Device for separating an uppermost sheet from a supply stack by means of air blowers

Abstract

Mechanism for swiveling, locking/unlocking and separating/pressing a first and second housing part, which are connected by means of a swivel axis, of which one housing part can be swiveled. Such mechanism has a common operating unit in the area of the free end of the housing opposite the swivel axis, in such a way that locking/unlocking, swiveling, and separating/pressing the first housing part is carried out together and with one hand by means of the operating unit in a single motion.

1 . Device ( 1 ) for separating an uppermost sheet (S 1 ) from a supply stack (S) with air blowers ( 3 . 1 ,  3 . 2 ) in the area of a sheet transport unit ( 4 ) operating with a partial vacuum and having a sheet bending means ( 41 ), for the purpose of grasping the separated uppermost sheet and feeding it to a processing station in a sheet processing device, wherein air blower ( 3 . 1 ) for spreading out several sheets of an upper sheet stack area (SR) and air blower ( 3 . 2 ) for separating the uppermost sheet (S 1 ) and holding back an adhering sheet (S), following the uppermost sheet (S 1 ), are located downstream in front of the supply stack and transverse to a sheet transport path ( 42 ) and act against a sheet transport device (T) and the upper area of the sheet stack, which may be positioned at the same predetermined height by means of a lifting device ( 5 ), and wherein air jets with different pressures, directions, and diameters may be generated by means of the air blower ( 3 . 1 ;  3 . 2 ) supplied from an air pressure source ( 6 ) with at least one air nozzle ( 31 ) located in the area of a center line (Y, Z) of the stack ( 2 ) and the transport path ( 42 ), and with several air nozzles ( 32 ) located on both sides of the center line, characterized in that an additional air blower ( 3 . 3 ), having several air nozzles (D 1 , D 1 ′, D 2 , D 2 ′), supplied from a high pressure air source ( 7 ) is located in the area of the center line (Y, Z) of the stack (S) and the transport path ( 42 ), by means of which air jets (ST) may be generated with a high excess air pressure and small diameter, which on the one hand support the separation of the uppermost sheet (S 1 ) from the stack as well as hold back the adhering sheet (S 2 ) following the uppermost sheet, and on the other hand are used to spread apart the sheets in the upper area of the sheet stack.  
     
     
         2 . Device according to  claim 1 , characterized in that air jets (ST) with an excess air pressure equal to or greater than 1.0 bar may be generated by means of the high pressure air source ( 7 ) and the air nozzles (D 1 , D 1 ′, D 2 , D 2 ′) of the additional air blower ( 3 . 3 ), and that the pressure ratio of the air jets of the additional air blower ( 3 . 3 ) to those of the spreading and separating air blower ( 3 , 1 ,  3 , 2 ) is equal to or greater than 20:1.  
     
     
         3 . Device according to  claim 1  or  2 , characterized in that the additional air blower ( 3 . 3 ) has two nozzle elements ( 33 , 1 ,  33 . 2 ) with several additional air nozzles (d 1 , D 1 ′, D 2 , D 2 ′) and the nozzle elements are positioned on both sides of the air blower ( 3 . 1 ), the first air blower ( 3 . 1 ) for spreading and is outside of the inner air nozzles ( 32 ) of the air blower ( 3 . 2 ), the second air blower ( 3 . 2 ) for separating and holding back.  
     
     
         4 . Device according to  claim 1  or  3 , characterized in that the additional, third air blower ( 3 . 3 ) has two nozzle elements ( 33 . 1 ,  33 . 2 ), in each case with a vertically overlapping arrangement, wherein the upper air nozzles (D 1 , D 1 ′) are directed toward a middle front edge area of the second and third sheets of the stack ( 6 ) for the purpose of separating and holding back the adhering second sheet (S 2 ) following the uppermost stack sheet (S 1 ), and the lower air nozzles (D 2 , D 2 ′) are directed toward the middle front edge area of the sheets located thereunder in order to spread them apart and lift them.  
     
     
         5 . Device according to  claim 4 , characterized in that the upper air nozzles (D 1 , D 1 ′) of the two nozzle elements ( 33 . 1 ,  33 . 2 ) are located at approximately the height of the upper edge of the air nozzle openings ( 32 ) of the air blowers ( 3 . 2 ) for separating and above the upper edge of the air nozzle opening ( 31 ) of the air blowers ( 3 . 1 ) for spreading, and that the two lower air nozzles (D 2 , D 2 ′) of the two nozzle elements ( 33 . 1 ,  33 . 2 ) are located at approximately the height of the middle of the nozzle opening ( 31 ) of the air blower ( 3 . 1 ) for spreading.  
     
     
         6 . Device according to  claim 4 , characterized in that the two nozzle elements ( 33 . 1 ,  33 . 2 ) are located with their air nozzle openings (D 1 , D 1 ′, D 2 , D 2 ′) along the direction of transport ( 1 ) of the sheet transport path ( 42 ) between the air nozzle openings of the spreading air blower ( 3 . 1 ) and the separating air blower ( 3 . 2 ).  
     
     
         7 . Device according to  claim 1  or  5 , characterized in that the air nozzles of the additional air blower ( 3 . 3 ) and thus the air jets ( 87 ) thereof are directed parallel to the horizontal plane of the sheets of the stack (S) and parallel to the center line (Y, Z) of the stack and the sheet transport path, and that the air jests ( 31 ,  32 ) of the spreading ( 3 . 1 ) and separating air blowers ( 3 . 2 ) and this the air jets are directed at an angle rising from the horizontal plane of the stack sheets to the upper area (SR) of the stack.  
     
     
         8 . Device according to  claim 1  or  4 , characterized in that the air nozzles (D 1 , D 1 ′, D 2 , D 2 ′) of the additional air blower ( 3 . 3 ) have an opening diameter equal to or smaller that 0.5 mm, and that the ratio of the opening diameter of the air nozzles of the additional air blowers to those of the spreading ( 3 . 1 ) and separating air blowers ( 3 . 2 ) is equal to or greater than 1:20.  
     
     
         9 . Device according to  claim 1 , characterized in that the air pressure of the air jet (ST) of the additional air blower ( 3 . 30 ) is essentially constant during an operating cycle, and that the air jets (ST) of the additional air blower ( 3 . 30 ) act simultaneously on the sheets of the upper sheet stack area (SR) with the air jets ( 31 ; 32 ) of the spreading air blowers ( 3 . 1 ) and separating air blowers ( 3 . 2 ), having a constant air pressure.  
     
     
         10 . Device according to  claim 9 , characterized in that the air pressure of the air jets (ST) of the additional air blower ( 3 . 3 ) is pulsating during an operating cycle.