This 34.21 x 32.52 m extendable roof structure provides protection against sun and rain and allows the courtyard to be used for balls, concerts and other events. The entire membrane, cable and cross-girder construction is assembled on roller bearings in tracks. The travelling roof is operated by motors attached to the cross-girders, with pinions engaging in toothed racks welded to the edge beams. The cables and cross-girders are guided by combined radial and axial rollers, which also transmit all loads to the longitudinal beams. At the start of the closing operation, the end girder is set in motion. When the membrane behind it has unfolded, the next transverse girder is moved, and so on until the roof is fully extended.