Patent ID: 7837025

Claim:
A centering drum for filter assembly machines, the centering drum ( 1 ) comprising: a substantially cylindrical shell ( 7 ) rotatable about a longitudinal axis ( 2 ) and defining a transverse reference plane (T); a plurality of seats ( 12 ) formed, parallel to and equally spaced from said longitudinal axis ( 2 ), on the outside of said shell ( 7 ) each of said seats ( 12 ) being dimensioned and adapted to receive a respective filter portion ( 5 ) in an offset position offset laterally with respect to said reference plane (T); and centering means ( 28 ) for moving each filter portion ( 5 ), along the respective seat ( 12 ), from the offset position to a center position to center the filter portion with respect to said reference plane (T); wherein the centering means ( 28 ) is fitted to said shell ( 7 ) to rotate with the shell ( 7 ) about said longitudinal axis ( 2 ), and comprises a plurality of stop members ( 40 ), each of the stop members being located adjacent to a respective seat ( 12 ) on a respective side of said reference plane (T) to define the centered position of the respective filter portion ( 5 ), and push means ( 29 ) for moving each of the filter portions ( 5 ) axially onto the respective stop member ( 40 ); wherein the stop members ( 40 ) includes a first succession of stop members disposed on a first side of said reference plane (T) and a second succession of stop members disposed on a second side of said reference plane (T) opposite said first side, the first and second successions of stop members being alternatingly disposed on the opposite sides of said reference plane (T) such that if a first seat is engaged by a stop member of the first succession, then the adjacent seats are engaged by stop members of the second succession; and wherein adjusting means ( 31 ) is provided to move the first and second successions of stop members equally and oppositely along said longitudinal axis ( 2 ) with respect to said reference plane (T).