Support, adjustable in height, for semi-trailer or similar

Height-adjustable support (10) comprises a fixed supporting outer tube (12), a longitudinally extending supporting inner tube (13), a drive delivery shaft on which a conical wheel sits and a drive shaft which is hollow or having an extension which is hollow. Preferred Features: The extension is a toothed wheel fixed to the drive shaft or a pinion gear. The hollow region is a concentric bearing bore. The drive shaft is formed as a tube.