Patent attributes
The invention modulates the air volume in foam cores of cushioning support devices and any other support apparatus using foam or similar materials. The foam core can be incrementally modulated to realize an infinite number of comfort levels as to softness and support firmness. The core consists of self-inflating open-cell flexible polyurethane foam and is completely sealed within an enclosure fitted over it, with one or more valves installed in the side walls which communicate with the outside air. Through the valves air is selectively withdrawn from the foam core, allowing the foam's density to increase. The invention uses relatively inexpensive foam, but through air volume modulation achieves a tactile feel of supreme softness for the user, without giving up the necessary firmness to support the body, as happens with very soft foam (bottoming-out or hammock-effect). When air is extracted from a self-inflating foam core, the surface of the core will soften uniformly while maintaining its support firmness. Contrary to this, when pressure is exerted on, for example, traditional coil spring core mattresses, their surface will harden. Integral part of the invention is a device using balanced springs in valve assemblies to avoid compression set, an irreversibly solid state of totally air-depleted foam.
