| 摘要 |
Adjustable staircase having a pair of stringers each provided with a pair of pantographs, disposed one above the other, identical in overall length and having diagonal levers also of equal length, which levers are pivoted at their center and end points. The ends of the pantographs are mounted to connectors that are intended to be fixed to the two different levels that are to be joined. This mounting is such that the ends of the two pantographs, at each level, can pivot about axes that lie in horizontal planes so that if the levels to be connected are moved away or toward one another, corresponding pivot points on the two pantographs move together in parallel horizontal pivot points planes. The threads of the staircase are fixed to the pantographs by means of supports each of which has a tread portion which is secured to one edge of one tread and a pantograph portion which is pivotally connected to corresponding pivot points lying in the same horizontal plane. Each pantograph is enclosed in a casing having open ends through which the connectors extend as well as further openings for the tread connectors.
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