Abstract:
A deployable cushion mechanism for a vehicle that provides a cushion deployed in case of vehicle tipping. The cushion is inflated from a folded condition through rapid release of stored energy. Air is allowed to enter the cushion by way of valves or other orifices. Ground contact of the tipped vehicle occurs with the inflated cushion so as to prevent injury to the passenger.

Description:
The present application claims priority from U.S. provisional application number 60/064,175, filed Nov. 4, 1997, now abandoned which is herein incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present invention pertains to a deployable cushion, and, in particular, to a deployable cushion for preventing injury to the passenger of a personal vehicle. 
     BACKGROUND OF THE INVENTION 
     In the design of vehicles, stability may be traded for maneuverability and certain vehicles may, by design, lack a certain degree of stability. Vehicles of such design are susceptible to tipping, whether due to collision, mechanical failure, sudden turns on inclines, operator error, or an encounter with a surface irregularity which a stabilization mechanism is incapable of overcoming. Under these circumstances, the occupant or contents of the vehicle must be protected so that injury or damage does not result from propulsion of the occupant or contents toward the ground. 
     Methods are known for absorbing or diverting kinetic energy inherent in the motion of a vehicle to insure that it is not converted to propulsion of the occupant of the vehicle into a solid body such as the ground. Common examples are bumpers on cars, which absorb kinetic energy in crumpling metal, and airbags, which couple the mechanical energy of car passengers into the compression and redistribution of gas in a bag before enough time has elapsed for the bodies of the passengers to hit the steering wheel or windshield of the car with resulting serious injury. 
     In automobiles, pyrochemical means are used to inflate the airbag. Pyrochemical means are able to inflate the airbag extremely rapidly, but are relatively expensive and frequently use toxic chemicals. Other drawbacks include the requirement of special training and tools for service and replacement, and the danger of deployment with excessive and injury-producing force. In an unenclosed vehicle such as a wheelchair, the forcible inflation of an airbag by pyrochemical means is impractical, unsafe, and unnecessary. Other means are known to employ the kinetic energy present in a subcomponent of the vehicle, to inflate a bellows or other cushion to protect the vehicle occupants in the case of a head-on collision. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the invention, in one of its embodiments, there is provided a deployable cushion mechanism for protecting the passenger of a personal vehicle. The cushion mechanism has a cushion for absorbing energy that has an interior surface and is coupled to the vehicle in such a manner as to permit inflation of the cushion outward from the vehicle. The cushion mechanism also has an actuator which releases the stored energy in such a manner as to introduce air from outside the cushion to within the interior surface of the cushion. In other embodiments of the invention, the cushion also has an energy reservoir for storing energy for inflation of the cushion, and at least one orifice for enabling air flow from outside the cushion to within the interior surface of the cushion. The valve for restricting airflow such that air may flow only in the direction from outside the cushion to within the interior surface of the cushion. 
     In an alternate embodiment of the invention, the energy reservoir may include a spring for storing mechanical energy, and the spring may be a compressible member. In further alternate embodiments, the deployable cushion may be coupled to the vehicle to permit inflation of the cushion backward, forward, or sideward of the vehicle. In yet further alternate embodiments, the cushion includes a valve for enabling air flow from outside the cushion to within the interior surface of the cushion, a plurality of bladders for constraining lateral motion of the passenger, an air-forcing device for propelling air from outside the cushion to within the interior surface of the cushion, and an aspirator adapted for increasing the volume of gas from outside the cushion introduced to within the interior surface of the cushion. The cushion may also have a latching mechanism which may be released upon pressurization of the cushion. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more readily understood by reference to the following description, taken with the accompanying drawings, in which: 
     FIG. 1 is a side view of a wheelchair-type vehicle employing an embodiment of the invention wherein a deployable cushion is shown in a stowed position. 
     FIG. 2 is a side view of the wheelchair-type vehicle of FIG. 1, wherein the deployable cushion is shown in a partially deployed rear-facing position. 
     FIG. 3 is a side view of the wheelchair-type vehicle of FIG. 1, wherein the deployable cushion is shown in a deployed rear-facing position. 
     FIG. 4 is a side view of the wheelchair-type vehicle of FIG. 1, wherein the deployable cushion is shown prior to contact with the ground. 
     FIG. 5 is a side view of the wheelchair-type vehicle of FIG. 1, wherein the deployable cushion is shown in contact with the ground. 
     FIG. 6 is a perspective view of the deployable cushion shown in a stowed position. 
     FIG. 7 is a perspective view of the deployable cushion shown in a deployed position. 
     FIG. 8 is an exploded front view of an another embodiment of the invention shown in a deployed position. 
     FIG. 9 is a side view of an alternative embodiment of the invention, showing a back bumper in a partially deployed position. 
     FIG. 10A is a front view of the wheelchair type vehicle of FIG.  1 . 
     FIG. 10B is a front view of the wheelchair-type vehicle of FIG. 1 employing an embodiment of the invention, wherein a deployable cushion is shown in a partially-deployed side-facing position. 
     FIG. 10C is a front view of the wheelchair-type vehicle of FIG. 1 employing an embodiment of the invention, wherein a deployable cushion is shown in a fully-deployed side-facing position. 
     FIG. 10D is a front view of the wheelchair-type vehicle of FIG. 1 employing an embodiment of the invention, wherein a deployable cushion is shown in contact with the ground. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to FIGS. 1 through 5, wherein like elements are designated by identical numerals, a side-view is shown of a wheelchair-type vehicle, designated generally by numeral  10 , in progressive stages of a backward-tipping motion. While the invention is applicable to many types of vehicles, the personal wheelchair-type vehicle is used, solely as an example, in the present description. One particular example of such a vehicle is described in U.S. Pat. No. 5,701,965, issued Dec. 30, 1997, which is hereby incorporated by reference. Referring, particularly, to FIG. 1, vehicle  10  is shown supported on a pair of laterally disposed wheels  12  which provide ground contact for vehicle  10 . The deployable cushion mechanism which is the subject of the present invention is designated by numeral  14  and is shown in FIG. 1 in a stowed position, attached at hinge  16  to seat assembly  18 . In case vehicle  10  undergoes rapid acceleration, with respect to the wheels, in rearward direction  20 , it becomes necessary to protect passenger  22  from injury due to backward tipping of the vehicle. Similarly, it may be necessary to protect passenger  22  from injury due to collision or tipping in either a forward or sideward direction. In a preferred embodiment, one or more deployable cushion mechanisms  14  are attached to vehicle  10 . 
     In FIG. 1, structural members  24  and  26  of deployable cushion mechanism  14  are shown in a retracted position, adjacent to one another. Structural members  24  and  26  are made of a stiff material such as metal, and, according to an embodiment of the invention, are held together, during routine operation of vehicle  10 , against a spring force tending to separate them about hinge  16 . The spring force may be provided, for example, by a coiled strip of spring metal contained within hinge  16 , or otherwise as known in the mechanical arts. The potential energy of the compressed spring is but one example of a reservoir of energy used for deployment of the cushion mechanism. In another preferred embodiment of the invention, a supply of compressed gas, such as air, is provided as a reservoir both of energy and gas for the inflation of the deployable cushion mechanism. 
     The initial stage of a backward tip, caused by an accelerating force along direction  20 , is shown and now described with reference to FIG.  2 . When a tilt or tilt rate is sensed, either by the controller (not shown) which monitors position angles of the wheels  12  and torques on the wheel drive motors (not shown), or else by a one of many tilt sensors known in the art, deployment of cushion mechanism  14  is initiated and the spring force is released to separate structural members  24  and  26  about hinge  16 . Other structural members may also be provided. This, in turn, causes cushion  28  to unfold, and to fill with air. Air enters cushion  28  from the ambient atmosphere or from a container of compressed gas via a series of valves  40  (shown in FIG.  8 ). A fan  32  (shown in FIG. 8) may be used to impel air into cushion  28  while acting as a pressure regulator during deflation by helping to keep pressure in cushion  28  but allowing a substantial quantity of air to escape from the cushion, thereby providing displacement that dissipates kinetic energy. Additionally, the pressure in cushion  28  produced by inflation may be used to release a latch  27 , such as a magnetic latch, that holds cushion  28  in a folded configuration. In a preferred embodiment, two flap valves are employed. The energy required to inflate cushion  28  is governed by the flow of air through valves  40 . 
     In an alternate embodiment, cushion  28  is initially held under an internal vacuum. The sensing of a tilt or rate of tilt provides for the release of a latching mechanism, such as latch  27 , which prevents the opening of valves  40  during normal operation of the vehicle. 
     Referring now to FIG. 3, cushion  28  is shown fully inflated, and structural members  24  and  26  are fully separated about hinge  16 . FIG. 4 shows vehicle  10  in a further state of rearward tilt towards the ground, with cushion  28  deployed to absorb the force of impact, and passenger  22  supported by seat assembly  18  and head support  30 . FIG. 5 shows vehicle  10  tipped backward, with cushion  28  in contact with the ground, having absorbed the energy of impact by compressing and redistributing the air contained within cushion  28 . Escape of air from the interior of cushion  28  is regulated through complete or partial closure of valves  40  (shown in FIG.  8 ). 
     FIG. 6 shows the attachment of deployable cushion mechanism  14  to seat assembly  18  at hinge  16 . Deployable cushion mechanism  14  is shown here in its stowed position. An electric fan  32 , provided in one embodiment, forces air into cushion  28  when a specified tilt or tilt rate is sensed and inflation of cushion  28  is initiated, in order to allow more rapid inflation than is provided through valves  40  (shown in FIG.  8 ). Deployable cushion mechanism  14  is shown in its deployed condition in FIG.  7 . 
     Referring now to FIG. 8, deployable cushion mechanism  14  is shown in its deployed condition, showing the position of flap valves  40  and fan  32 . 
     FIG. 9 shows an alternative embodiment of the invention, in which a back bumper  42  is shown attached to seat assembly  18 . Back bumper  42  is a deployable mechanism, operating in the same manner as described above with respect to deployable cushion mechanism  14 . Back bumper  42  contains one or more spring devices (not shown) which expand a bellows when an impending tip is sensed, to provide additional absorption of energy and protection for passenger  22 , either instead of, or in addition to, the absorption of energy provided by deployable cushion mechanism  14 . In the embodiment depicted in FIG. 9, deployable cushion mechanism  14  is shown attached to seat assembly  18  at hinge  16 . 
     Referring now to FIGS. 10A-10D, in which front views are shown of wheelchair-type vehicle  10 , shown, again, by way of example, although other vehicles are within the scope of the appended claims. With more particular reference to FIG. 10A, passenger  22  is shown seated in vehicle  10  during normal operation of the vehicle. The initial stage of a sideward tip, such as might be caused by a surface irregularity, is shown and now described with reference to FIG.  10 B. When a tilt or tilt rate is sensed in one of the ways described above with reference to a backward tilt, deployment of cushion mechanism is initiated, and the reservoir of energy is actuated to cause cushion  28  to unfold about axis  16 . Air, or another gas, is either drawn or forced into the volume within the interior surface of cushion  28 . In one embodiment of the invention, an aspirator (not shown) is used to entrain an additional volume of gas, such as ambient air, in order to more rapidly fill the expanding cushion  28 . FIG. 10C shows cushion mechanism  14  fully inflated. FIG. 10D shows vehicle  10  tipped fully sideward, with cushion  28  in contact with the ground, having absorbed the energy of impact by compressing and redistributing the air, or other gas, contained within cushion  28 . 
     The described embodiments of the invention are intended to be merely exemplary and numerous variations and modifications will be apparent to those skilled in the art. All such variations and modifications are intended to be within the scope of the present invention as defined in the appended claims.