| 摘要 |
<p>Foldable ladder consisting of two uprights bent into angle-pieces arranged opposite one another and whose faces perpendicular to the plane of the ladder carry two longitudinal ribs provided with opposite perforations which receive pegs for articulating the steps so as to be able to fold up. Three essential points are improved: the holding of the ladder against the wall, the electrical system for triggering the opening of the ladder, and the correct placing of the system for triggering the ladder at the various positions along its height at which its complete opening will be manually or electrically controllable.</p> |
