Support structure consisting of a plurality of mobile elements for chairs, beds and the like

A support structure for chairs, beds and the like, comprising:

• a plurality of support elements movable individually or in groups between a support position and a lower position, wherein at any given time at least some of said support elements are in said support position and said support elements in said support position at any given time generally define a body support surface for supporting a person's body;
• and
• a plurality of mechanisms each associated with one of said support elements for lowering support elements from and successively returning said support elements to said support position to temporarily relieve body supporting pressure on a portion of the body, each mechanism including an articulated parallelogram structure including the respective support element, said parallelogram structure hingedly connected to a frame, each mechanism also including a follower connected to said support element and a cam engaging said follower, said cam comprising a disk mounted on-center on a shaft supported by said frame and including a circular portion and a depression, said support elements being lowered from and successively returned to said support position when respective followers travel along the depressions of said cams during rotation of said cams, said support elements remaining at said support position when respective followers travel along said circular portion of said cams during rotation of said cams.