Patent Publication Number: US-2005120483-A1

Title: Heat diffusing cushion or mattress

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application claims priority to provisional application Ser. No. 60/527,472, filed Dec. 5, 2003, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION  
      The invention relates generally to cushions and mattresses and more specifically to cushions and mattresses comprising upstanding air cells having air circulating and heat diffusing characteristics.  
      Seating cushions and resting mattresses are known to the art. In most cases, these devises are comprised of a supportive, yet resilient material that usually deforms in some manner to accommodate the anatomy of the user so as to provide support and comfort. Such cushions and mattresses may be constructed from a myriad of materials having desired supportive and comfort characteristics. For example, such devices are constructed from batting filled fabrics, foam rubber, or air filled bladders or the like.  
      In recent years, the assignee of the present invention has determined that cushions and mattresses having medical applications can be constructed of upstanding air cells that have support characteristics that allow for the even distribution of pressure on the user&#39;s body, such as the buttocks and back, to prevent or relieve decubitus ulcers or pressure sores. These cushions are the subject matter of “shape fitting technology”. Examples of cushions and mattresses derived from such shape fitting technology, employing these therapeutic characteristics are disclosed in U.S. Pat. No. 4,541,136; U.S. Pat. No. 4,698,864; and U.S. Pat. No. 5,163,196.  
      In general, these representative therapeutic cushions and mattresses are comprised of a base with an array of individual, interconnected upstanding air cells. The cells, when deflected under seating pressure, remain at the same internal pressure. Because the air cells of these representative embodiments generally deflect to contact each other along their sides to provide a generally continuous seating surface, there is very little space between the deflected cells, for example to allow air flow between the cells.  
      Although the above described cushions and mattresses are the design of choice when seeking the benefit of a therapeutic cushion, there are situations that do not require shape-fitting technology. These uses may include recreational cushions or mattresses, cushions for office or desk chairs, portable cushions to place on vehicle seats. It would be desirable to have a cushion design for these non-therapeutic uses that have different deflection characteristics that allow air flow among the upstanding air cell so as to provide some ventilation and heat dissipation.  
     SUMMARY OF THE INVENTION  
      It is among the various aspects and objects of the invention to provide a cushion having a base and an array of upstanding air cells arranged in longitudinal and transverse rows that have deflection characteristics that create airflow paths between the deflected cells so as to provide for ventilation and heat dissipation.  
      In one aspect of the invention, the cushion of the present invention includes a base with an array of individual upstanding, spaced apart, interconnected air cells arranged in a desired pattern of transverse and longitudinal rows having ambient air flow paths between the cells. In this aspect of the invention, the cells have a generally circular horizontal cross section. Each cell has a dome-shaped top and a perimeter wall that tapers inwardly from the base to the top resulting a cone-shaped cell with a rounded top surface. The circumference of the cell at its base is greater that the circumference of the top of the cell so that when the cell is depressed or compressed, the cell collapses inwardly and the periphery of the compressed cell does not protrude beyond the circumference of the base to impinge upon the ambient air flow paths between the cells. When the cell is depressed or collapsed by the weight of the seated user, ambient air can circulate among the cells to dissipate heat generated by the seated user.  
      These same characteristics may be employed in a cushion having cells of different configurations that allow for the cells to collapse inwardly so that the periphery of the collapsed cell does not protrude beyond the perimeter of the base. Such designs could be pyramidal, pyramidal with a flattened top surface, conical, frusto-conical, or the like, wherein the dimension around the perimeter of the base of the cell is greater than the dimension of the perimeter of the top of the cell.  
      The overall configuration of the cushion can be any desired configuration so as to conform to a seating surface such as a chair, vehicle seat, bench and so forth. The cushion can include cells of varying configurations around the periphery of the bases so as to create rear or side bolsters or transition areas between the cushion and the seating surface. The cushion can be expanded in size to conform to the size of a bed, for example, and be employed as a mattress.  
      The cushion of the present invention preferably is vacuum molded from a suitable plastic material, but also can be dip molded from alternative materials such as neoprene or the like. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a rear perspective view of a cushion of the present invention;  
       FIG. 2  is a perspective view of an alternative configuration of the cushion of the present invention;  
       FIG. 3  is a perspective view of another alternative configuration of the cushion of the present invention;  
       FIG. 4  is a top plan view of the cushion of  FIG. 1 ;  
       FIG. 5  is a vertical cross sectional view of an air cell taken along line  5 - 5  of  FIG. 4 ;  
       FIG. 6  is a vertical cross sectional view of the air cell of  FIG. 5  in a compressed state;  
       FIG. 7  is top plan view of another configuration of the cushion of the present invention; and  
       FIG. 8  is another top plan view of the cushion of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      A cushion of the present invention is indicated generally by reference numeral  10  in  FIGS. 1 and 4 . A similar, but alternative configuration of the cushion is also illustrated in  FIG. 8  as  10 A. Referring to these particular figures, cushion  10  or  10 A comprises a base  12  and an array of upstanding individual air cells  14  arranged in transverse and longitudinal rows resulting in a desired peripheral configuration, in the case of cushion  10  and  10 A, the cushion is configured to adapt to placement on a seating surface such as a chair or vehicle seat.  
      Base  12  is comprised of a top layer  16  ( FIGS. 5 &amp; 6 ), which includes the integrally molded cells  14 , and a bottom layer  18 . The respective layers generally are vacuum molded from a suitable material, such as polyvinyl chloride or other plastic material. The layers also can be dip molded from neoprene following the principles set out in U.S. Pat. No. 4,541,136, which is incorporated herein by reference.  
      The two layers have complementary air channels formed between the cells so that when the two layers are appropriately bonded together, either by RF welding or gluing or the like, there are patent air channels  19  interconnecting the cells. There is an air-filling valve  20  in fluid connection with at least one cell for introducing air into the cushion. Because the cells are interconnected, air introduced through valve  20  flows among the cells until the cells have equal internal pressure.  
      As will be appreciated by referring to  FIGS. 4 and 5 , the cells  14  in the primary seating area, which generally comprises the center of the cushion, are of a uniform configuration having and circular base  22 , a rounded or dome shaped top surface  24  and a peripheral wall  26  that tapers inwardly from bottom to top, giving, in the preferred embodiment, an overall appearance of cone, better illustrated in  FIG. 5 .  
      Referring again to figures, the cells  14  are spaced apart in the array, resulting in ambient air flow paths between the cells, as shown by reference numeral  28 . These paths allow air to circulate among the cells so as to provide some cooling and dissipation of heat that may build up between the body of the user seated on the cushion and the cushion itself. As shown in  FIG. 6 , when cell  14  compressed or depressed by the weight of the user, the top surface of the cell and the cell wall curl into the cell itself, resulting in a compressed cell having a perimeter dimension generally less than, and no greater than, the circumference of the base of the cell.  
      Because cell  14  has the above described compression characteristics, the cell wall is not deflected in such a manner as to impinge on the surrounding airflow paths  28 . Consequently, the cushion maintains its heat dissipating characteristics even under load. This ventilation and heat-dissipating feature of the novel cushion allows prolonged seating comfort in situations where the user does not require the benefit of therapeutic shape fitting technology.  
      The ventilation and heat dissipating structure can be incorporated into complex cushion designs, such as those shown in  FIGS. 1, 4  and  8 . For example, cushions  10  and  10 A include cells  30  along the rear periphery that function as bolsters to give added structure and support to the cushion. Cell  30  has a generally elongated base  32  and cell wall  34  that tapers inwardly toward the apex  36 . However, as illustrated by  FIGS. 4 and 5 , the cross section of cell  30  taken across the center of the cell discloses that the cell has the same compressive qualities as cell  14 . The apex of cell  30  will collapse into cell and the cell wall does not deflect beyond the perimeter of the cell base.  
       FIGS. 2, 3  and  7  illustrate other general configurations of cushions of the present invention, illustrated as  10 B,  10 C and  10 D respectively. Similarly numbered structures in cushions  10 B- 10 D correspond to the same structures in the previously described cushions. The configurations of cushions of the present heat dissipating design are limited only by the configuration of the seating surface on which they are to be used. In other words, the invention lies in the configuration, spacing and compression characteristics of the cells and not in the ultimate use of the cushion. The cells of the various embodiments  10 B- 10 D have the same generally configuration so as to fold in upon themselves when compressed or depressed and not deflect inordinately into the surrounding ambient air passage areas  28  to allow for flow of air among the cells and the dissipation of heat.  
      These same characteristics may be employed in a cushion having cells of different configurations that allow for the cells to collapse inwardly so that the periphery of the collapsed cell does not protrude beyond the perimeter of the base. Such designs could be pyramidal, pyramidal with a flattened top surface, conical, frusto-conical, or the like, wherein the dimension around the perimeter of the base of the cell is greater than the dimension of the perimeter of the top of the cell. Consequently, any cell design, that collapses into itself resulting in air flow paths around or between the cells is intended to be included within the scope of the claims, whether that cell design is now for seeable or unforeseeable to one skilled in the art.  
      The cushions of the instant invention can be used as shown or with a cover, preferably a cover that has some elasticity, such as a stretchable fabric, and also some porosity or airflow characteristics through the material.  
      Various changes and modifications may be made in the heat-dissipating cushion of the present invention without departing from, or limiting the scope of, the invention.