Patent AT-E40071-T1: [Translated] ADJUSTABLE FORMWORK FOR MAKING CONCRETE ELEMENTS, SUCH AS STAIRS.

The present invention has as an object an adjustable mold for the manufacture of concrete elements such as staircases of the type having a straight line extent, of which the treads are perpendicular or not perpendicular to the risers. The adjustable mold according to the invention comprises a frame (1) on which is mounted a base (2), a front lateral wall, a back lateral wall (4) and two longitudinal walls (5), the said base being constituted by juxtaposed molding elements (6) each provided in a dihedral angle which dihedral angle is constituted by a wall intended to form the tread and by a wall intended to form the riser and is characterized in that each molding element (6) is supported by carriages mounted movably on horizontal guide rails (10) longitudinally to the mold, mounted on the frame (1) and in that a flexible strip (11) sealed to the concrete is stretched by stretchers (12) mounted at each extremity of the mold and is forced to cover and conform to the shape of the base (2) of the mold by winding on rollers (13), mounted beneath the base (2) each between two elements (6), and by gripping between the molding elements when these latter are maintained pressed the ones against the others by jacks.