Abstract:
A double chambered transfer mattress is provided capable of partial deflation that that includes a top inflatable mattress and a bottom inflatable mattress that are separated by a common wall from one another. A selectable inlet/outlet valve is arranged for airflow communication between an interior chamber of the bottom inflatable mattress and a source of pressurized air. A one-way valve is positioned through the common wall so as to provide selective air flow communication between the top inflatable mattress and the bottom inflatable mattress so that when the inlet/outlet valve is closed, so that air continues to escape from perforations in the bottom inflatable mattress, the one-way valve is actuated so as to prevent deflation of the top inflatable mattress.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part application of copending U.S. application Ser. No. 11/191,674, filed on Jul. 28, 2005, which itself claims priority from co-pending Provisional Patent Application Ser. No. 60/592,251, filed Jul. 28, 2004, and entitled DOUBLE CHAMBERED AIR MATTRESS. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention generally relates to patient transfer devices and, more particularly to a patient transfer apparatus which employs an air bearing to facilitate the transfer.  
       BACKGROUND OF THE INVENTION  
       [0003]     Patient handling mattresses are known in the art which include at least two flexible material sheets, that together define a plenum chamber, with at least one sheet being perforated with small pinholes over at least a central surface area, and which open up directly to the interior of the plenum chamber. Such prior art mattresses are used by arranging the perforated sheet so that it faces an underlying fixed, generally planar support surface, such as a floor or table. When the mattress is charged with pressurized air, the escape of air under pressure through the pinholes acts initially to jack a load placed upon the mattress above the perforated flexible sheet, and thereby creates an air bearing of relatively small height between the underlying fixed, generally planar support surface and the perforated flexible sheet.  
         [0004]     For example, in U.S. Pat. No. 4,517,690, issued to Wegener, an air pallet is disclosed that is formed from upper and lower thin flexible film sheets sealed at their edges to form a plenum chamber. Wegener&#39;s air pallet functions to move a load with minimal friction over an underlying generally planar fixed support surface. The bottom thin flexible material sheet is perforated by small diameter perforations such as pin holes at the load imprint area.  
         [0005]     In U.S. Pat. No. 5,561,873, issued to Weedling, provides an inflatable flexible pallet within which an array of structurally interrelated inflatable chambers are formed to support a load when inflated. The flexible pallet is configured to resist lateral and longitudinal shrinkage of the load support surface, as well as ballooning and hot dogging. Rotational instability is also reduced by providing a greater load surface support area.  
         [0006]     In U.S. Pat. No. 6,073,291, issued to Davis, an inflatable medical patient transfer apparatus is disclosed that has a combination of transverse partition members and a raised perimeter section to reduce deleterious ballooning and uneven inflation as well as quick emergency deflation. Additional differentially inflatable patient rolling chambers are disclosed on the top of the transfer apparatus to provide assistance to medical personnel in beginning to roll patients reclining or lying upon the transfer apparatus, particularly in a deflated condition on a hospital bed.  
         [0007]     All of the foregoing devices have suffered from an inability to be used during X-ray imaging of a patient lying upon the mattress. Proper X-ray imaging requires that the patient remain motionless during the exposure. Prior art transfer mattresses tend to drift or move, and are easily moved by even small perturbations. Thus, they are required to be deflated prior to effecting X-ray imaging of the patient. Unfortunately, when deflated, the patient is forced to lie upon a very stiff table that can be quite uncomfortable for heavier patients.  
         [0008]     Many of the foregoing devices also suffer from the fact that when uninflated they tend to bunch causing photo images to appear upon the x-ray exposures that mask underlying physiological features of the patient. There is a continuing need to be able to easily and safely x-ray a patient on an inflated transfer mattress.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention provides a double chambered transfer mattress that is capable of partial deflation. In one embodiment, a transfer mattress is provided that includes a top inflatable mattress and a bottom inflatable mattress that are separated by a common wall from one another. The bottom inflatable mattress includes a plurality of holes or perforations disposed in a bottom panel. A selectable inlet/outlet valve is arranged for airflow communication between an interior chamber of the top inflatable mattress and a source of pressurized air. A one-way valve is positioned through the common wall so as to provide selective air flow communication between the top inflatable mattress and the bottom inflatable mattress so that when said inlet/outlet valve is closed-off from the source of pressurized air, the bottom inflatable mattress deflates by air escaping through the plurality of holes or perforations whereby the one-way valve is actuated so as to prevent deflation of the top inflatable mattress.  
         [0010]     In another embodiment a top sheet is provided having a width, a length, and peripheral edges, an intermediate, barrier sheet having the same width, the same length, and peripheral edges, and a bottom sheet having the same width, the same length, peripheral edges and a plurality of perforations. A first perimeter band is sealingly fastened between the peripheral edges of the top and barrier sheets and a second perimeter band is sealingly fastened between the peripheral edges of the barrier and bottom sheets. The peripheral edges of the top, barrier, and bottom sheets are sealingly fastened to the respective perimeter bands by heat sealing. A plurality of baffles, each having a width and a length, are attached to an inner surface of the top sheet and the barrier sheet so as to be oriented between the top sheet and the barrier sheet. A second plurality of baffles, each having a width and a length, are attached to an inner surface of the barrier sheet and an inner surface of the bottom sheet so as to be oriented between the barrier sheet and the bottom sheet. One or more inlet/outlet openings are located within the perimeter bands so that the double chambered transfer mattress may be inflated or deflated. Advantageously, one or more one-way valves are located through the barrier sheet so as to provide selective air flow communication between a first chamber formed between the top sheet, the barrier sheet, and the first perimeter band and a second chamber formed between the barrier sheet, the bottom sheet, and the second perimeter band. In this way, an inlet/outlet located in the first perimeter band may be closed-off from the source of pressurized air so that the second chamber deflates by air escaping through the plurlaity of holes or perforations. As the second chamber deflates, the one or more one-way valves are actuated so as to present deflation of the first chamber. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     These and other features and advantages of the present invention will be more fully disclosed in, or rendered obvious by, the following detailed description of the preferred embodiment of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein:  
         [0012]      FIG. 1  is a perspective view of a double chambered transfer mattress formed in accordance with the present invention;  
         [0013]      FIG. 2  is a cross-sectional view of the transfer mattress shown in  FIG. 1 ;  
         [0014]      FIG. 3  is a broken-away, cross-sectional view of a portion of  FIG. 2 ;  
         [0015]      FIG. 4  is a cross-sectional view of the double chamber transfer mattress shown in  FIG. 2 , with the second chamber deflated and the mushroom valve actuated to a closed position; and  
         [0016]      FIG. 5  is a broken-away, cross-sectional view of a portion of  FIG. 4 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]     This description of preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. The drawing figures are not necessarily to scale and certain features of the invention may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. In the claims, means-plus-function clauses, if used, are intended to cover the structures described, suggested, or rendered obvious by the written description or drawings for performing the recited function, including not only structural equivalents but also equivalent structures.  
         [0018]     Referring to  FIGS. 1-5 , a double chambered transfer mattress  2  formed in accordance with the present invention comprises a top panel  4 , an internal barrier panel  5 , a bottom panel  6 , a top perimeter band  8 , a bottom perimeter band  10 , and a plurality of baffle-panels  11 . More particularly, top panel  4  comprises a head portion  12 , a foot portion  14 , and a peripheral edge  16 . Top panel  4  is formed from a sheet of fabric, e.g., nylon scrim or the like, that may be coated on at least its outer surface  18  with a water proof coating. Inner surface  19  of top panel  4  may also be coated with a water proof coating as well. The water proof coating may be any of the well known polymeric or elastomeric compounds that are known to be impervious to semi-solids and liquids, such as, blood, urine, feces, hospital strength disinfecting compounds, alcohol, or the like. For example, a nylon twill fabric that is coated on one side with a heat sealable, polyurethane coating (e.g., an inner side) and the outer side coated with a Durable Water Repellant (patient side). The presence of polyurethane on the interior surfaces allows for heat sealing, eliminating needle holes.  
         [0019]     Barrier panel  5  comprises a head portion  17 , a foot portion  19 , a top inner surface  20 , a bottom inner surface  21 , and a peripheral edge  23 , and is often formed from a sheet of fabric, e.g., nylon scrim or the like. One or more openings  27  are defined through the peripheral side surface of barrier panel  5  so as to provide for air flow communication. In one embodiment of the invention, a one way valve  31  is positioned within each opening  27 . One way valve  31  often takes the form of a so-called “mushroom valve” which operates so as to keep gases traveling in one direction only. One way valve  31  is biased so as to be normally in an open, free air flow configuration.  
         [0020]     It should be understood that some or all of top panel  4 , internal barrier panel  5 , bottom panel  6 , top perimeter band  8 , bottom perimeter band  10 , and plurality of baffle-panels  11  are most often, but not always formed from a sheet of fabric, e.g., nylon scrim or the like, and may be coated on at least its outer surface with a water proof coating. The water proof coating may be any of the well known polymeric or elastomeric compounds that are known to be impervious to semi-solids and liquids, such as, blood, urine, feces, hospital strength disinfecting compounds, alcohol, or the like. For example, a nylon twill fabric that is coated on one side with a heat sealable, polyurethane coating (e.g., an inner side) and the outer side coated with a Durable Water Repellant (Patient side). A practical benefit associated with the use of the foregoing preferred materials is that double chambered transfer mattress  2  retains a better appearance for longer periods of time during use. A double coated double chambered transfer mattress  2  can be easily wiped down, and can be put back into use more quickly.  
         [0021]     Alternatively, in those instances where a single use, single patient mattress is provided, i.e., where patient use lasting less than twenty four hours is desired, some or all of top panel  4 , internal barrier panel  5 , bottom panel  6 , top perimeter band  8 , bottom perimeter band  10 , and plurality of baffle-panels  11  may be formed from fibers for forming fabrics suitable for single use top panel  4  may be made of materials, such as, acetate, acrylic, anidex, aramid, azlon, cotton, elastoester, fluorocarbon, fur, glass, lyocell, melamine, metallic, modacrylic, modal, mosacrylic, novoloid, nylon, nytril, olefin, PAN, PBI, PEEK, Pelco, PEN, PLA, PTT, polyester, polyester-polyarylate, rayon, saran, spandex, sulfar, triacetate, vinal, vinyon, and wool. A common characteristic of the foregoing and like materials is their propensity to stain or discolor as a result of contact with blood, urine, feces, hospital strength disinfecting compounds, alcohol, or the like. Additionally, a variety of films may be used to form a single patient, single use double chambered transfer mattress  2 , for example, copolyester, copolyether, ethylene vinyl acetate, fluorocarbon, polyamide, olefins, polybutylene, polycarbonate, polyester, polystyrene, polyurethane, polyvinyl, alcohol, polyvinyl chloride, polyvinyl fluoride, and polyvinylidene chloride. A practical benefit associated with the use of the foregoing preferred materials is that double chambered transfer mattress  2  retains a stained and discolored appearance for longer periods of time after use thereby alerting hospital staff or other care givers that a particular double chambered transfer mattress  2  has completed its useful life, and must be discarded.  
         [0022]     In one embodiment, some or all of top panel  4 , internal barrier panel  5 , bottom panel  6 , top perimeter band  8 , bottom perimeter band  10 , and plurality of baffle-panels  11  may comprise a cold water soluble partially hydrolyzed polyvinyl alcohol, cold water insoluble hot water disintegrable aliphatic polyester, and minor proportions of processing and performance aids. The aliphatic polyester has a melt temperature above the normal body temperature of a human (37 degrees C.; 98.6 degrees F.) and is present in the resin blend at a concentration sufficient to constitute the continuous phase of the blend, with the polyvinyl alcohol constituting a discontinuous phase of the blend. The aliphatic polyester renders the resin blend, and the partially hydrolyzed polyvinyl alcohol in the blend is, cold water insoluble and determines the temperature at which articles formed from the blend will be subject to dissolution in an aqueous bath and subsequent disposal. A practical benefit associated with the use of the foregoing material is that double chambered transfer mattress  2  not only retains a stained and discolored appearance for longer periods of time after use, thereby alerting hospital staff or other care givers that a particular double chambered transfer mattress  2  has completed its useful life, and must be discarded, but also if an attempt is made to launder the mattress after a single use it disintegrates during the washing process.  
         [0023]     Bottom panel  6  comprises a head portion  22 , a foot portion  24 , and a peripheral edge  26 . Bottom panel  6  includes a plurality of tiny holes  30  that are defined through its thickness to allow air, that is supplied by a high-pressure air supply to double chambered transfer mattress  2 , via an air supply hose  34 , to escape in a controlled manner. The air supplied to double chambered transfer mattress  2  escapes through plurality of holes  30 , providing a weight-bearing cushion of air that facilitates the sliding of double chambered transfer mattress  2  along a surface, as well as, from one surface to another.  
         [0024]     Top perimeter band  8  and a bottom perimeter band  10  often take the form of elongate, rectangular strips of any of the foregoing materials. Top perimeter band  8  is sealingly fastened between peripheral edge  16  of top panel  4  and peripheral edge  20  of barrier panel  5 , e.g., by heat sealing, gluing or sewing, so as to form a first chamber  35 . Bottom perimeter band  10  is sealingly fastened between peripheral edge  20  of barrier panel  5  and peripheral edge  26  of bottom panel  6 , so as to form a second chamber  37 .  
         [0025]     Plurality of baffle-panels  11  each comprise substantially rectangular sheets of nylon scrim or the like, and include a top edge  40  and a bottom edge  42 . Baffle-panels  11  may have differing widths, depending upon their position within double chambered transfer mattress  2 . Two sets of baffle panels  11  are installed within double chambered transfer mattress  2 , a first set of baffle panels  11  is located in first chamber  35  and a second set of baffle panels  11  is located in a second chamber  37 . For the first set on baffle panels  11 , each top edge  40  is fastened transversely to a portion of inner surface  19  of top panel  4  and each bottom edge  42  is fastened transversely to a portion of inner surface  20  of barrier panel  5 . For the second set of baffle panels  11 , each top edge  40  is fastened transversely to a portion of inner surface  21  of barrier panel  5  and each bottom edge  42  is fastened transversely to a portion of inner surface  29  of bottom panel  6 .  
         [0026]     An inlet/outlet opening  50  is formed in perimeter band  8  that sealingly accepts an air supply hose  34 . Inlet opening  50  is sized and shaped so that air supply hose  34  may be inserted, with the inlet being thereafter snapped shut or otherwise closed to hold air supply hose  34  in place while double chamber transfer mattress  2  is being inflated. Inlet openings  50  may also include a valve (not shown) that is biased to be normally closed to prevent air from exiting through the inlet, and opened when air supply hose  34  is inserted into inlet opening  50 . Other arrangements known to those skilled in the art may be used to inflate double chambered transfer mattress  2 .  
         [0027]     A double chambered transfer mattress  2  is assembled according to the present invention in the following manner. Bottom panel  6  is laid out on a suitable support surface so that second set of baffle-panels  11  may be transversely arranged in the center section of inner surface  29 . Once in this position, bottom edge  42  of each baffle-panel  11  is fixedly fastened to inner surface  29  of bottom panel  6 . Baffle-panels  11  are advantageously heat sealed along the interface between bottom edge  42  and inner surface  29  of bottom panel  6 . This heat sealing may be done with the application of heat or ultra sonic energy at the edge interface. In this way, a re-solidified interface structure is formed so as to improve the bond and its resistance to rupture under normal loading.  
         [0028]     Once second set of baffle-panels  11  are fastened to inner surface  29  of bottom panel  6 , barrier panel  5  is arranged in overlying confronting relation with bottom panel  6  so that head portion  17  of barrier panel  5  is confronting head portion  22  of bottom panel  6  and foot portion  19  of barrier panel  5  is confronting foot portion  24  of bottom panel  6 . Once in this position, each top edge  40  of each baffle-panel  11  is fixedly fastened to inner surface  21  of barrier panel  5 .  
         [0029]     At this point in the assembly, top panel  4  is arranged in overlying confronting relation with barrier panel  5  so that head portion  12  of top panel  4  is confronting head portion  17  of barrier panel  5  and foot portion  14  of top panel  4  is confronting foot portion  19  of barrier panel  5  . Once in this position, second set of baffle panels  11  may be assembled by fixedly fastening each top edge  40  of each baffle-panel  11  to inner surface  29  of top panel  4  and each bottom edge  42  of each baffle-panel  11  is fixedly fastened to inner surface  20  of barrier panel  5 . Top and bottom perimeter bands  8  and  10  are then sealingly fastened to peripheral edge  16  of top panel  4 , peripheral edge  20  of barrier panel  5  and peripheral edge  26  of bottom panel  6  so as to complete construction of double chambered transfer mattress  2 .  
         [0030]     Double chambered transfer mattress  2  is used when positioning a patient for X-ray photography in the following manner. The patient (not shown) is positioned atop outer surface  18  so that the patient&#39;s head is resting adjacent to head portion  12  atop panel  4 . Double chambered transfer mattress  2  is inflated by passing high pressure air through opening  50  in top perimeter band  8 . As the high pressure air enters first chamber  35  it passes through one-way valve  31  disposed in opening  27  so as to also pressurize second chamber  37 . Once first chamber  35  and second chamber  37  are fully inflated, with air flowing through holes  30  so as to effect the cushion of air necessary for transfer of the patient, double chamber transfer mattress  2  is shifted laterally from a gurney or table onto the table in the X-ray theater. Once in this position, the source of high pressure air connected to opening  50  in top perimeter band  8  is shut-off, and inlet/outlet opening  50  is closed so that pressurized air continues to escape only through holes  30  in bottom panel  6 . As the air escapes second chamber  37 , one-way valve  31  is biased closed as barrier panel  5  moves toward bottom panel  6 . In this way, air escaping from first chamber  35  is stopped by one-way valve  31 . As a consequence, the patient is comfortably positioned on top panel  4  while the X-ray is taken. Once the X-ray procedure is completed air is reintroduced into double chamber transfer mattress  2  so as to reinflate second chamber  37  and reopen one-way valve  31 . Once second chamber  37  has been inflated with air flowing through holes  30 , double chamber transfer mattress  2  and the patient may be shifted from the X-ray table onto the gurney for removal from the X-ray theater.  
         [0031]     It is to be understood that the present invention is by no means limited only to the particular constructions herein disclosed and shown in the drawings, but also comprises any modifications or equivalents within the scope of the claims.