A New Approach to Design of Retractable Roofs

The paper presents a method of constructing a foldable frame using a chain of four-bar linkages forming a closed loop. The frame can then be enlarged by adding more elements provided that certain geometric constraints are satisfied. This method guarantees that the structure has a degree of mobility and it has fixed point supports where hinges can be used to connect the structure to the foundation. The design process is simple. Furthermore, it can be shown that the structures designed with an old method which are capable of being fixed at certain points can be obtained as special case from the new approach, i.e. the new method has led to discovery of new structures with the same feature.