PURPOSE: To simplify the construction work of a spiral stairway by disposing a receiving portion at the lower part of a pillar core member, installing a support member in the receiving portion to place a footboard thereon, and inserting the corner end of footboard into a notch of a covering member.
CONSTITUTION: A receiving portion 2 is disposed at the lower part of a pillar core member 1, and above the receiving portion is installed a support member 5. Next, a footboard 3 of the lowest stage is placed on the support member 5, and a covering member 4 is disposed along the surface of pillar core member 1 so that the corner end 31 of footboard 3 is inserted into the notch 41 of the covering member 4. On the upper side of the covering member 4, the support member 5 and the corner end 31 of footboard 3 are disposed sequentially. This method simplifies the construction work of spiral stairway 10 and shortens the work time.
NAKAHARA KAZUO
KANBE HIDEKI
AZUMA TADAO
