Air cushion apparatus

TLDR: In this paper, a flexible walled chamber is used under a rigid pallet for transporting a load over irregular surfaces, where flapper valves are constructed and arranged to rapidly respond to the pressure differential across the holes.

Abstract: Air pressure is conserved in an air cushion load conveying apparatus by valve elements disposed within the air pressure chamber in operative association with an array of relatively small holes which provide the pressurized air cushion between the wall of the chamber and an adjacent surface. The valve elements are constructed and arranged to rapidly respond to the pressure differential across the holes. They quickly open and transmit chamber pressure to the pressurized air cushion when an object is disposed close to the hole and rapidly close and preserve pressure when there is no object and concomitant air cushion disposed adjacent the hole. The valve elements are flapper valves made of a single large perforated flexible sheet or a number of smaller sheets which substantially obstruct the holes in the presence of a high differential pressure. The flapper valves inherently leak, which makes them sensitively respond to changes in pressure. The leakage is, however, not enough to cause an undue loss of air through closed holes. Bleed holes may be provided, if necessary, to accelerate movement under special conditions. The perforated chamber wall may be rigid for operating against regular smooth surfaces or it may be flexible for operating against irregular or interrupted surfaces. A flexible walled chamber may be used under a rigid pallet for transporting a load over irregular surfaces. The upper surface of the rigid pallet may also be perforated and valved to facilitate sliding loads on and off, and the pressurized air may be alternately supplied to the upper and lower portions to facilitate loading, unloading and transport.