Bending cantilevered retractable umbrella

Retractable umbrella structures have experienced a great development over the past decades. Technological advances have made it possible to create ever more sophisticated structures, with increased spans. As a result of a long development process, the optimization of structures has achieved the highest level by now, but the opening-closing process is quite complicated with very complex kinematics and steel structure. The umbrella structure suggested by this work is based upon a new operational principle, which significantly simplifies it. The innovativ solution is a use of bended composit arms instead of complicated steel arms with hinges. The bended arms could prestress the membrane surface and in the same time the membrane bend the arms, this interaction produce a harmonic structure with effective properties.