Single-piece staircase, has set of stairs rigidly fixed at vertical intermediate parts of staircase framework, where intermediate parts are horizontally extended backward for rigidly and directly fixing at adjacent end parts of framework

摘要

The staircase has a staircase framework supporting a set of stairs (30) and another set of stairs (31), and formed of a vertical lower front end part (10), vertical intermediate parts (12) and a vertical upper rear end part (11) that are arranged at regular intervals and increasing heights. The former set of stairs is rigidly fixed at top of the parts. The latter set of stairs is rigidly fixed at the intermediate parts below the respective former set of stairs. The intermediate parts are horizontally extended backward for rigidly and directly fixing at the adjacent end parts.