| 摘要 |
<p>The adjustable metal ladder has two sections, a rung of the lower section supporting the upper section by sprung pivoted levers mounted in recesses in the uprights of the upper ladder section. The supporting levers (9), release levers (21) and spring (17) are accommodated within the upper uprights. When loaded, the projecting portion (11) of the supporting lever (9) rests on a rung of the lower ladder section. The outer end (14) of the lever bears against the inside (15) of the ladder upright. To retract the ladder, the upper section is lifted, causing a rung of the lower section to press the release lever (21) downwards and then release it.</p> |
