Platform unit

A platform unit for a scaffolding, comprising at least one rectangular support frame defining longitudinal sides and ends, the support frame comprising a plurality of longitudinal bars and a plurality of crossbars joined at corner joints, the crossbars be oriented at the ends of the support frame, the longitudinal bars be oriented at the longitudinal sides of the support frame, a floor surface being provided on the support frame and serving as a user supporting surface, and at least two hook-shaped mounting brackets being fastened to the respective crossbar at each end of the support frame, the mounting brackets being adapted to be received on respective transverse spars of the scaffolding, the mounting brackets extending from the crossbars in a direction parallel to the longitudinal sides and being inwardly spaced from the longitudinal sides of the support frame, the mounting brackets arranged at one of the ends being laterally offset with respect to the longitudinal bars, at least one of the crossbars and the longitudinal bars having an extruded hollow profile which is generally rectangular in cross section, and each of the crossbars and longitudinal bars having an inner web facing inwardly of the support frame, an outer web facing outwardly of the support frame, an upper horizontal segment joining upper portions of the inner and outer webs, and a lower horizontal segment joining lower portions of the inner and outer webs, the inner and outer web being oriented vertically and parallel to each other, the inner web of each of the longitudinal bars being cut out at the corner joints of the support frame by a width of the adjacent, there-connected crossbar, the height of the crossbars being less than the height of the longitudinal bars by an amount equal to a thickness of the upper and lower segments of the longitudinal bars, the entire profile of the crossbar extending laterally through the hollow interior of the longitudinal bar to the outer web of the longitudinal bar, and guide ribs being positioned on the upper and lower horizontal segments of the longitudinal bars extending along the side of the support frame, the guide ribs having a height less than the height of the floor surface provided on the support frame, the guide ribs on the upper horizontal segment and the longitudinal side of the floor surface defining a region for receiving the guide ribs on the lower horizontal segment from another frame when at least two frames are stacked on top of each other.