referring now to the drawings wherein the showings are for purposes of illustrating preferred embodiments of the present invention only and not for purposes of limiting the same , fig1 perspectively illustrates a wheelchair 10 constructed in accordance with a first embodiment of the present invention . wheelchair 10 generally comprises a frame portion 12 having a vertical cushion 14 and a horizontal cushion 16 connected thereto . disposed within or positioned upon horizontal cushion 16 are plural weight sensors preferably implemented as four pressure sensitive switches 18 which are arranged in a generally square configuration . referring now to fig3 pressure sensitive switches 18 are electrically interconnected to each other and to a valve mechanism 20 in a manner whereby switches 18 are operable to generate a signal to valve mechanism 20 when pressure , i . e . weight , is removed from each of the switches 18 . fluidly connected to valve mechanism 20 is a replaceable canister 22 containing a supply of compressed gas therein . valve mechanism 20 is also fluidly connected to an inflatable air cushion 24 ( shown in phantom in fig1 and 3 ) by a connection line 26 . the valve mechanism 20 is normally closed whereby the compressed gas is retained within canister 22 and operable to an open position whereby the compressed gas is free to flow from canister 22 into air cushion 24 by way of valve mechanism 20 and connection line 26 . in this regard , the signal generated from pressure sensitive switches 18 is operable to actuate valve mechanism 20 from its closed position to an open position . as seen in fig2 when wheelchair 10 hits an obstruction 28 which causes the wheelchair occupant 30 to move forward , the removal of the occupant 30 from horizontal cushion 16 will cause the downward pressure formerly exerted by the occupant 30 onto pressure sensitive switches 18 to be removed . as previously specified , the removal of pressure from pressure sensitive switches 18 causes a signal to be generated which , due to the electrical interconnection of switches 18 to valve mechanism 20 , will cause valve mechanism 20 to actuate to an open position . when valve mechanism 20 actuates to an open position , compressed gas is released from container 22 and into air cushion 24 through connection line 26 thereby facilitating the inflation of air cushion 24 . as shown in fig1 - 3 , air cushion 24 is contained within a foot pedal 32 of frame portion 12 , though it will be appreciated that air cushion 24 may be attached to other areas of frame portion 12 of wheelchair 10 . in this respect , air cushion 24 need only be attached to wheelchair 10 in a manner wherein air cushion 24 will inflate outwardly from wheelchair 10 so as to create a barrier between wheelchair occupant 30 and the floor 34 in the manner shown in fig2 . though not shown , wheelchair 10 further includes an on / off switch which is movable between an on position and an off position for selectively activating and deactivating pressure sensitive switches 18 . in this respect , the on / off switch is operable to block the signal from pressure sensitive switches 18 to valve mechanism 20 when the switch is in the off position . as can be appreciated , this particular feature is necessary so that when removing wheelchair occupant 30 from wheelchair 10 , air cushion 24 is not unnecessarily inflated . though also not shown , it is further contemplated that valve mechanism 20 will include an audible or visual alarm electrically connected thereto . in this regard , the alarm is activated when valve mechanism 20 actuates to an open position , thereby informing hospital personnel that the occupant 30 has fallen from the wheelchair 10 . referring now to fig4 and 5 , illustrated is a second embodiment of the present invention , wherein a hospital bed 36 is constructed to include an impact cushioning device . hospital bed 36 generally comprises a frame portion 38 and a mattress portion 40 . disposed within or positioned upon mattress portion 40 are plural weight sensors preferably implemented as six pressure sensitive switches 42 which are arranged in a generally rectangular configuration as shown in fig4 . as seen in fig5 pressure sensitive switches 42 are electrically connected to each other and to a first valve mechanism 44 and a second valve mechanism 46 in a manner whereby switches 42 are operable to generate a signal to first valve mechanism 44 and second valve mechanism 46 when pressure , i . e . weight , is removed from each of switches 42 . fluidly connected to first valve mechanism 44 is a replaceable first canister 48 containing a supply of compressed gas therein , while fluidly connected to second valve mechanism 46 is a replaceable second canister 50 containing a supply of compressed gas therein . first valve mechanism 44 is also fluidly connected to a first air cushion 52 stored within a first release unit 54 , by a first connection line 56 . similarly , second valve mechanism 46 is fluidly connected to a second air cushion 58 stored within second release unit 60 , by a second connection line 62 . in the second embodiment , first valve mechanism 44 and second valve mechanism 46 are each normally closed whereby the compressed gas is retained within the respective canister and operable to an open position whereby the compressed gas is free to flow from the respective canister into the respective air cushion . in this regard , the signal generated from switches 42 is operable to actuate both first valve mechanism 44 and second valve mechanism 46 from their closed positions to open positions . as shown in fig4 and 5 , first release unit 54 and second release unit 60 are attached to frame portion 38 in a manner wherein air cushions 52 , 58 will extend outwardly from the opposed longitudinal edges of bed 36 when inflated . thus , air cushions 52 , 58 serve to form barriers between the bed occupant ( not shown ) and the floor 64 , thereby preventing injury to the bed occupant if the occupant falls off either edge of the hospital bed 36 . it will be appreciated that either first air cushion 52 or second air cushion 58 may be constructed to have a generally l - shaped configuration so as to be operable to form a barrier between the bottom of hospital bed 36 and the floor 64 . in this respect , either first release unit 54 or second release unit 60 would be adapted to store a cushion having such a configuration . as with the first embodiment , the hospital bed 36 further includes an on / off switch ( not shown ) which operates in the same manner as described with respect to the first embodiment . in this regard , the on / off switch is operable to block the signal generated from pressure sensitive switches 42 to valve mechanisms 44 , 46 . additionally , the valve mechanisms 42 , 44 of the second embodiment also include an audible or visual alarm electrically connected thereto which is activated when the valve mechanisms 44 , 46 actuate to the open position , thereby informing medical personnel that the bed occupant has fallen . it will be appreciated that the second embodiment of the present invention may be constructed so as to have only one air cushion which extends outwardly from only one of the longitudinally extending edges of bed 36 . though the present invention has been described as being utilized in conjunction with a wheelchair and a hospital bed , it will be appreciated that the present invention is equally usable in relation to toilets as well as ambulation therapy applications . additionally , either embodiment of the present invention may incorporate a conventional inflation device as currently known and utilized with respect to automobiles . additional modifications and improvements of the present invention may also be apparent to those skilled in the art . thus , the particular combination of parts described and illustrated herein is intended to represent only one embodiment of the invention and it is not intended to serve as limitations of alternative devices within the spirit and scope of the invention .
this invention relates to an impact cushioning device for protecting wheelchair or hospital bed occupants from fall - related injuries . the cushioning device generally comprises an inflatable air cushion which is supported by the wheelchair or hospital bed and adapted to inflate when the occupant is removed from the wheelchair or bed . the air cushion is oriented on the wheelchair or bed in a manner wherein the cushion creates a barrier between the wheelchair or bed occupant and the floor when inflated .