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US 4,674,911 AGranted
Energy absorbing pneumatic crash cushion
AssigneeEnergy Absorption Systems, Inc.
InventorDavid C. Gertz
Life of this patent
Estimating the term…
Abstract
A reusable energy absorbing apparatus comprising a plurality of air chambers and valve members. The air chambers and valves are constructed so that the valve members close upon the application of an axial force, thereby sealing air within the air chambers. After the energy absorbing apparatus has reached the end of its compressive stroke, the valve members release sequentially, thereby venting the pressurized air in the air chambers to minimize rebound.
Claims33
An energy absorbing apparatus comprising:
- at least one air chamber for partially compressing upon the application of an axial impact force, the air chamber comprising valve means for substantially sealing the air chamber upon the application of the axial force to trap air within the air chamber throughout the compressive stroke of the air chamber, and for automatically releasing a portion of the air within the air chamber after the air chamber has reached the end of its compressive stroke to reduce rebound.
A reusable energy absorbing apparatus comprising:
- a plurality of air chambers for partially compressing upon the application of an axial impact force;
- each of the air chambers comprising valve means for substantially sealing the air chamber throughout the compressive stroke of the air chamber upon the application of the axial impact force to trap air within the air chamber, and for then automatically releasing a portion of the air within the air chamber after the air chamber has reached the end of its compressive stroke to reduce rebound.
An energy absorbing apparatus for preventing a vehicle from impacting a stationary object comprising:
- a first air chamber, a second air chamber and at least one additional air chamber, each constructed to compress at least partially upon the application of an axial impact force;
- the first air chamber being located farthest from the stationary object and including means for sealing air within the first air chamber upon the application of the axial impact force and for venting a portion of the air from the first air chamber after the energy absorbing apparatus has reached the end of its compressive stroke;
- the second air chamber including means for sealing air within the second air chamber after the first chamber has been sealed and for venting a portion of the air from the second air chamber after the first air chamber has begun to vent air;
- and
- each of the additional air chambers including means for sealing air within the respective air chamber after the first and second air chambers have been sealed and for venting air from the respective additional air chambers after the first air chamber has begun to vent air.
2 more elements
An energy absorbing apparatus comprising:
- first and second air chamber walls adapted to compress axially in response to an axial impact force, each comprising a respective valve seat extending around at least a portion of a perimeter of the respective chamber;
- first and second valve plates;
- first and second means for mounting the first and second valve plates for limited axial motion adjacent to the respective valve seat such that each of the valve plates is movable between a sealed position, in which the respective air chamber is substantially sealed, and a vent position, in which the respective air chamber is vented;
- said first valve plate exposed to ambient air pressure on one side and to the pressure of the first air chamber on the other side;
- said second valve plate exposed to the pressure of the first air chamber on one side and to the pressure of the second air chamber on the other side;
- said valve plates, valve seats and first and second means cooperating upon the application of the impact force to the first valve plate to automatically move the valve plates to the sealed positions to trap and compress air within the air chambers, and automatically to move the valve plates to the vent position after the air chambers have reached the end of their compressive stroke to reduce rebound.
3 more elements
An energy absorbing apparatus for dissipating kinetic energy of an axial impact, said apparatus comprising:
- a plurality of air chambers successively arranged along an axis, said plurality of air chambers comprising first and second adjacent air chambers, wherein the first air chamber is positioned forwardly of the second air chamber with respect to the axial impact, and said air chambers are configured to compress axially in response to the axial impact;
- valve means included in the second air chamber and positioned between the first and second air chambers for sealing the second air chamber as the air chambers compress in response to the axial impact and for venting the second air chamber after the energy absorbing apparatus has reached the end of its compressive stroke to reduce rebound, said valve means responsive to a net axial force which varies as a function of the air pressure of the first and second air chambers such that the valve means is biased to a sealing position when the net force is oriented in the direction of the axial impact and the valve means is biased to a venting position when the net force is oriented opposite to the direction of the axial impact.
An energy absorbing apparatus for dissipating kinetic energy of an axial impact, said apparatus comprising:
- an air chamber configured to compress axially in response to the axial impact;
- valve means included in the air chamber for sealing the air chamber as the air chamber compresses in response to the axial impact and for venting the air chamber after the energy absorbing apparatus has reached the end of its compressive stroke to reduce rebound, said valve means responsive to a net axial force which varies as a function of the air pressure of the air chamber and forces applied to the valve means by the axial impact such that the valve means is biased to a sealing position when the net force is oriented in the direction of the axial impact and the valve means is biased to a venting position when the net force is oriented in a direction opposite the axial impact.
Dependencies are inferred from the claim text.