Mattress with capacitive immersion control

Abstract

A mattress and a capacitive immersion system for adjusting the support that the mattress provides to a user are disclosed. In one embodiment, a mattress includes one or more air cells and a capacitive immersion system. The system relates generated capacitance between conductors mounted to an air cell to a pressure inside the air cells on which the conductors are mounted. More specifically, the measured capacitance may be related to a distance between the conductors. This distance may then be related to pressure with the air cells. The air cell may be inflated or deflated as required or desired to maintain a suitable minimum distance or distance that a user finds to be subjectively comfortable.

What is claimed is: 
     
         1 . An adjustable mattress for supporting a user thereon, comprising:
 at least one adjustable fluid chamber, said fluid chamber having respective top and bottom sides thereof;   a control system associated with said fluid chamber for controlling the degree of inflation of said fluid chamber, for thereby controlling the distance between the respective top and bottom sides thereof;   a pair of conductor elements respectively associated with said top and bottom fluid chamber sides, for comprising a capacitive component for generating capacitance between said conductor elements based at least in part on the distance between such conductor elements; and   a feedback loop interconnecting said capacitance with said control system, with said control system configured to control the inflation of said fluid chamber so as to maintain at least a predetermined distance between said fluid chamber respective top and bottom sides, so that a user received on said mattress is prevented from bottoming out against the fluid chamber bottom side.   
     
     
         2 . An adjustable mattress as in  claim 1 , wherein:
 said at least one adjustable fluid chamber comprises a plurality of air cells; and   at least one of said pair of conductor elements comprises a wire conductor.   
     
     
         3 . An adjustable mattress as in  claim 1 , wherein:
 said at least one adjustable fluid chamber comprises a plurality of air cells; and   said control system is configured to control inflating and deflating of said air cells.   
     
     
         4 . An adjustable mattress as in  claim 3 , further including:
 a frame formed of respective foam elements, and having a central cavity formed by said foam elements, and receiving said plurality of air cells; and   a shield within said frame and situated between said air cell upper sides and a user received on said mattress for reducing interference with capacitance generated between said conductor elements.   
     
     
         5 . An adjustable mattress as in  claim 4 , wherein:
 said shield comprises one of metal strips and metal plate construction; and   said metal comprises at least one of aluminum, copper, nickel, and iron.   
     
     
         6 . An adjustable mattress as in  claim 3 , further including:
 a plurality of said pairs of conductor elements, with at least one top conductor and at least one associated bottom conductor mounted to each of said respective plurality of air cells, and with each top conductor and associated bottom conductor defining a capacitance therebetween; and   wherein said conductor elements comprise one of wire, strip, and plate metal sensors.   
     
     
         7 . An adjustable mattress as in  claim 3 , wherein:
 said control system further includes a controllable pump and associated air hoses interconnected with said air cells for controllably inflating and deflating said air cells; and   said plurality of air cells are respectively aligned with respective portions of a user's body supported thereon.   
     
     
         8 . A patient support mattress with capacitive immersion control for adjusting the support that the mattress provides to the patient, comprising:
 a frame formed of respective foam elements, and having a generally central cavity formed by said foam elements;   a plurality of air cells received in said cavity, and adapted to be controllably inflated;   an inflation pump system associated with said air cells and configured for being activated for controlling the degree of inflation of said air cells;   at least one pair of conductors, associated with respective upper and lower surfaces of said air cells and configured for generating capacitance based on the distance between such upper and lower surfaces; and   a controller for receiving an input based on such generated capacitance, and configured for activating said inflation pump system so as to maintain a predetermined distance between said upper and lower surfaces, so as to immerse a patient in said mattress while preventing bottoming out of such patient against said air cell lower surfaces.   
     
     
         9 . A patient support mattress as in  claim 8 , wherein:
 said frame comprises a casing;   said foam elements comprise foam bolsters and foam sides running the length of said mattress and on either side thereof, and a foam header and foam footer at the respective ends of said mattress and capping the foam bolsters and sides;   said mattress further includes a topper in said casing and defining a support surface for a patient received on said mattress.   
     
     
         10 . A patient support mattress as in  claim 8 , wherein said controller is calibrated based on measured capacitances with and without a patient received on said mattress to establish what is a minimum distance greater than a bottoming out distance, and is configured to inflate and deflate said air cells so as to keep said mattress from bottoming out. 
     
     
         11 . A patient support mattress as in  claim 8 , wherein said inflation pump system includes an air pump and air hoses interconnecting said air pump to said air cells, so that said controller can inflate or deflate said air cells through activation of said air pump as needed for preventing a patient from bottoming out. 
     
     
         12 . A patient support mattress as in  claim 8 , further including:
 a plurality of said pairs of conductor elements, with at least one top conductor and at least one associated bottom conductor mounted to each of said respective plurality of air cells, with each top conductor and associated bottom conductor defining a capacitance therebetween;   a shield within said frame and situated between said air cell upper surfaces and a patient received on said mattress for reducing interference with capacitance generated between said conductors; and   wherein said conductor elements comprise one of wire, strip, and plate metal sensors.   
     
     
         13 . A method for controlling an adjustable support to prevent bottoming out of a patient received thereon, comprising:
 providing an adjustable support having at least one air cell supporting a patient and adapted to be controllably inflated and deflated;   providing at least one pair of conductors, associated with respective upper and lower surfaces of the air cell and configured for generating capacitance based on the distance between such upper and lower surfaces; and   controlling the degree of inflation of the air cell based on the generated capacitance to maintain a predetermined distance between the upper and lower surfaces, so as to immerse a patient in such support while preventing bottoming out of such patient against the air cell lower surface.   
     
     
         14 . A method as in  claim 13 , wherein the adjustable support comprises one of a bed, wheelchair, and specialized transport. 
     
     
         15 . A method as in  claim 13 , wherein the adjustable support comprises a patient support mattress having a plurality of air cells interconnected with a controllable air pump and corresponding plurality of air hoses, for controlled inflating and deflating of such air cells. 
     
     
         16 . A method as in  claim 15 , wherein the air cells are grouped into respective patient support regions and respectively controlled. 
     
     
         17 . A method as in  claim 16 , wherein the grouped air cells are respectively controlled through alternate inflation and deflation to assist turning a patient supported on the mattress, while using the generated capacitance to controllably inflate the air cells at at least minimum levels to prevent patient bottoming out. 
     
     
         18 . A method as in  claim 15 , further including:
 a frame formed of respective foam elements, and having a central cavity formed by such foam elements, and receiving the plurality of air cells; and   a plurality of pairs of conductors, with at least one top conductor and at least one associated bottom conductor mounted to each of the respective plurality of air cells, with each top conductor and associated bottom conductor defining a capacitance therebetween; and   wherein such conductors comprise one of wire, strip, and plate metal sensors.   
     
     
         19 . A method as in  claim 18 , further including a shield within such frame and situated between the air cell upper surfaces and a patient received on such mattress for reducing interference with capacitance generated between such conductors. 
     
     
         20 . A method as in  claim 18 , wherein:
 such controller is calibrated based on measured capacitances with and without a patient received on the mattress;   such controller is configured for being calibrated to know what is a minimum distance greater than a bottoming out distance, and to inflate and deflate such air cells so as to keep the mattress from bottoming out; and   such controller input comprises one of a constant feedback loop and a signal received at determined intervals.