| 摘要 |
<p>The invention relates to an extendable ladder with a safety feature for preventing finger injury, which comprises: two vertical stiles with a plurality of rungs disposed between two stiles, each stile being formed by a plurality of telescopically collapsible columns (1), characterized in that each column (1) receives a cover (2) at the bottom opening to cover the bottom opening, the cover (2) has a small cylindrical portion (21) and a large cylindrical portion (22), an annular groove (23) is formed on the peripheral surface of the large cylindrical portion (22), a plurality of through holes (24) are vertically provided on the bottom inner wall of the annular groove (23) for enabling air to exit from the annular groove, a sealing ring (3) is disposed inside the annular groove (23) and capable of sliding up and down in the annular groove (23), and the sealing ring (3) touches the inner wall of the next lower column (1) when the stile is extending or collapsing and forms a movable frictional seal for the next lower column (1). During the collapsing of the next upper column (1), the cover (2) of the next upper column (1) will be affected by the resistance of gas inside the closed space, and the gas inside the closed space may be exited slowly from the gaps at the junctions of components of the extendable ladder, therefore the purposes of preventing finger injury and eliminating potential safety hazards are achieved; since through holes (24) are provided inside the annular groove (23), when the columns (1) move upward while the extendable ladder is extending for use, air in the columns (1) may be in circulation by the through holes (24), which saves labor to extend the extendable ladder.</p> |
