Method and apparatus for laterally aligning a sheet in a processing machine and sheet-fed printing machine having the apparatus

Abstract

A method and an apparatus for laterally aligning a sheet in a processing machine, in particular a printing machine, carries out lateral sheet alignment on a cylinder of the printing machine, e.g. a feed cylinder. In order to achieve large correction distances in relation to a possible lateral movement capability of a gripper bar, the latter is prealigned prior to correction in such a way that, in the event of deviation from predetermined desired values, it is prealigned laterally to defined positions. A sheet-fed rotary printing machine having the apparatus, is also provided.

The invention claimed is: 
     
       1. A method for laterally aligning sheets on a cylinder of a processing machine, the method comprising the following steps:
 sensing an actual position of the sheet with at least one sensor; 
 prealigning a gripper device to a predetermined position in accordance with the actual position of the sheet relative to its side position, prior to the sheet being gripped by the gripper device; and 
 repeating the prealigning step 
 gripping the sheet with the gripper device in the predetermined position; and 
 aligning the sheet with the gripper device, as needed, during a transfer of the sheet by the gripper device. 
 
     
     
       2. The method according to  claim 1 , which further comprises, with the grippers of the gripper device closed, sensing the sheet another time with the at least one sensor, and executing a lateral correction movement with the gripper device following a desired-value/actual-value comparison. 
     
     
       3. The method according to  claim 1 , which further comprises sensing the actual position of the sheet with another sensor for subsequent prealignment of the gripper device. 
     
     
       4. The method according to  claim 1 , which further comprises, during the prealignment of the gripper device, raising up a control roller for actuating grippers of the gripper device with a control cam for controlling opening and closing times of the grippers. 
     
     
       5. An apparatus for laterally aligning sheets on a cylinder of a processing machine, the apparatus comprising:
 an actuating drive for generating a linear movement; 
 a connecting rod connected to said actuating drive; 
 a movably mounted gripper device; 
 a driver fastened on said gripper device and mounted rotatably and secured against displacement on said connecting rod; and 
 a rotary disengagement device disposed in a cylinder body of the cylinder and interconnecting said connecting rod and said driver. 
 
     
     
       6. An apparatus for laterally aligning sheets on a cylinder of a processing machine, the apparatus comprising:
 a stationary linear actuating drive disposed outside the cylinder; 
 a gripper device; and 
 a gear mechanism, disposed in a cylinder body of the cylinder, for converting a rotary movement of said actuating drive into a linear movement of said gripper device. 
 
     
     
       7. The apparatus according to  claim 6 , wherein said gear mechanism has a driver fastened on said gripper device. 
     
     
       8. The apparatus according to  claim 7 , which further comprises a rotatably drivable actuating shaft for actuating said gear mechanism. 
     
     
       9. The apparatus according to  claim 8 , wherein said actuating shaft is configured to be driven by said actuating drive. 
     
     
       10. The apparatus according to  claim 5 , which further comprises a control cam, and a control roller in operative contact with said control cam for actuating grippers of said gripper device, said control roller being spaced apart from said control cam during prealignment of said gripper device. 
     
     
       11. The apparatus according to  claim 6 , which further comprises a control cam, and a control roller in operative contact with said control cam for actuating grippers of said gripper device, said control roller being spaced apart from said control cam during prealignment of said gripper device. 
     
     
       12. The apparatus according to  claim 10 , wherein said control cam has a transporting-path region with a contour having a radius and an idling-path region with a contour having a smaller radius than said radius of said contour in said transporting-path region. 
     
     
       13. The apparatus according to  claim 11 , wherein said control cam has a transporting-path region with a contour having a radius and an idling-path region with a contour having a smaller radius than said radius of said contour in said transporting-path region. 
     
     
       14. The apparatus according to  claim 5 , which further comprises a machine-control device, and at least one sensor connected through said machine-control device to said actuating drive for sensing a sheet position. 
     
     
       15. The apparatus according to  claim 6 , which further comprises a machine-control device, and at least one sensor connected through said machine-control device to said actuating drive for sensing a sheet position. 
     
     
       16. The apparatus according to  claim 14 , which further comprises another sensor connected through said machine-control device to said actuating drive for sensing a sheet position, said sensors being spaced apart from one another in a sheet-transporting direction. 
     
     
       17. The apparatus according to  claim 15 , which further comprises another sensor connected through said machine-control device to said actuating drive for sensing a sheet position, said sensors being spaced apart from one another in a sheet-transporting direction. 
     
     
       18. A sheet-fed rotary printing machine, comprising an apparatus according to  claim 5 . 
     
     
       19. A sheet-fed rotary printing machine, comprising an apparatus according to  claim 6 .