DE19906439A1 - Thermoplastic container, especially PET bottle, blow molding machine with swiveling tool carriers on swiveling arms whose separate movements are mechanically controlled - Google Patents

Abstract

Tool carriers (4,5) are connected by swiveling joints to carrier arms (6,7) which also swivel. Main swiveling bearings (10,11) for the carrier arms are at a fixed spacing and coordination of the swiveling movements both of the arms relative to their main bearings and of tool carriers relative to the carrier arms is mechanically controlled. An Independent claim is made for a process for blow molding thermoplastic containers in which during opening and closure movements of the each blowing station the tool carriers (4,5) are swiveled relative to the carrier arms (6,7).

Description

The invention relates to a device for blow molding of containers made of a thermoplastic material, the a heating device for tempering the preforms and position at least one relative to each other has blow molds provided with mold carriers.

The invention also relates to a method for Blow molding of containers from a thermoplastic Material in which preforms are tempered and in the loading range at least one blowing station to containers be shaped and during the shaping to specify the container ture contour of mold carriers that are supported by Support arms can be positioned.

Such devices are used to preform  linge from a thermoplastic material, for example white preforms made of PET (polyethylene terephthalate) to form into containers within a blow molding machine. Such a blow molding machine typically has one Heating device and a blowing device in de the pre-tempered preform Biaxial orientation to a container expands becomes. The expansion takes place with the help of compressed air, which are introduced into the preform to be expanded becomes. The procedural process at one of these expansion of the preform is carried out in the DE-OS 43 40 291 explains. The device is flat if equipped, ready-blown containers to be removed from the blowing device and transported further.

The basic structure of a blowing station for loading Container shaping is described in DE-OS 42 12 583. Options for tempering the preforms in DE-OS 23 52 926 explained.

Within the blow molding device, the Preforms as well as the blown containers with the help different handling devices transport be animals. In particular, the Verwen has proven itself of mandrels on which the preforms are placed be put.

The preforms can also be used with other carriers directions are handled. The use of griffin pliers for handling preforms is used, for example as described in FR-OS 27 20 679. On Expanding mandrel, which is used for holding in a mouth area of the preform is insertable in the WO 95 33 616 explains.  

The handling of the preforms already explained follows on the one hand in the so-called two-stage procedure ren, in which the preforms first in one Injection molding process, then between stored and only later with regard to their temperature conditioned and inflated to a container. On the other hand, it is used in the so-called One-step process in which the preforms are telbar after their injection molding manufacture and an adequate hardening suitably tempered and then inflated.

With regard to the blowing stations used are un Different embodiments are known. At Blassta tions arranged on rotating transport wheels is a book-like opening of the form encountered frequently. For fixed blowing stations, which are particularly suitable for several cavities for container formation, are typically plates arranged parallel to each other as mold carriers used.

Mostly in the area of a blowing station becomes one blown one container at a time. Especially when manufacturing small containers However, it may be advantageous to use two or more preforms in a blow station to a container inflate ter. Such a procedure will for example in WO-PCT 95/05933 and WO-PCT 96/26826. Also in the area of the so-called The one-step process and extrusion blowing is the simultaneous expansion of several preforms together already known with rotating blowing wheels. At Blow machines with stationary blow molds  the vast majority of machines with blassta equipped with multiple cavities.

Different ways to enter a more Number of preforms in a blow molding station with several ren cavities and for the removal of a plurality of ge blowing containers from such blowing stations explained in DE-OS 198 10 238.

The previously known constructions for blowing stations With several cavities, not all requirements can be met meet requirements that require a compact arrangement A number of blowing stations placed side by side become. Especially when arranging the Blassta on a rotating blowing wheel at book-like The blowing stations must be opened up relatively large ß opening angle are specified so that the in blown container out of the Blow station can be removed. As a result that on the one hand a relatively large distance between the Blow stations is required and that from the other to travel relatively large distances to the masses to be moved are running.

The object of the present invention is to provide a direction of the type mentioned in such a way ier that improved kinematics in the implementation opening and closing movements of the blassta tion is provided.

This object is achieved in that the mold carriers are held by support arms, each Weil pivoted and with the mold carriers are pivotally connected that abge the mold carriers  turns arranged base pivot bearing of the support arms rela tiv have a distance from each other and that to Ko ordination of the pivoting movements of the support arms relatively to their basic swivel bearings and to coordinate the Swiveling movements of the mold carrier relative to the tragar a mechanical control is provided, the one Relative movement between the support arms and the form supports gladly pretends.

Another object of the present invention is a Approaches of the type mentioned in the introduction ben that when performing opening and Closing movements of the blowing stations to move Mas must travel as short as possible.

This object is achieved in that when performing opening and closing movements towards the blow station, the mold carriers relative to the carrier arms are swung.

Due to the pivotable relative to the support arms arrangement of the mold carrier and by the pivotable An order of the support arms relative to the basic pivot bearings it is possible to relative the orientation of the mold carrier to each other at the. Implementation of opening and To specify closing movements. In particular, it is thought when performing pivoting movements of the Bracket arms approximately parallel to each other To maintain the orientation of the mold carrier. Here by it is possible to extend the area of the mold carrier is facing away from the basic swivel bearings, only to the extent of to remove each other that easily a removal of the blown container is possible.  

When using protruding receiving elements to carry out a locking process of the form carrier relative to each other, it is also possible to the superimposition of pivoting movements of the support arms and of pivoting movements of the mold carriers relative to the Support arms one in the open state relative to each other angular orientation of the mold carriers give. The angle of inclination is chosen such that that the blown container between unobstructed the protruding locking elements can be led. The opening angle of the mold carrier relative to each other is small in any case ner than the opening winch spanned by the support arms kel.

By mechanical control, for example reali siert as curve control, a defined and right producible execution of all movements ge ensures. In particular, this reproducibility even with different external influences rivers are maintained.

To ensure a robust connection the mold carrier with each other when the Blow pressure is suggested that the mold carrier so probably facing the basic swivel bearings limits as well as in the area of their base swivel bearings facing away from each other provided opposite locking devices are.

To increase the production output is suggested that the blowing station has at least two cavities Has container shape.  

The use of simply designed components is there supported by that each of the cavities with separate Mold halves is provided.

Easy loading and unloading of the Blassta tion are supported in that the cavities right relative to a blowing wheel axis of the blowing station tra blowing wheel in succession in the radial direction are arranged.

To ensure collision-free handling of preforms and containers it is proposed that the mold carrier can be pivoted relative to one another in this way are that the base in an open state areas further away from each other are removed than facing the basic swivel bearings areas.

A typical application is that a more Number of blow stations along a perimeter of the blow wheel are arranged.

This ensures good access to the cavities supports that the base pivot bearing of the blowing wheel axis are arranged facing.

Favorable kinematics can be achieved that is in an open state of the blowing station between the support arms about a twice as large opening angle extends as between the mold carriers.

A reduction in the number of construction required Groups can be done in that the blowing station  common stretching device with one of the number of Ka corresponding number of horizontal bars for simultaneous stretching of at least two preforms gene.

To provide favorable parameters for the container It is suggested that the blowing station with a blown air control for the specification of at least two different pressure levels is connected.

Exemplary embodiments of the invention are shown in the drawing shown schematically. Show it:

Fig. 1 A summary representation of an apparatus for blow molding containers, which has display devices, a heating device, a shipping with blowing stations Henes rotating blowing wheel, and various About,

Fig. 2 is an enlarged schematic representation of egg ner blow molding station in an open state,

Fig. 3 is a schematic representation of a Blassta tion in a closed state,

Fig. 4 is a perspective view of drive elements for a stretching system and

Fig. 5 shows a cross section along section line VV in Fig. 3 with a partially expanded ter and retracted stretching rod.

Fig. 1 shows the basic structure of a Blasma machine, which is equipped with a rotating blowing wheel ( 1 ) and egg ner heating device ( 2 ) for preforms to be tempered. Blow stations ( 3 ) are arranged along a circumference of the blowing wheel ( 1 ), each of which has mold carriers ( 4 , 5 ). The mold carriers ( 4 , 5 ) are held by support arms ( 6 , 7 ) and are used to position mold elements, typically mold halves ( 8 , 9 ).

The support arms ( 6 , 7 ) are rotatably mounted relative to the basic pivot bearings ( 10 , 11 ). In addition, the support arms ( 6 , 7 ) via swivel bearings ( 12 , 13 ) are rotatably coupled to the mold carriers ( 4 , 5 ).

The blowing wheel ( 1 ) rotates relative to a blowing wheel axis ( 14 ) and the base pivot bearings ( 10 , 11 ) are arranged in the radial direction of the blowing wheel axis ( 14 ). The base pivot bearings ( 10 , 11 ) have a bearing spacing ( 15 ) relative to one another.

In the embodiment shown in Fig. 1, the heating device ( 2 ) with a transport chain ( 18 ) ver see that transports the preforms to be heated along heating elements ( 16 ). The heating elements ( 16 ) can be designed, for example, as IR emitters. However, it is also possible to provide operating radiators or convection heating in other frequency ranges. In the illustrated embodiment, the heating elements ( 16 ) are arranged on one side along the transport path of the preforms and the heating elements ( 16 ) opposite reflectors ( 17 ) are seen before. Basically, a bilateral arrangement of heating elements ( 16 ) can also be realized.

In the area of the transport chain ( 18 ), the preform lin are held by supporting elements ( 19 ). The support elements ( 19 ) can be, for example, ausgebil det as transport mandrels on which the preforms are attached. It is also conceivable to provide a holder for the preforms using pliers or expanding mandrels. In the embodiment shown in Fig. 1 Tragele elements ( 19 ) are used, each holding two preforms simultaneously.

The preforms can be entered in such a way that the preforms are first fed along a transport rail ne ( 20 ), in the area of which the preforms are arranged with their mouths upwards, a turning device ( 21 ), which the preforms with their mouths downwards turns and passes to an input wheel ( 22 ). The input wheel ( 22 ) is coupled by transfer wheels ( 23 , 24 ) to the heating device ( 2 ). In particular, it is contemplated that the preform already linge of the set up the input wheel (22) facing the transfer wheel (23) on the support elements (19) in the region.

The heating device ( 2 ) is coupled to the blowing wheel ( 1 ) by a transfer wheel ( 25 ), and containers which have been blown in the area of the blowing stations ( 3 ) are transferred from the transfer wheel ( 1 ) to a removal wheel ( 26 ). The removal wheel ( 26 ) is coupled via the transfer wheel ( 23 ) to an output wheel ( 27 ) which transfers the blown containers ( 28 ) into the area of an output section ( 29 ). An expedient change in the spatial orientation of the blown containers ( 28 ) can be carried out in the area of the discharge wheel ( 27 ).

To allow a high heat input into the preforms without risk of overheating the outer surface, it is possible in the area of the heating device ( 2 ) in addition to the heating elements ( 16 ) to arrange fans which guide cooling air into the area of the preforms. For example, it is possible to alternately position heating elements ( 16 ) and blowers in succession in the transport direction of the preforms.

In order to be able to form a preform into a container ( 28 ) in such a way that the container ( 28 ) has material properties that ensure a long usability of food filled inside the container ( 28 ), in particular beverages, special process steps must be followed the heating and orientation of the preforms are observed. In addition, advantageous effects can be achieved by adhering to special dimensioning regulations. Different plastics can be used as the thermoplastic material. For example, PET, PEN or PP can be used.

The expansion of the preform during the orien tation process is carried out by compressed air supply. The Compressed air supply is in a pre-blowing phase, in which gas, for example compressed air with a low pressure level is fed and a subsequent main blow phase se divided into the gas with a higher pressure level is fed. Typi usually compressed air with a pressure in the interval of 10 bar used up to 25 bar and during the main blowing phase becomes compressed air with a pressure in the interval of 25 bar fed up to 40 bar.  

Fig. 2 shows the blowing station ( 3 ) in an enlarged Dar position and with additional details. The blow molding station is opened according to this illustration, so that preforms can be fed before carrying out the blow molding process or finished containers ( 28 ) can be removed after the blow molding process has ended.

It can be seen in particular that the blowing station ( 3 ) is provided with two cavities ( 30 , 31 ) in order to be able to produce two containers ( 28 ) at the same time. The cavities ( 30 , 31 ) are arranged one behind the other in the radial direction with respect to the blowing wheel axis ( 14 ). In principle, it is conceivable to provide more than two cavities ( 30 , 31 ) per blowing station ( 3 ).

In the embodiment shown, each cavity ( 30 , 31 ) is assigned separate and separate mold halves ( 8 , 9 ). In principle, however, it is also conceivable to form the mold halves ( 8 , 9 ) arranged in the area of one of the mold carriers ( 4 , 5 ) in one piece. The multi-part design, however, makes production cheaper by using a larger number of simpler parts and, if necessary, simplifies any adjustment work required.

To ensure a sufficiently stable connection between the mold carriers ( 4 , 5 ) when exposed to a blowing pressure, the mold carriers ( 4 , 5 ) are provided with locking devices ( 32 , 33 ). The locking devices ( 32 , 33 ) can, for example, be designed as projecting segments which have bores ( 34 ) for receiving locking bolts. To ensure a sufficient stability as well in the area of the base pivot bearings (10, 11) facing boundaries of the mold carriers (4, 5) and in the area of the base pivot bearings (10, 11) abge facing boundaries of the mold carriers (4, 5) Locking devices ( 32 , 33 ) positioned.

FIG. 3 shows the blowing station ( 3 ) according to FIG. 2 in a closed state, in which the locking devices ( 32 , 33 ) corresponding to each other are assembled. In the closed state of the blowing station ( 3 ), the cavities ( 30 , 31 ) are delimited on all sides so that the preforms can expand to form the containers ( 28 ).

The respective pivoting movements of the support arms ( 6 , 7 ) and the mold carrier ( 4 , 5 ) can be specified with the aid of cam rollers which, together with assigned guideways, provide cam controls.

Fig. 4 shows a possible implementation for a stretching device ( 35 ), which is intended to insert stretching bars ( 38 , 39 ) before inflating the preforms to perform longitudinal stretching in the preforms. In particular, it is possible to use the stretching device ( 35 ) to insert two or more stretching bars simultaneously into the respectively assigned preforms of the blowing station ( 3 ) concerned.

In the embodiment shown in Fig. 4, the stretching system is designed such that a tandem arrangement of two cylinders ( 36 ) is provided. From a primary cylinder ( 37 ), the stretching rods ( 38 , 39 ) are first moved into the area of the bottom of the preform before the actual stretching process begins. During the actual stretching process, the primary cylinder ( 37 ) with extended stretching rod is positioned together with a carriage ( 40 ) carrying the primary cylinder ( 37 ) by a secondary cylinder ( 41 ) or via a cam control. In particular, it is contemplated to use a cam control instead of the secondary cylinder ( 41 ) in such a way that a current stretching position is specified by a guide roller ( 42 ) which slides along a cam track while the stretching process is being carried out. The guide roller ( 42 ) can also be pressed by the secondary cylinder ( 41 ) against a guideway. The carriage ( 40 ) slides along two guide elements ( 43 ).

To enable the preforms to be inserted into the blowing station ( 3 ) and to enable the finished containers ( 28 ) to be removed, the blow mold in addition to the mold halves ( 8 , 9 ) consists of a base part ( 44 ) which can be positioned by a lifting device . The preform can be held in the area of the blowing station ( 3 ) by a support element ( 19 ), for example a transport mandrel, which together with the preform passes through a plurality of treatment stations within the device. However, it is also possible to insert the preform directly into the blowing station ( 3 ), for example using pliers or other handling means.

For adaptation to different shapes of the port portion of the parison is shown in FIG. 5, the application Ver separate threaded inserts (45) provided in the region of the blow mold (3).

For example, curve controls can be used to coordinate the movements of the support arms ( 6 , 7 ) and the mold carriers ( 4 , 5 ). In particular, it is contemplated to install a cam control for specifying the pivoting movements of the support arms ( 6 , 7 ) and a further cam control for specifying the pivoting movements of the mold carriers ( 4 , 5 ) relative to the support arms ( 6 , 7 ). However, it is also conceivable to implement the pivoting movement of the mold carriers ( 4 , 5 ) relative to the support arms ( 6 , 7 ) by means of a parallelogram adjustment or by using an oblique parallelogram. By using such parallel logogram adjustments, a pivoting movement of the support arms ( 6 , 7 ) into a pivoting movement of the mold carriers ( 4 , 5 ) relative to the support arms ( 6 , 7 ) is set by two spaced-apart coupling levers. When using an oblique parallelogram, the respective transmission ratio can be specified with regard to the respective pivoting movements.

Claims (12)

1. Device for blow molding of containers made of a thermoplastic material, which has a heating device for tempering preforms and at least one blowing station provided with mold carriers which can be positioned relative to one another, characterized in that the mold carriers ( 4 , 5 ) of support arms ( 6 , 7 ) are held, each pivotally arranged ver and pivotally connected to the mold carriers ( 4 , 5 ), that the mold carriers ( 4 , 5 ) facing away from the base pivot bearing of the support arms ( 6 , 7 ) have a distance from each other and that for coordination the Schwenkbe movements of the support arms ( 6 , 7 ) relative to their Ba sisschwenkagerern ( 10 , 11 ) and to coordinate the pivoting movements of the mold carrier ( 4 , 5 ) relative to the support arms ( 6 , 7 ) a mechanical control is provided, which is a relative movement between the support arms ( 6 , 7 ) and the mold carriers ( 4 , 5 ). 2. Device according to claim 1, characterized net gekennzeich that the mold carriers (4, 5) both in the region of the base pivot bearings (10, 11) facing boundaries and pivot bearings in the region of the base (10, 11) limits facing away opposite to each other Locking devices ( 32 , 33 ) are provided. 3. Device according to claim 1 or 2, characterized in that the blowing station ( 3 ) has at least two cavities ( 30 , 31 ) for container formation. 4. Device according to one of claims 1 to 3, characterized in that each of the cavities ( 30 , 31 ) is provided with separate mold halves ( 8 , 9 ). 5. Device according to one of claims 1 to 4, characterized in that the cavities ( 30 , 31 ) relative to a blowing wheel axis ( 14 ) of the blowing station ( 3 ) carrying blowing wheel ( 1 ) are arranged one behind the other in the radial direction. 6. Device according to one of claims 1 to 5, characterized in that the mold carriers ( 4 , 5 ) can be pivoted relative to one another in such a way that, in an open state, the areas facing away from the base pivot bearings ( 10 , 11 ) are further apart than the areas facing the basic pivot bearings ( 10 , 11 ). 7. Device according to one of claims 1 to 6, characterized in that a plurality of blowing stations ( 3 ) along a circumference of the blowing wheel ( 1 ) are arranged. 8. Device according to one of claims 1 to 7, characterized in that the base pivot bearing ( 10 , 11 ) of the blowing wheel axis ( 14 ) are arranged facing. 9. Device according to one of claims 1 to 8, characterized in that in an open state of the blowing station ( 3 ) between the support arms ( 6 , 7 ) extends approximately twice the opening angle as between the mold carriers ( 4 , 5 ) . 10. Device according to one of claims 1 to 9, characterized in that the blowing station ( 3 ) has a common stretching device with a number of cavities ( 30 , 31 ) corresponding to the number of stretching bars ( 38 , 39 ) for simultaneous stretching of at least has two preforms. 11. The device according to one of claims 1 to 10, characterized in that the blowing station ( 3 ) is connected to a blowing air control for specifying at least two different pressure levels. 12. A method for blow molding containers from a thermoplastic material, in which preforms are tempered and formed into containers in the area of at least one blow molding station, and in which molds for specifying the container contour are held by mold carriers which can be positioned by support arms, characterized in that that when performing opening and closing movements of the blowing station, the mold carriers ( 4 , 5 ) are pivoted relative to the support arms ( 6 , 7 ).