| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce generation of creak when a person elevates/descends a step by fitting an upper end of a riser into a bottomed groove formed on a tip side of a lower surface of a tread through a protective frame and an elastic material. SOLUTION: A bottomed groove 4 in which an upper end of a riser 3 is fitted, is formed on a tip side of a lower surface of treads 2, 2 in a shape to reduce the groove width upward. Groove-shaped protective frames 6, 6 formed of a hard material are fitted to an upper edge of the riser 3 to be fitted into the bottomed groove 4. Elastic materials 5, 5 abutted on an upper bottom surface 4a of the bottomed groove 4 are fixed to an upper surface of the protective frame 6. The tread 2 is thus supported by the riser 3 through the protective frame 6 and the elastic material 5, and neither upper end face of the riser 3 nor any sides thereof are brought into direct contact with an inner surface 4b of the bottomed groove 4. Generation of creak when a person elevates/ descends a step 1, can be reduced.</p> |
