Abstract:
A seat cushion for use in a wheel chair includes a foam pad contoured to the anatomy of a user positioned thereon and has an indentation in the middle thereof, which receives and drains incontinence fluid from the user. The foam pad encloses an air channel between the indentation and at least one side of the foam pad. A fan housed inside the pad pushes air through the air channel, into the indentation and onto the user. Alternatively, the seat cushion may house an air conditioner to circulate cooled air to the skin of the user.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based on U.S. Provisional Patent Application Ser. No. 60/816,834, filed Jun. 27, 2006, and claims priority based on the earlier filed provisional patent application, the entire disclosure of which is incorporated herein by reference. 
     
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to a seat cushion; more specifically, a seat cushion that may be used in a wheelchair to drain incontinence fluid and deliver conditioned air to the skin of the user. 
         [0004]    2. Description of the Prior Art 
         [0005]    U.S. Pat. No. 4,923,248 teaches a cooled seat cushion having a bottom and a back. Both the bottom and the back have a series of air passageways forming a plenum. This plenum is fed air from a Peltier unit which is attached to a DC power source, preferably a cigarette lighter in a car. The air passageways of the plenum are constructed of wound metallic coils; the passageways crisscross throughout the interior of both the seat bottom and back. The Peltier unit feeds the plenum air at the seat cushion&#39;s bottom, between the user&#39;s legs, or at the juncture between the bottom and the back, where it traverses the seat cushion and exits at the top of the seat back. The chilled air, in traversing the plenum, cools the seat cushion. 
         [0006]    Seat constructions having a recessed region allowing incontinence fluids from a user to drain off are common to the field. Additionally, augmenting user comfort with an additional cushion in a chair is also common in the field. 
         [0007]    However, the above described systems suffer from the drawbacks of an inability to combine functions of cooling and handling incontinence material, and utilization of an insufficient and weak cooling system; thus there is a need for a seat cushion that can convectively cool the skin of a user, receive and remove the byproducts of incontinence, and provide additional, comfortable support. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is directed to a seat cushion that delivers air to a user and removes moisture. In one embodiment of the invention, an indentation is formed into the center of the top of a foam pad and an air channel is formed through the foam pad, communicating between one of the sides of the foam pad and the indentation. In the air channel a cavity is formed and a chamber subassembly is inserted therein. This chamber subassembly has apertures on two of the sides and serves to maintain the viability of the channel after a user compresses the foam pad. Air naturally circulates through the air channel, through the chamber assembly, and into the indentation, which is filled with a permeable mesh. This permeable mesh insert allows the air to flow freely, while maintaining a comfortable level of support for the user, with the added benefit of allowing incontinence liquid to flow out through the insert drain through the indentation. 
         [0009]    In another embodiment, the same configuration is used, except that the chamber subassembly includes an air circulating device, such as a fan, which forces room-temperature air into the indentation. In a third embodiment, an air conditioner or air cooling unit is integrated into the foam pad, in conjunction with the fan, with both preferably mounted inside the foam pad so that the air channel receives air conditioned by the air conditioner and distributes it into the indentation. 
         [0010]    It is an object of this invention to augment the comfort and support of one sitting, especially one sitting for prolonged period in a wheelchair. 
         [0011]    It is further an object of this invention to drain incontinence fluid released from a body of a user to avoid unsanitary and moist conditions on the skin of the user and to mitigate the risks of consequent skin breakdown. 
         [0012]    It is another object of this invention to deliver conditioned air to the skin of the user to cool and dry the skin of the user to reduce the formation of skin ulcers and pressure sores. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is an exploded view of a seat cushion embodiment constructed in accordance with the present invention and including a chamber subassembly. 
           [0014]      FIG. 2  is a perspective view of a foam pad shown in  FIG. 1 . 
           [0015]      FIG. 3  is a cross sectional view, taken along line  3 - 3  of  FIG. 2 . 
           [0016]      FIG. 4  is a side view of the permeable mesh, with the arrows representing the direction of the flow of air. 
           [0017]      FIG. 5  is an elevated perspective view of the chamber subassembly shown in  FIG. 1 , with the arrows representing the direction of the flow of air. 
           [0018]      FIG. 6  is a perspective view of the bottom of the chamber subassembly with the mounting plate removed. 
           [0019]      FIG. 7  is a perspective view of the seat cushion in a wheelchair application. 
           [0020]      FIG. 8  is an exploded isometric view of the seat cushion embodiment that includes an integrated air conditioner. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    With reference to the drawings,  FIG. 1  shows a seat cushion comprising a foam pad  10  formed with a metal mold; however, other molds or methods of construction could be used to achieve the shape and function of this foam pad  10 . The foam pad  10  is constructed of foam that gently compresses to comfortably support the user and is coated with a material that is substantially impervious to liquid. The foam pad  10  further has a top  12 , which is contoured to the anatomy of a user when the user is sitting on the seat cushion, a bottom  14 , a side  16 , a back side  18 , a front side  20 , and a side  22 . 
         [0022]    Formed into the top  12  of the foam pad  10  is an indentation  24 , which, in the preferred embodiment, has a roughly concave surface  26 . However, alternatively shaped surfaces that comfortably support the user, which receive and drain incontinence fluids, will suffice. The indentation  24  is sloped away from the front side  20  and towards the back side  18 , such that fluids received into the indentation flow on the concave surface  26  towards the back side  18 , evacuating the fluids from the skin of the user. Formed in the middle of the indentation  24 , protruding up from the concave surface  26 , is a support protrusion  28 . 
         [0023]    An insert  30  having an outer layer  32 , inner layer  34 , and an air barrier  36 , fills the indentation  24 . The inner layer  34  has an opening  35  in the middle roughly the size of the support protrusion  28 . The inner layer  34  fits snugly around the support protrusion  28  and against the concave surface  26  of the indentation  24  such that the support protrusion  28  keeps the inner layer  34  in place. This arrangement ensures that the area around the support protrusion remains a viable region through which fluid may permeate towards the back side  18 . 
         [0024]    The outer layer  32 , which rests along the top of the support protrusion  28  and the inner layer  34 , is dimensioned roughly the same as the indentation  24 . The outer layer  32  makes a top for the indentation  24 . To maintain the ability of the indentation  24  to receive incontinence fluid and circulate air, the outer layer  32  and the inner layer  34  of the insert are comprised of permeable mesh  38 , illustrated in  FIG. 4 . The permeable mesh  38  has a first hide  40 , a second hide  42 , and a multiplicity of resilient fibers  44  in between that bias the first hide  40  and the second hide  42  apart. When in use, the fibers resiliently compress. Thus, when the permeable mesh  38  is compressed, the fibers  44  flex and provide a force to oppose the compression. There is space between the fibers  44  so that even when the fibers  44  are compressed, the space between them remains vacant, allowing air and fluid to permeate through in all directions. These fibers  44  also add stiffness to the insert  30 . 
         [0025]    Constructing the insert  30  with the permeable mesh  38  ensures that the insert  30  provides support for the user in the indentation  24 , but does not become a sponge that holds the incontinence fluid and blocks air circulation. Instead, the permeable mesh  38  of the insert  30  allows the incontinence fluids to flow between the fibers  44  along the concave surface  26 , towards back side  18 , while not significantly impeding air circulation in the indentation  24 . 
         [0026]      FIG. 3  exposes the interior of the foam pad  10  in a cross-section view, along line  3 - 3  from  FIG. 2 . As shown in  FIG. 3 , an air channel  46  is formed into the foam pad  10 . The air channel  46  has entrance holes  46 A formed into the front side  20  of the foam pad  10  and an exit  46 B formed into the concave surface  26  of the indentation  24 . Intersecting the air channel  46  is a cavity  48 . The cavity  48  is formed into the bottom  14  of the foam pad  10 ; however, in alternative embodiments, the cavity  48  may be formed in one of the sides  16 ,  18 ,  20 , or  22 . 
         [0027]    A chamber subassembly  50 , as shown in  FIG. 1 , fits snugly inside the cavity  48 . The chamber subassembly  50 , as shown in  FIG. 5 , has a preferably substantially rectangular base  51 , though alternative shapes are contemplated. The chamber subassembly  50  also includes a shell  52  preferably made of a sturdy but slightly flexible material such as certain plastics, thermoplastic olefins, or other composite materials, and a mounting plate  53  that fits on the rectangular base  51 . The mounting plate  53  attaches to the bottom  12  of the foam pad  10 , shown in  FIG. 1 , holding the chamber subassembly  50  in place in the cavity  48  (the cavity  48  is shown in  FIG. 3 ). The shell  52  is shaped to have a bulge  54 , and there are apertures in the shell  52  on both sides of the bulge  54 . These are the intake apertures  56  and the outlet apertures  57 . The sturdiness of the plastic shell  52  ensures that neither the cavity  48  nor the air channel  46  collapse when a user sits on the foam pad  10 , while the shape of the shell  52  allows the top  12  of the foam pad  10  to remain shaped to the anatomy of the user when the user is seated on the seat cushion. 
         [0028]    As shown in  FIG. 6 , in one embodiment a fan  58  is mounted inside the shell  52  and powered by a battery pack  59  so that the fan  58  pulls air through the intake apertures  56  and pushes it out the outlet apertures  57 . Other embodiments may not require the addition of the fan  58 , relying on natural convection of air through the shell  52 , or an external method of pushing air through the chamber subassembly  50 . 
         [0029]    The intake apertures  56  and outlet apertures  57  on the shell  52  of the chamber subassembly  50  are aligned with the air channel  46  and secured in place with the mounting plate  53 . The chamber subassembly  50  is inserted into the bottom  14  of the foam pad  10  as shown in  FIG. 1 . The air, once pushed through the outlet apertures  56 , travels to the exit of the air channel  46 B. The stream of air then, instead of flowing as a condensed stream into the user, collides with the air barrier  36 , thus disbursing the air in the indentation  24 , throughout the insert  30 . 
         [0030]    The majority of wheelchair use is done in-doors, where the air temperature and humidity are controlled by the building&#39;s air conditioning unit. The chamber subassembly  50 , when installed into the cavity  48  as depicted in  FIG. 1 , delivers this conditioned ambient air to the skin of the user. Thus the relatively low humidity and low temperature ambient air is delivered to the indentation  24  to ventilate the skin of the user, convecting heat away and evaporating moisture. This promotes cool dry skin conditions adverse to the formation of skin ulcers. 
         [0031]    Further, an air conditioner  60  may be used in addition to, or instead of, the chamber subassembly  50  as shown in  FIG. 8 . The air conditioner  60  is described in U.S. Pat. No. 6,240,742, the details of which are incorporated herein by reference. The air conditioner  60  employs a method of evaporating and condensing a fluid to chill, with the option to heat, a fin arrangement (not shown) across which air is forced which is located in the path to the skin of the user; however, unlike other air chillers, this air conditioner  60  is small enough to be mounted inside the foam pad  10 . Further, the air conditioner  60  functions utilizing evaporative cooling between sealed low pressure chambers, combined with absorptive air pressure reduction technology, and thus does not require a bulky or heavy battery. It merely requires enough battery power to control the operation of a valve. 
         [0032]    In the preferred embodiment, the air conditioner  60  fits snugly in the cavity  48 . Thus the air conditioner  60  chills or, if desirable, heats air, which then flows to the indentation  24  where it collides with the air barrier  36 , which disburses it throughout the insert  30 . At night, or when the seat cushion is not in use, the air conditioner  60  may be removed to recharge its evaporative cooling system (not shown). 
         [0033]    As shown in  FIG. 1 , a cover  64  envelops or fits over at least a portion of the foam pad  10  and preferably covers all of the foam pad  10 . The cover  64  is partially constructed of the permeable mesh  38 , illustrated in  FIG. 4 . When the user sits on the cushion, the permeable mesh  38  of the cover  64  compresses, but remains air and liquid permeable because the multiplicity of resilient fibers  44  between the first hide  40  and the second hide  42  flex and exert reactionary force. Further, these fibers  44  add a pressure redistribution function to the cover  64 , increasing the support provided to the user. In one embodiment, the permeable mesh  38  comprises a side  65  of the cover  64 , which fits over the back side  18  of the foam pad  10 , for allowing air to ventilate the indentation  24 . In other embodiments, the permeable mesh  38  could also comprise a portion  67  of the cover  64  over the front side  20  of the foam pad  10 , to allow increased flow of air to the chamber subassembly  50  or the air conditioner  60 ; the permeable mesh  38  could also comprise the cover  64  in its entirety. Areas of the cover  64  not comprised of the permeable mesh  38  are preferably made of a breathable fabric suitable for comfortably supporting a user. 
         [0034]    Thus, the cover  64  allows air to circulate into the air channel  46  into the chamber subassembly  50 , and/or air conditioner  60 , depending on the embodiment, and throughout the indentation  24 . Further, even when compressed by a user, the permeable mesh  38  of the cover  64  remains liquid permeable, allowing incontinence fluid flowing from out of the indentation  24  to traverse the cover and be evacuated from the seat cushion. 
         [0035]    Illustrated in  FIG. 7 , the preferred application of this seat cushion is in a wheelchair, to increase the health and welfare of a prolonged, continuous user. 
         [0036]    Thus it is seen that the apparatus of the present invention readily achieves the ends and advantages mentioned, as well as those inherent therein. While certain preferred embodiments of the invention have been illustrated and described for purposes of the present disclosure, numerous changes in the arrangement and construction of parts and steps may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present invention as defined by the appended claims. Although there have been described particular embodiments of the present invention of a new and useful ventilated seat cushion, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the appended claims.