EP2161201A1 - Centring unit for aligning at least two grouped containers and method for aligning two grouped containers - Google Patents

Abstract

The centering unit (51) comprises a liftable and lowerable precentering mechanism (53), and a liftable and lowerable final centering mechanism (57). The precentering mechanism has multiple individual subcentering mechanisms. The precentering mechanism and the final centering mechanism are formed independently liftable and lowerable. Independent claims are included for the following: (1) a handling machine for handling two grouped vessels; and (2) a method for aligning two grouped vessels.

Description

The invention relates to a centering unit for aligning at least two grouped vessels to each other and a machine for treating such vessels and a method for aligning at least two grouped vessels.

Such a device is from the DE 201 14 368 U1 known. This describes a device for wrapping at least two parallel juxtaposed objects with a common for all items, this bundling into a container label. For this purpose, instead of, as usual in conventional labeling machines, just past an object on a turntable on a labeling device, two vessels are arranged together on a turntable and then wrapped together with a single label. So that the two vessels remain correctly aligned relative to one another during the labeling process, the two vessels are clamped axially with respect to the turntable by means of a centering bell.

A disadvantage of the known machine has been shown that it came again and again difficulties despite the centering bell in the axial clamping of the vessels. In addition, the device lacks flexibility in terms of labeling more than two vessels.

Accordingly, the invention has the object to enable improved centering of the device described.

This object is achieved with the centering unit for aligning at least two grouped vessels according to claim 1. Accordingly, the centering unit for aligning at least two grouped vessels to each other comprises a raisable and lowerable pre-centering means and a liftable and lowerable Endzentriermittel. Thanks to the pre-centering agent, the grouped vessels can be better aligned with each other and then finally fixed in position by the final centering agent. In addition, by providing two centering means the vessels be aligned and held at two different heights to each other, which further improves the stability of alignment with each other.

The pre-centering agent may preferably comprise a plurality of individually liftable and lowerable partial centering agents. By providing a plurality of sub-centering means, the centering unit can be flexibly adapted to the number of grouped vessels. In particular, it is possible to form the group of several sub-groups and / or individual vessels and to align the sub-groups gradually relative to each other thanks to the individual lifting and lowering of the sub-centering.

Preferably, the pre-centering agent and the Endzentriermittel can be independently raised and lowered formed. In particular in connection with the partial centering means, the final centering can only be carried out when all partial groups are aligned with one another in order to arrive at the final local definition of the vessels.

According to a preferred embodiment, the precentering means, in particular the sub-centering means, can be raised and lowered by means of a pneumatic control. In this case, for example, the process of centering can be triggered in particular for the Teilzentriermittel via a remote lift curve and pneumatic valve.

The partial centering means may each preferably have at least one vessel receiving opening. The number of vessel receiving openings is adapted to the number of vessels in the subgroups. A continuous vessel receiving opening has the advantage that the partial centering means can not only pre-center at the vessel extremities, but can be pushed over the vessels, so that the positioning can be further stabilized to one another.

Preferably, the lifting and lowering paths of the vessel receiving openings of the pre-centering means and the Endzentriermittels can be formed coaxially with each other. This allows constructive simplifications, since, for example, the required stroke for the pre-centering can be at least partially realized from the stroke of the final centering.

Advantageously, the pre-centering means may comprise two or three sub-centering means and each sub-centering means each having two vessel receiving openings. Thus, the popular in the beverage industry Quadropacks or six-packs can be treated with this centering unit.

The invention further relates to a machine for treating at least two grouped vessels, in particular for wrapping with a common label, with a treatment station, in particular designed as a carousel, with at least one turntable for receiving the vessels and at least one each associated with a turntable centering unit according to one of Claims 1 to 7. Thanks to the advantageous centering unit, it is possible to accurately and safely position the individual vessels of the group to each other.

The machine may preferably have at least one, but in particular two or three, vessel feeding devices for providing the vessels on the at least one turntable in the treatment station. In this case, each vessel feeding device can be assigned a sub-centering means of the centering unit used to pre-center the vessels, each coming from a Gefäßzuführvorrichtung, regardless of the possibly existing other Gefäßzuführvorrichtungen each other and with respect to the vessels of the other Gefäßzuführvorrichtungen. This further expedites the flexibility of the machine.

In particular, different vessels - different in terms of shape and / or content - can be fed to the machine via different vessel feed devices in order to be able to produce containers of interest to the buyer. Depending on the number of Gefäßzuführvorrichtungen example Twinpacks, Quadropacks but also six-packs can be treated.

Advantageously, a Gefäßzuführvorrichtung may have a grouping device for providing groups of vessels, in particular pairs of vessels, with a predetermined mutual distance. Thus, can not from a Gefäßzuführvorrichtung only one vessel but a couple or more vessels are pushed into the treatment station. This further increases the flexibility of the machine.

Preferably, the Gefäßzuführvorrichtungen may have an inlet star wheel and a Einteilschnecke. The spatial separation of the grouping and the supply to the treatment station a particularly simple machine structure is achieved.

The object of the invention is likewise achieved by the method according to claim 13. Accordingly, the invention relates to a method for aligning at least two grouped vessels, preferably in a machine for treating vessels, more preferably for wrapping with a common label, comprising the steps of: a) pre-centering the grouped vessels with a raisable and lowerable pre-centering agent and b) Final centering of the precentered vessels with a liftable and lowerable final centering agent. In particular, the centering unit can be used according to the different embodiments described above. Thanks to the pre-centering, a particularly effective centering and axial clamping of the vessels, so that their position remains stable to one another during treatment, can be achieved.

Preferably, the vessels of at least one, preferably two or three, Gefäßzuführvorrichtungen, in particular in pairs, can be provided. As a result, interesting products, in particular twin packs, quadropacks or six packs, can be treated for the customer.

According to a preferred embodiment, the pre-centering agent may comprise at least two partial centering agents and the process steps a) b) at least the steps: a1) pre-centering a first vessel group by lowering a first partial centering agent, then a2) precentering a second vessel group by lowering a second partial centering agent and then b1) Final centering of the pre-centered vessels by lowering the Endzentriermittels include.

Through the individual pre-centering, vessels provided by different vascular delivery devices can be effectively positioned to each other, and then, after all vessels have been pre-centered, through the Endzentrierung each other to be held stable in position. The method described may, of course, comprise more than two vascular groups, each vascular group each having a partial centering agent assigned to it and being used before final centering with the final centering agent.

Figur 1

eine schematische Übersicht einer Vorrichtung zum Umwickeln von nebeneinander stehenden Gegenständen,

Figur 2

eine 3-D-Ansicht einer Zentriereinheit gemäß einer ersten Ausführungsform zum Ausrichten von zwei gruppierten Gefäßen,

Figur 3

schematisch das Zentrierverfahren gemäß einer zweiten Ausführungsform,

Figur 4

eine Vorrichtung zum Umwickeln von sechs nebeneinander stehenden Gegenständen,

Figur 5

schematisch einen Teil einer Zentriereinheit zum Ausrichten von sechs gruppierten Gefäßen entsprechend einer dritten Ausführungsform der Erfindung, und

Figur 6

schematisch die Schritte zur Zentrierung dieser gruppierten Gegenstände gemäß einer vierten Ausführungsform der Erfindung.

Preferred embodiments of the invention will now be described with reference to the accompanying figures. Show it:

FIG. 1

a schematic overview of a device for wrapping adjacent objects,

FIG. 2

a 3-D view of a centering unit according to a first embodiment for aligning two grouped vessels,

FIG. 3

schematically the centering method according to a second embodiment,

FIG. 4

a device for wrapping six juxtaposed articles,

FIG. 5

schematically a part of a centering unit for aligning six grouped vessels according to a third embodiment of the invention, and

FIG. 6

schematically the steps for centering these grouped objects according to a fourth embodiment of the invention.

FIG. 1 shows a machine for treating at least two grouped vessels according to a first embodiment of the invention. A labeling machine 1 is shown. Vessels 3, in particular bottles or the like, are fed to the machine 1 via a conveyor belt 5. Via a Einteilschnecke 7, the vessels are grouped into pairs 11 and the pitch of the subsequent inlet star wheel 13, which is driven in synchronism with the Einteilschnecke 7 brought in this embodiment, thanks to the increasing in the conveying direction pitch of the flights 9. The inlet star wheel 13 has receiving pockets 15 arranged around the circumference, to which the bottle pairs 11 are transferred. A guide bow 17, together with the inlet starwheel 13, enables the transfer of the bottle pairs 11 to the turntable 19 of a treatment station 21.

The treatment station 21, here in the form of a carousel has a plurality of such turntable 19 in a uniform pitch. The turntables 19 and the carousel 21 have drive elements which allow a controlled rotation of the turntable 19 during the passage of the orbit. As drive elements, for example program-controlled servo, stepper motors or even mechanical control devices are used.

The bottle pairs 11 are wrapped with the aid of a labeling module 23 with a common label 25. The labeling module 23 comprises a knife roller 27, a vacuum transfer cylinder 29 and at the periphery of a glue roller 31. A withdrawn from a label tape roll 33 label tape 35 is fed to a knife edge of the knife roller 27 and thereby divided into individual labels 25. These are then transferred to the vacuum transfer cylinder 29. About the glue roller 31, a glue application is provided, for example, at the leading front label edge and at the trailing label trailing edge respectively at the back of the label. The label module 23 is position and speed synchronously driven to the carousel 21. The described labeling module 23 is to be regarded as a possibility for labeling and not restrictive, any other way of providing a label is also possible.

As the group passes the vacuum roller 29, one end of the label 25 is adhered to a vessel 37. Then, the group 11 rotates on its turntable 19, so that with the aid of a Andrückgeländers 39, for example, formed as a vacuum sponge, the label 25 is pressed against the vessel group 11. Once the label 25 has been wound around the two containers, a container 41 is formed from the two containers 11. The finished containers 41 are then fed via an outlet starwheel 42 to the corresponding receiving pockets 45, to a discharge conveyor 47.

In the manufacture of these containers 41, the correct alignment of the two vessels 3 is extremely important to one another. For this purpose, the vessels 3 are clamped between a centering unit 51 and the already mentioned turntables 19 (see Figure 2). FIG. 2 shows a first embodiment of the centering unit according to the invention for aligning at least two grouped vessels 11th

Elements and features with reference numerals already in the FIG. 1 are not described again in detail below. Their description is hereby referred to.

The centering unit 51 according to the invention comprises a pre-centering means 53, which is designed here as a centering plate. The centering plate 53 has two vessel receiving openings 55. In FIG. 2 the second opening is hidden and invisible. This opening is designed so that, for example, a bottleneck, as in FIG. 2 shown, passes through.

About the Vorzentrierplatte 53 is a Endzentriermittel 57, here also in the form of a plate arranged. The Endzentriermittel 57 also includes two recesses 59 (again only the one in FIG. 2 is visible), whose openings are designed so that they receive the upper limb 61 of the vessels 11 and bring into position. Since the vessels 11 are already aligned with each other thanks to the Vorzentrierplatte 53, the inner diameter of the recess 59 is selected so that it corresponds substantially to the outer diameter of the upper limb 61 of the vessel 11. This allows a precise alignment of the two vessels 11 to each other.

The Endzentriermittel 57 is arranged via a rotary connection 63 and a spring system 65 height and rotation adjustable. The lifting movement of the Endzentriermittels 57 is accomplished by means of a cam guide roller 67. By an up and down movement of the cam guide roller 67 along a control link, not shown, a connected to the spring system 65 plate 69 is also moved up and down, whereby against the spring forces of the spring system 65, the Endzentriermittel 57 can be moved up and down.

However, not only is the end centering means 57 raised and lowered, but also the pre-centering means 53. In this embodiment, the raising and lowering of the pre-centering means 53 is effected by a pneumatic control. To the plate 69 is to a projection 71, via which a valve 73 is triggered during the raising and lowering of the plate 69 according to the movement of the cam guide roller 67 along the control link. The valve 73 switches compressed air (the connecting hoses are not shown here for clarity), which over a lift cylinder 75 (a second lift cylinder is in FIG. 2 not visible because it is located behind the rotary joint 63), the pre-centering plate 53 can raise and lower via the lifting cylinder rod 77 independently of the final centering means 57.

By disposing the lift cylinder 75 on the end centering means 57 in this embodiment, the total lift of the pre-centering plate 53 is composed of the possible stroke of the end centering means 57 and the lift height of the lift cylinder 75. This is optimally embodied, in particular, when the stroke of the end centering means 57 is coaxial with the stroke of the pre-centering means 53, as in FIG FIG. 2 shown, is formed.

The boom 79, which is still arranged on the centering unit 51, serves only to keep the plane of the Endzentriermittels 57 stable during rotation.

In this embodiment, the end centering means 57 has continuous vessel receiving openings 61. According to an alternative embodiment, the vessel receiving openings 61 could also be formed as blind holes.

For wrapping standard bottles, a stroke for the end centering plate 57 of 43 to 53 mm and a stroke of 45 to 50 mm for the precentering plate 53 is usually sufficient.

Schematically is in FIG. 2 also the turntable 19 shown on which the vessels 11 are. For secure clamping of the pair of bottles 11 between turntable 19 and centering unit 51, the turntable 19 may be provided with corresponding to the shape of the vessels formed recesses 81.

Further to be recognized in FIG. 2 two guide pins 83 and 85, which prevent unwanted tilting of the Vorzentrierplatte 53 when lowering. The pins 83 and 85 are guided in sleeves 87, 89 fastened to the end centering means 57.

FIG. 3 shows schematically with reference to three cross-sectional views of a second embodiment, namely a method for aligning at least two grouped vessels according to the invention. Elements and features with Reference numerals in the FIGS. 1 and 2 already used, will not be described again in detail. Their description is hereby referred to.

The three in FIG. 3 States I to III shown on the in FIG. 1 shown points in the labeling machine 1 between the inlet star 13 and the labeling module 23 instead. The three states are indicated schematically next to the carousel 21 by the Roman numerals I, II, III.

State I: After the inlet star 13 has transferred a pair of vials 11 to a turntable 19, slightly above the upper extremities 91 of the vessels 11 is a centering unit 51 according to the first embodiment of the invention. It can be seen in this side view, the rotary joint 63, the two lifting cylinder 75 and a guide pin 83 in its guide sleeve 87. In the illustrated state, the Vorzentrierplatte 53 and the Endzentrierplatte 57 abut each other.

Condition II: After the carousel 21 has moved a bit further ( FIG. 1 ), the Endzentrierplatte 57 moves together with the Vorzentrierplatte 53 together due to a lowering of the cam guide roller 67 along the slide control in the direction of the upper extremities 91 of the bottles, and succeeded to state II of FIG. 3 , Here, the pre-centering plate 53 and the Endzentrierplatte 57 still abut each other, which is also recognizable by the fact that the guide pin 83 still closes with the upper end of the lifting cylinder 75. However, in contrast to state I, the upper extremities 91 of the vessels 11 are now located within the vessel receiving openings 55 of the precentering plate 53.

Condition III: In the third state of the FIG. 3 , the projection 71 releases (see FIG. 2 ) on the plate 69, the valve 73 and causes the pneumatic lowering of Vorzentrierplatte 57. The bottleneck of the vessels 11 is now located on the inner walls of the vessel receiving openings 55 at. In addition, the upper extremities 91 of the vessels 11 are fixed in the vessel receiving openings 61 of the Endzentrierplatte 57. As can be seen, the guide pin 83 has now also lowered relative to the lifting cylinder 75.

Thanks to the Vorzentriermittels 53 and the final centering 57, the two vessels are not only on the upper limbs 91 itself, but also further down on Bottle neck fixed relative to each other, so that overall the positioning of the two vessels 11 can be stabilized to each other. In particular, together with the recesses 81 in the turntable 19 thus the vessels 11 are supported at three different positions to each other.

FIG. 4 shows a second machine for treating grouped vessels, in particular for wrapping with a common label according to the invention. Features with reference numerals already in the FIGS. 1 to 3 are not described again in detail here. It is hereby referred to the description above.

The difference between the machine 101, the in FIG. 4 is shown, and the machine 1, the in FIG. 1 has been described and described is that not only a Gefäßzuführvorrichtung of inlet star wheel 13 and Einteilschnecke 9, but three Gefäßzuführvorrichtungen are arranged at the treatment station 21.

The second feed station comprises a separate feed conveyor 103 and a dividing screw 105 for pairing the vessels 107, which are fed via the conveyor 103. The vessel groups 109 then pass via a second inlet starwheel 111 onto the turntable 19, the pair of vessels 109 being arranged next to the vessel pair 11 already pushed by the inlet starwheel 13.

The third vessel feeder includes a third feeder 113 and a third sub-feeder 115 for grouping the vessels 117 fed through the third conveyor 113 into pairs 119 as well. These are then fed via a third inlet star wheel 121 to the turntable 19, on which the pair of vessels 11 and 109 are already arranged.

As can be seen, in this embodiment, the turntable 19 is rotated 180 ° between the second vessel feeding device and the third vessel feeding device. This is in the FIG. 3 schematically indicated by the hatching and the value 180 °.

After pushing on the three pairs of vessels 109, 11 and 119, the carousel 21 continues to rotate past the labeling module 23. Along the Andrückgeländer 39, here a vacuum unit with special sponge contours, the three vessel pairs 109, 11 and 119 are completely wrapped with the label 25 and glued. For this purpose, the turntable rotates once at least 360 °, which in FIG. 3 again indicated by hatching with the value 360 °.

Thereafter, a container 123 is obtained which, in contrast to the first embodiment, does not comprise two vessels but six vessels (six-pack).

As a variant of the machine FIG. 1 includes the machine of FIG. 3 additionally a label inspection station 125, for example a camera or a sensor.

Thereafter, the container 123 is again transported with the aid of an outlet star wheel 43 with matching receiving pockets 45 on the discharge conveyor 47.

By providing three vessel feed stations, different vessels and / or different products can be merged into a container 123. Here each pair of tubes 11, 109, 119 were postponed, but it can be pushed at each Gefäßzuführstation independently more or less vessels.

FIG. 5 schematically shows a third embodiment of a part of a centering unit 151 for aligning grouped vessels according to the invention. Shown is a section of a centering unit, as in the machine, as in FIG. 4 shown, can be used. Features with reference numerals already in one of FIGS. 1 to 4 are not described in detail. Their description is hereby referred to.

In FIG. 5 only the lower part of a centering unit 151 is shown. One recognizes a Endzentriermittel 153, here again a plate, with six vessel receiving openings 155, 157, 159 161, 163, 165. Below the Endzentriermittels 153 three independently arranged Teilzentriermittel, in turn plates 167, 169 and 171 are arranged. These form the precentering means 53. These sub-centering means 167, 169, 171 each have two Vessel receiving openings 173, 175 and 177 (the second openings per centering means are again not visible in this view).

In FIG. 5 can be seen on the Endzentrierplatte 153 the lifting cylinder 75, wherein at the front in each case the pneumatic connection tubes 179 are shown schematically. In this illustration, the representation of the guide pins has been omitted. However, these are the same as in the first embodiment.

The Endzentrierpatte 153 is then in turn at a rotational connection 63 and a spring system 65 via a cam guide roller 67 height adjustable (shown by the double arrow on the left side) arranged in the carousel.

In contrast to the first embodiment, in which the Vorzentrierplatte 53 was completely lowered, this embodiment now has three independently from each other on the lifting cylinder 75 raised and lowered trained Teilzentriermittel 167, 169 and 171. The independent lifting and lowering is shown by the right below Double arrows per sub-centering means 167, 169, 171 indicated.

As in the first embodiment, the lifting and lowering is pneumatically controlled, with the required control air can be provided via three independent valves. These valves can be independently controlled, for example via the cam guide roller.

Otherwise, both the final centering plate 153 and sub-centering means 167, 169 and 171 of the pre-centering means correspond to the final centering means 57 and the pre-centering means 53 of the first embodiment.

The centering unit 151 is used in a machine for treating grouped vessels such as in FIG FIG. 3 shown. FIG. 6 schematically shows a fourth embodiment of the invention, namely a second embodiment of the method according to the invention for centering grouped vessels, and shows the use of the centering unit 151 at four different locations IV, V, VI and VII of the machine 101, which in FIG. 4 are indicated. Features with reference numerals already in one of FIGS. 1 to 5 are not described in detail. Their description is hereby referred to.

State IV: After pushing the first group of vessels 11 onto the turntable 19, only the central precentering plate 169 is initially lowered in order to align the vessels of the vessel group 11 relative to one another. The pre-centering plate 167 and the pre-centering plate 171 still remain in contact with the final centering plate 153.

State V: After the second vessel group 109 has been pushed onto the turntable 19, the left precentering plate 167 has also been lowered relative to the final centering plate 153 in order, on the one hand, to align the vessels of the vessel group 109 relative to one another and, on the other hand, to align this vessel group 109 also with respect to the first group 11. The third partial centering plate 171 remains in contact with the final centering means 153.

State VI: After pushing the third vessel group 119 onto the turntable 19, the third partial centering plate 171 now also drops. Now all three Vorzentrierplatten 167, 169 and 171 are lowered, which now on the one hand, the vessels of the third group 119 are aligned with each other and beyond the three groups of vessels 11, 109 and 119 are also aligned with each other.

Finally, in the next state VII, shortly before the labeling station 23, the final centering plate 153 is finally lowered in order to receive the extremities 91 of the vessels into the corresponding vessel receiving openings 155 to 165. Together with the depressions in the turntable 19 thus the six vessels are supported at three different points, so that a stable positioning of the six-pack is achieved. The lowering of the Endzentrierplatte 153 may simultaneously lead to a further lowering of the three Vorzentrierplatten 167, 169 and 171 or the two centering - final centering and Vorzentriermittel - approach again.

Finally, it should be noted that in FIG. 6 the different states are shown only schematically and that the actual dimensions may differ. In particular, the vessels abut each other in their abdominal region, as in FIG FIG. 2 shown.

Thanks to the centering unit of the third embodiment, a flexible machine for treating grouped vessels, in particular for wrapping vessels with a label. At the same time, improved centering is ensured by the presence of the pre-centering means at one point of the vessels and the final centering agent at another point of the vessels (the upper extremity).

Claims (15)

Centering unit for aligning at least two grouped vessels to each other with a raisable and lowerable Vorzentriermittel (53) and a liftable and lowerable Endzentriermittel (57). The centering unit according to claim 1, wherein the pre-centering means (53) comprises a plurality of individually raisable and lowerable part centering means (167, 169, 171). Centering unit according to claim 1 or 2, wherein the pre-centering means (53) and the Endzentriermittel (57) are formed independently raised and lowered. Centering unit according to one of claims 1 to 3, wherein the Vorzentriermittel (53), in particular the Teilzentriermittel (167, 169, 171) via a pneumatic controller (71, 73, 75) are raised and lowered formed. Centering unit according to one of claims 1 to 4, wherein the partial centering means (167, 169, 171) each have at least one vessel receiving opening (173, 175, 177). The centering unit according to any one of claims 1 to 5, wherein the raising and lowering paths of the vessel receiving openings (55, 173, 175, 177) of the pre-centering means (53, 167, 169, 171) and the final centering means (155, 157, 159, 161, 163 , 165) are formed coaxially with each other. A centering unit according to claim 5 or 6, wherein the pre-centering means (53) comprises two or three sub-centering means (167, 169, 171) and each sub-centering means (167, 169, 171) each comprise two vessel receiving openings (173, 175, 177). Machine for treating at least two grouped vessels, in particular for wrapping with a common label (25), with a treatment station (21), in particular designed as a carousel, with at least one turntable (19) for receiving the vessels (3, 11, 109, 119) and at least one respective turntable (19) associated with centering unit (51, 151) according to one of claims 1 to 7. Machine according to claim 8, comprising at least one, in particular two or three, vessel feed devices (13, 111, 121) for providing the vessels (11, 109, 119) on the at least one turntable (19) in the treatment station (21). Machine according to claim 9, wherein a partial centering of the centering device is associated with a respective Gefäßzuführvorrichtung, so that the supply of the vessel supply device vessels are pre-centered by the Teilzentriermittel. Machine according to claim 9 or 10, wherein at least one vessel feed device (13, 111, 121) has a grouping device (9, 105, 115) for providing vessel groups (11, 109, 119), in particular vessel pairs, at a predetermined mutual distance. Machine according to one of claims 9 to 11, wherein de Gefäßzuführvorrichtung an inlet star wheel (13, 111, 121) and a Einteilschnecke (9, 105, 115). Method for aligning at least two grouped containers, preferably in a machine for treating containers, more preferably for wrapping with a common label (25), with the steps: a) precentering the grouped vessels (9, 109, 119) with a raisable and lowerable Vorzentriermittel (53), and b) Final centering of the precentered vessels with a liftable and lowerable final centering means (57). The method of claim 13, wherein the vessels of at least one, preferably two or three, Gefäßzuführvorrichtungen, in particular in pairs, are provided. Method according to claim 13 or 14, wherein the precentering means (53) comprises at least two sub-centering means (167, 169, 171) and steps a) and b) comprise at least the steps: a1) precentering a first group of vessels by lowering a first sub-centering means (167), then a2) precentering a second vessel group by lowering a second sub-centering means (169), and then b1) Final centering of the pre-centered vessels by lowering the Endzentriermittels (153). include.

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