Abstract: The mattress is mounted on a rectangular frame and underlying the rectangular frame, at the front and rear ends thereof, are vertical adjusting systems. Each vertical adjusting system includes an expandable air cushion, which is expandable and contractable in the vertical direction, and intersecting link arrangements at the front and rear of each expandable cushion. Each expandable cushion is separately connected to a source of air under pressure which may be either the air compression system of the vehicle in which the system is mounted or a separate air compression system. With the arrangement, the mattress can either be raised or lowered vertically, or it can be tilted.