Device for lifting and lowering the roof of a load vehicle supported on telescopic posts

The device has a telescopic post comprising a housing element (16), a supporting profile and a lifting element, where height of the lifting element is adjustable relative to the housing element. The lifting element is supported opposite to the housing element over a piston and cylinder unit (20). The lifting element is locked in adjustable height positions by a locking element (26). The locking element is fixed in different positions along the supporting profile for adjusting height of the lifting element, and has an upper front side that encloses a piston rod (24) of the cylinder unit.