Image Number 3 for United States Patent #5504952.
A bed including a base, a mattress overlying the base and apparatus for varying the hardness of the bed to take into account the changing personal circumstances of the user, for example, aging, gaining weight etc. and to compensate for the wear and tear on the mattress. The base includes a generally rectangular frame and a plurality of crosspieces traversing thereacross such that the hardness of the bed is varied by varying the number of crosspieces. The mattress includes a filling in which its hardness is varied by varying the amount of the filling, its components or adjusting the packing density of a composite filling having a foam substrate with a plurality of substantially incompressible marble-size balls embedded therein.