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(11) | EP 0 822 317 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Foldable ladder with high strength |
| (57) The ladder has a plurality of ladder sections (1) pivotally connected together by
hinged joints (2). Each ladder section (1) has two uprights (11) with respective rung
holes (111) and at least one rung (12) fitted into and fixed to the rung holes (111)
of the uprights (11). The ladder further includes inner and outer reinforcing parts
(21) on both side surfaces of each upright (11). The reinforcing parts (21) axially
extend from each hinged joint (2) to a predetermined length along an upright (11)
and are used for uniformly distributing the vertical or lateral load to all directions
of the upright (11) thus giving high strength to the ladder. Both ends of a rung (12)
is compressed to integrate the upright (11), rung (12) and reinforcing parts (21)
into a single body thus giving an operational safety to the ladder and lengthening
the expected life span of the ladder. |