characterized in that the forming device (1) has a feed line (42) for supplying the flowable medium, wherein by means of this feed both the pressure pad means (12) and the drive means (30) can be supplied are. Forming device (1) after Claim 4 , characterized in that the forming device (1) has a valve device (60) to supply the drive device (30) Forming device (1) after Claim 5 , characterized in that the valve device (60) is designed as a 2/2 - way valve. Forming device according to at least one of the preceding Claims 5 - 6 , characterized in that the forming device has a control device for controlling the valve device (60) and this control device is designed such that a switching time in which the valve device (60) is switched, is variable. Method for forming plastic preforms into plastic bottles with the slides: - introducing a plastic preform into a blow mold, this blow mold having at least two side parts (4, 6) and a bottom part (2), which in a closed state of the blow mold has a cavity (15 ), within which the plastic preform (10) is expanded by application of a flowable medium to a plastic bottle - loading a pressure pad assembly (12) with a flowable medium to one of two side parts (4, 6) towards the other side part (6, 4) to urge characterized in that the base part (2) is sent at least once in a closed state of the blow molding of the plastic preform (10). Method according to Claim 8 , characterized in that the bottom part (2) is delivered by application of the gaseous medium to the plastic preform (10). Method according to Claim 9 , characterized in that the movement and / or the supply of the bottom part (2) and the actuation of the pressure pad assembly from the same source for the flowable medium are fed.

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