Vacuum formed support structures and immobilizer devices

Claim 1

A lightweight immobilizer support device alternately convertible between a collapsed mode in which it is easily manipulated and formed to conform to the object to be supported and a rigidified support mode in which it retains a firm, solid shape immobilizing the object being supported, comprising: A. a lightweight, stretchable, elastic envelope formed of thin supple sheet material less than 0.014 inches thick surrounding and enclosing a central cavity, B. a large plurality of lightweight compressible particles of expanded polymer foam material having a density between 1.00 and 2.00 pounds per cubic foot loosely filling less than half of the volume of the central cavity, said particles having outside diameters falling substantially within a range between 0.015 inches and 0.125 inches, C. a foraminous distributor unit inside the cavity, and D. an evacuation conduit extending through the envelope and connecting the cavity through the distributor unit to the region outside the envelope, E. said envelope material being sufficiently supple to stretch interfittingly into the interstices between adjacent peripheral particles in the rigidified support mode of the device, whereby a vacuum source may be connected to the evacuation conduit for withdrawing air from inside the envelope to permit atmospheric pressure to deform the compressible particles by collapsing and stretching the flexible envelope, thus clamping the device in its rigidified support mode, and whereby atmospheric air may be readmitted to the interior of the envelope through the evacuation conduit and the porous distributor unit to convert the device from its rigidified support mode to its collapsed mode.