| 摘要 |
PCT No. PCT/NO89/00108 Sec. 371 Date May 17, 1991 Sec. 102(e) Date May 17, 1991 PCT Filed Oct. 18, 1989 PCT Pub. No. WO90/04693 PCT Pub. Date May 3, 1990.An adjustable mold for casting stairways of concrete enables the total length of a stairway and also the dimension of the separate steps to be adjusted. The mold includes a longitudinal horizontal frame supporting two identical parallel articulated arm systems positioned scissor-like and being linked together at intersection points of arms of the system along a longitudinal center axis thereof. At oppositely located and linked outer ends of the arms are provided pivotable supports for a number of step units, each of which includes an upstep and an instep. An inner edge of each instep substantially by its own weight rest against the upstep of an adjacent step unit. The total length of the articulated arm link system may be adjusted, thereby simultaneously adjusting the distance between adjacent step units. Also, the angular position of the step units relative to the support frame can be adjusted.
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