Abstract:
An inflatable cushion is disclosed, having features that allow deflation of the cushion to be controlled. The cushion includes an inflatable bladder having a support therein and a valved exhaust tube in fluid communication therewith. An indicator coupled to the exhaust tube indicates when fluid is exiting the exhaust tube. When sat upon, the cushion deflates only by a preselected amount. This allows the cushion to be consistently and easily deflated to a predetermined inflation height.

Description:
BACKGROUND 
     This invention relates to inflatable cushions. One application of inflatable cushions is for people who sit for extended periods of time, such as wheelchair users. After extended periods of remaining seated, a person&#39;s body will commonly become uncomfortable and sore, and might even develop bedsores. The weight of the seated person&#39;s body is typically supported only at a limited number of points creating pressure points on the body, which can become painful and sore over time. This problem can be alleviated by seating the person on an inflatable cushion that has been inflated enough to provide support, but not so much that the cushion can&#39;t conform to the shape of the seated person&#39;s backside and legs. It is this conformability that allows the person&#39;s weight to be distributed more evenly over the entire surface of his backside and legs that is in contact with the cushion, thereby eliminating painful pressure points. 
     In the prior art, an inflatable cushion would have commonly been inflated fully, then allowed to deflate somewhat while a user sits on it. When the user thought sufficient air was released, a valve would have been closed to prevent further deflation of the cushion. The amount of deflation would have been determined by a judgement call of the user. The problem with this method is that the results are very inconsistent. Over-inflation of the cushion does not provide the needed conformability, while under-inflation does not provide enough support. A need exists for a cushion that allows a user to consistently and easily deflate an inflated inflatable cushion to an appropriate height to provide the needed support and conformability. 
     SUMMARY OF THE INVENTION 
     An embodiment of the invention is an inflatable cushion having an inflatable bladder. The inflatable bladder has a support positioned therein and a valved exhaust tube in fluid communication with the inflatable bladder. An indicator is coupled to the exhaust tube for indicating when fluid is exiting the exhaust tube. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, in which like reference numerals indicate corresponding parts in all views: 
     FIG. 1 is a perspective view of a first embodiment of an inflatable cushion. 
     FIG. 2 is a cross-sectional view of the inflatable cushion of FIG.  1 . 
     FIG. 3 is an end view of the support of the inflatable cushion of FIG.  2 . 
     FIG. 4 is an end view of an alternative embodiment of the support of the inflatable cushion of FIG.  2 . 
     FIG. 5 is a cross-sectional view of a second embodiment of an inflatable cushion prior to application of a compressive force. 
     FIG. 6 is a cross-sectional view of the inflatable cushion of FIG. 5 after application of a compressive force and adjustment to a predetermined inflation height. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A description of the preferred embodiments of the present invention will now be had by way of example, and not limitation, with reference to FIGS. 1 through 6. 
     FIG. 1 is a perspective view of a first embodiment of inflatable cushion  10 . FIG. 2 is a cross-sectional view of the same cushion  10 . Inflatable cushion  10  has an inflatable bladder  11 . The bladder  11  may be inflated with any fluid and is inflated with air in a preferred embodiment. Positioned within inflatable bladder  11  is a support which includes foam element  15  and exhaust channel  16 , which lies adjacent a surface of the foam element  15 . The foam element  15  may be an open cell foam. Exhaust channel  16  provides fluid communication between the interior of inflatable bladder  11  and exhaust tube  12 . The exhaust channel  16  may be made from a thermoplastic material heat sealed to the top of foam element  15 . Alternatively, the exhaust channel  16  may be formed from a portion of a thermoplastic material surrounding foam element  15 . Exhaust tube  12  has a valve  13  thereon to control airflow through exhaust tube  12 . Coupled to the exhaust tube  12  is an audible indicator  14  which emits a sound, e.g. a whistle, when air passes through it, thereby alerting someone using the inflatable cushion  10  that air is escaping and the cushion is deflating. The indicator  14  may be a visual indicator such as a flow meter. 
     FIG. 3 is an end view of the foam element  15  and adjacent exhaust channel  16 , which together form the support within inflatable bladder. It can be seen in this view that the interior of the exhaust channel  16  is empty. 
     FIG. 4 is an end view of an alternative support for use with the inflatable cushion  10  of FIGS. 1 and 2. Like the embodiment of FIG. 3, the support includes foam element  15  and adjacent exhaust channel  16 . In this embodiment, however, exhaust channel  16  has a second foam element  17  therein. This foam element  17  helps to retain the exhaust channel  16  in an open position. This prevents premature or unintentional blockage of airflow along the channel  16 . 
     In use, a person sits on the inflatable cushion  10  of FIGS. 1-2 while the inflatable bladder  11  is fully inflated. Valve  13  is opened and the compressive force exerted by the weight of the seated person causes air to escape through exhaust channel  16 , exhaust tube  12 , and audible indicator  14 . Indicator  14  emits a whistle (or other suitable noise) while air is escaping to alert a user to the fact that the cushion  10  is deflating. When the top of the inflatable bladder  11  reaches exhaust channel  16 , exhaust channel  16  is compressed against foam element  15 , which cuts off the passage of air out of the cushion  10 . The user is alerted to this by the fact that the audible indicator  14  reduces intensity or stops making noise. The user then closes valve  13  and the cushion  10  is thereby set at a preselected inflation height. 
     With regard to the second embodiment, reference will now be made to FIGS. 5 and 6. Inflatable cushion  20  includes an inflatable bladder  21  that has first exhaust tube  22  having a valve  23  thereon to control airflow through the first exhaust tube  22 . Coupled to the first exhaust tube  22  is an audible indicator  24 , which emits a sound, e.g. a whistle, when air passes through it, thereby alerting someone using the inflatable cushion  20  that air is escaping and the cushion  20  is deflating. The indicator  24  may be a visual indicator such as a flow meter. Positioned within inflatable bladder  21  is a support that includes an inflatable support bladder  25 . The bladder  21  and support bladder  25  may be inflated with any fluid and are inflated with air in a preferred embodiment. A second exhaust tube  26  provides fluid communication between inflatable support bladder  25  and second exhaust tube  26 . Second exhaust tube  26  has a valve  27  thereon to control airflow through the second exhaust tube  26 . 
     In use, a person sits on the inflatable cushion  20  of FIGS. 5-6 while the inflatable support bladder  25  and the inflatable bladder  21  are fully inflated and both valves,  23  and  27 , are closed. Valve  23  is opened and the compressive force  28  exerted by the weight of the seated person causes air to escape through first exhaust tube  22  and audible indicator  24 . Audible indicator  24  emits a whistle (or other suitable noise) while air is escaping to alert a user to the fact that air is escaping and cushion  20  is deflating. When the top of the cushion  21  reaches the inflatable support bladder  25 , the person&#39;s weight is supported by the inflatable support bladder  25  and air flow through the first exhaust tube  22  decreases or ceases. The user is alerted to this by the fact that the audible indicator  24  reduces intensity or stops making noise. The user then closes first valve  23  and opens second valve  27 , whereupon the air in inflatable bladder  25  escapes through second exhaust tube  26 . The cushion is thereby set at the preselected inflation height. 
     It is to be understood the preferred embodiments of this invention herein disclosed and illustrated are by way of illustration, and not limitation, and that changes and modifications can be made without departing from the spirit or scope of this invention.