| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide spiral stairs capable of dispensing with large-scaled work with a crane in mounting treads, and being manufactured without using a ladder and a stepladder. SOLUTION: The spiral stairs S are provided with a pole 1 stood in the vertical direction, a plurality of holder members 2, and tread members 3. The holder members 2 respectively comprise a cylindrical body 11 provided with a hollow part inserted to the pole 1, and a locking piece 12 mounted on the cylindrical body 11. A rear face of the tread member 3 is provided with a locking projection part 22 engaged with the locking piece 12 of the holder member 2. The plurality of holder members 2 are successively inserted to the pole 1 in the height direction, and locking pieces 12 of the holder members 2 are mounted in a state of being shifted from each other at a predetermined angle around the pole 1 in a plane view. The locking projection parts 22 of the tread members 3 are engaged with the locking pieces 12.</p> |
