Patent ID: 7374392

Claim:
A device for forming a stack of n packets, the device ( 1 ) comprising a conveyor channel ( 8 ) having an input ( 7 ) and an output ( 11 ); feed means ( 5 ) for feeding said packets ( 3 ) successively to said input ( 7 ) in a first direction ( 6 ), the conveyor channel ( 8 ) extending in a second direction ( 9 ) substantially crosswise to said first direction ( 6 ); a screw push device ( 10 ) for moving said packets ( 3 ) along said conveyor channel ( 8 ) to said output ( 11 ), and in turn comprising at least one start screw ( 22 ), which has a first axis ( 25 ) substantially crosswise to said first direction ( 6 ), rotates about said first axis ( 25 ), and comprises a core ( 26 ) coaxial with said first axis ( 25 ), and n helical channels ( 27 ), each extending about said core ( 26 ) and through said conveyor channel ( 8 ); an output conveyor ( 13 ) extending from said output ( 11 ) in a third direction ( 14 ) crosswise to said first axis ( 25 ); and having a second axis ( 43 ) perpendicular to said first axis ( 25 ); the output conveyor ( 13 ) comprising a number of fixed partitions ( 42 ), which are parallel to the third direction ( 14 ) and define n channels ( 44 ), each for receiving a respective succession of packets ( 3 ), which are each aligned vertically with a respective packet ( 3 ) in the other channel ( 44 ) to form a respective stack ( 2 ); and extracting means ( 12 ) independent of said screw push device ( 10 ), movable along an annular path ( 48 ) comprising a work portion ( 49 ) and a return portion ( 50 ) different from the work portion ( 49 ), and for forming said stack ( 2 ) by transferring at the same time n packets ( 3 ) from top portions of n helical channels to the respective channels ( 44 ) of the output conveyor ( 13 ) at said output ( 11 ); wherein said work portion ( 49 ) extends in said third direction ( 14 ), through said conveyor channel ( 8 ) and top portions of all said n helical channels ( 27 ), from a first position tangent to said core ( 26 ), to a second position outside said screw push device ( 10 ) and said conveyor channel ( 8 ); and wherein said extracting means ( 12 ) comprise a comb ( 45 ) which, in said first position, is substantially tangent to said core ( 26 ) and crosswise to said third direction ( 14 ); said comb ( 45 ) comprising n teeth ( 46 ), each of which, in said first position, is located radially inside said conveyor channel ( 8 ) to engage a top portion of a respective said helical channel ( 27 ); and actuating means ( 47 ) being provided to move said comb ( 45 ) cyclically along said annular path ( 48 ) and through the top portion of the respective said helical channel ( 27 ) and said conveyor channel ( 8 ).