Abstract:
A centering unit for aligning at least two grouped vessels, a liftable and lowerable precentering mechanism as well as a liftable and lowerable final centering mechanism being provided so as to improve the alignment. According to a preferred embodiment, the precentering mechanism may include a plurality of subcentering mechanism so that vessels coming from different infeeds can be centered by mechanism a centering unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the benefit of priority of German Patent Application No. 102008046366.3, filed Sep. 9, 2008. The entire text of the priority application is incorporated herein by reference in its entirety. 
       FIELD OF THE DISCLOSURE 
       [0002]    The present disclosure relates to a centering unit for aligning at least two grouped vessels relative to one another as well as a machine for treating such vessels and a method for aligning at least two grouped vessels. 
       BACKGROUND 
       [0003]    Such a device is known from DE 201 14 368 U1. This reference describes a device for wrapping a label around at least two parallel juxtaposed objects, said label being common to all the objects and tying them into a bundle. To this end, two respective vessels are arranged in common on a rotary plate and are then both wrapped with a single label, instead of moving only one object on a rotary plate past a labeler, as is normally the case in conventional labelling machines. In order to maintain the two vessels in correct alignment with one another during the labelling process, the two vessels are axially fixed with respect to the rotary table with the aid of a centering bell. 
         [0004]    The known machine proved to be disadvantageous insofar as, in spite of the centering bell, it was often difficult to axially fix the vessels. In addition, the device lacks flexibility as regards the labelling of more than two vessels. 
       SUMMARY OF THE DISCLOSURE 
       [0005]    It is therefore an aspect of the present invention to allow improved centering of the device described. 
         [0006]    This aspect is achieved by the centering unit for aligning at least two grouped vessels. The centering unit for aligning at least two grouped vessels relative to one another comprises a liftable and lowerable precentering means and a liftable and lowerable final centering means. Thanks to the precentering means, the grouped vessels can be aligned more precisely relative to one another and can then be secured at their final position by the final centering means. In addition, due to the provision of two centering means, the vessels are aligned relative to one another and held at two different levels, whereby the stability of the alignment relative to one another will be improved still further. 
         [0007]    According to a preferred embodiment, the precentering means can comprise a plurality of subcentering means that can be lifted and lowered individually. Due to the fact that a plurality of subcentering means is provided, the centering means can be adapted to the number of grouped vessels in a flexible manner. In particular, it is possible to form the group of a plurality of subgroups and/or individual vessels and, thanks to the fact that the subcentering means can be lifted and lowered individually, the subgroups can be aligned relative to one another step by step. 
         [0008]    According to a preferred embodiment, the precentering means and the final centering means can be implemented such that they can be lifted and lowered independently of one another. Especially in connection with the subcentering means, it is thus possible to execute final centering only when all the subgroups have been aligned relative to one another so as to finally secure the vessels in position. 
         [0009]    According to a preferred embodiment, the precentering means, in particular the subcentering means, can be implemented such that they can be lifted and lowered via a pneumatic control. For example, the centering process, in particular the centering process for the subcentering means, can be triggered via a recessed control track and a pneumatic valve. 
         [0010]    A preferred embodiment can be so conceived that the subcentering means are each provided with at least one vessel reception opening. The number of vessel reception openings is adapted to the number of vessels comprised in the subgroups. A vessel reception opening which is implemented as a through hole has the advantage that the subcentering means cannot only be used for precentering the vessel extremities but can also be pushed onto the necks of the vessels so that the positioning of the vessels relative to one another can be stabilized still further. 
         [0011]    According to a preferred embodiment, the lifting and lowering paths of the vessel reception openings of the precentering means and of the final centering means can be formed coaxially with one another. This allows structural simplifications, since e.g. the stroke required for precentering can be realized, at least partially, from the stroke executed for final centering. 
         [0012]    It will be advantageous when the precentering means comprises two or three subcentering means and when each subcentering means is provided with two vessel reception openings. Quadropacks or sixpacks which are very popular in the beverage industry can be dealt with by such precentering means. 
         [0013]    The disclosure additionally relates to a machine for treating at least two grouped vessels, in particular for wrapping said vessels with a common label, comprising a treatment station, in particular a treatment station configured as carousel, said machine comprising at least one rotary plate for receiving thereon the vessels and at least one centering unit associated with a respective rotary plate. Thanks to the advantageous centering unit, the individual vessels of the group can be positioned precisely and reliably relative to one another. 
         [0014]    According to a preferred embodiment, the machine can comprise at least one, in particular two or three vessel feeding devices for providing the vessels on the at least one rotary plate in the treatment station. Each vessel feeding device can have associated therewith a subcentering means of the centering unit used, so as to precenter the respective vessels fed by a vessel feeding device relative to one another and relative to the vessels of possibly existing other vessel feeding devices, independently of the other vessel feeding devices. The machine is thus rendered even more flexible. 
         [0015]    In particular, different vessels—i.e. vessels which are different with respect to shape and/or content—can be fed via various vessel feeding devices, so that bundles that are interesting to the customer can be produced. Depending on the number of vessel feeding devices, e.g. twinpacks, quadropacks and also sixpacks can be dealt with. 
         [0016]    According to an advantageous embodiment, a vessel feeding device can include a grouping device for providing vessel groups, in particular vessel pairs, in predetermined spaced relationship with one another. Hence, a vessel feeding device can be used for pushing not only one vessel, but a pair or a plurality of vessels into the treatment station. This increases the flexibility of the machine still further. 
         [0017]    According to a preferred embodiment, the vessel feeding devices can comprise an infeed star wheel and an infeed worm. Due to the spatial separation of the grouping of the vessels and of their feeding into the treatment station, a particularly simple structural design of the machine is accomplished. 
         [0018]    The disclosure also relates to a method of aligning at least two grouped vessels, preferably in a machine for treating vessels, even more preferably for wrapping the grouped vessels with a common label, the method comprising the following steps: a) precentering the grouped vessels with a liftable and lowerable precentering means, and b) final centering of the precentered vessels with a liftable and lowerable final centering means. This allows in particular the use of the centering unit in accordance with the various above-described embodiments. Thanks to the precentering, a particularly effective centering and axial fixing of the vessels will be accomplished, so that the position which said vessels occupy relative to one another will remain stable during the treatment. 
         [0019]    According to a preferred embodiment, the vessels can be provided, in particular in pairs, by at least one, preferably two or three vessel feeding device(s). It is thus possible to treat products that are interesting to the customer, in particular twinpacks, quadropacks or sixpacks. 
         [0020]    According to a preferred embodiment, the precentering means can comprises at least two subcentering means, and the method steps a), b) can comprise at least the following steps: 
         [0000]    a1) precentering a first vessel group by lowering a first subcentering means, then
 
a2) precentering a second vessel group by lowering a second subcentering means, and then b1) final centering of the precentered vessels by lowering the final centering means.
 
         [0021]    Due to individual precentering, vessels which are provided by different vessel feeding devices can effectively be positioned relative to one another, so that, when all the vessels have been precentered, they can stably be held in position relative to one another through final centering. It goes without saying that the method described can comprise more than two vessel groups. Each vessel group can have associated therewith a subcentering means, said subcentering means being used before the final centering operation is carried out with the final centering means. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    Preferred embodiments of the present disclosure are now described with reference to the attached figures, in which: 
           [0023]      FIG. 1  shows a schematic overview of a device for enwrapping juxtaposed objects, 
           [0024]      FIG. 2  shows a 3D view of a centering unit according to a first embodiment used for aligning two grouped vessels, 
           [0025]      FIG. 3  schematically shows the centering method according to a second embodiment, 
           [0026]      FIG. 4  shows a device for enwrapping six juxtaposed objects. 
           [0027]      FIG. 5  schematically shows a part of a centering unit for aligning six grouped vessels in accordance with a third embodiment of the present disclosure, and 
           [0028]      FIG. 6  schematically shows the steps for centering these grouped vessels in accordance with a fourth embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0029]      FIG. 1  shows a machine for treating at least two grouped vessels according to a first embodiment of the present disclosure. The machine shown is a labelling machine  1 . Vessels  3 , in particular bottles or the like, are supplied to the machine  1  via a conveyor belt  5 . In the present embodiment, the vessels are grouped in pairs  11  via an infeed worm in  7 —thanks to the pitch of the screw flights  9  which increases in the conveying direction—and adjusted to the pitch of the infeed star wheel  13 , which follows the infeed worm  7  and which is driven synchronously therewith. The infeed star wheel  13  has circumferentially distributed reception pockets  15  to which the bottle pairs  11  are transferred. A guide arc  17  allows, together with the infeed star wheel  13 , a transfer of the bottle pairs  11  to rotary plates  19  of a treatment station  21 . 
         [0030]    The treatment station  21 , which is here provided in the form of a carousel, comprises a plurality of regularly spaced rotary plates  19  of this type. The rotary plates  19  and the carousel  21  are provided with drive units allowing a controlled rotation of the rotary plates  19  while the rotary plates are moving along their circular paths. The drive units used are e.g. program-controlled servo motors, stepping motors or mechanical control units. 
         [0031]    The bottle pairs  11  are wrapped with a common label  25  with the aid of a labelling module  23 . The labelling module  23  comprises a knife cylinder  27 , a vacuum transfer cylinder  29  as well as a gluing roller  31  on the periphery of said vacuum transfer cylinder  29 . A label strip  35 , which is unwound from a label strip roll  33 , is fed to a knife edge of the knife cylinder  27  and thus divided into individual labels  25 . These individual labels  25  are then transferred to the vacuum transfer cylinder  29 . By means of the gluing roller  31  glue is then applied e.g. to the leading front edge of the label as well as to the trailing rear edge of the label, the glue being in both cases applied to the back of the label. The labelling module  23  is driven such that it rotates in position- and speed-synchronism with the carousel  21 . The labelling module  23  described should here be regarded as one possibility of attaching the labels, but without any restrictive effect; any other way of providing a label is possible as well. 
         [0032]    When the group is travelling past the vacuum roller  29 , one end of the label  25  is glued onto a vessel  37 . Subsequently, the group  11  rotates on its rotary plate  19  so that the label  25  will be pressed onto the vessel group  11  with the aid of a press-on rail  39  configured e.g. as a vacuum sponge. When the label  25  has been wound once around the two vessels, a bundle  41  comprising the two vessels  11  is formed. The finished bundles  41  are then fed to a discharge belt  47  via a discharge star wheel  42  which, too, has formed thereon appropriate reception pockets  45 . 
         [0033]    For forming these bundles  41 , it is extremely important that the two vessels  3  are in correct alignment with one another. To this end, the vessels  3  are clamped between a centering unit  51  and the rotary plates  19 , which have already been mentioned, (cf.  FIG. 2 ).  FIG. 2  shows a first embodiment of the centering unit according to the present disclosure, which is used for aligning at least two grouped vessels  11 . Elements and features with reference numerals that have already been used in  FIG. 1  will not be described in detail once more hereinbelow. Reference is herewith made to the description of these elements and features. 
         [0034]    The centering unit  51  according to the present disclosure comprises a precentering means  53  which is here implemented as a centering plate. The centering plate  53  has two vessel reception openings  55 . In  FIG. 2  the second opening is hidden and cannot be seen. This opening is configured such that, as can be seen in  FIG. 2 , e.g. a bottle neck can be passed therethrough. 
         [0035]    Above the precentering plate  53 , a final centering means  57  is arranged, said final centering means  57  being here also configured as a plate. Also the final centering means  57  comprises two openings  59  (only one of them being visible in  FIG. 2 ) whose apertures are configured such that they accommodate and position the upper extremity  61  of the vessels  11 . Since, thanks to the precentering plate  53 , the vessels  11  are already in alignment with one another, the inner diameter of the opening  59  is dimensioned such that it essentially corresponds to the outer diameter of the upper extremity  61  of the vessel  11 . The two vessels  11  can be precisely aligned with one another in this way. 
         [0036]    The final centering means  57  is arranged such that it is vertically and rotationally displaceable via a rotary connection  63  and a spring system  65 . The lowering and lifting movement of the final centering means  57  is accomplished with the aid of a cam guide roller  67 . Due to the up and down movement of the cam guide roller  67  along a control track, which is here not shown, also a plate  69  connected to the spring system  65  is moved up and down, whereby the final centering means  57  can be moved up and down against the spring forces of the spring system  65 . 
         [0037]    It is, however, not only the final centering means  57  that can be lifted and lowered, but the precentering means  53  can be moved up and down as well. In the present embodiment, the precentering means  53  is lifted and lowered through pneumatic control. To this end, the plate  69  has provided thereon a projection  71  through which a valve  73  is activated during lifting and lowering of the plate  69  in accordance with the movement of the cam guide roller  67  along the control track. The valve  73  switches pressurized air (the connection tubes are not shown here for the sake of clarity), whereby the precentering plate  53  can be lifted or lowered via the lift cylinder rod  77  of a lift cylinder  75  (a second lift cylinder is not visible in  FIG. 2  because it is arranged behind the rotary connection  63 ), independently of the final centering means  57 . 
         [0038]    Due to the fact that the lift cylinder  75  is arranged on the final centering means  57  in the present embodiment, the total stroke of the precentering plate  53  comprises the possible stroke of the final centering means  57  and the height of stroke of the lift cylinder  75 . This is an optimum structural design, in particular in cases where the stroke of the final centering means  57  is coaxial with the stroke of the precentering means  53 , as can be seen in  FIG. 2 . 
         [0039]    The stabilizer  79 , which is additionally arranged on the centering unit  51 , only serves to stabilize the plane of the final centering means  57  during rotations. 
         [0040]    In the present embodiment, the final centering means  57  is provided with through holes  59  for receiving the vessels therein. According to an alternative embodiment, the vessel reception openings  59  may also be implemented as blind holes. 
         [0041]    For wrapping standard bottles, a stroke of 43 to 53 mm will normally suffice for the final centering plate  57  and a stroke of 45 to 50 mm will normally suffice for the precentering plate  53 . 
         [0042]    Also the rotary plate  19 , on which the vessels  11  are positioned, is schematically shown in  FIG. 2 . For reliably fixing the bottle pair  11  between the rotary plate  19  and the centering unit  51 , the rotary plate  19  can be provided with depressions  81  whose shape is adapted to that of the vessels. 
         [0043]      FIG. 2  additionally shows two guide pins  83  and  85  preventing unintentional tilting of the precentering plate  53  during the lowering movement. The pins  83  and  85  are guided in sleeves  87 ,  89  that are secured to the final centering means  57 . 
         [0044]      FIG. 3  schematically shows, on the basis of three cross-sectional views, a second embodiment, viz. a method for aligning at least two grouped vessels according to the disclosure. Elements and features with reference numerals that have already been used in  FIGS. 1 and 2  will not be described in detail once more. Reference is herewith made to the description of these elements and features. 
         [0045]    The three states I to III shown in  FIG. 3  occur at the points shown in  FIG. 1  and located between the infeed star wheel  13  and the labelling module  23  in the labelling machine  1 . The three states are schematically indicated by the Roman numerals I, II, III adjacent the carousel  21 . 
         [0046]    State I: When the infeed star wheel  13  has transferred a bottle pair  11  to a rotary plate  19 , a centering unit  51  according to the first embodiment f the present disclosure is positioned slightly above the upper extremities  91  of the vessels  11 . In this side view, the rotary connection  63 , the two lift cylinders  75  as well as a guide pin  83  in its guide sleeve  87  can be seen. In the state shown, the precentering plate  53  and the final centering plate  57  are in contact with one another. 
         [0047]    State II: When the carousel  21  has slightly moved on ( FIG. 1 ), the final centering plate  57  moves together with the precentering plate  53  in response to a lowering of the cam guide roller  67  along the control track in the direction of the upper extremities  91  of the bottles and arrives at state II of  FIG. 3 . The precentering plate  53  and the final centering plate  57  are here still in contact with one another, as can also be seen from the fact that the guide pin  83  is still flush with the upper end of the lift cylinder  75 . However, other than in the case of state I, the upper extremities  91  of the vessels  11  are now positioned within the vessel reception openings  55  of the precentering plate  53 . 
         [0048]    State III: In the third state shown in  FIG. 3 , the projection  71  (cf.  FIG. 2 ) on plate  69  activates the valve  73  and causes pneumatic lowering of the precentering plate  53 . The bottle neck of the vessels  11  is now in contact with the inner walls of the vessel reception openings  55 . In addition, the upper extremities  91  of the vessels  11  are fixed in position in the vessel reception openings  59  of the final centering plate  57 . As can be seen from the figure, also the guide pin  83  has now been lowered relative to the lift cylinder  75 . 
         [0049]    Thanks to the precentering means  53  and the final centering means  57 , both vessels are fixed relative to one another not only on the upper extremities  91  themselves but also further down on the bottle neck so that the whole positioning of the two vessels  11  relative to one another can be stabilized. It follows that, especially in cooperation with the depressions  81  formed in the rotary plate  19 , the vessels  11  are held relative to one another at three different positions. 
         [0050]      FIG. 4  shows a second machine for treating grouped vessels, in particular for wrapping them with a common label according to the present disclosure. Features with reference numerals that have already been used in  FIGS. 1 to 3  will not be described in detail once more. Reference is herewith made to the above description of these features. 
         [0051]    The difference between the machine  101  shown in  FIG. 4  and the machine  1  that has been shown and described in  FIG. 1  is that not only one vessel feeding device comprising an infeed star wheel  13  and an infeed worm  9  is provided at the treatment station  21 , but three vessel feeding devices are provided there. 
         [0052]    The second feeding station comprises a separate feeder  103  and an infeed worm  105  for grouping the vessels  107  in pairs, which are fed via the conveyor  103 . The vessel groups  109  are then transferred via a second infeed star wheel  111  to the rotary plate  19 , where the vessel pair  109  is arranged in juxtaposition with the vessel pair  11  that has already been pushed onto the rotary plate  19  by the infeed star wheel  13 . 
         [0053]    The third vessel feeding device comprises a third feeder  113  and a third infeed worm  115  for grouping in pairs  119  also the vessels  117  fed via the third feeder  113 . These pairs  119  are then fed via a third infeed star wheel  121  to the rotary plate  19  which has already arranged thereon the vessel pairs  11  and  109 . 
         [0054]    As can be seen, the rotary plate  19  is rotated by 180° between the second vessel feeding device and the third vessel feeding device in this embodiment. This is schematically indicated in  FIG. 3  by the cross-hatching and the value 180°. 
         [0055]    When the three vessel pairs  109 ,  11  and  119  have been pushed onto the rotary plate  19 , the carousel  21  rotates further and past the labelling module  23 . Along the press-on rails  39 , which are here a vacuum unit with special sponge contours, the three vessel pairs  109 ,  11  and  119  are fully wrapped with the label  25  which is then fixed by gluing. For this purpose, the rotary plate rotates once by at least 360°; also this is indicated in  FIG. 3  by cross-hatching and the value 360°. 
         [0056]    In this way, a bundle  123  is obtained, which comprises, other than in the case of the first embodiment, not two but six vessels (sixpack). 
         [0057]    As a variant of the machine according to  FIG. 1 , the machine according to  FIG. 3  additionally comprises a label inspection station  125 , e.g. a camera or a sensor. 
         [0058]    Subsequently, the bundle  123  is, again with the aid of a discharge star wheel  43  with appropriate reception pockets  45 , transported to the discharge conveyor  47 . 
         [0059]    Due to the fact that three vessel feeding stations are provided, different vessels and/or different products can be combined so as to form one bundle  123 . In the present case, respective vessel pairs  11 ,  109 ,  119  were pushed onto the rotary plate, but it would also be possible to push on a larger or a smaller number of vessels at each vessel feeding station, independently of one another. 
         [0060]      FIG. 5  shows schematically a third embodiment of a part of a centering unit  151  for centering grouped vessels according to the present disclosure. The figure shows a detail of a centering unit which can be used in the machine shown in  FIG. 4 . Features with reference numerals that have already been used in one of the  FIGS. 1 to 4  will not be described in detail once more. Reference is herewith made to the description of these features. 
         [0061]    In  FIG. 5  only the lower part of a centering unit  151  is shown. The final centering means  153 , which are here again a plate and which are provided with six vessel reception openings  155 ,  157 ,  159 ,  161 ,  163 ,  165 , can be seen in this figure. Below the final centering means  153  three subcentering means are disposed, which are again defined by plates  167 ,  169  and  171  and which are arranged independently of one another. These plates  167 ,  169  and  171  define the precentering means  53 . Each of these subcentering means  167 ,  169 ,  171  is provided with two vessel reception openings  173 ,  175  and  177  (the respective second opening per centering means is not visible in this view). 
         [0062]      FIG. 5  also shows the lift cylinders  75  on the final centering plate  153 ; in the case of the front lift cylinders  75 , also the pneumatic connection tubes  179  are schematically shown. In this representation, the guide pins are not shown. Just as in the first embodiment, these guide pins are, however, provided. 
         [0063]    The final centering plate  153  is again arranged on a rotary connection  63  and a spring system  65  in the carousel such that it is vertically adjustable (represented by the double arrow on the left side) via a cam guide roller  67 . 
         [0064]    Other than in the case of the first embodiment, where the precentering plate  53  could be lowered as a whole, this embodiment comprises three subcentering means  167 ,  169  and  171  which are adapted to be lifted and lowered independently of one another through the lift cylinders  75 . The fact that the subcentering means can be lifted and lowered independently of one another is indicated by the double arrows shown on the lower right in the case of each subcentering means  167 ,  169 ,  171 . 
         [0065]    In correspondence with the first embodiment, the lifting and lowering movements are controlled pneumatically, the respective control air required being provided via three independent valves. These valves can be controlled independently of one another, e.g. via the cam guide roller. 
         [0066]    As for the rest, the final centering plate  153  as well as the subcentering means  167 ,  169  and  171  of the precentering means correspond to the final centering means  57  and the precentering means  53  of the first embodiment. 
         [0067]    The centering unit  151  is used in a machine for treating grouped vessels of the type shown in  FIG. 3 .  FIG. 6  shows a schematic representation of a fourth embodiment of the present disclosure, viz. a second embodiment of the grouped-vessel centering method according to the present disclosure, and the use of the centering unit  151  at four different locations IV, V, VI and VII of the machine  101 , said locations being indicated in  FIG. 4 . Features with reference numerals that have already been used in one of the  FIGS. 1 to 5  will not be described in detail once more. Reference is herewith made to the description of these features. 
         [0068]    State IV: When the first group of vessels  11  has been pushed onto the rotary plate  19 , only the central precentering plate  169  is first lowered so as to align the vessels of vessel group  11  relative to one another. The precentering plate  167  and the precentering plate  171  are at this time still in contact with the final centering plate  153 . 
         [0069]    State V: When the second vessel group  109  has been pushed onto the rotary plate  19 , also the left precentering plate  167  is lowered relative to the final centering plate  153  so as to align, on the one hand, the vessels of said vessel group  109  relative to one another and, on the other hand, this vessel group  109  also relative to the first group  11 . The third subcentering plate  171  remains still in contact with the final centering plate  153 . 
         [0070]    State VI: When the third vessel group  119  has been pushed onto the rotary plate  19 , also the third subcentering plate  171  is lowered. Now, the three precentering plates  167 ,  169  and  171  have all been lowered, which means that also the vessels of the third group  119  are now aligned relative to one another and that, in addition, also the three vessel groups  11 ,  109  and  119  are aligned relative to one another. 
         [0071]    In the next state VII, a short distance before the labelling station  23 , also the final centering plate  153  is lowered so as to receive the extremities  91  of the vessels in the respective vessel reception openings  155  to  165 . It follows that, together with the depressions provided in the rotary plate  19 , the six vessels are held at three different points so that a stable positioning of the sixpack is accomplished. The lowering of the final centering plate  153  can simultaneously lead to a further lowering of the three precentering plates  167 ,  169  and  171 , or the two centering means—the final centering means and the precentering means—reapproach one another. 
         [0072]    Finally, it should be pointed out that the various states are only shown schematically in  FIG. 6  and that the actual dimensions may deviate from that which is shown. In particular, the vessels abut on one another in their belly regions, as can be seen in  FIG. 2 . 
         [0073]    Thanks to the centering unit of the third embodiment, a flexible machine for treating grouped vessels, in particular for wrapping a label around vessels, can be provided. The machine simultaneously guarantees improved centering due to the fact that precentering means are provided at one point of the vessels and final centering means are provided at another point of the vessels (the upper extremity).