| 摘要 |
<p>A telescopic hang-on ladder including a set of ladder elements ( 1 1, 1 2 , 1 3 , 1 4 ...) coupled to each other so that the sequential ladder elements are telescopically movable relative to each other in order to extend and collapse the ladder. Each ladder element includes two parallel stringers (2 1 , 2 2 ) spaced apart from each other. The cross-sectional profile of a stringer comprises a planar web (3), and both long edges of the web comprise guide members, wherein the guide members of the stringer of each upper ladder element constitute a slide guide for the stringer of the adjacent lower ladder element. A step (4) extends between the stringers substantially perpendicularly to the lengthwise direction of the stringers (2 1 , 2 2 ) and is mounted at each end to the web (3) of the stringer. The stringers (2 1 , 2 2 ) of each ladder element are substantially fitted, for the most of their part, within the corresponding stringers of the adjacent upper ladder element. Both long edges of the web (3) comprise a planar flange (5, 6) bent at an acute angle relative to the plane of the web, wherein the flanges together with the web constitute said guide members, so that each stringer of the upper ladder element constitutes a dovetail guide for the stringer of the lower ladder element fitted within said stringer.</p> |
