Abstract: A continuous positive airway pressure (CPAP) system provides positive airway pressure therapy. It has been recognized that users generally prefer to breathe freely rather than to fight the pressurized air when possible. A continuous positive airway pressure (CPAP) system provides positive airway pressure therapy when required, but allows the user to breathe freely with the mask on when positive airway pressure is not required. The system has a valve that moves between two positions to open and close the unassisted breathing vent and the outlet from the flow generator.

Abstract: A knee brace includes a thigh cuff having inner and outer spaced brace arms adapted to extend along the user's thigh toward the knee, a calf cuff including inner and outer spaced brace arms adapted to extend along the user's calf toward the knee, and floating pivot axis hinges rotatably connecting the inner and outer brace arms of each pair. The hinge is formed by a pair of juxtaposed hinge plates, each having a pivot face in opposition to a pivot face on the juxtaposed plate, with a concave groove in each of the face. A pivot bearing ball is confined between the opposed faces and retained in the concave grooves. A spring, bellville spring, or disk spring biases the hinge plates together when the pivot bearing ball is positioned in the opposed grooves between.