A rollo assembly comprises a rollo screen with opposite longitudinal ends and opposite transverse ends, a winding shaft for winding and unwinding the rollo screen at one of said longitudinal ends, a pull beam connected to the other one of said longitudinal ends and two longitudinal guides for cooperation with the transverse ends of the rollo screen and for guiding the pull beam. At least one support member for the rollo screen extends underneath the rollo screen between two opposite longitudinal support member guides. The support member moves in said longitudinal direction along the support member guides when the rollo screen moves between its fully wound position and a partially wound off position, and is kept stationary in an end position when the rollo screen moves between its partially wound off position and its fully wound off position.