<p>The structure has a rectangular outer frame (1) with two side pieces (11) and two transverse connectors (12) connecting the side pieces. A moving mechanism (3) is provided for pivoting a lamella (2) between an open position and a closed position. A drive (4) applies and transfers movement force. A switching pivotal axle is arranged in end regions of lamella frame side pieces (24). The moving mechanism is operated by the drive and provided for pivoting the lamella at the switching pivotal axle and switching the switching pivotal axle from the outer frame.</p>
