| 摘要 |
Elements to be assembled to form in situ a temporary stair, from a pair of planks (1,1') or longitudinally sawn boards, or identical cross-section, intended for serving as stringers and which elements consist of steps (2), identical with one another, the steps being self-locking one by means of another onto and against the planks (1,1'), with the exception of the top step which has to be wedged against these planks (1,1'); each step (2) rests, at each side at the front, on the upper edge of a plank and, at the rear, is brought against the lower edge of the plank by a pair of flats (14,14') terminating in a hook (16) and mounted freely pivotal in the step placed next above. |
