reference will now be made in detail to a presently preferred embodiment of the invention , an example of which is discussed in conjunction with the accompanying drawings . such example is provided by way of an explanation of the invention , not limitation thereof . in fact , it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention , without departing from the spirit and scope thereof . for instance , features illustrated or described as part of one embodiment can be used on or in another embodiment to yield a still further embodiment . still further , variations in selection of materials and / or characteristics may be practiced , to satisfy particular desired user criteria . thus , it is intended that the present invention cover such modifications and variations as come within the scope of the present features and their equivalents . as referenced above , the present invention is particularly concerned with , in exemplary broad terms , an air flotation mattress 100 and mattress coverlet 200 for the prevention and treatment of decubitus ulcers ( pressure sores and bedsores ). the air flotation mattress 100 provides a user selectable flotation or alternating pressure support surface . the mattress coverlet 200 provides a low air loss feature that can be turned on or off as desired by the user ( here , broadly referencing a patient or person resting on such coverlet and / or a caregiver therefore ). as shown in the bottom elevational view of fig1 , the air flotation mattress 100 is formed by a foam shell topper 20 ( best seen in fig2 and 3 ) with foam bolsters 22 and foam sides 24 running the length of the mattress 100 on either side . at the respective ends of the air flotation mattress 100 and capping the foam bolsters and sides 22 and 24 , respectively , are a foam header 26 and foam footer 28 , which along with the bolsters 22 form a cavity in the mattress 100 . this cavity is for positioning of air cells , such as the exemplary grouped ( i . e ., zoned ) air cells 30 , 32 , 34 and 36 . the cavity formed by the foam bolsters 22 , header 26 , and footer 28 , contains the air cells 30 , 32 , 34 and 34 . the air cells 30 , 32 , 34 , and 36 are essentially inflatable air bladders connected directly to an external control system 300 via passageways 76 , 78 , and 80 ( see fig6 and 7 and corresponding discussion ) for their inflation / deflation . such air cells 30 , 32 , 34 , and 36 may be operated to provide the primary support surface for the patient . there are twelve exemplary air cells 30 , 32 , 34 and 36 . other numbers thereof ( or none at all ) may be practiced in various embodiments of the subject invention . such air cells 30 , 32 , 34 , and 36 are divided into four separate zones . the first exemplary zone ( hereinafter the head zone ) comprises three air cells 30 each of which may be maintained in an equal state of inflation / deflation relative to each other . the second exemplary zone ( hereinafter the foot zone ) comprises three air cells 36 each of which may be maintained in an equal state of inflation / deflation relative to each other . exemplary zones three and four together ( all of the remaining cells ) comprise the central or torso zone . each of zones three and four comprise an alternating set of three air cells 32 and 34 , respectively , within the torso zone . the torso zone ( i . e ., all six air cells 32 and 34 ) may be maintained at an equal state of inflation / deflation . as part of the capability of air flotation mattress 100 to provide alternating pressure support , zones three and four can alternate between specific states of inflation / deflation , thus dynamically changing the location of the support for the patient &# 39 ; s torso . as part of the ecs 300 , a firmness control may be provided which allows the user to specify the level of inflation of the air cells 30 , 32 , 34 , and 36 both during the flotation and alternating pressure support treatment cycles . as represented to those of ordinary skill in the art by the cross - sectional view of fig2 , the foam shell topper 20 of such air flotation mattress 100 may have on its upper surface 38 a geo - matt ® surface treatment to aid in redistributing skin pressure . the bottom surface 40 of such foam shell topper 20 may be cut to provide predetermined ridges 42 running side - to - side to act as retainers for such air flotation mattress respective air cells 30 , 32 , 34 and 36 . in order for the mechanical connections between the ecs 300 and both the mattress 100 and mattress coverlet 200 to be made an exemplary foam block 44 with a hole there - through may be located at the end of one foam bolster and side 22 and 24 , respectively . as best seen in the cross - sectional views of fig2 and 3 , the foam shell topper 20 extends across almost the entire width and substantially the entire length of such mattress 100 . the foam shell topper &# 39 ; s 20 width extends from each foam side 24 . similarly , the topper &# 39 ; s 20 length is terminated only by the foam header 26 and the foam footer 28 . the bolsters 22 act as both supports for the connection between the topper 20 and the sides 24 and as retainers for the air cells 30 , 32 , 34 , and 36 . the exemplary mattress coverlet 200 is comprised of three separate layers . as seen in fig4 and 5 , the first layer 46 of such mattress coverlet 200 is a sheet of waterproof , vapor permeable material . it is designed to allow moisture - vapor and heat from the patient &# 39 ; s body or relatively immediately adjacent thereto to pass through to the second ( i . e ., middle ) layer 48 . the second layer 48 of such mattress coverlet 200 is a non - crush three - dimensional fabric that is moisture resistant and vapor and air permeable . it is through this middle layer 48 of the mattress coverlet 200 that the low air loss feature of the present invention forces air , which aids in removing the warm moist air generated by the patient . an exemplary depiction of the direction of airflow through the mattress coverlet 200 is indicated by exemplary airflow 50 . in accordance with the present preferred embodiment , the third layer 52 of the mattress coverlet 200 is a waterproof , vapor impermeable sheet . this final layer 52 acts as a retainer of the warm moist air generated by the patient and transmitted through the first layer 46 to the second layer 48 . it maintains the warm moist air within the second layer 48 so it can be removed by the low air loss airflow ( as indicated in fig5 by exemplary air flow 50 ). similarly , it acts as a boundary to prevent heat transfer from the air within the air flotation mattress &# 39 ; s air cells 30 , 32 , 34 , and 36 , to the patient . such third layer 52 may additionally comprise a zippered coverlet - mattress topper for encasing a mattress . in other embodiments , an exemplary coverlet 200 in accordance with the subject invention may be modularly applied to other supports including mattresses , wheelchair / seating cushions , and / or patient positioners ( whether air powered , pre - existing , disclosed herewith , or later developed ). several exemplary such support surfaces can be found in commonly owned u . s . pat . no . 5 , 568 , 660 to raburn et al . ; u . s . pat . no . 5 , 797 , 155 to maier et al . ; and des . 355 , 488 to hargest et al ., the disclosures of which are full incorporated herein by reference . some former mattress coverlets have suffered from the problem of billowing . as further represented in the top elevational view of present fig4 , in accordance with the present invention the occurrence of billowing may be reduced through the use of spot welds 54 of the first layer 46 to the third layer 52 in locations throughout the surface of the mattress coverlet 200 . in making such spot - welds 54 , small sections of the material of the second layer 48 of the mattress coverlet 200 have been removed to allow for an unimpeded welding of the first and third layers ( 46 and 52 , respectively ). the mattress coverlet 200 is preferably constructed of a first layer 46 comprising a polyurethane coated polyester which is perimeter welded 58 to the third layer 52 . along the head end of the coverlet 200 , where the first and third layer 46 and 52 , respectively , are connected the perimeter weld 58 is intermittent to provide for exhaust air ports 60 . it is through these exhaust air ports 60 that the warm moist air trapped within the second layer 48 is disposed . the third layer 52 of the coverlet 200 preferably comprises a polyurethane coated nylon so as to be moisture and vapor impermeable . the second ( i . e ., middle ) layer 48 is preferably a non - crush three - dimensional fabric . the third layer 52 additionally may have skirt welds 63 along substantially the entire perimeter of the material . as best seen in fig5 , in the presently preferred exemplary embodiment the third layer 52 forms a coverlet - mattress topper , which may encase a mattress . the coverlet - mattress topper comprises an upper ( i . e ., the third layer 52 of the mattress coverlet 200 ) and lower sheet connected to two side panels , a head panel , and a foot panel in a bag - like configuration . around the perimeter of the coverlet - mattress topper , running along the middle of the side , head , and foot panels is a zipper 56 for encasing a mattress within the topper . it is this coverlet - mattress topper that may maintain the mattress coverlet 200 in place despite the movement of the patient while on the support surface . as will be clear to those of ordinary skill in the art from fig6 - 9 and their associated discussion , the air flotation mattress 100 and the mattress coverlet 200 are regulated by the ecs 300 . the exemplary ecs 300 comprises two pumps 62 and 64 , a regulator 66 , a rotary valve 68 , a single quick - disconnect connector 70 for connection of air passageway 72 to the mattress coverlet 200 , and three quick - disconnect connectors 74 for connecting air passageways 76 , 78 , and 80 to the air flotation mattress air cells 30 , 32 , 34 , and 36 . air is provided to the head and foot zones via air passageway 76 and is provided to zones three and four ( i . e ., the central or torso zone ) via air passageways 78 and 80 , respectively . the ecs features are preferably all within a stand - alone housing 82 . the housing 82 is provided with rubber feet 84 for positioning the housing on the floor and with hooks 86 for hanging the ecs 300 from a bedframe . the ecs 300 has two pumps 62 and 64 for separate operation of the air flotation mattress 100 and the mattress coverlet 200 . the first pump 62 operates the air flotation mattress 100 . it is preferably a pump which provides quiet operation and a quick response to an inflation request . the second pump 64 functions to provide air for the low air loss system in the mattress coverlet 200 . the low air loss system pump 64 is preferably a pump which provides a higher air flow rate for the mattress coverlet 200 than would be provided by the air flotation mattress pump 62 . the first pump 62 operates in connection with a regulator 66 and a rotary valve system 68 to provide air for the air flotation mattress 100 . in operation of this exemplary embodiment , the air provided to the head and foot zones ( i . e ., exemplary air cells 30 and 36 , respectively ) is delivered through a first passageway 76 . this first passageway 76 serves to interconnect the head and foot zones to insure consistent inflation / deflation . the air provided to the torso zone , exemplary air cells 32 and 34 , respectively , enters through separate passageways 78 and 80 , respectively . with each of the passageways 78 and 80 associated with the torso zone are control valves 88 to either allow inflation / deflation or to maintain the current state of inflation / deflation of the air cells 32 and / or 34 . such valves 88 are separately operable which allows for the provision of an alternating pressure support surface within the air flotation mattress 100 . when the control valves 88 within passageways 78 and 80 are set to mimic the inflation / deflation of the head and foot zones , the air flotation mattress 100 is able to provide a static support surface . the construction of such valves 88 and pumps 62 and 64 are well known to those of ordinary skill in the art , and details thereof form no particular part of the subject invention . the second pump 64 may be operated in accordance with the subject invention to provide a continuous flow of air to the low air loss mattress coverlet 200 . as shown in fig4 , the first layer 46 of the mattress coverlet 200 contains air exhaust ports 60 for the expulsion of the low air loss air flow through the mattress coverlet 200 . an air input port ( not shown ) is preferably generally located at the foot end of the mattress coverlet 200 and the air exhaust ports 60 are preferably located at the opposite end of the mattress coverlet 200 . however , one of ordinary skill in the art will recognize that alternative configurations of such features fall within the scope and spirit of the present invention . in operation , the ecs 300 functions to provide the user the widest variety of treatment options . the user can select from either a static pressure support surface , in which the air flotation mattress 100 maintains a consistent inflated state across all zones , or an alternating pressure support surface , in which the head and foot zones maintain a consistent inflation state and zones three and four within the torso zone dynamically fluctuate between opposed states of inflation / deflation , respectively . in addition to the choice of support surface function to be provided by the air flotation mattress 100 , the ecs 300 allows the user to choose whether or not to allow the operation of the low air loss mattress coverlet 200 to aid in removing warm moist air away from the patient &# 39 ; s skin . it is this wide range of user ( and / or caregiver ) choice in treatment methods and its modularity that allows the system , the air flotation mattress 100 , the low air loss mattress coverlet 200 and the ecs 300 , to be so flexible . additionally , in emergency operations , the system is designed to be as flexible as possible in order to aid in the treatment of the patient . should the need arise to quickly provide a more sturdy surface for the patient , such as in the case where a patient suffers a heart attack and requires chest compression , the present invention provides the user three options : inflate the air flotation mattress 100 fully by utilizing the static support surface feature , terminate the operation of the pumps and allow the air flotation mattress to deflate , or to utilize the quick - disconnect connectors 74 between the ecs 300 and the air passageways 76 , 78 , and 80 to allow for complete deflation of the air flotation mattress 100 . similarly , when there is a loss of power to the ecs 300 , the system is designed to retain its functionality to aid in the treatment of the patient . the air flotation mattress is designed to maintain the inflation pressure within the air cells 30 , 32 , 34 , and 36 . it performs such function by allowing the pressure across all the cells 30 , 32 , 34 , and 36 to even out and become consistent ( as when utilizing the static pressure support surface feature ). the system is able to maintain the air within the cells through the use of several three - way control valves 88 which open to allow communication between the air cells 30 , 32 , 34 , and 36 and through the use of a two - way control valve 90 which closes to deny an exit path for the air already in the system . an alternative presently preferred embodiment may comprise an air flotation mattress 100 with a multi - layer mattress topper 400 and / or mattress coverlet 200 for the prevention and treatment , of decubitus ulcers ( pressure sores and bedsores ). the mattress coverlet 200 provides a low air loss feature that can be turned on or off as desired by the user ( here , broadly referencing a patient or person resting on such coverlet and / or a caregiver therefor ). as best seen in fig1 , a foam shell topper 20 with foam bolsters 22 and foam sides 24 running the length of the mattress 100 on either side forms the air flotation mattress 100 . at the respective ends of the air flotation mattress 100 and capping the foam bolsters and sides 22 and 24 , respectively , are a foam header 26 and foam footer 28 , which along with the bolsters 22 form a cavity in the mattress 100 . this cavity is for positioning of air cells 35 . unlike the above - preferred embodiment , the air cells 35 of the presently preferred embodiment run head - to - foot with such cavity . as above , the cavity formed by the foam bolsters 22 , header 26 , and footer 28 , contains the air cells 35 . the air cells 35 are essentially inflatable air bladders connected directly to an external control system 300 as above described for their inflation / deflation . such air cells 35 are operated to provide the primary support surface for the patient . as represented to those of ordinary skill in the art by the cross - sectional view of fig2 , the foam shell topper 20 of such air flotation mattress 100 may have on its upper surface 38 a geo - matt ® surface treatment to aid in redistributing skin pressure . the bottom surface 40 of such foam shell topper 20 may be alternatively cut to provide predetermined ridges 42 running head - to - foot to act as retainers for such air flotation mattress &# 39 ; respective air cells 35 . in accordance with this alternative presently preferred embodiment , the mattress coverlet 200 may be additionally sheathed in a multi - layer mattress topper 400 . the first layer 51 of the multi - layer mattress topper 400 is a waterproof , vapor impermeable sheet . the second ( i . e ., middle ) layer 53 may comprise a non - crush three - dimensional fabric , such as a knit , cloth , polymeric film , foam or extruded woven fibers . finally , the third layer 52 may additionally comprise a waterproof , vapor impermeable sheet for protection of the underlying mattress coverlet 200 . such third layer 52 may additionally comprise a zippered sheath for encasing the mattress coverlet 200 . the exemplary mattress coverlet 200 is comprised of two separate layers . as seen in fig1 , the first layer 47 of such mattress coverlet 200 is a sheet of waterproof , vapor permeable material . it is designed to allow moisture - vapor and heat from the patient &# 39 ; s body or relatively immediately adjacent thereto to pass through ( such as perforations or relatively small holes 59 in layer 47 ) to the second layer 49 . the second layer 49 of such mattress coverlet 200 is a non - crush three - dimensional fabric that is moisture resistant and vapor and air permeable . it is through this middle layer 49 of the mattress coverlet 200 that the low air loss feature of the present invention forces air , which aids in removing the warm moist air generated by the patient . an exemplary depiction of the direction of airflow through the mattress coverlet 200 is indicated by exemplary airflow 50 . the two layers 47 and 49 of the mattress coverlet 200 are sewn together around their perimeter . various methods of attaching such a coverlet 200 may be utilized . for example , said coverlet 200 may be formed with an elastic band sewn around its outer perimeter so as to envelop such a mattress 100 as would a fitted sheet . in the case of a “ fitted - sheet ” style coverlet 200 , the entirety , of the outer perimeter of the first and second layers 47 and 49 , respectively , may be sewn together . in such an embodiment , the forced air from the ecs 300 along with the warmth and moisture from the air in the second layer 49 of the coverlet may escape around the entire perimeter through the loose friction fit of the elastic band of the coverlet 200 . as described above , this alternative presently preferred embodiment may be regulated by an ecs 300 . the two pumps 62 and 64 of the ecs 300 serve to provide the airflow for both the primary patient support ( i . e ., the mattress 100 and the airflow through the middle layer 53 of the multi - layer mattress topper 400 ) and for the mattress coverlet 200 . the method of connection of the ecs 300 , its operation and features is as discussed in detail above . as in other embodiments , the exemplary coverlet 200 in accordance with the subject invention may be modularly applied to other supports including mattresses , wheelchair / seating cushions , and / or patient positioners ( whether air powered , pre - existing , disclosed herewith , or later developed ). it is to be understood that the present invention may be practiced in conjunction with combinations of additional features , not necessarily shown or discussed in detail . in particular , the size , shape and support characteristics of the air flotation mattress 100 , the multi - layer mattress topper 400 and / or the mattress coverlet 200 may vary as desired or as needed . additionally , both the mattress coverlet 200 and the multi - layer mattress topper 400 may be utilized with mattresses of various size and shape ( regardless of whether air powered , pre - existing , disclosed herewith , or later developed ), in addition to being useful with other support devices such as patient positioner and wheelchair / seating cushions . all such variations , as would be understood by one ordinarily skilled in the art are intended to fall within the spirit and scope of the present invention . likewise , the foregoing presently preferred embodiments are exemplary only , and their attendant descriptions are similarly intended to be examples of the present invention rather than words of limitation .
an air inflatable mattress and mattress coverlet are provided for the prevention and treatment of decubitus ulcers . the mattress incorporates a user selectable static or alternating air powered support surface for more uniformly redistributing pressure exerted on a patient &# 39 ; s skin . the mattress coverlet encompasses a low air loss feature independent of the mattress &# 39 ; s user selectable air powered support surface . such low air loss feature provides a patient contact surface exhibiting a high moisture vapor transfer ratio in conjunction with a forced air flow to aid in reducing the moisture and heat near the patient &# 39 ; s body . both the mattress and mattress coverlet are driven by an external control system which houses the user controls , as well as the necessary pumps , regulators , and valving .