Abstract: A size-adjustable platform for scaffolding comprises a plurality of overlapping sections extending from a central core, the sections including separate panels reciprocable with respect to the central core whereby the extent of the platform from the central core may be varied in size upon actuation of a ram or equivalent to cater for variable dimensions.

Abstract: A driving apparatus includes a roller screw that includes a main shaft, a plurality of roller shafts projecting radially outwardly and upwardly at an angle from the radial direction of the main shaft and arranged along a helical line there around, and a plurality of rollers rotatably mounted on the roller shafts. The rollers are tapered to the same angle inwardly toward the main shaft. A rail member, adjacent to and axially oriented with the main shaft, includes a plurality of spaced projections adapted for radial engagement with the tapered rollers. The angle of the tapering is pre-determined to provide a sliding free engagement between the rollers and the projections with the interface there between being oriented to intersect the rotation axis of their respective roller shaft on the rotation axis of the main shaft. The rotation of the main shaft axially moves the roller screw relative to the rail member.

Abstract: A raising system for scaffolding, elevator cabins and the like which comprises a vertical stationary beam member from one side of which equally vertically spaced similar rack teeth are protruding, each tooth having a substantially horizontal straight top face, a framework guided for up and down movement along said beam member, a power driven shaft rotatably supported by said framework and carrying spaced radial supports, a series of parallel idle shafts extending between the supports, equally spaced from one another and radially equally spaced from the driven shaft, and a plurality of cylindrical roller assemblies rotatably mounted on the idle shafts and adapted to come in successive rolling engagement with the top faces of said teeth during upward or downward movement of said framework. Each roller assembly includes several rollers disposed side by side.

Abstract: A driving apparatus comprising a roller screw member that includes a main shaft, a plurality of roller shafts projecting radially outwardly and upwardly at an angle from the radial direction of the main shaft and arranged at equally spaced intervals along a helical line around the main shaft, and a plurality of rollers rotatably mounted on the roller shafts. The rollers tapered to the angle are mounted on the roller shafts and oriented with the tapering inwardly to the main shaft thereby providing each roller with a bottom region of its tapered surface being perpendicularly oriented with the axis of the main shaft. The driving apparatus also includes a rail member adjacent and axially oriented with the main shaft of the roller screw member.

Abstract: A work platform is supported by a sleeve which is movable along a tower having a plurality of vertically equally spaced rungs. The raising system of the invention comprises two hydraulic rams pivotably attached to the sleeve and equipped with corresponding hooks at the extremity of their piston rods. The rams are activated simultaneously in up and down movement but in alternate directions, bearing in a hooking engagement in turn on the rungs of the tower to pull the sleeve upwards along the tower. When a rung is in the path of a hook in the upward movement, the latter pivots backwards to clear the rung and is pivoted back by means of springs.

Abstract: The present invention relates to a device for reducing the aerodynamic drag of a cavity in a flow, said device comprising a blade disposed upstream from the cavity so that it overlaps at least one edge of the cavity and the corresponding wall of the corresponding vehicle, and so that it is in the vicinity of said wall. The invention also relates to a vehicle, in particular a rail vehicle, provided with such a device.