| 摘要 |
<p>An adjustable stablising device which is attached to an extension ladder without requiring modification of the ladder structure or affecting normal operation of the ladder is described. The device has two stabilising elements made of aluminum which are located at different side of the ladder. Each stabilising element has an upper and a lower bracket which are connected together by two rigid pivotably-linked longitudinal members. The stabilising elements are connected to each other by rods which extend through the rungs of the ladder and which connect the upper and the lower brackets. The lower bracket and the lower longitudinal member are pivotably connected, and the upper bracket has a number of apertures spaced lengthwise of the ladder. By choosing the aperture to which the upper longitudinal member is connected, the attitude of each of the lower members is varied via the pivotable connection so as to conform to the surface adjacent the ladder side. When not in use, the stabilising elements are retained flush against the sides of the ladder for storage.</p> |
