Abstract:
An infeed station has a stack feeder and a first and second chamber, which can each receive stacks from the stack feeder. The stacks can be conveyed in the chambers and can be transferred to a stack gripper with the conveyors assigned to the first chamber and the second chamber. First centering units serve to center the stacks in the first chamber, and second centering units serve to center the stacks in the second chamber. Third conveyors are arranged between the first and second conveyors. The first and second centering units can be shifted relative to each other so that the third conveyors are positioned in the first or second chamber, and the chamber with the third conveyors is much wider than the other chamber. The infeed station can be changed between double infeed with parallel processing of two stacks and single infeed with processing of only one stack of relatively great width at a time.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an infeed station of a stack palletizing system, with a stack feeder, a first and second chamber, which can each receive stacks from the stack feeder, first conveying means assigned to the first chamber and second conveying means assigned to the second chamber, with which stacks are conveyed in the chambers and can be transferred to a stack gripper, and first centering means for centering the stacks in the first chamber and second centering means for centering the stacks in the second chamber. 
         [0003]    2. Description of the Related Art 
         [0004]    A prior-art infeed station of this type is disclosed by EP 1 801 047 A. In the cited document, the station is referred to as a transfer unit and has a displacement unit, on which a carriage is mounted in such a way that it can be displaced horizontally and transversely to the direction of conveyance. Two placement means are provided. They are arranged side by side and support one stack each. In the present case, these placement means are conveyor belts. Two stacks located on the two placement means of the infeed station (or transfer unit, as it is referred to in the cited document) are seized with a stack gripper and set down on a pallet. To process stacks that are relatively wide, the infeed station must be constructed correspondingly wide, but this is a disadvantage with respect to the amount of space that it requires and with respect to the manufacturing costs. Adaptation to different formats is thus possible only with a comparatively wide infeed station. 
       SUMMARY OF THE INVENTION 
       [0005]    The object of the invention is to create an infeed station of the type described above, with which stacks of greatly varying width can be transferred to a stack gripper but which nevertheless can be constructed relatively narrow. 
         [0006]    In accordance with the invention this problem is solved by the fact that third conveying means are arranged between the first and second conveying means and that the first and second centering means can be shifted relative to each other in such a way that the third conveying means are positioned in the first or second chamber, and the chamber with the third conveying means is much wider than the other chamber. 
         [0007]    The infeed station of the invention provides the option of double infeed or single infeed of stacks. In the case of double infeed, two relatively narrow stacks are received parallel to each other and successively in time and are simultaneously transferred to the gripper. In the case of single infeed, only one relatively wide stack at a time is received and transferred to the gripper. Accordingly, the gripper then palletizes only this relatively wide stack. In the case of single infeed, the stacks are conveyed by the first or the second conveying means and the third conveying means. In the case of double infeed, the conveyance in the first chamber is preferably carried out with the first conveying means and in the second chamber with the second conveying means. The third conveying means is preferably not active here. The infeed station thus allows the processing of relatively narrow stacks as well as much wider stacks and thus has the advantage that it is highly versatile with respect to the stack formats it can handle. 
         [0008]    In a further development of the invention, the first and second centering means have two centering members each, which are spaced some distance apart and are supported at an upper end or at a lower end in such a way that they can be shifted transversely to the direction of conveyance of the conveying means. By shifting these centering members, which are preferably designed as centering plates, chambers of highly variable width can be formed. In particular, an asymmetrical arrangement is possible. For double infeed, the two chambers can be adjusted, for example, by shifting the centering members, to a width on the order of, for example, 100-300 mm. For single infeed, a chamber with a width of, for example, 100-500 mm is possible. Preferably, the centering members or centering plates are shifted by a motor, for example, by means of a spindle. 
         [0009]    In a further development of the invention, the two chambers and the conveying means and centering means are installed on a table that can be moved transversely to the direction of conveyance, so that the stacks are fed to the first and second chamber by the stack feeder. In the case of double infeed, for example, a first stack is thus fed to the first chamber, and then the table is moved, so that a second stack can be fed to the second chamber. In the case of single infeed, the table is moved in such a way that the correspondingly wide stack is fed to the chamber provided for it. 
         [0010]    In a further development of the invention, the centering means can be adjusted independently of one another. This allows a very fast and simple changeover between single infeed and double infeed without the use of tools. The centering means preferably are each supported at an upper end in such a way that they can be displaced on horizontal guide rods. 
         [0011]    In a further development of the invention, the conveying means each have rollers. The stacks can be conveyed and centered especially easily and reliably on these rollers. In this connection, it is preferably provided that each of the centering means has a contour at its lower end that is designed to correspond to the contour of the rollers. The centering means thus mesh with the spaces between the rollers and allow especially reliable centering of the stacks. 
         [0012]    The invention also concerns a method for transferring stacks to a stack gripper with an infeed station. 
         [0013]    The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0014]    In the Drawing: 
           [0015]      FIG. 1  is a schematic perspective view of a stack palletizing system with an infeed station of the invention. 
           [0016]      FIG. 2  is a perspective view of the infeed station. 
           [0017]      FIG. 3  is another perspective view of the infeed station of the invention. 
           [0018]      FIGS. 4 to 7  are top views of the infeed station of the invention, showing the infeed station in different phases of the changeover to a single infeed. 
           [0019]      FIG. 8  is a perspective view of the infeed station of the invention, which is set for a single infeed. 
           [0020]      FIG. 9  is a side view of a stack gripper. 
           [0021]      FIG. 10  is a perspective view of a pallet with palletized stacks. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    Stacks  15  and  15 ′ can be palletized on a pallet  11 , as shown in  FIG. 10 , with the palletizing system  1  shown in  FIG. 1 . Cardboard separators  45  are arranged between the stacks  15  and  15 ′. The palletization itself is performed automatically and is controlled in such a way that the stacks  15  and  15 ′ are set down on the pallet  11  optimally and exactly. The cardboard separators  45  are also set down automatically. The stacks  15  and  15 ′ are any type of stacked products, preferably printed products, such as signatures, newspapers, books and the like. The stacks  15  and  15 ′ can be wrapped in sheets or bound in any other way, but this is not necessary. The stacks  15  and  15 ′ can also consist of individual printed products, for example, thick catalogues. 
         [0023]    The palletizing system  1  consists of a machine frame  2 , in front of which a stack feeder  3  is arranged, as shown in  FIG. 1 . The stack feeder  3  serves to feed the stacks  15  and  15 ′ to a stack infeed station  4 , which is installed inside the frame  2 . The stacks  15  and  15 ′ are conveyed one after another in a row, and for this purpose the stack feeder  3  is provided, for example, with a conveyor belt  3   a.  In  FIG. 1 , the arrow  46  shows the direction in which the stacks  15  and  15 ′ are fed to the stack infeed station  4 . The stack feeder  3  can be designed in basically any desired way. 
         [0024]    The palletizing system  1  also has a stack gripper  5 , which is shown in detail in  FIG. 9 . The stack gripper  5  removes stacks  15  from the stack infeed station  4  and sets them down on the pallet  11 . To grip at least one stack  15 , the stack gripper  5  has a finger  38  and a ram  39  as well as a stop element  40 , on which the stack  15  can be positioned. The finger  38  is mounted on an arm  41 , which can be moved by means of an actuating cylinder  44 . The stack  15  consists here of a plurality of printed products  37 . In addition, the stack gripper  5  has a cardboard separator gripper  43  with suction devices  6 . The cardboard separator gripper  43  removes cardboard separators  45  from a cardboard separator magazine  10  and sets them down on the pallet  11 . To control the individual movements, the stack gripper  5  has a suitable control unit  42 . The stack gripper  5  can be moved in all directions in space and along a vertical upright  7 . The upright  7  is supported on a bridge  8 , which can be moved on two horizontal crossbeams  9  spaced some distance apart ( FIG. 1 ). 
         [0025]    Finally, the palletizing system  1  has a pallet dispenser  12  and a pallet magazine  14 . By means which in themselves are already well known, the pallets  11  can be removed from the pallet magazine  14  one at a time and dispensed for palletization of the product. After the stacks  15  and  15 ′ have been palletized on the pallets  11 , the pallets can be moved out by a runout conveyor  13  and, for example, loaded onto a vehicle. The pallet  11  can also be loaded only with stacks  15  or only with stacks  15 ′. 
         [0026]    As shown in  FIG. 2 , the stack infeed station  4  has a table  18 , which is mounted by means of rollers  19  on two parallel tracks  20 . As shown in  FIG. 3 , first conveying means  31 , second conveying means  32 , and third conveying means  33  are installed on the table  18 . These conveying means  31 - 33  are, for example, endless conveyors, with, for example, a belt or a chain with drivers. The conveying means  31 - 33  can also each have more than one conveying member, for example, two or more than two endless belt conveyors or chain conveyors. 
         [0027]    The table  18  and thus the stack infeed station  4  are arranged in such a way that they can be moved transversely to the direction of conveyance of the conveying means  31 - 33 . The table  18  is moved under automatic control by means of a drive (not shown). In this regard, the table  18  can be shifted in such a way that the stacks  15  can be optionally fed to a first chamber A or a second chamber B of the stack infeed station  4 . In  FIG. 2 , the table  18  is positioned in such a way that the stacks  15  are fed to the second chamber B. If the table  18  in  FIG. 2  is shifted to the left, a position can be reached in which the stacks  15  are fed to the first chamber A. 
         [0028]    In addition, rollers  34  and  35  are arranged on the table  18  as supports. These rollers extend transversely to the direction of conveyance and allow very slip-free conveyance of the stacks  15  and  15 ′. In  FIG. 3 , a stack  15  is present in the chamber B. As the drawing shows, the stack  15  is supported on the rollers  34 . The second conveying means  32  is in contact with the stack  15  and is thus able to convey it. A stack  15  that is the same or similar can be similarly conveyed in the chamber A. To assist the conveyance of the stacks, the rollers  34  and  35  can also be designed to be driven. 
         [0029]    The first chamber A is laterally bounded by first centering means C, which comprise a first centering member  27  and a second centering member  28 . The second chamber B is laterally bounded by second centering means D, which comprise a third centering member  29  and a fourth centering member  30 . These centering members  27 - 30  extend vertically and parallel to one another. They are designed, for example, as plates. The centering members  27 - 30  are each displaceably supported at an upper end with beams  22 - 25  on guide rods or other suitable guide means. These guide rods  21  are mounted on a supporting frame  16 , which is mounted on the table  18  and extends upward. The purpose of the centering members  27 - 30  is to center the stacks  15  and  15 ′ during their conveyance in chambers A and B. To this end, the centering members  27 - 30  can be shifted relative to one other and transversely to the direction of conveyance. The shifting is preferably carried out automatically with a drive  17  and spindles  26 , which engage the beams  22 - 25 . Preferably, the centering members  27 - 30  can be shifted independently of one another. The shifting is carried out by a suitable control unit. The centering members  27 - 30  extend downward as far as the rollers  34  and  35 . They preferably have profiling  50  on their lower edges, which is designed to correspond to the rollers  34  and  35  in such a way that the centering members  27 - 30  can be moved over the rollers  34  and  35  with as little clearance as possible. This makes it possible to ensure that the stacks  15  and  15 ′ cannot get stuck between a centering member  27 - 30  and the rollers  34  and  35 . 
         [0030]    The centering members  27 - 30  can be adjusted in such a way that stacks  15  and  15 ′ can be transferred to the stack gripper  5  in a double infeed mode or in a single infeed mode. This is explained in greater detail below with reference to  FIGS. 4 to 8 . 
         [0031]    In the arrangement according to  FIG. 4 , the stack infeed station  4  is set up for double infeed. The two chambers A and B have essentially the same design. The table  18  is positioned in such a way that one stack  15  at a time can be fed by the stack feeder  3  to chamber B. If a stack  15  is located in chamber B, the table  18  in  FIG. 4  is shifted to the left, so that another stack  15  can be fed to the first chamber A. The two stacks  15  can be conveyed with the first conveying means  31  and the second conveying means  32  and delivered to the stack gripper  5 . 
         [0032]      FIGS. 5 to 7  show the changeover of the stack infeed station  4  for single infeed. The individual steps can be carried out under automatic control. 
         [0033]    First, the two centering members  27  and  28  are shifted into the position shown in  FIG. 5 . These shifts are indicated by the double arrow  36 . The distance between the first centering member  27  and the second centering member  28  is reduced by this shift. The third centering member  29  and the fourth centering member  30  in  FIG. 5  are then shifted to the right into the positions shown in  FIG. 6 . The third centering member  29  is thus located some distance from the third conveying means  33 , as shown in  FIG. 6 . In a further step, the distance between the third centering member  29  and the fourth centering member  30  is further increased by suitable shifting of these two members into the positions shown in  FIG. 7 . Finally, the table  18  is moved into the position shown in  FIG. 7 , which results in the formation of a relatively wide, second chamber B′, which is centered with respect to the stack feeder  3 , as shown in the drawing. The two conveying means  32  and  33  are located within the chamber B′. A relatively wide stack  15 ′ can be conveyed in the chamber B′. In this regard, the stack  15 ′ is simultaneously conveyed by the second conveying means  32  and the third conveying means  33  and is laterally guided by the third centering member  29  and the fourth centering member  30 . The stack  15 ′ can be essentially about twice as wide as a stack  15 . The stack  15 ′ alone is seized by the stack gripper  5  and set down on the pallet  11 . Naturally, a plurality of stacks  15 ′ can be successively conveyed in the chamber B′ and delivered to the stack gripper  5 . During this process, the first conveying means  31  are preferably inactive, and the relatively narrow, first chamber A′ is not used ( FIG. 8 ). 
         [0034]    If a double infeed is necessary, the centering members  27 - 30  are brought back to the positions shown in  FIG. 4  by making suitable shifts. This changeover can also be automatically controlled. 
         [0035]    While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.