Device and process for feeding sheets to a finishing line for documents formed from these sheets

Abstract

The device ( 1 ) for feeding sheets to a finishing line for documents formed from these sheets comprises, for supporting a pack ( 4 ) of sheets, a table ( 5 ) which cooperates with sheet extraction means ( 6 ) for transferring a sheet, to a filter ( 8 ) defining a slot ( 9 ), and to means ( 11 ) for its expulsion towards the finishing line. The device comprises means ( 13 ) for adjusting the thickness of the slot ( 9 ) and/or means ( 15 ) for controlling the force exerted by the extraction means ( 6 ). The process for feeding sheets to a finishing line comprises the steps of extracting a sheet from a pack ( 4 ), passing the sheet ( 7 ) through a slot ( 9 ) which allows one sheet at a time to pass, and expelling the sheet ( 7 ) towards the finishing line. The thickness of the slot ( 9 ) and/or the extraction force exerted on each sheet extracted from the pack ( 4 ) are automatically adjusted.

1 . A device ( 1 ) for feeding sheets to a finishing line for documents formed from these sheets, comprising, for supporting a pack ( 4 ) of sheets, a table ( 5 ) which cooperates with sheet extraction means ( 6 ) arranged to transfer a sheet ( 7 ) extracted from said pack ( 4 ) to a filter ( 8 ) defining a slot ( 9 ) enabling one sheet at a time to pass and to means ( 11 ) for expelling the sheets towards the finishing line, characterised by comprising means ( 13 ) for adjusting the thickness of said slot ( 9 ) and/or means ( 15 ) for controlling the force exerted by said extraction means ( 6 ), such as to be able to extract from the pack ( 4 ), and supply to the finishing line, sheets for one and the same document which are of different thickness and/or porosity.  
   
   
       2 . A device ( 1 ) as claimed in  claim 1 , characterised in that said extraction means ( 6 ) comprise a movable portion ( 16 ) provided with at least one aperture ( 17 ) and associable by vacuum with a sheet to be extracted such that, when said movable portion ( 16 ) is associated with a sheet, it can drag the sheet towards said filter ( 8 ).  
   
   
       3 . A device ( 1 ) as claimed in  claim 1 , characterised in that at least said movable portion ( 16 ) is supported by said support table ( 5 ).  
   
   
       4 . A device ( 1 ) as claimed in  claim 1 , characterised in that said movable portion ( 16 ) comprises a hollow cylinder provided with a plurality of said apertures ( 17 ) connecting its interior chamber ( 18 ) to the outside, within said chamber ( 18 ) there sliding a hollow element ( 19 ) presenting at least one hole ( 20 ) alignable with at least some of said apertures ( 17 ) of said cylinder, and an internal cavity ( 21 ) connected to a vacuum pump ( 22 ).  
   
   
       5 . A device ( 1 ) as claimed in  claim 1 , characterised in that said slot ( 9 ) is defined between said filter ( 8 ) and said extraction means ( 6 ).  
   
   
       6 . A device ( 1 ) as claimed in  claim 1 , characterised in that said means ( 13 ) for adjusting the thickness of the slot ( 9 ) comprise at least one member ( 25 ) for controlling the position of said support table ( 5 ) carrying said extraction means ( 6 ), said control members ( 25 ) causing at least one region of said table ( 5 ) to approach or withdraw from said filter ( 8 ) in order to move said extraction means ( 6 ) towards or away from said filter ( 8 ) and vary the thickness of said slot ( 9 ).  
   
   
       7 . A device ( 1 ) as claimed in  claim 1 , characterised in that said control member ( 25 ) comprises at least one cam supporting a first end of said support table ( 5 ).  
   
   
       8 . A device ( 1 ) as claimed in  claim 1 , characterised in that said support table ( 5 ) presents, opposite said first end, a second end hinged to a frame ( 27 ) of said device ( 1 ).  
   
   
       9 . A device ( 1 ) as claimed in  claim 1 , characterised in that said adjustment means ( 13 ) comprise an actuator ( 29 ) arranged to move at least one portion of said filter ( 8 ) towards and away from said sheet support table ( 5 ).  
   
   
       10 . A device ( 1 ) as claimed in  claim 1 , characterised in that said means ( 15 ) for controlling the force exerted by said extraction means ( 6 ) comprise a solenoid valve for throttling the suction flow of the pump ( 22 ).  
   
   
       11 . A device ( 1 ) as claimed in  claim 1 , characterised by comprising at least one sensor ( 33 ) for reading a code which defines information relative to the characteristics of the entering sheets and is impressed thereon, said sensor ( 33 ) being connected to a control processor ( 34 ) connected to said means ( 13 ) for adjusting the dimension of said slot ( 9 ) and/or said means ( 15 ) for controlling the extraction force exerted by said extraction means ( 6 ), to automatically control said parameters in relation to the characteristics of the sheet being handled.  
   
   
       12 . A process for feeding sheets to a finishing line for documents formed from these sheets, comprising the steps of extracting from a pack ( 4 ) a sheet ( 7 ) to be fed to the finishing line to form a document, passing said sheet ( 7 ) through a slot ( 9 ) which allows one sheet at a time to pass, and expelling said sheet towards the finishing line, characterised by automatically adjusting the thickness of the slot ( 9 ) and/or the extraction force exerted on each sheet extracted from the pack ( 4 ), to feed to the finishing line a single sheet presenting characteristics different from those of a previous sheet.  
   
   
       13 . A process as claimed in  claim 12 , characterised by comprising a step in which a code impressed on the sheets and defining information relative to the sheet characteristics is read, said information being processed to adjust the dimensions of the slot ( 9 ) and/or to adjust the extraction force exerted by the extraction means ( 6 ).