air cushion

(redirected from air cushions)
Also found in: Dictionary, Thesaurus.

air cushion

1. the pocket of air that supports a hovercraft
2. a form of pneumatic suspension consisting of a constricted volume of air

Air Cushion


a region of increased air pressure between the base of a machine and a supporting surface or between the movable and fixed elements of mechanisms in instruments and machine tools. It is used in transportation equipment (hovercraft, ram-wing craft, and other flying vehicles), various instruments (gyroscopes), and mechanisms as an”air bearing” to reduce the friction between contiguous surfaces .

Static and dynamic methods of forming an air cushion exist. In the static method, pressure is created in the air cushion by a fan or compressor, and in the dynamic method it is developed by the relative velocity of an airflow. Of the many known methods for producing an air cushion, the principal ones are the chamber, nozzle, slot, and wing types.

In the chamber method, the lifting force is produced by the static air pressure forced under the base of the chamber by a fan. Owing to the lifting force, the chamber is raised, and the air then escapes through the gap formed between the chamber rim and the supporting surface. Since the leakage area is fairly large, a substantial air flow rate is needed even with relatively small gaps. In the nozzle method, the air cushion is created by an airflow from an orifice located around the perimeter of the nozzle assembly. The lifting force is made up of the static pressure force on the base of the nozzle assembly and the reaction forces from the outflow of air through the nozzle. This method permits larger gaps between the base of the nozzle assembly and the supporting surface with lower airflow rates. In the slot method, the air cushion is created in a thin, slotlike cavity from which the air flows out in all directions. This cavity is located between specially shaped carrying and supporting surfaces in the case of transportation equipment and between the movable and fixed elements of mechanisms in machine tools. The increased pressure of the air cushion is maintained as a result of relative motion between the surfaces and because of the viscosity of the air passing through the slot. In the wing method an air cushion is formed by the increased air pressure under the wing of a flying vehicle (such as a ram-wing craft) as it moves with a certain angle of attack close to a supporting surface.


Stepanov, G. lu. Gidrodinamicheskaia teoriia apparatov na vozdushnoi podushke. Moscow, 1963.


air cushion

[′er ‚ku̇sh·ən]
(mechanical engineering)
A mechanical device using trapped air to arrest motion without shock.
References in periodicals archive ?
These patents of FP International relate to materials, methods and machines for making and conveying air cushion packaging.
District Court for the Eastern District of Virginia, allege that Pactiv and Storopack's air cushion product lines infringe FP International's patents.
The patented NOVUS air cushions made by the MINI PAK'R offer more protection than other products because air moves between channels instead of popping the cushion like standard bubble wrapping products.
The MINI PAK'R air cushion machine can be purchased at http://www.
It uses air cushions above and below the foot to apply firm pressure to each toe, while ankle air cushions work hard to massage the difficult heel area, resulting in a deeply effective massage.
The Whole Foot Shiatsu feature uses air cushions above and below the foot to apply firm pressure to each toe, while ankle air cushions work hard to massage the difficult heal area, resulting in a pleasant, relaxing sensation and a deeply effective massage.
The SLIPA airway represents the first cuffless supralaryngeal airway that is superior to other equivalent airways because it maximizes on the space available for trapping and storing liquids that could be aspirated if regurgitation occurs during anaesthesia or resuscitation Air cushions limit that possibility Being preshaped, selection of the best site for sealing is achieved with resultant good quality seal pressures and the relief of pressure is achieved at selected sites where injury to vulnerable nerves may occur.