| 摘要 |
<p>The multi-purpose ladder comprises four equal-length pieces which fold together, with paired hinge components, linking them, and is adaptable as a single long ladder, step-ladder or ladder frame. The locking hinge has a stop lever (i) mounted in one half (f), notching in a groove (d) in the other half (e) under spring pressure. The two stop levers in a pair of hinges at any one hinge point are joined to a connecting rod (1), so that locking or release is always effected on both sides simultaneously. Release may be effected by balls (g) pressing the lever out of the groove when the activating knob is turned.</p> |
