of the frames and when the lift platform is in its lowered position the sliding articulations are substantially below the outlines of the outer frame and above the outlines of the inner frame application_number US 20166094 A description an inner frame 14 is mounted on a bottom plate 12 so as to be pivotable about two stationary articulations 16 arranged in a transverse direction at its lower end an outer frame 18 has two sliding articulations 20 which are guided in runners 122 the two frames 14 18 are articulatedly connected in their central portion by means of a transverse rod 120 the upper end of the inner frame 14 has a pair of sliding articulations 120 corresponding to those on the lower end of the outer frame which are movably guided in runners 22 on the underside of a lift platform 24 on the upper end of the outer frame 18 there are two fixed articulations 16 corresponding to those on the lower end of the inner frame and mounted in brackets on the underside of the lift platform 24 a flexible pressure hose 26 between the bottom plate 12 and the lift platform 24 serves to raise and lower the lift platform in the lowered position 24 39 of the lift platform 24 the two frames 14 18 are parallel in their respective positions 14 39 and 18.