Patent Publication Number: US-8529186-B2

Title: Collecting and transport device for a stack formed by layers of sheets

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the US national stage of PCT application PCT/EP2009/006679, filed 16 Sep. 2009, published 25 Mar. 2010 as WO2010/031538, and claiming the priority of German patent application 102008047785.0 itself filed 17 Sep. 2008, whose entire disclosures are herewith incorporated by reference. 
     The invention relates to a collecting and transport apparatus for stacks formed by sheets with a supply conveyor for the sheets, a collecting station in which stacks are formed from the sheets, an output conveyor for carrying off the finished stacks and a transfer apparatus for moving the stacks from the collecting station to the output conveyor. 
     A collecting and transport apparatus with these features is described in DE 10 2004 056 018 A1. The collecting and conveying apparatus is part of a paper-processing machine in which paper strips are cut to length in a defined format by longitudinal and transverse cutters to form sheets that are collected to form sheet stacks that are subsequently packaged. 
     The sheets that are delivered continuously in rows next to one another and in overlapping form are collected in the collecting station until the stacks each have the desired number of sheets. The sheet stacks formed next to one another are conveyed by a transfer apparatus that has a number of slides and movable grabs corresponding to the number of stacks formed from the collecting station onto an output conveyor formed as a transverse conveyor. The transverse conveyor transports the rows of stacks to downstream packaging apparatuses in which the stacks are packed. 
     With a format change, the individual elements of the collecting station must be repositioned transversely according to format width and number of stacks. In operation, in particular with the transfer of the finished stacks, a collision of individual elements must not occur. Since for the formation of eight stacks and more next to one another a plurality of stack-forming elements are necessary, with a format change a large number of parts must be adjusted without collisions occurring. 
     The object of the invention is therefore to improve a collecting and transport apparatus of the type described such that a simplified transverse positioning to a new format is possible. 
     This object is attained with the features of claim  1 . 
     Another object is to provide a collecting apparatus with conveyors that are simply designed and have a low construction height. 
     This object is attained with the features of claim  4 . 
     The dependent claims recite particularly advantageous and hence preferred embodiments of the invention. 
    
    
     
       The apparatus is described in more detail below based on a preferred illustrated embodiment. 
         FIG. 1  is a perspective view of an apparatus according to the invention, 
         FIG. 2  is a detail view the vibratory stop elements, 
         FIG. 3  is a detail view of the stacking station seen against the product travel direction, 
         FIG. 4  shows a vibratory stop element for the trailing sheet edges. 
     
    
    
     The collecting and transport apparatus shown in  FIGS. 1 and 2  is part of a paper-processing machine in which paper strips are cut to length in a defined format by longitudinal and transverse cutters to form sheets that are collected to form sheet stacks that are subsequently packaged. Preferably, the sheets are cut to length in the small format of A3 to A5 and subsequently collected to form stacks with between 200 and 500 sheets to a ream. Eight stacks or more can thereby be formed next to one another and subsequently transported away for further processing, for example, for wrapping. 
     The collecting and transport apparatus has a supply conveyor  1  that transport the sheets to a collecting station  3  in which stacks  4  are formed from the sheets. The supply conveyor  1  is preferably composed of a plurality of parallel rows of conveyor belts  5  that preferably extend into the region of the collecting station  3  to transport the sheets. Upstream of the stacking station, the sheets lie on a conveyor table  2 . 
     The collecting station  3  is formed by rows of is transversely spaced supports  6  that extend in the production/travel direction and whose coplanar upper surfaces carry the stacks  4 . A transverse conveyor  7  extends across the downstream ends of the supports  6  as an output conveyor that moves the finished sheet stacks  4  transversely of the production/travel direction to an unillustrated packing station. 
     At the collecting station  3  further stack-forming and transfer elements are provided that align edges of the sheets to form stacks  4  that are transferred to the transverse conveyor  7 . The upstream end of the stacking station is formed by rows of vibratory stop elements  8 , one of which is shown in more detail in  FIG. 4 . It is formed by two spaced and horizontally extending support parts  8 . 1  and, extending perpendicularly downwardly therefrom, respective stops  8 . 2  whose vertical downstream edges serve to align the sheets as they are stacked. To ensure correctly aligned edges, the sheets are vibrated as they are dropped onto the stacks. This is done by a respective vibratory plate  8 . 3  that projects downward between each pair of stop edges and that is vibrated by a respective drive  8 . 4 . Respective holding plates  8 . 5  are attached on top of the pairs of support parts  8 . 1  and are fitted to a guide rail  14  extending transversely across the working width. The guide rail  14  carries the vibratory stop elements  8 . 
     Vertical vibratory side plates  9  extending in the product travel direction between the supports  6  shake the side edges of the stacks  4  during stack formation. The leading edges of the sheets are arrested by stop elements extending transversely across the working width and not shown in the figures. The supports  6 , the vibratory stop elements  8 , the pairs of vibrating plates  9  and the stop elements thus during deposition of the sheets form open collecting boxes in which the stacks  4  are formed. 
     Slides  10  that are shown in more detail in  FIG. 2  are used to push the finished stacks  4  out of the stack boxes in the production direction toward the transverse conveyor  7 . Each slide  10  is formed by two vertical slide rails  10 . 1  that extend transversely of the product travel direction each outside and parallel to a respective one of the stops  8 . 2 . A horizontal support rail  10 . 2  extends from each slide rail  10 . 1  next to the respective support part  8 . 1  of the respective element  8 . The slide rails  10 . 1  push a finished stack  4  out of the respective collection box in the product travel direction, so that a new stack can be formed therein. Advantageously, sheets are intermediately stored on the support rails  10 . 2 , while the finished stacks  4  are transported away. When the slides are moved back against the product travel direction, the intermediately stored sheets are transferred to the supports  6 . 
     For the subsequent transfer of the stacks  4  to the transverse conveyor  7 , elements are used that grip the stacks  4  firmly during transport in order to prevent the stacked sheets from slipping relative to one another. Suitable elements are carriages with clamping fingers that hold the stacks  4  such that their shapes are retained. These elements are not shown in the figures so that the other parts are visible. 
     The elements of the collecting and transport apparatus described above are supported in the frame of the apparatus in the is following manner: 
     The stop elements of the collection box and the transverse conveyor  7  are maintained stationary. The supply conveyor  5 , the vibratory stop elements  8 , the vibratory side plates  9  and the slides  10  are supported on vertically movable cheek plates  11  so that their vertical position can be adjusted to the growing stack heights. In addition, the slides  10  are moveable vertically and at the same time horizontally in and against the product travel direction relative to the other elements supported on the side cheek plates  11  by a drive, so that they can be raised and can slide. In order to be able to adjust the upstream end of the collection box depending on the format length of the sheets, the side cheek plates  11  with the elements attached thereto are also adjustably supported in a limited horizontal manner in and against the product travel direction. 
     In order that different format widths and numbers of sheet stacks can be processed, according to the invention the elements to be positioned transversely in a manner dependent on the format width and/or number of blanks are designed and supported in a particularly advantageous manner: 
     The vibratory side plates  9  acting on the stack sides are jointly transversely adjustable with the upper belts  5  that feed the sheets are guided into the stacking station. The vibratory side plates  9  are positioned between two adjacent parallel sheet stacks  4 . If fewer stacks than possible are to be formed, the superfluous elements are moved into side parked positions. 
     In order to substantially reduce the number of transverse adjustments in a format change, one support  6 , one respective vibratory stop element  8  and one respective slide  10  are jointly displaced transversely as a unit. To this end, the two slide rails  10 . 1  of a slide  10  are each provided outside a respective one of the two stops  8 . 2  of a respective vibratory stop element  8 . The vibratory plate  8 . 3  is attached between the two respective stops  8 . 2 . A support  6  forming the floor of a respective collection box is provided underneath the respective vibratory plate  8 . 3  and also between the respective stops  8 . 2 . This design makes it possible for a single adjustment element, for example, an adjustment rod  13  bearing transversely on a stop  8 . 2  to adjust the entire unit composed of one support  6 , one slide  10 , and one vibratory stop element  8  transversely to the product travel direction and to position it for the new format width. This substantially simplifies the transverse positioning of the elements. 
     The two slide rails  10 . 1  of a slide  10  are preferably interconnected by a cross strip beneath the respective support  6 , so that they can be moved upward without colliding with the vibratory stop element  8  and can be moved in and against the product travel direction without colliding with a vibratory side plate  9 . 
     One or more conveyors are provided in a particularly advantageous manner for transporting the overlapping sheets and/or the stacks  4 . The conveyors are formed or partially formed by planar faces of supports that are made from an open-pore ceramic. The pores have an average diameter of less than 100 μm. The supports are connected on their underside to a compressed air is supply so that compressed air exits the conveying surface and forms an air cushion exits so at to reduce friction with the sheets and/or stacks  4  to minimum values. This construction makes possible conveyors with very low construction height compared to conveyor belts. Thus transversely adjustable conveyor elements can be provided inside the region of the maximum height of fall of the sheets during stacking. With the collecting and transport apparatus, the supports  6 , the transverse conveyor  7  and the inlet into the collecting station  3 , in particular the guide table  2 , are preferably made of open-pore ceramic plates.