An apparatus for advancing positions of a web material has a first transporter at which the pieces are separated from a web, a clamp which transfers the pieces to the plane of a second transporter and a second transporter operating in this plane in a direction orthogonal to the displacement direction of the first transporter. The second transporter has at least one conveyor at least part of which is movable toward and away from the clamp and toward which the clamp can be moved so that the pieces are transferred to the conveyor and can be displaced by the latter with no spacing between them or with only a limited spacing between them.