Spiral staircase with height adjustable step modules - has spacing wedge pieces displaced by jack or helicoidal ramps and acting on support sleeve

摘要

The spiral staircase comprises separate step modules mounted on a central column of circular section, and each step (5) module is interposed by a height adjustable wedge piece (2). By this system identical step modules may be utilised with each riser individually adjustable within specified limits. The position of the wedge piece (2) may be altered by a jack (3) or the wedge may comprise a rotatable tube incorporating an external helicoidal ramp. The ramp engages a reciprocal ramp formation on the inner face of the sleeve (1) of the supported step module, and vertical adjustment is effected by a relative rotation. The wedge piece and the step module may be locked at the desired relationship by a locing screw.