A STAIR LIFT AND A SUPPORTING UNIT FOR A STAIR LIFT

摘要

A stair lift comprising a supporting unit (10) and a rail system, wherein said rail system comprises a circular tube (1), on which the tread (5) of a wheel of the supporting unit (10) can roll. The wheel (2) has a radially extending centre plane, in which plane the tread (5) diameter is smaller than the tread diameter at some distance from said centre plane. The tread (5) comprises a concave, substantially arced portion, seen in longitudinal sectional view through the axis of the wheel, whose radius is larger than half the outside diameter of said tube.