| 摘要 |
A folding ladder of the type made up of a pair of side rails to which rungs are pivoted at opposite ends for folding of the structure from an open mode, in which the rungs are horizontal, to a closed or folded mode in which the rails move lengthwise relative to each other as well as toward each other as the rungs pivot about their respective pivots, parallel-link fashion. The present improvement resides in the design of each rail in semi-circular section in which the open side of the C thus formed faces inwardly toward the open side of the C of the other rail, whereby, in the closed mode, the two rails form a cylindrical shell within which the rungs are housed or confined, leading to a compact package that is easily carried, shipped, etc.
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