Apparatus for depositing sheets onto a stack

Abstract

An apparatus for depositing sheets onto a stack permits improved alignment of the sheets on the stack. At least one conveying element provides for cyclical forward movement of the sheets into a position above the stack. At least one reciprocating aligning element is provided for stacked sheets. A device for controlling movements of the aligning element includes a computer. At least one linear actuator moves the aligning element and may be controlled by the computer.

1 . An apparatus for depositing sheets onto a stack, the apparatus comprising: 
 at least one conveying element for cyclical forward movement of the sheets into a position above the stack;    at least one reciprocating aligning element for stacked sheets;    a device, including a computer, for controlling movements of said at least one aligning element; and    at least one linear actuator, to be controlled by said computer, for moving said at least one aligning element.    
   
   
       2 . The apparatus according to  claim 1 , wherein said at least one aligning element is a vibrating plate, and said at least one linear actuator is a plunger-type coil actuator coupled to said vibrating plate.  
   
   
       3 . The apparatus according to  claim 1 , which further comprises a sensor connected to said control device for sensing a movement of said at least one aligning element.  
   
   
       4 . The apparatus according to  claim 3 , which further comprises a magnetic part fastened to said at least one aligning element, and a Hall sensor oriented toward said magnetic part.  
   
   
       5 . The apparatus according to  claim 1 , which further comprises a sensor connected to said control device for sensing a magnetic field of said at least one linear actuator.  
   
   
       6 . The apparatus according to  claim 1 , which further comprises a configuration connected to said control device for measuring a control current of said at least one linear actuator.  
   
   
       7 . The apparatus according to  claim 1 , which further comprises a sensor connected to said control device for sensing a rotary position of said at least one conveying element, upon sheets being deposited in a delivery of a rotary printing press.  
   
   
       8 . The apparatus according to  claim 1 , wherein said at least one aligning element has a phase relation to be set relative to a cycle of said at least one conveying element.  
   
   
       9 . The apparatus according to  claim 1 , which further comprises grippers for the forward movement into the position above the stack, said grippers to be opened at a predefined instant, and said at least one aligning element having a phase relation to be set relative to said predefined instant.  
   
   
       10 . The apparatus according to  claim 1 , wherein said at least one aligning element includes aligning elements disposed on two sides of the stack, said aligning elements having phase relations to be set relative to one another.  
   
   
       11 . The apparatus according to  claim 1 , wherein said at least one aligning element has a movement profile to be set.  
   
   
       12 . The apparatus according to  claim 1 , wherein said at least one aligning element is to be set to a predefined start/stop position.  
   
   
       13 . The apparatus according to  claim 1 , wherein said at least one linear actuator is a linear motor stepping drive.  
   
   
       14 . The apparatus according to  claim 1 , which further comprises a sensor connected to said control device for sensing acceleration of said at least one aligning element.  
   
   
       15 . The apparatus according to  claim 1 , wherein movement of said at least one aligning element is to be controlled as a function of impact energy exerted on a sheet.  
   
   
       16 . The apparatus according to  claim 1 , which further comprises an elastic coupling element disposed between said at least one aligning element and said at least one linear actuator.  
   
   
       17 . The apparatus according to  claim 1 , wherein said at least one aligning element is to be set as a function of signals representing quality of a sheet.  
   
   
       18 . The apparatus according to  claim 1 , which further comprises a marking apparatus for sheets, said marking apparatus being associated with the stack and having a control signal, and said at least one aligning element to be set as a function of the control signal for said marking apparatus.