US Patent 7284554 Continuous positive airway pressure device

A continuous positive pressure device which includes an air reservoir connected to a delivery device (e.g. mask or mouthpiece) by an air supply hose; the reservoir includes a rigid protective housing and a plate which applies uniform pressure on the reservoir irrespective of its degree of inflation; the plate is connected to the housing by a non distorting and expandable frame which can expand or contract to permit movement of the plate only in a single plane, as the reservoir inflates or deflates.