SPIRAL STAIRS

摘要

PROBLEM TO BE SOLVED: To provide a spiral stairs capable of smoothly and safely ascending and descending the stairs. SOLUTION: For the spiral stairs continuously providing straight lines 2a and 2b in a U-shape through a spiral section 1, and treads 3 located at the spiral section 1 and straight lines 2a and 2b are so formed in the shape of a narrow width toward the inside end 4 of the spiral section that both front and rear width sizes L of each of the treads 3 are approximately equivalent to the positions having the same distance from the inside end 4 of the spiral section.