Advancement unit of sheets of paper in a machine for paper converting and related advancement method

Abstract

An advancement unit () for causing a plurality of sheets () of paper, or any other material permeable to air, to move along a predetermined advancing direction () in a machine for paper converting, comprises a cutting group () which divides a web () made of paper, or another material permeable to air, into the sheets (). The advancement unit (), furthermore, provides a transfer roll () positioned downstream del cutting group (), having an external surface () and adapted to rotate at a first predetermined angular velocity (ω1) about a longitudinal rotation axis () and to hold, alternately, on a first and on a second predetermined portion () of the external surface () the head edge () and the tail edge () of the sheets () coming from the cutting group (). A displacement group () is, furthermore, positioned downstream of the transfer roll () to move a plurality of catching members () along a movement trajectory () comprising at least one curvilinear portion () and at least one straight portion () to move the sheets () in a partly overlapped configuration along a predetermined advancement trajectory ().