| 摘要 |
PROBLEM TO BE SOLVED: To provide an auxiliary ladder for an underground structure, which is attachable through one-touch operation and resistant to easy detachment from the structure. SOLUTION: The auxiliary ladder is comprised of a ladder body 12 which is formed such that the auxiliary ladder is left in a housing space S of a cover bearing frame 11 when a cover body is placed. The ladder body 12 has a pair of base portions 15, 15 which are detachably attached to the cover bearing frame 11 via spindles 13, and each have a slot 16 for moving the ladder body 12. Then, at least one of the slots has an open port 17 communicating with the outside, and the spindle 13 can pass through the open port 17. Further, to prevent unintentional slipout of the spindle 13 from the open port 17, a slipout preventive member 18 for blocking the open port 17 is rigidly superposed on the one base portion 15. COPYRIGHT: (C)2004,JPO
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