Patent Publication Number: US-2004051366-A1

Title: Seat Cushion

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to a seat cushion, and more particularly to a seat cushion that provides better sitting stability and a massage effect.  
       BACKGROUND OF THE INVENTION  
       [0002] A type of seat cushion of the prior art has a hollow pad body whose interior is a closed space filled with a gas. The pad body further contains a number of equally spaced slip-resisting projections around the rim and in the central portion thereof.  
       [0003] The slip-resisting projections serve for enhancing the frictional effect on the top surface of the pad body, so as to achieve better sitting stability. Filled with a gas, which is generally air, the pad body becomes inflated and firm, suitable for supporting a sitter. The top surface of the pad body can adjust itself to the contour of a sitter&#39;s lower body by redistributing the surface tension as the pad body gets depressed. However, after actually using the seat cushion, we have discovered some disadvantages.  
       [0004] In the consideration of sitting comfort, the slip-resisting projections are made of soft materials and therefore easy to get deformed under pressure exerted by a sitting body. In this way, the slip-resisting projections cannot effectively stop tangential body movements across the surface of seat cushion. To reinforce a slip-resisting effect, the slip-resisting projections have to be made of hard materials and inevitably cause a sitter&#39;s discomfort. Further, though a gas-filled pad body of a conventional seat cushion can adjust itself to a sitter&#39;s body, the sitter must sit upright at the central portion of the seat cushion. If a sitter&#39;s body departs from the central portion, the shape of the rim portion of the seat cushion will become unstable and easy to collapse. To maintain a steady sitting position, a sitter has to sit askew under an uneven weight distribution of the lower body, resulting in back pain after sitting for a while. It is a further disadvantage that the material of the pad body is impermeable, which causes a rise in body temperature in the part of skin in contact with the pad body. Therefore, continuously sitting on the seat cushion may cause skin irritations.  
       SUMMARY OF THE INVENTION  
       [0005] Accordingly, the primary object of the present invention is to provide a seat cushion having a more stable holding mechanism for a sitter. Different from the above-mentioned conventional seat cushions, a seat cushion according to the present invention comprises an inner hollow body and an outer hollow body surrounding the inner hollow body. The outer hollow body has a gas inlet. The inner hollow body has a gas inlet and a liquid inlet. The outer hollow body filled with a gas, generally air, forms a boundary of the seat cushion that prevents a sitter from slipping off. The inner hollow body is filled with both a gas and a liquid, generally air and water, so that there exists inside the seat cushion free spaces for liquid surface wave motion; the wave motion producing a massage effect. Further, the liquid in the inner hollow body generally has better thermal conductivity, which provides a sitter a better cooling effect.  
       [0006] The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing. 
     
    
    
     BRIEF DESCRIPTION OF THIE DRAWINGS  
     [0007]FIG. 1 is a top view of a seat cushion according to the present invention.  
     [0008]FIG. 2 is a lateral view of a seat cushion according to the present invention.  
     [0009]FIG. 3 is a lateral cross-sectional view of the liquid inlet of a seat cushion according to the present invention.  
     [0010]FIG. 4 is a lateral cross-sectional view of the gas inlet of a seat cushion according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0011] Referring to FIGS. 1 and 2, a seat cushion according to the present invention comprises an inner hollow body  10  and an outer hollow body  20 ; the outer hollow body  20  surrounds the inner hollow body  10 . The inner hollow body  10  is of generally a round shape and has a suitable height. The outer hollow body  20  is of a toroid or donut-like shape. The inner rim of the outer hollow body  20  is bound to the outer rim of the round inner hollow body  10  to form the seat cushion.  
     [0012] The outer hollow body  20  has a gas inlet  21 . The inner hollow body  10  has a gas inlet  11  and a liquid inlet  12 . The structure of the gas inlet  11  is shown in FIG. 4, and that of the liquid inlet  12  is shown in FIG. 3. By injecting a suitable amount of gas, generally air, the outer hollow body  20  becomes inflated and firm, preferably for holding a sitter. The inner hollow body  10  is injected by a gas and a liquid, generally air and water, in suitable amounts through respectively the gas inlet  11  and liquid inlet  12  thereof. Therefore, there are gas parcels formed in the filled liquid, which provides free spaces for liquid surface wave motion and thus results in a massage effect.  
     [0013] Therefore, a seat cushion according to the present invention is composed of two independent hollow bodies, an inner hollow body surrounded by a toroid or donut-like outer hollow body. The outer hollow body filled with a gas, generally air, forms a boundary of the seat cushion that provides a sitter better sitting stability.  
     [0014] The gas inlets  11  and  21  are respectively for injecting a gas into the inner and the outer bodies. As shown in FIG. 4, a common gas inlet comprises a hole, a plug, and a valve at the bottom of the hole. When a gas is injected into the hole of the gas inlet, the valve is pushed inward and open, allowing air to flow into a hollow body. Once gas loading is stopped, the pressurized gas within the hollow body pushes the valve back to a closure state for preventing gas leakage. To release gas within the hollow body through the same gas inlet, the bottom portion of the gas inlet has to be clipped by usually fingers so that the valve is forced open and the gas can go out. This action must go on persistently till the gas releasing is complete, which is inconvenient to common users. The inner hollow body  10  of a seat cushion according to the present invention has a gas inlet and a liquid inlet. The liquid inlet, as shown in FIG. 3, is especially for injecting liquid into the hollow body, because liquid is difficult to fill in through a gas inlet. The liquid inlet has a hole with a large diameter, which allows convenient water injection and change. At the same time, the gas can be easily exhausted from the hollow body.  
     [0015] The present invention is thus described, it will be obvious that the same invention may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.