| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a spiral staircase unit capable of being easily and accurately assembled into a stable finish. <P>SOLUTION: The spiral staircase unit includes a center support plate 1, an outer support plate 2, a plurality of treads 31 to 33 arranged at predetermined intervals between both support plates 1 and 2, and a plurality of risers 41 to 43 disposed vertically at the lower sides of the fronts of the treads 31 to 33. The second and subsequent risers 42 and 43 are each secured to the center support plate 1 at their inner ends while their outer ends are not fixed. Clearances C are provided at the backs of the outer ends of the second and subsequent risers 42 and 43. <P>COPYRIGHT: (C)2004,JPO</p> |
