DE102012106821A1 - Device for molding plastic preforms into plastic containers, has transformation station comprising first and second biasing units for holding first and second locking units in positions, where biasing units comprise magnetic elements - Google Patents

Abstract

The device (1) has a transformation station (20) arranged on a movable carrier (2) and comprising movable side parts (22, 24) that are movable between open state and closed state of a forming station. The transformation station comprises a locking mechanism to which movable side parts are locked together in closed state of the transformation station. The transformation station comprises first and second biasing units for holding first and second locking units in the first and second positions, respectively, where the biasing units comprise magnetic elements. An independent claim is also included for a method for reshaping plastic preforms.

Description

The present invention relates to an apparatus for forming plastic preforms into plastic containers. Such devices have been known for a long time from the prior art. In particular, so-called stretch blow molding machines are known with which the plastic preforms are expanded by means of blowing air and are additionally stretched in their longitudinal direction by means of a stretch rod.

Usually, such a stretch blow molding machine has a plurality of blowing stations or forming stations, in which the preforms are blown into bottles by applying an internal pressure. An important component of such a conversion station is a locking mechanism. This connects or locks the two mold carrier halves during the blowing process. After completion of the blowing process, the lock opens, the mold carrier halves can be moved apart and the finished blown containers can be removed after opening the mold and it can be introduced another plastic preform. In a known locking mechanism engages a locking element, which is arranged for example on one of the mold carrier parts, in a second locking element, which is arranged on another mold carrier part. In this case, a locking shaft may be provided, which is mounted on one of the two mold carriers.

Several distributed over the height of the mold carrier bearings ensure a uniform force distribution in the components. This is advantageous because the latch has to hold a holding force of several 10,000N. The locking process consists of a rotational movement of the lock. This movement is generated by a stationary, for example, in the basic structure of the machine attached curve and forwarded via different deflections to the Verrieglungswelle.

At present many solutions for locking the mold carriers are known. For example, from the Applicant's internal state of the art a locking mechanism is known which is attached to the right mold carrier. In this case, an S-contour is fastened to a locking flap or a locking element, along which the opening rollers of a locking mechanism run. In this way the unlocking or locking process is carried out.

To control the opening waves, double rollers pass through a stationary fixed curve. The locking flap or latch is open in a situation and must now be kept open until the finished bottle is replaced with a new preform. This is achieved in the above-mentioned machine by the Applicant by a spring-loaded fixing roller, which is pressed into a recess or pit. The locking element is locked again by the double role passes through a stationary fixed locking curve and is pushed up. This approach has been proven, but has the disadvantage that situations of the locking mechanism may occur in which the locking element is in an intermediate position between a locked and an unlocked state.

From the EP 2 234 789 B1 is a molding unit for a plant for blow molding plastic containers known. In this case, a fastener between a position of locking and a position of unlocking the two half-molds is movable. In this case, a spring is provided between the first half-mold and the fastening element in order to move the fastening elements in the locked position and to keep them in this position normally. The presence of locking and unlocking curves requires a high cost technical and mechanical effort, since usually the curves are pivotally mounted in order to deflect in case of malfunction can. Larger damage is avoided. The rollers are usually designed as a double role and the curves have a kind Nutverlauf on. In this Nutverlauf even the rollers are at different curve edges, so that alternating rotational movements are avoided. To get the smoothest possible rolling movement, it is again advantageous if the curves accompany the mold carrier for a relatively long time and therefore become very large and long in dimension.

The present invention is based, to reduce the hitherto necessary technical and mechanical effort the task. This object is achieved by the subject of the independent claims. Advantageous embodiments and further developments are the subject of the dependent claims.

A device according to the invention for converting plastic preforms into plastic containers has a movable carrier on which at least one forming station is arranged, this forming station having two movable side parts which are movable between an open state of the forming station and a closed state of the forming station. The forming station forms a cavity in a closed state, within which the Plastic preforms are expandable to the plastic containers. Furthermore, the forming station has a locking mechanism which locks the mutually movable side parts together in a closed state of the forming station, the locking mechanism having a first locking element, which mechanically cooperates for locking the forming station with a second locking element. In this case, the first locking element relative to the second locking element between a first position and a second position is movable.

According to the invention, a first loading means is provided at the forming station which holds the first locking element in the first position (and / or urges the first locking element into the first position) and a second loading means which holds the first locking element in the second position (and / or urging the first locking element to the second position), wherein at least one loading means comprises a magnetic element.

By the mutually movable side parts is meant that two side parts are provided, wherein at least one of these side parts is movable and thus causes the movement of the one side part relative to the other side part. So it would also be possible that one of the two side parts is fixedly arranged on the carrier and the other movable. Also, both side parts could be arranged to be movable relative to the carrier.

The first and the second position are, in particular, different geometric positions of the first locking element relative to the second locking element. Preferably, the first position and the second position of the first locking element are defined by different pivot positions of the first locking element. Both loading means (which can also be referred to as holding means) are thus advantageously arranged at the forming station and move together with the latter.

Advantageously, the side parts are locked together in the first position of the first locking element and unlocked in the second position, so that the deformation station can be opened. Advantageously, the first locking element is a locking lever or a locking flap. Advantageously, this first locking element on engaging segments, which engage in correspondingly adapted rear engagement portions of the second locking element.

It is therefore proposed that at least the unlocked or the locked state of the conversion station is held by a magnetic element. Preferably, the loading means are arranged such that the locking element is always in the locked or unlocked position without the action of external forces. Thus, as mentioned above, at least one position is held by the magnetic element.

Preferably, said positions of the locking element are end positions with respect to a trajectory of this locking element (opposite the forming station). Preferably, at least one loading means urges the first locking element into the at least one end position.

Advantageously, the movable carrier is a carrier rotatable about a predetermined axis of rotation, and in particular a so-called blowing wheel.

Advantageously, each forming station has a blowing nozzle device, which acts on the plastic preforms via the mouth thereof with a gaseous medium and in particular with blowing air. Furthermore, the forming station advantageously has a stretching rod, which is introduced into the plastic preforms during the expansion process and stretches along its longitudinal direction.

In a further advantageous embodiment, the device has a guide curve, against which the forming station is movable and which causes a movement of the locking element. Strictly speaking, the guide curve causes a locking operation and / or unlocking the forming station. In this case, therefore, only one guide curve would be necessary to bring about locking and / or unlocking of the forming station. In principle, however, it would also be conceivable to arrange a respective guide curve, which causes a locking operation, and to arrange a further guide curve, which causes an unlocking process.

In a further advantageous embodiment, this guide curve is arranged stationary. Accordingly, it would be conceivable that a continuous stationary guide curve is arranged, which brings about both an unlocking and a locking operation of the forming station.

In a further advantageous embodiment, the device has a further guide curve, which causes a movement of the side parts with respect to each other. Under a relative mobility of the side parts to each other is understood that at least one of the two side parts is moved. In an advantageous embodiment, the first locking element is arranged pivotable about a predetermined pivot axis. In this case, this pivot axis may be arranged on a mold carrier part. Advantageously, the pivot axis about which the locking element is pivotable, parallel to a pivot axis about which the side part or mold support part is pivotable. However, it would also be conceivable that the first locking element (in particular along a straight direction) is movable.

Advantageously, the other locking element is arranged on the other mold carrier part or side part.

In a further advantageous embodiment, at least one magnetic element is a permanent magnet or an electromagnet.

In a further advantageous embodiment, at least one loading means has a spring element. This spring element can also serve as energy storage. The spring element can urge the corresponding locking element in a locked or unlocked position. Advantageously, the spring element urges the first locking element in a locked position of the forming station.

In a further advantageous embodiment, a plurality of forming stations of the type described above is arranged on the carrier.

Preferably, a guide body is arranged directly on the first locking element, which cooperates for moving the locking element with a guide curve. This guide body is in particular a leading role. Advantageously, this guide body is arranged without transmission elements directly on the locking element, so that the locking element directly follows the movement of the guide body.

In a further advantageous embodiment, at least one magnetic element is arranged movably with respect to the transformation station. In other words, this magnetic element is advantageously movably mounted. Nevertheless, this magnetic element is advantageously arranged at the forming station and is moved along with it.

The present invention is further directed to a method of forming plastic preforms into plastic containers. In this case, the plastic preforms are formed by means of at least one forming station, which moves along a predetermined transport path to the plastic containers. Furthermore, the forming station has two side parts which are moved relative to each other for opening and closing the forming station. Furthermore, a locking mechanism locks the two side parts together in a closed state of the forming station, the locking mechanism having a first locking element which mechanically cooperates to lock the forming station with a second locking element and wherein the first locking element relative to the second locking element between a first position of the locking element and a second position of the locking element is moved (in particular for locking and unlocking of the forming station).

According to the invention, a first loading means is provided at the forming station, which at least temporarily urges the first locking element into the first position (ie the locked position of the forming station) and / or holds it in this position, and a second loading means which at least temporarily engages the first locking element in the first locking element second position, ie urges in the unlocked position of the forming station and / or holds in this unlocked position, wherein at least one loading means comprises a magnetic or magnetizable element. Preferably, at least the first position of the locking element is an end position. Preferably, at least the second position of the locking element is an end position.

Advantageously, the plastic preforms are formed by applying compressed air to the plastic containers.

Furthermore, the forming station advantageously moves along a circular path. In a further advantageous method, the plastic preforms are heated prior to their transformation. In a further advantageous method, at least one magnetic element is electrically activated. This means that this is preferably an electromagnet whose magnetic force can consequently be switched off or switched on.

In a further advantageous method, at least one guide curve transfers the conversion station from an unlocked state into a locked state and / or from a locked state into an unlocked state. In this case, the locking element is advantageously achieved by the said guide curve of a magnet and / or fed to a magnet.

In a further advantageous method, the first locking element is fixed by at least one loading means and in particular by a magnetic element in an end position of its path.

In a further advantageous embodiment, a clamping element is provided, which returns the first locking element after the unlocking process back to its starting position.

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

Show:

1 a schematic representation of an apparatus for forming plastic preforms to plastic containers;

2 an illustration of a forming station according to the invention;

3 a further illustration of a transformation station;

4 a more detailed representation of a forming station according to the invention;

5 a detailed view of loading means for a forming station according to the invention;

6 a schematic representation to illustrate the functional principle of the invention;

7 a side view of in 4 shown forming station.

8th a representation of another embodiment of a transformation station; and

9 a plan view of the forming station 8th ,

1 shows a device 1 for the manufacture of plastic containers. These are plastic preforms 10 initially guided on a transport chain and by means of a heating device 3 heated. Subsequently, the thus-heated plastic preforms of a feed star 52 taken over and sent to a variety of transformation stations 20 to hand over. This feed star 52 has a variety of opposite this star swiveling arms 54 on, in each case holding elements for holding the plastic preforms 10 are arranged.

The reference number 2 refers to a rotatable support to which a plurality of transformation stations 20 (shown schematically only four) are arranged. These conversion stations 20 have a first Blasformträgerteil or side part 22 and a second blow mold carrier part or side part 24 on (hereinafter also referred to as carrier part). At this support parts blow moldings (not shown) are arranged so that when these Blasformträgerteile closing the blow moldings are closed and thus form a cavity in its interior, which serves to expand the plastic preforms. The reference number 56 indicates a discharge star, with which the expanded plastic containers 11 can be removed.

2 shows a representation of a forming station according to the invention 20 , This transformation station 20 has again the first side part 22 as well as the second side part 24 on that with respect to a pivot shaft 18 are mutually pivotable. It is possible that to open and close the forming station 20 Both side parts are moved, but it would also be conceivable that a side part stationary relative to the carrier 2 is held and the other side part is opened and closed. This forms the pivot shaft 18 at the same time the pivot axis, with respect to which the side parts are pivotable. The reference number 19 indicates an articulation lever, which on the side part 22 is arranged. A corresponding lever is also on the second side part 24 arranged. At this Anlenkhebeln can attack an arrangement for pivoting the side panels.

The reference number 30 indicates in its entirety a locking mechanism for locking the two side parts 22 . 24 serves each other. This locking mechanism 30 has a first locking element 32 on, which here by means of a wave 35 or with respect to an axis Z formed by this shaft is pivotable. The pivot axis of this side part is parallel to the pivot axis about which the side parts 22 . 24 be panned.

The reference number 34 indicates a second locking element. It can be seen that the two locking elements 32 and 34 interlock to lock the forming station in a closed state.

At the two side parts 22 and 24 are still arranged (not shown) blow moldings. Within these blow moldings, a cavity is formed, which serves for expanding the plastic preforms. Furthermore, a loading means or (Vor) clamping means between the Be provided side panels and the blow moldings, which (for example, by applying compressed air) biases the blow molded parts to each other.

The reference number 38 shows a second loading means, which holds the first locking element in an open state, that is not in the in 2 shown state, but a state in which the first locking element 32 opened.

The reference number 6 schematically indicates a (stationarily arranged) guide curve for opening the locking mechanism 30 serves. This is a leading role 28 on the first locking element 32 arranged, which is pulled by the guide curve here to the outside and in this way the first locking element 32 pivots into the open position.

3 shows another illustration of in 2 shown forming station. Here is more exactly the second load device 38 shown. This has a magnetic element 44 on (for example, a permanent magnet), but preferably an electromagnet, in an open position of the locking element 32 this can hold. Also in 3 is the transformation station 20 shown in the locked position.

4 shows a further embodiment of a device according to the invention. Also in this embodiment is on the first locking element 32 or the locking flap, a roll holder with a roller 28 attached. The roll holder thus stores this guide roller or unlocking roller 28 , which preferably consists of plastic. Furthermore, two tension springs or spring devices are on this role holder 46 arranged. These tension springs 46 make here a link between the first locking element 32 and the side panel 22 In a normal or unloaded state, the two spring elements pull 46 the first locking element or the flap with a defined force and thus the forming station is locked.

5 shows a more detailed representation of in 4 shown device. You can see here again the two spring elements 46 , In addition, one is in its entirety with 70 designated damping element provided which dampens the closing movement or the locking movement. The reference number 36 here in its entirety denotes the loading means which the first locking element 32 pushes into the closed position.

The reference number 38 indicates the second loading means, which here the first locking element 32 can hold in an open position. For this purpose, the second loading means 38 a magnetic element 44 , which is designed here as an electromagnet, on. The locking element 32 can around the in 4 shown pivot axis Z are pivoted and in this way approaches the end 74 of the arm 72 which preferably comprises a magnetizable element, the magnetic element 44 , By activation of the electromagnet 44 can the locking element 32 against the force of the springs 46 be kept in the open position and thus in an unlocked position of the forming station.

6 illustrates a schematic representation of an embodiment of the present invention. Again, the first locking element is again 32 shown, which is pivotable about the axis Z and in a locked state in the second locking element 34 intervenes. Furthermore, the spring element 46 shown, which is the locking element 32 in the closed or locked position urges. At the first locking element 32 is the leadership 28 arranged, which moves with the forming station along the arrow P and thus with respect to the guide curve 6 rolls. The arrow P gives it, as well as in 1 the transport direction of the conversion stations. In this way, the locking element, as soon as the guide roller in the area 6a the guide curve 6 can be pulled down and thus the lock can be opened. In this position can also be the end 74 the locking element to the second loading means 38 or the electromagnet 44 come to the plant. Once this solenoid is deactivated again, the locking element 32 under the action of the spring 46 in the in 6 Swing back the position shown.

In this way is at the in 6 shown embodiment, only a guide curve, namely for unlocking the forming station, necessary, the locking is done via the spring means 46 ,

In other words, that of the spring device 46 held in the locking position flap or the first locking element 32 with the plastic roller 28 over the stationary arranged curve 6 open. In this case, the pivoting movement of the locking element 32 as far as possible, until the section 74 the locking element on the electromagnet 44 strikes. The lever length of the first locking element, the spring force of the springs 46 and the magnetic strength is designed so that the locking element holds in the open position with the magnet switched on this position. The locking is done by a Signal, which is the electromagnet 44 turns off and the traction of the springs 46 the first locking element locked again.

In order to prevent a sudden impact of the locking element, advantageously a stop sleeve with a damping (for example in the form of a damper or with a plastic mushroom) is provided.

7 shows a side view of in 5 shown device. It can be seen that here are two magnets 44 are arranged at different heights to better distribute the holding force over the height of the forming station.

8th shows a further embodiment of a device according to the invention. Also in this embodiment is again the first locking element 32 pivotable with respect to the axis Z. However, in this embodiment, instead of a guide roller 28 two guide rollers 28a and 28b intended. Instead of the spring device 46 Here is a permanent magnet on the locking element 32 intended. In this embodiment, both the locking and the unlocking movement is achieved via guide curves, on each of which one of the double rollers 28a and 28b rolls. Also advantageous are the guide rollers 28a and 28b made of a plastic.

9 shows a plan view of in 8th shown device. When unlocking, one of the two double rollers enters a stationary bearing unit consisting of two curves.

An unlocking curve tears the magnetic coupling with the permanent magnet 42 apart, so far, on the other side, the second magnetic element 44 the arm 72 (which is a part of the first locking element 32 is and is arranged on this) attracts. This position is thus secured and the forming station moves in a further step to a locking curve. Here this locking curve tears over the other guide roller, the first locking element 32 from the magnet 44 go and drive this again against the magnet 42 at. At the in 8th As shown embodiment, it would also be possible to provide only two permanent magnets.

The Applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided they are novel individually or in combination with respect to the prior art.

LIST OF REFERENCE NUMBERS

1

contraption

2

rotatable carrier

3

heater

6

guide curve

6a

Range of the guide curve 6

10

Plastic preform

11

Plastic container

18

pivot shaft

19

Feedback lever

20

forming station

22

first (movable) side panel

24

second (movable) side panel

28

Leadership / unlocking roller / plastic roller

28a

Leadership / dual role

28b

Leadership / dual role

30

locking mechanism

32

first locking element

34

second locking element

35

wave

36

first stress agent

38

second loading means / loading means

42

magnetic element / permanent magnet

44

magnetic element / electromagnet

46

Bungee / spring means / electromagnet

52

feed star

54

swiveling arm

56

outlet star

70

damping element

72

poor

74

End of the arm

P

Arrow, transport direction

Z

swivel axis

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2234789 B1 [0006]

Claims (10)

Contraption ( 1 ) for forming plastic preforms ( 10 ) to plastic containers ( 11 ), with a movable support ( 2 ), at which at least one transformation station ( 20 ), said forming station ( 20 ) two with respect to each other movable side parts ( 22 . 24 ), which between an open state of the forming station ( 20 ) and a closed state of the conversion station ( 20 ), wherein the conversion station ( 20 ) forms a cavity in a closed state, within which the plastic preforms ( 10 ) are expandable to the plastic containers, and wherein the forming station ( 20 ) a locking mechanism ( 30 ), which the mutually movable side parts ( 22 . 24 ) in a closed state of the forming station ( 20 ) are locked together, and wherein the locking mechanism ( 30 ) a first locking element ( 32 ), which for locking the forming station ( 20 ) with a second locking element ( 34 ) cooperates mechanically, wherein the first locking element ( 32 ) relative to the second locking element ( 34 ) between a first position and a second position is characterized in that at the forming station ( 20 ) a first loading means ( 36 ) is provided, which the first locking element ( 32 ) holds in the first position and a second loading means ( 38 ), which holds the first locking element in the second position, wherein at least one loading means ( 36 . 38 ) a magnetic element ( 42 . 44 ) having. Contraption ( 1 ) according to claim 1, characterized in that the device ( 1 ) a guide curve ( 6 ) facing the forming station ( 20 ) is movable, and the one movement of the first locking element ( 32 ) causes. Contraption ( 1 ) according to at least one of the preceding claims, characterized in that the first locking element ( 32 ) is arranged pivotably about a predetermined pivot axis (Z). Contraption ( 1 ) according to at least one of the preceding claims, characterized in that at least one magnetic element ( 42 . 44 ) is a permanent magnet or an electromagnet. Contraption ( 1 ) according to at least one of the preceding claims, characterized in that at least one loading means ( 36 . 38 ) a spring element ( 46 ) having. Contraption ( 1 ) according to at least one of the preceding claims, characterized in that directly on the first locking element ( 32 ) a guide body ( 28 ) arranged to move the locking element ( 32 ) by means of a guide curve ( 6 ) cooperates. Contraption ( 1 ) according to at least one of the preceding claims, characterized in that at least one magnetic element ( 42 . 44 ) movable opposite or at the forming station ( 20 ) is arranged. Method for shaping plastic preforms ( 10 ) to plastic containers ( 11 ), wherein plastic preforms ( 10 ) by means of at least one transformation station ( 20 ), which moves along a predetermined transport path, to the plastic containers ( 11 ), and wherein the transformation station ( 20 ) two side parts ( 22 . 24 ), which for opening and closing the forming station ( 20 ) are moved relative to each other, and wherein a locking mechanism ( 30 ) the two side parts ( 22 . 24 ) in a closed state of the forming station ( 20 ) locked together, wherein the locking mechanism ( 30 ) a first locking element ( 32 ), which for locking the forming station ( 20 ) with a second locking element ( 34 ) cooperates mechanically, wherein the first locking element ( 32 ) relative to the second locking element ( 34 ) between a locked position of the conversion station ( 20 ) and an unlocked position of the conversion station ( 20 ) is characterized in that at the forming station ( 20 ) a first loading means ( 36 ) is provided, which the first locking element ( 32 ) at least temporarily holds in a first position and a second loading means ( 38 ), which the first locking element ( 32 ) at least temporarily in a second position, wherein at least one loading means ( 36 . 38 ) a magnetic element ( 42 . 44 ) having. Method according to claim 8, characterized in that at least one guide curve ( 6 ) transfers the conversion station from an unlocked state to a locked state and / or from a locked state to an unlocked state. Method according to claim 8, characterized in that the first locking element ( 32 ) is fixed by at least one loading means in an end position of its movement.

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