SELF-ADJUSTMENT FOR BODY SUPPORT CUSHION

In combination with a body support cushion unit where open-cell foam is used in an air-tight envelope and a manually controllable valving means in a passageway to the envelope is utilized so as to regulate flow of ambient air pressure into and out of the foam, there is additionally provided a special valving device as a part of the valving means for the unit which includes a separate movable blocking member seatable over a separate small bleed-in orifice. Thus, when there is no weight on the cushion unit and no back pressure on the member over the bleed-in orifice the latter can permit a slow metered flow of air into the open-cell foam as long as it is under a vacuum condition, while, conversely, any pressure on the foam will cause a back pressure condition and a seating of the movable blocking member over the bleed-in orifice.