| 摘要 |
<p>The invention relates to a rigid ladder 1 comprising a crossbar 2 having a first end at one end of the crossbar 2 and a second end at the opposite end of the crossbar, and two longitudinal members 3, each longitudinal member 3 located at each end of the crossbar 2, wherein the crossbar 2 has been manufactured from a first metal sheet 4 formed to a tubular form, each of the longitudinal members 3 has been manufactured from a second metal sheet 5 having a first longitudinal edge 6, a second longitudinal 7 edge opposite the first longitudinal edge 6, a first planar surface 8 and a second planar surface 9 opposite the first planar surface, wherein a hole 10, having an edge, for the crossbar 2 has been provided in the second metal sheet 5, the edge of the hole has been bent for providing a rim 11 extending from the second planar surface 9, the crossbar 2 has been attached from an end to the rim 11, the second metal sheet 5 has been bent in the direction of the second planar surface 9, and the first longitudinal edge 6 has been connected to the second longitudinal edge 7 for a forming tubular longitudinal member 3.</p> |
