| 摘要 |
<p>The ladder consists of two uprights (1) (4), provided with an internal groove (5), and connected together by rungs (3) which can pivot at both ends about axles (6) fitted into hollow rungs. The ladder can be folded up, the rungs then laying in the grooves of the uprights. This improves the ease with which the ladder can be handled and transported. One upright is provided with a tenon piece (2) which limits the movement of the rungs and acts as a stop when the ladder is unfolded.</p> |
