Abstract: Lockable piston-cylinder assembly to be mounted between two parts being movable relative to each other such as a frame and top or foot end of a bed structure. The two chambers resulting from the division of the cylinder in a piston are interconnected by a hollow piston rod provided with openings. At least one of these openings can be closed by valve member arranged in said piston rod and so fluid communication between these chambers is controlled. Valve member is actuatable from one end of the piston rod outside cylinder. For obviating undesired pressure build up in space or for controlling the pressure in this space a connection is provided to the exterior of cylinder.

Abstract: A body support comprising one or more flexible containers and a plurality of load transmitting elements which have contact surfaces the area of which at a number of elements differs from the area of other elements to obtain an adaptation to the differing ratio of volume to weight of the parts of the human body, and a container which can be used in the body support which container has two outer layers of nonpermeable material and two inner layers all layers, being interconnected by cross seams to form chambers interconnected at the edges.