Abstract:
An ergonomic passive support surface comprising a set of foam support elements and a pressure equalization layer which is preferably a fibrous fill material layer or foam layer. Pressure distribution is controlled by the characteristics and shape of a foam material. Preferably, the foam material is provided as a set of transverse oriented cylindrical sections, selected for desired support characteristics.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of mattresses, and more particularly to mattresses which relieve excess pressure. 
     BACKGROUND OF THE INVENTION 
     There are many different types of mattresses which relieve pressure, and which include foam elements or foam-filled pneumatic chambers useful for pressure relieving patient support surfaces. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a set of designs incorporating a foam support, which acts below a fiber layer, see, e.g., U.S. Pat. No. 6,946,196, expressly incorporated herein by reference, or the like, to distribute the patient&#39;s weight over the mattress to avoid pressure injury or necrosis. 
     According to this embodiment, a non-powered pressure relieving patient support surface is provided which in a preferred embodiment, comprises a fluid, stain and odor resistant, anti-bacterial, anti-fungal top cover; a set of foam elements, e.g., closed cell polyurethane foam, preferably hemi-cylindrically shaped, providing a set of zones to provide proper support for various parts of the body; and a fibrous material which interfaces the cover with the foam elements, to evenly distribute the patients weight. The foam elements are preferably longitudinally oriented, and provided in sequential adjacent groups, arranged in longitudinal series each group forming a zone intended for a body region, such as head, seat, and foot. The foam elements of each zone, for example, may differ in the diameter of the foam cylinder and the respective portion thereof, the firmness of the foam, and the longitudinal compaction. 
     It is thus appreciated that a variety of parameters of the foam may be varied to achieve the desired firmness, for example the closed-cell or open cell nature, the density of the foam, the tapering of the foam from base, which generally forms a contiguous foam region, and the top (beneath the fiber layer), which is discontinuous, having gaps between the respective foam elements, and the number and size of the elements, which are typically longitudinally disposed within a zone. 
     A relatively firm foam edge is optionally provided, to give increased support (e.g., the ProCair VR™), such that edge of the mattress does not compress as easily, thus supporting a person sitting at the edge of the bed, and reducing the tendency to roll out of the bed. 
     The construction and method of operation of the invention will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a partial cutaway perspective view of an exemplary mattress design. 
         FIG. 2  shows the relatively uniform pressure distribution, as measured using an XSensor X2 pressure assessment tool, of the mattress according to  FIG. 1 . 
         FIGS. 3A ,  3 B and  3 C show, respectively, a top, side and end view of the mattress, showing the various sections of the mattress and their respective foam elements. 
         FIG. 4  shows an exploded view of the mattress design. 
         FIGS. 5A ,  5 B,  5 C,  5 D and  5 E show, respectively, a top, section AA, section BB, side and end view of the foam elements arranged in position. 
         FIG. 6  shows a perspective view of the foam elements in the mattress of  FIGS. 5A-5E . 
         FIGS. 7A ,  7 B and  7 C show, respectively, a top, side and end view of a full fiber layer. 
         FIGS. 8A ,  8 B and  8 C show a top, side and end view of a partial fiber layer. 
         FIG. 9  shows a perspective view of the fiber pad(s) on the mattress. 
         FIGS. 10A ,  10 B, and  10 C show an end, top, and side view of a mattress cover, including hold-down loops. 
         FIGS. 11A ,  11 B and  11 C show a perspective view of the mattress cover and details of a cover and hold-down loop, respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Now, the exemplary mattress design will be described in detail with reference to the accompanying drawings. 
       FIG. 1  shows a partial cutaway perspective view, and  FIG. 4  shows an exploded view, of the exemplary mattress design.  FIG. 4  shows an exploded view of the mattress design. The illustrated mattress is an elongated mattress, and extends along a longitudinal axis. The longitudinal axis of the illustrated mattress extends from a head end  1 ′ (shown in  FIG. 4 ) to a heel section  5 . A set of tubular foam elements  1  are provided on a dense foam bottom  6  (not shown in  FIG. 1 ). The illustrated tubular elements have a diameter and a perpendicular length dimension. The illustrated tubular foam elements  1  are disposed with the length dimension extending along the longitudinal axis. The tubular foam elements  1  are inside of a firm foam surround  4  formed of four sides bonded together. On top of the foam elements  1  are full foam layer  7  and partial foam layer  8  and corresponding partial fibrous fill layer  9  and full fibrous fill layer  2 , for example Triline Medical LLC “Trifill” or Fossfill® Supreme. The sloped heel section  5  provides heel pressure relief. A low shear upper surface  3 , which is fluid proof, stain resistant, anti-bacterial and antifungal is zippered to the mattress, permitting replacement and cleaning.  FIGS. 3A ,  3 B and  3 C show, respectively, a top, side and end view of the mattress, showing in dotted lines the various sections of the mattress and their respective foam elements  1 .  FIGS. 5A ,  5 B,  5 C,  5 D and  5 E show, respectively, a top, section AA, section BB, side and end view of the foam elements arranged in position.  FIG. 9  shows a perspective view of the fiber pad(s) on the mattress, which are bonded to the firm foam surround  4 . 
       FIGS. 7A ,  7 B and  7 C show, respectively, a top, side and end view of the full fiber layer  2 .  FIGS. 8A ,  8 B and  8 C show a top, side and end view of the partial fiber layer  9 . The fill layers are, for example, navy stretch interlock fabric with Fossfill® Supreme filling. At the head portion of the mattress, the partial foam layer  8  is absent and the partial fibrous fill layer  9  is present. 
       FIG. 6  shows a perspective view of the foam elements in the mattress of  FIGS. 5A-5E . The foam elements at the head end  1 ′ and body section  1 ″ are preferably 2.3 HR 23 ILD, with respectively different element radii. The firm foam surround is preferably 1.8 LD 55 ILD, the foam bottom  6  preferably 1″ thick 1.4 Lb 44 ILD. The full and partial foam layers  7 ,  8  are preferably each 1″ thick 2.3 HR 23 ILD. 
     The foam bottom  6  is preferably supported in an Integrity 30 Fire Barrier, cut to fit 80″×36″×7″, sewn closed on the ends. 
       FIG. 2  shows the relatively uniform pressure distribution, as measured using an XSensor X2 pressure assessment tool, of the mattress according to  FIG. 1 . As shown in  FIG. 2 , the pressure distribution of the back and buttocks is well distributed and relatively even, and pressure extremes are not seen at the head, arms and legs. 
       FIGS. 10A ,  10 B, and  10 C show an end, top and side view of a mattress cover  10 , including hold-down loops  11  (two per lateral side) and corner web extensions  12  (two per corner).  FIG. 11A  shows an isometric view of the mattress cover  10 , while  FIGS. 11A and 11B  show details of a corner web extension  12  cover and hold-down loop  11 , which is reinforced with a webbing strip  13 , respectively. Vent holes  14  are provided in the cover  10  to avoid ballooning. 
     The present invention therefore provides a simple passive patient support system which is simple in construction, readily manufactured using known techniques, and which provides enhanced patient comfort and therapy. 
     According to the exemplary mattress design, the patient is supported by foam elements, with a pressure equalization layer which is preferably a non-woven fibrous material fill layer. Pressure measurements of this design show superior performance over traditional designs. Optionally, a firm foam surround is provided to support a person sitting at the edge of the mattress and to avoid a tendency to roll out of bed. 
     The exemplary mattress design is also applicable to non-medical mattresses and other ergonomic support surfaces, such as beds, couches, chairs, lounges, and the like. 
     Although the invention is illustrated and described herein as embodied in a foam mattress, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.