Apparatus and method for dispensing sheets

Abstract

Apparatus and method for dispensing individual sheets from a stack of sheets ( 10 ). A support ( 30 ) is provided for accommodating the stack of sheets in overlying parallel relationship. A suitable pickup device ( 20 ) overlying the support and having blowing means ( 62 ) is provided for producing airstreams over one end (A) of the upper sheet of the stack, such as to curl up this end and separate a portion of the upper sheet including this end from the stack. The pickup device also provides a holding force ( 60, 66 ), typically in the form of a suction force ( 60, 66 ) such as to hold at least part of this portion abutted against said pickup device, whereupon the airstreams may be terminated. A peeling mechanism ( 50 ) is also provided, having a clamping mechanism ( 70 ) for clamping the separated portion of the upper sheet, and adapted for displacing at least part of the sheet in a peeling motion in a direction substantially away from the original position of the end and/or the stack.

1 . Apparatus for dispensing sheets comprising: 
 a) a support for accommodating a stack of sheets in overlying parallel relationship;    b) a pickup device overlying said support and comprising: 
 (i) blowing means for producing airstreams over one end of the upper sheet of a stack that may be accommodated by said support, such as to curl up said end and separate a portion of said upper sheet including said end from the stack; and  
 (ii) suitable holding means such as to hold at least part of said portion abutted against said pickup device such that said airstreams may be terminated;  
   c) a peeling mechanism having a clamping mechanism for clamping the separated portion of the upper sheet and adapted for displacing at least a portion of the sheet in a peeling motion with respect to a remainder of said stack that may be accommodated by said support.    
     
     
         2 . Apparatus as claimed in  claim 1 , wherein said pickup head comprises a displacement arrangement for reciprocally moving said pickup device towards and away from the stack that may be accommodated by said support.  
     
     
         3 . Apparatus as claimed in  claim 2 , wherein said displacement arrangement is adapted for providing vertical as well as horizontal motion to said pickup device.  
     
     
         4 . Apparatus as claimed in  claim 3 , wherein said pickup head is configured to reciprocally rotate about a suitable axis such as to provide a desired vertical and horizontal movement to a part of said pickup head, wherein said part of said pickup head comprises said blowing means and said holding means.  
     
     
         5 . Apparatus as claimed in  claim 2 , wherein said displacement arrangement comprises a piston driver that is electrically actuable and controllable by any suitable electric, electronic or computer means.  
     
     
         6 . Apparatus as claimed in  claim 1 , wherein said holding means comprises a suitable suction means.  
     
     
         7 . Apparatus as claimed in  claim 6 , wherein said suction means comprises a cylindrical member having suitable apertures operatively connected to a suitable suction source.  
     
     
         8 . Apparatus as claimed in  claim 7 , wherein said cylindrical member is substantially aligned with said end of said upper sheet.  
     
     
         9 . Apparatus as claimed in  claim 8 , wherein said blowing means comprise suitable openings provided in a plenum chamber accommodated in said pick up head, said openings being operatively connected to a suitable compressed air source such as to provide substantially tangential airstreams with respect to said cylindrical member.  
     
     
         10 . Apparatus as claimed in  claim 9 , wherein said compressed air source comprises an air compressor arrangement, including a fan or air blower.  
     
     
         11 . Apparatus as claimed in  claim 10 , wherein said suction means and said blowing means are operatively interconnected.  
     
     
         12 . Apparatus as claimed in  claim 10 , wherein said air compressor arrangement is electrically actuable and controllable by any suitable control means including electric, electronic or computer means.  
     
     
         13 . Apparatus as claimed in  claim 7 , wherein said vacuum source comprises a suitable vacuum pump, ejector or suction pump arrangement.  
     
     
         14 . Apparatus as claimed in  claim 13 , wherein said pump arrangement is electrically actuable and controllable by any suitable control means including electric, electronic or computer means.  
     
     
         15 . Apparatus as claimed in  claim 1 , wherein said clamping mechanism comprises a support member having clamping means at each end thereof adapted for clamping said separated portion of said upper sheet, and a pair of arms substantially orthogonal to said support member pivotally mounted with respect to a suitable swinging axis.  
     
     
         16 . Apparatus as claimed in  claim 15 , wherein said clamping means comprise suitable jaws.  
     
     
         17 . Apparatus as claimed in  claim 16 , wherein said clamping means comprise a substantially stationary clamping member adapted for clamping with respect to said cylinder after said pickup head separates and holds an end of an upper sheet.  
     
     
         18 . Apparatus as claimed in  claim 16 , wherein said jaws are electrically actuable and controllable by any suitable control means including electric, electronic or computer means.  
     
     
         19 . Apparatus as claimed in  claim 15 , wherein said clamping mechanism is displaceable by means of a suitable driving mechanism.  
     
     
         20 . Apparatus as claimed in  claim 19 , wherein said driving mechanism is electrically actuable and controllable by any suitable control means including electric, electronic or computer means.  
     
     
         21 . Apparatus as claimed in  claim 15 , wherein said peeling mechanism is suitably synchronised with said pickup device.  
     
     
         22 . Apparatus as claimed in  claim 21 , wherein said synchronisation is provided by suitable mechanical means.  
     
     
         23 . Apparatus as claimed in  claim 21 , wherein said synchronisation is provided by suitable synchronisation means including electrical, electronic or computer means.  
     
     
         24 . Apparatus as claimed in  claim 1 , wherein said support comprises a tray.  
     
     
         25 . Apparatus as claimed in  claim 24 , wherein said tray is in horizontal alignment.  
     
     
         26 . Apparatus as claimed in  claim 25 , wherein said tray is horizontally reversibly movable from a position outside the apparatus to a position inside the apparatus.  
     
     
         27 . Apparatus as claimed in  claim 1 , further comprising a suitable spraying system for spraying at least one suitable liquid to a said sheet, said spraying system being operatively connected to at least one source of said liquids and comprising at least one nozzle adapted for spraying said at least one liquid.  
     
     
         28 . Apparatus as claimed in  claim 27 , wherein said spraying system is adapted for spraying a said sheet after the sheet has been substantially fully separated from the said stack.  
     
     
         29 . Apparatus as claimed in  claim 27 , wherein said spraying system is suitably synchronised with at least with said peeling system.  
     
     
         30 . Apparatus as claimed in  claim 29 , wherein said synchronisation is provided by suitable mechanical means.  
     
     
         31 . Apparatus as claimed in  claim 30 , wherein said mechanical means comprises suitable mechanical linkage between said pickup device and said peeling mechanism.  
     
     
         32 . Apparatus as claimed in  claim 29 , wherein said synchronisation is provided by suitable synchronisation means including electrical, electronic or computer means.  
     
     
         33 . Apparatus as claimed in  claim 27 , wherein said spraying system further comprising suitable means for enabling any desired combination of said liquids to be sprayed in any desired relative proportions onto said sheet.  
     
     
         34 . Apparatus as claimed in  claim 27 , wherein said spraying system is operatively connected to said blowing means, wherein said blowing means generate suitable airstreams to carry said liquid to said sheet.  
     
     
         35 . Apparatus as claimed in  claim 34 , wherein said spraying system is suitably synchronized with said blowing means such as to enable a sheet to be sprayed after the sheet has been fully separated from the said stack.  
     
     
         36 . Apparatus as claimed in  claim 1 , wherein said holding means constitute said clamping mechanism.  
     
     
         37 . Apparatus as claimed in  claim 1 , wherein said peeling mechanism is incorporated in said pick up head.  
     
     
         38 . Apparatus as claimed in  claim 37 , wherein said peeling mechanism includes suitable means for swinging the pickup head with respect to the stack.  
     
     
         39 . Method for dispensing sheets from a stack of sheets in overlying substantially parallel relationship, comprising: 
 (a) providing suitable airstreams over a first end of an upper sheet of the stack such as to curl up said first end and separate a portion of said upper sheet including said first end from the stack;    (b) creating a suitable holding force such as to hold said first end abutted against a suitable pickup device, and terminating the said airstreams;    (c) clamping the separated portion of the upper sheet in (b) and terminating the holding force;    (d) displacing at least a part of the sheet in a peeling motion with respect to a remainder of said stack.    
     
     
         40 . Method as claimed in  claim 39 , wherein in step (d) said at least a part of the sheet is displaced in a direction substantially towards a second end of said upper sheet opposed to said first end of the sheet.  
     
     
         41 . Method as claimed in  claim 39 , wherein said holding force comprises a suction force.  
     
     
         42 . Method as claimed in  claim 39 , wherein in step (d) all of said sheet is displaced in a peeling motion from said stack.  
     
     
         43 . Method as claimed in  claim 40 , wherein a remaining part of said sheet which is still in overlying relationship with said stack is removed from the stack by providing a force to the sheet in a direction substantially towards said first end.  
     
     
         44 . Method as claimed in  claim 43 , wherein said force is provided by generating suitable airstreams to impinge on said sheet.  
     
     
         45 . Method as claimed in  claim 39 , wherein said first end comprises an edge of said sheet.  
     
     
         46 . Method as claimed in  claim 39 , wherein said first end comprises a corner of said sheet.  
     
     
         47 . Method as claimed in  claim 39 , further comprising the step (e) of impregnating the separated sheet with at least one suitable liquid after the sheet has been separated.  
     
     
         48 . Method as claimed in  claim 39 , further comprising the step (f) of releasing the separated sheet for collection or further processing.  
     
     
         49 . Method as claimed in  claim 39 , wherein step (a) is effected by bringing together a suitable pickup and said upper sheet, said blowing means comprising a cylindrical member having suitable openings for providing said airstreams.  
     
     
         50 . Method as claimed in  claim 49 , wherein said pickup device is lowered onto device until it rests gently on said upper sheet.  
     
     
         51 . Method as claimed in  claim 49 , wherein said upper sheet is raised until it is in gentle contact with said pick up device.  
     
     
         52 . Method as claimed in  claim 40 , wherein said suction force in step (b) is provided via suitable apertures in said pickup device operatively connected to a suitable vacuum source.  
     
     
         53 . Method as claimed in  claim 39 , wherein step (c) is effected by means of a suitable peeling mechanism including a clamping mechanism having a pair of opposed clamping means adapted for clamping said separated portion of said upper sheet, and a pair of arms extending orthogonally from said jaws and pivotally mounted with respect to a suitable swinging axis.  
     
     
         54 . Method as claimed in  claim 53 , wherein said clamping means are in the form of jaws.  
     
     
         55 . Method as claimed in  claim 47 , wherein step (e) is effected by means of a spraying system adapted for spraying said liquid to the separated sheet.  
     
     
         56 . Method as claimed in  claim 39 , wherein steps (a) to (d) are synchronised with respect to one another.  
     
     
         57 . Method as claimed in  claim 47 , wherein at least steps (d) to (e) are suitably synchronised with respect to one another.  
     
     
         58 . Method as claimed in  claim 55 , wherein steps (a) to (d) are at least partially synchronised by any suitable mechanical means.  
     
     
         59 . Method as claimed in  claim 58 , wherein said mechanical means includes suitable mechanical linkage between said pickup device and said peeling mechanism.  
     
     
         60 . Method as claimed in  claim 55 , wherein said synchronisation is provided by suitable synchronization means including electrical, electronic or computer means.  
     
     
         61 . Method as claimed in  claim 57 , wherein said synchronisation is provided by suitable synchronization means including electrical, electronic or computer means.