BLOW STATION AND BLOW FORMING MACHINE INCLUDING THE BLOW STATION

Description

[0001] The invention relates to a blow molding station and a blow molding machine comprising the blow molding station.

[0002] Blow molding machines can be used, for example, to manufacture plastic containers. In these machines, plastic preforms are transformed into containers in blow molding stations. These stations have molds for forming the preforms into the containers to be produced, and the molds can have at least two halves. One half can be pivoted relative to the other, allowing the mold to be opened for inserting a preform or removing a container, and closed for forming a preform into a container. Centering elements, for example, can be used to ensure the correct positioning of the mold halves. Furthermore, the forming process can be carried out by introducing a fluid into the preform under high pressure, for example, with compressed air up to 40 bar.US Patent 2011 / 052747 A1 describes a device for forming plastic containers using a blow mold, wherein the blow mold comprises at least a first and a second blow mold part and may include at least a first and a second support element for holding the blow mold parts. The support elements are movable relative to each other in at least one plane to allow transition from a closed configuration to an open configuration. Each support element has a receiving area for receiving a blow mold part, and in the closed configuration, the blow mold parts form at least one cavity for container expansion. The blow mold parts may be magnetically and detachably coupled to each other, and / or at least one of the blow mold parts may be magnetically and detachably coupled to at least one support element.

[0003] EP 2 554 357 A1 describes a half-part for forming a plastic container, comprising: a support and a half-mold attached to the support by: a first set of protruding elements screwed into corresponding receptacles of the support to strike the half-mold; a bracket mounted outside the support, from which a second set of protruding elements branches off, such that the rotation of the bracket causes the protruding elements to be inserted into through-cavities formed in the support, in such a way that they strike the half-mold and block it; a clamping element to block the rotation of the bracket.

[0004] DE 10 2014 019 722 A1 describes a forming device (1) for forming plastic preforms into plastic containers, comprising a blow molding device which forms a cavity within which the plastic preforms can be formed into the plastic containers by applying a flowable medium, wherein the blow molding device has at least two side parts which are arranged at least indirectly on blow mold carriers, wherein the side parts are arranged on the blow mold carriers by means of a fastening device. According to the invention, the fastening device also has a restoring means which, at least temporarily during operation, pushes at least one side part towards the blow mold carrier on which this side part is arranged.

[0005] To prevent the mold halves from being forced apart, it is known from DE 20 2004 011 785 U1 and DE 42 12 584 A1 to support one mold half on a pressure cushion, which presses this mold half against the other mold half while compressed air is applied to the preform. Furthermore, this allows tolerances, deviations, and deformations between the mold halves to be compensated for.

[0006] Furthermore, US patent 6729868 B1 discloses the provision of a mold carrier with a bushing mounted in an elastomer. The mold half is attached to the bushing by a screw and is thus floating on the mold carrier.

[0007] The object of the invention is to provide a blow molding station and a blow molding machine that are simpler in design and further provide compensation for deviations, tolerances and deformations between the mold halves.

[0008] The problem is solved by the features of the independent claims. Advantageous further developments are the subject of the dependent claims and the following description.

[0009] In a blow molding station for forming a preform into a container for a blow molding machine for manufacturing plastic containers, comprising a first mold carrier, a second mold carrier, a first mold half mounted on the first mold carrier, and a second mold half mounted on the second mold carrier, wherein at least one of the mold carriers is pivotably mounted, and the blow molding station is open in a first pivot position of the pivotably mounted mold carrier for inserting a preform into one of the mold halves or for removing a container from one of the mold halves, and is closed in a second pivot position of the pivotably mounted mold carrier in which the second mold half and the first mold half are in contact, wherein at least one of the mold halves is self-aligning with respect to the other mold half for changing into the second pivot position, the invention provides that the mold carrier,on which the self-aligning mold half is mounted, has a sliding bearing for the self-aligning mold half, wherein the sliding bearing is arranged radially spaced from a central axis of a mold formed by the mold halves between the self-aligning mold half and the mold carrier on which the self-aligning mold half is mounted, or that the mold carrier on which the self-aligning mold half is mounted has an elastomeric body on which the self-aligning mold half is mounted, wherein the elastomeric body is vulcanized to the self-aligning mold half and the mold carrier.

[0010] The invention thus provides a blow molding station in which at least one mold half self-aligns when switching to the second pivoting position. Active alignment of the self-aligning mold half, for example by means of a pressure pad, is no longer required. If, for example, the second mold half is self-aligning on the second mold carrier, it can be mounted on the second mold carrier in such a way that, when switching to the second pivoting position, e.g., from the first pivoting position, the second mold half self-aligns with respect to the first mold half. The first mold half, which can, for example, be fixed to the first mold carrier, acts as a reference point for the alignment of the second mold half. Active alignment, for example by means of a pressure pad, is no longer required.The self-alignment of the second mold half occurs passively and therefore automatically when switching to the second pivoting position. This self-alignment of the self-aligning mold half compensates for tolerances, deviations, and deformations between the two mold halves. This eliminates seams on the manufactured containers, thus increasing their quality. Furthermore, it reduces the stress on the centering elements that center the two mold halves relative to each other, thereby reducing wear on these elements.

[0011] The self-aligning mold half is mounted on the mold carrier via a sliding bearing. If, for example, the second mold half is the self-aligning mold half, it can slide on the sliding bearing and rotate relative to the first mold half, thus self-aligning when transitioning to the second pivot position. The axis of rotation for this relative rotation can be located between the first and second mold halves when the second mold half is in the second pivot position, i.e., when the mold or blow molding station is closed. The sliding bearing can be flexibly positioned on the second mold half. For example, the sliding bearing can be arranged radially spaced from a central axis of the mold between the second mold half and the second mold carrier. Alternatively or additionally, the sliding bearing can also be arranged axially between the second mold half and the second mold carrier.

[0012] Alternatively or additionally, the first mold half can be self-aligning on the first mold support. The explanations above then apply analogously to the first mold half.

[0013] For example, the blow molding station can be designed without pressure cushions and / or pancake cylinders.

[0014] Eliminating the pressure pad or pancake cylinder simplifies the construction of the blow molding station and reduces costs. Thanks to the automatic alignment of the self-aligning mold half, containers of improved quality can still be produced.

[0015] According to another example, the sliding bearing can have a sliding bearing film.

[0016] A sliding bearing film can be used to provide a sliding bearing for the second mold half in a simple and cost-effective way.

[0017] In another example, the self-aligning mold half can be attached to the mold carrier on which it is mounted using flexible connecting elements, in particular an ultra bushing.

[0018] The flexible connecting elements thus provide a connection between the mold carrier supporting the self-aligning mold half and the mold half, which allows the self-aligning mold half to slide and rotate relative to the mold carrier on which it is mounted and relative to the other mold half.

[0019] The self-aligning mold half can, for example, be attached to the mold support on which it is mounted using spring-loaded connecting elements.

[0020] The spring-loaded connecting elements can be used as an alternative or in addition to the flexible connecting elements. The spring-loaded connecting elements also provide a connection between the mold carrier, on which the self-aligning mold half is mounted, and the self-aligning mold half itself, allowing the self-aligning mold half to slide and rotate relative to the mold carrier and relative to the other mold half.

[0021] It is also conceivable that the elastomer body could be designed as a rubber cushion.

[0022] The rubber preferably has a low hardness.

[0023] According to another example, the elastomer body can be largely bounded on all sides.

[0024] In this example, the elastomer body cannot expand beyond the boundaries, so the behavior of the elastomer body can be adjusted by the expansion of the boundaries around the elastomer body.

[0025] Furthermore, the elastomer body can, for example, be designed in such a way that it exhibits behavior like an incompressible hydraulic fluid.

[0026] This behavior allows the mold carrier, on which the self-aligning mold half is mounted, to continue exerting pressure on the self-aligning mold half, pressing it against the other mold half in the second pivot position. Simultaneously, the elastomer body enables automatic alignment of the self-aligning mold half when transitioning to the second pivot position. This behavior can be adjusted, for example, using the limit described above.

[0027] The invention further relates to a blow molding machine for producing plastic containers comprising a blowing wheel and a plurality of blowing stations according to the preceding description, wherein the blowing stations are arranged distributed around the circumference of a blowing wheel, preferably equidistantly.

[0028] The advantages, effects, and further developments of the blow molding machine derive from the advantages, effects, and further developments of the blow molding station described above. To avoid repetition, reference is therefore made to the preceding description in this regard.

[0029] The invention further relates to a system for manufacturing containers, comprising at least one device for thermally conditioning the preforms, at least one transport device and at least one blow molding machine according to the description above, wherein the transport device removes the thermally conditioned preforms from the device and feeds them to the blow molding machine.

[0030] The invention is described below with reference to exemplary embodiments and the accompanying drawing. The drawing shows: Figure 1a, a schematic representation of a blowing station according to a first example in longitudinal section (a) and in plan view (b); Figure 2a, a schematic representation of a blowing station according to a second example in longitudinal section (a) and in cross-section (b); and Figure 3, a schematic representation of a plant for manufacturing containers.

[0031] The blowing station for transforming a preform into a container for a blow molding machine for manufacturing plastic containers is hereinafter referred to in its entirety by reference numeral 10.

[0032] As in Figure 1a The blow molding station 10, as shown, has a first mold support 12 and a second mold support 14, which carry parts of a mold 32 for the container to be formed. The mold 32 has at least a first mold half 16 and a second mold half 18. The mold 32 may have further mold parts, e.g., a bottom mold 26. The first mold half 16 can be rigidly connected to and supported on the first mold support 12 by means of connecting elements 34, in particular screws. However, this does not preclude the possibility that the first mold half 16 can be movably supported on the first mold support 16. The second mold half 18 is supported on the second mold support 14.

[0033] As in Figure 1bAs shown, the second mold carrier 14 is pivotably mounted relative to the first mold carrier 12. A joint 36 connects the first mold carrier 12 to the second mold carrier 14, with the joint 36 having a pivot axis 38. The second mold carrier 14, and thus also the second mold half 18, can therefore be pivoted about the pivot axis 38 relative to the first mold carrier 12 or the first mold half 16. However, this does not preclude the possibility that the first mold carrier 12 could also be pivotably mounted.

[0034] In this example, the mold 32 can be opened and closed by means of a pivoting movement of the second mold carrier 14. In the open state, the blow molding station 10 is in a first pivoting position in which a preform can be inserted into the first mold half 16 or a container can be removed from the first mold half 16.

[0035] In the closed state, the blowing station 10 is in a second pivoting position in which the second mold half 18 rests against the first mold half 16, so that at least part of the mold 32 of the container to be produced is formed. Centering elements 39 can be provided on both mold halves 16 and 18 to center the second mold half 18 on the first mold half 16.

[0036] The bearing of the second mold half 18 is designed such that it is self-aligning when the blowing station 10 moves to its second pivot position, e.g., from the first pivot position. The second mold half 18 can therefore be automatically aligned when placed against the first mold half 16. A pressure pad or pancake cylinder is not required for this.

[0037] In the example according to the Figures 1a and 1bThe second mold half 18 is mounted on a sliding bearing 20 on the second mold carrier 14. The second mold half 18 can therefore be moved axially and circumferentially around the central axis 30 of the container to be produced, at least along the central axis 30. In this way, deviations, tolerances, and deformations can be compensated for.

[0038] The sliding bearing 20 can be designed as a sliding bearing film which can be attached to a surface of the second mold carrier 14 facing the second mold half 18.

[0039] Furthermore, the second mold carrier 14 can have flexible connecting elements 24 with which the second mold half 18 can be attached to the second mold carrier 14. Alternatively or additionally, the second mold carrier 14 can have ultra-bushings 22 in which connecting elements 24 for attaching the second mold half 18 to the second mold carrier 14 can be mounted. The connecting elements 24 can be movably mounted in the ultra-bushings 22 with respect to the second mold carrier 14. In this case, the connecting elements 24 can, for example, be rigidly designed.

[0040] The mold 32 of the blowing station 10 can further include a ring carrier 28 for the base mold 26. The base mold 26 can be mounted in the ring carrier 28 and, together with the two mold halves 16, 18, form the mold 32 for the container to be produced. However, this does not preclude the possibility that the mold 32 may include further mold components for forming areas of the container to be produced.

[0041] If, alternatively or additionally, the first mold half 16 is self-aligning on the first mold half 12, the above explanations regarding the second mold half 18 and the second mold support 14 apply analogously to the first mold half 16 and the first mold support 12.

[0042] In the Figures 2a and 2b An alternative example of the invention is presented. Elements that are shown in the example according to the Figures 1a and 1b already described, point in the Figures 2a and 2b the same reference numerals. The swivel mechanism 36, 38 from Figures 1a and 1b is omitted in this example, but can of course also be included.

[0043] Instead of the plain bearing 20 Figures 1a and 1bIn this example, the blow molding station 10 has an elastomer body 40 on which the second mold half 18 is mounted on the second mold carrier 14. The elastomer body 40 can be designed as a rubber cushion. Furthermore, the elastomer body 40 is, for example, vulcanized to both the second mold half 18 and the second mold carrier 14, thus securing the second mold half 18 to the second mold carrier 14.

[0044] The second form carrier 14 can be according to Figure 2a furthermore, the elastomer body 40 has an upper limit 42 and a lower limit 44. Furthermore, the second mold carrier 14 can be configured according to Figure 2b also have a first lateral boundary 46 and a second lateral boundary 48, which are arranged on opposite sides of the elastomer body 40. In particular, the elastomer body 40 is further limited in the second pivot position by the second mold half 18 and the second mold carrier 14. As can be seen from the Figures 2a and 2bAs can be seen, the elastomer body 40 is thus almost completely bounded.

[0045] During elastic movements of the elastomer body 40, the material of the elastomer body 40 is positively constrained by the boundaries 42-48. Therefore, in the second pivot position, the material of the elastomer body 40 can only deviate from its original shape to a very limited extent, if at all, so that the elastomer body 40 can exhibit behavior similar to an incompressible hydraulic fluid.

[0046] In this example, the second mold half 18 is therefore mounted as if it were floating on an incompressible hydraulic fluid. When switching to the second pivot position, the second mold half can thus compensate for deviations, tolerances, and deformations of the two mold halves 16 and 18.

[0047] The elastomer body 40 can, for example, be designed as a rubber cushion. The rubber material can have a low hardness of 10 to 100 Shore A, preferably 30 to 60 Shore A.

[0048] In Figure 3 A plant 50 for the production of containers is shown. The plant 50 comprises at least one device 54 for the thermal conditioning of preforms, at least one transport device 56, and at least one blow molding machine 52.

[0049] The blow molding machine 52 has a plurality of blowing stations 10, at least one of which is designed according to the preceding description. The blowing stations 10 are arranged along the circumference of a blowing wheel 64. The blowing stations 10 can be positioned equidistant from one another. By rotating the blowing wheel 64, the blowing stations 10 can be transported past the transport device 56 one after the other and alternately switch between the first and second pivot positions depending on the angular position of the respective blowing station 10.

[0050] The system 50 can further include a feed device 62 for preforms with a feed wheel 60. The feed wheel 60 can feed the preforms from the feed device 62 to the device 54, in which the preforms can be thermally conditioned for forming in the blow molding machine 52. The transport device 56 can pick up the thermally conditioned preforms from the device 54 and place them into the blow molding stations 10 of the blow molding machine 52, which are arranged at the transfer position. For this purpose, the blow molding stations 10 at the transfer position of the transport device 56 are in the first pivot position. The preforms can then be placed into the first mold half 16.

[0051] The blow molding stations 10 are continuously transported in the direction of the arrow by a rotation of the blow molding wheel 64 of the blow molding machine 52 and thereby switch to the second pivoting position. During this change, the self-aligning second mold halves 18 of the blow molding stations 10 can automatically compensate for deviations, tolerances and deformations.

[0052] When the blowing stations 10 are in the second pivot position, the preforms are transformed into containers. This can be done with a blowing gas or with a liquid and takes place during the rotation of the blowing wheel 64.

[0053] After the containers have been formed, the blowing stations 10 are returned to their first pivot position and, through the rotation of the blowing wheel 64, reach a further transfer position. A further transport device 58 can then remove the manufactured containers from the open blowing stations 10. The containers can be removed from the first mold half 16 for this purpose.

[0054] The blowing station 10 can optionally, in all exemplary embodiments described here, further comprise at least one element not shown in the figures from the following group: a drive for pivoting the second mold carrier 14, a locking mechanism for locking the second mold half 18 to the first mold half 16 in the second pivoting position, and further components for operating the blowing station 10.

[0055] The example described above does not in any way limit the invention. Rather, the invention can be modified in numerous ways. All features of the invention described above can be essential to the invention, either alone or in combination. Reference symbol list

[0056] 10 Blow molding station 12 First mold carrier 14 Second mold carrier 16 First mold half 18 Second mold half 20 Plain bearing 22 Ultra bushing 24 Connecting element 26 Bottom mold 28 Ring carrier 30 Central axis 32 Mold 34 Connecting element 36 Joint 38 Swivel axis 39 Centering element 40 Elastomer body 42 Upper limit 44 Lower limit 46 First lateral limit 48 Second lateral limit 50 System 52 Blow molding machine 54 Device for thermal conditioning of preforms 56 Transport device 58 Transport device 60 Feed wheel 62 Feed device 64 Blow wheel

Claims

1. Blowing station (10) for transforming a preform into a container for a blow moulding machine (52) for producing plastic containers, comprising a first mould carrier (12), a second mould carrier (14), a first mould half (16) mounted on the first mould carrier (12) and a second mould half (18) mounted on the second mould carrier (14), wherein at least one of the mould carriers (12, 14) is pivotably mounted and the blowing station (10) with the pivotably mounted mould carrier (12, 14) in a first pivotal position is opened in order to insert a preform into one of the mould halves (16, 18) or to remove a container from one of the mould halves (16, 18), and with the pivotably mounted mould carrier (12, 14) in a second swivel position in which the second mould half (18) and the first mould half (16) rest against each other, is closed, at least one of the mould halves (16, 18) being mounted in a self-aligning manner with respect to the respective other mould half (16, 18) in order to change to the second swivel position, characterised in that the mould carrier (12, 14) on which the self-aligning mould half is mounted has a plain bearing (20) for the self-aligning mould half (16, 18), the plain bearing being radially spaced from a central axis of a mould formed by the mould halves (16, 18) between the self-aligning mould half (16, 18) and the mould carrier (12, 14) on which the self-aligning mould half is mounted, or that the mould carrier (12, 14) on which the self-aligning mould half (16, 18) is mounted has an elastomer body (40) on which the self-aligning mould half (16, 18) is mounted, the elastomer body (40) being vulcanised onto the self-aligning mould half (16, 18) and the mould carrier (12, 14).

2. Blowing station (10) according to claim 1, characterised in that the blowing station (10) is designed without pressure pads and / or pancake cylinders.

3. Blowing station (10) according to claim 1 or 2, characterised in that the plain bearing (20) has a plain bearing film.

4. Blowing station (10) according to any of the preceding claims, characterised in that, if the mould carrier (12, 14) has the plain bearing (20), the self-aligning mould half (16, 18) is attached to the mould carrier (12, 14) on which it is mounted by means of flexible connecting elements (22), in particular an ultra bush.

5. Blowing station (10) according to any of the preceding claims, characterised in that, if the mould carrier (12, 14) has the plain bearing (20), the self-aligning mould half (16, 18) is attached to the mould carrier (12, 14) on which it is mounted by means of resilient connecting elements (24).

6. Blowing station (10) according to any of the preceding claims, characterised in that, if the mould carrier (12, 14) has the elastomer body (40), the elastomer body (40) is designed as a rubber cushion.

7. Blowing station (10) according to any of the preceding claims, characterised in that, if the mould carrier (12, 14) has the elastomer body (40), the elastomer body (40) is largely confined on all sides.

8. Blowing station (10) according to any of the preceding claims, characterised in that, if the mould carrier (12, 14) has the elastomer body (40), the elastomer body (40) is designed such that it behaves like an incompressible hydraulic fluid.

9. Blow moulding machine (52) for producing plastic containers, comprising a blowing wheel and a plurality of blowing stations (10) according to any of the preceding claims, wherein the blowing stations (10) are arranged distributed around the circumference of a blowing wheel (64), preferably equidistantly.

10. Plant for producing containers, which has at least one device (54) for thermal treatment of the preforms, at least one transport device (56) and at least one blow moulding machine (52) according to claim 9, wherein the transport device (56) removes the thermally treated preforms from the device (54) and feeds them to the blow moulding machine (52).