Device for stacking sheets for printing machine

Abstract

A device for stacking sheets for a printing machine, including at least a sheet deflection device which can be driven in rotation, and which is provided for receiving or grabbing a front edge of a sheet and for stacking the sheet after it has moved through a rotation path, and having at least two sheet conveyance devices that can be rotated substantially independently of each other about the common axle, and thus one of these sheet conveyance devices is ready to receive or grab a next sheet, when another one of these sheet conveyance devices is still occupied with the transport and the stacking of a preceding sheet.

1 . Device for stacking sheets for a printing machine, including at least a sheet deflection device ( 1 ), which can be driven in rotation, and which is provided for receiving a front edge of a sheet and for stacking the sheet after it has moved through a rotation path, said sheet stacking device comprising: 
 at least two sheet conveyance devices ( 4 ,  5 ) that can be rotated substantially independently of each other about the common axle ( 9 ), and thus one of said at least two sheet conveyance devices ( 4 ,  5 ) is ready to receive or grab a next sheet, when another one of said sheet conveyance devices ( 4 ,  5 ) is still occupied with the transport and the stacking of a preceding sheet.    
   
   
       2 . Device according to  claim 1 , wherein said sheet deflection device ( 1 ), which works in cooperation with said at least two sheet conveyance devices ( 4 ,  5 ), forms, with a surface which serves as support for the sheet, a substantially curved path for the sheet to be conveyed, and each of said at least two sheet conveyance devices ( 4 ,  5 ) presents at least one overlapping element ( 6 ) which overlaps the received sheet front edge, in such a manner that the sheet front edge can be grabbed so it can be moved along between one of these overlapping elements ( 6 ) of a sheet conveyance device ( 4 ,  5 ) and the surface of said sheet deflection device ( 1 ).  
   
   
       3 . Device according to  claim 2 , wherein sheet deflection device ( 1 ) is substantially a disk or wheel.  
   
   
       4 . Device according to  claim 2 , wherein each sheet conveyance device ( 4 ,  5 ) is substantially a two-arm pivoting beam which presents, in the area of each of its two radially outward directed free ends, an overlapping element ( 6 ).  
   
   
       5 . Device according to  claim 4 , wherein said overlapping element ( 6 ) is a tongue or cover plate which substantially parallels the curved path of said sheet deflection element ( 1 ).  
   
   
       6 . Device according to  claim 5 , wherein said sheet conveyance devices ( 4 ,  5 ) and said sheet deflection device ( 1 ) are in each case doubled, and arranged, on the common axle ( 9 ), in an arrangement with mirror symmetry to each other, in such a manner that all sheet conveyance devices ( 4 ,  5 ) are arranged between the two sheet deflection devices ( 1 ), so that a sheet front edge, in its orientation parallel to the common axle ( 9 ) of said sheet conveyance devices ( 4 ,  5 ) and said sheet deflection device ( 1 ), can be grabbed jointly by two of said sheet conveyance devices ( 4 ,  5 ), of which there is a total of at least four, and said two sheet deflection devices ( 1 ).  
   
   
       7 . Device according to  claim 6 , wherein the side of the overlapping elements ( 6 ) of the sheet conveyance devices ( 4 ,  5 ), which is turned toward the sheet, is at a smaller radial distance from the common axle ( 9 ) than the overlapped external side of the sheet which applies its thickness onto the radius of the surface of said sheet deflection devices ( 1 ), so that the sheet front edges, in their travel, are forced and bent through, in a tension producing manner, in the area of said overlapping element ( 6 ) approximately in the direction of the common axle ( 9 ).  
   
   
       8 . Device according to  claim 2 , wherein a stop ( 7 ) for the sheet front edges, with which the sheet conveyance devices ( 4 ,  5 ) work in cooperation during the stacking of the sheets.  
   
   
       9 . Device according to  claim 2 , wherein at least one guiding element ( 3 ), which blocks a grabbed sheet at least in the centrifugal direction, between a grabbing place and a delivery place of the sheet to force the sheet, to maintain the radius of curvature.  
   
   
       10 . Device according to  claim 1 , wherein at least one shifting device which is coupled to at least one of said sheet conveyance devices ( 4 ,  5 ) or said sheet deflection device ( 1 ), to transversely shift a sheet to be stacked, where the shift is oriented substantially parallel to the common axle ( 9 ) of said sheet conveyance devices.