SPIRAL STAIRS Russian patent published in 2002 - IPC

FIELD: civil engineering, designed for communication between the building storeys or different levels of structures. SUBSTANCE: the stair has steps, as well as supporting members of supports positioned in the plane perpendicular to the axis, on the Archimedean spiral, with a uniformly increasing radius and height determined by the pace of the ruled helical surface - right helicoid in its maximum section. EFFECT: enhanced convenience of transportation and reliability in service, as well as reduced occupied area and weight of the spiral stairs. 2 cl, 3 dwg