Support surface

Abstract

A support surface including a cutout on a bottom surface of the support surface. The cutout, which can include a set of cutouts, provides a controlled structural collapse of the support surface by varying a stiffness in a cross-section. That is, the area in which the cutouts are positioned collapses more easily than the surrounding area of the support structure, thus making the area with the cutouts perceived as being softer. The cutouts can reduce the peak pressures on the portion of the user's body (for example, the user's ischial tuberosities) that is positioned over the cutouts. The support surface can also include a low-friction interface extending across a top surface of the support surface.

What is claimed is: 
     
         1 . A support surface for a user comprising:
 a one-piece, unitary body; and   cutouts in a bottom surface of the unitary body, the cutouts configured to collapse beneath bony prominences of the user.   
     
     
         2 . The support surface of  claim 1 , wherein the one-piece, unitary body comprises a single density substrate having a common cross-sectional stiffness, the common cross-sectional stiffness being constant therethrough when in an unloaded state, and wherein a region of the unitary body including the cutouts provides a variable cross-sectional stiffness in a loaded state such that the variable cross-sectional stiffness is less than the common cross-sectional stiffness. 
     
     
         3 . The support surface of  claim 1 , wherein the one-piece, unitary body comprises a single density substrate having a uniform cross-sectional stiffness when in an unloaded state, and wherein a region of the unitary body including the cutouts provides a variable cross-sectional stiffness when in a loaded state, the variable cross-sectional stiffness being less than the uniform cross-sectional stiffness. 
     
     
         4 . The support surface of  claim 1 , wherein the cutouts are geometric shapes selected from the group consisting of a dome, an elongated dome, a flat-topped dome, an ellipsoid, a semi-ellipsoid, a sphere, an elongated sphere, a semi-sphere, an elongated semi-sphere, a pyramid, a flat-topped pyramid, a box, a rectangular prism, a cone, a flat-topped cone, a cylinder, and a tapered cylinder. 
     
     
         5 . The support surface of  claim 1 , wherein a cross-section of the cutouts includes a semi-elliptical shape. 
     
     
         6 . The support surface of  claim 1 , wherein the cutouts include a set of cutouts having at least two cutouts. 
     
     
         7 . The support surface of  claim 6 , wherein at least one cutout of the set of cutouts being positioned near a back edge of the unitary body. 
     
     
         8 . The support surface of  claim 1 , further comprising a low-friction interface extending across a top surface of the unitary body, the low-friction interface positioned between the top surface of the unitary body and a fabric cover and the low-friction interface comprising a low-friction fabric. 
     
     
         9 . The support surface of  claim 1 , wherein the one-piece, unitary body and the cutouts are configured such that when the user sits on the support surface, a peak pressure on the user is less than about 81 mm Hg. 
     
     
         10 . A chair comprising:
 a base; and   a support surface provided on the base, the support surface comprising:
 a one-piece, unitary body; and
 cutouts in a bottom surface of the unitary body, the cutouts configured to collapse beneath bony prominences of a user. 
 
   
     
     
         11 . The chair of  claim 10 , wherein the cutouts are geometric shapes selected from the group consisting of a dome, an elongated dome, a flat-topped dome, an ellipsoid, a semi-ellipsoid, a sphere, an elongated sphere, a semi-sphere, an elongated semi-sphere, a pyramid, a flat-topped pyramid, a box, a rectangular prism, a cone, a flat-topped cone, a cylinder, and a tapered cylinder. 
     
     
         12 . The chair of  claim 10 , wherein the support surface and the cutouts are configured such that when the user sits on the support surface, a peak pressure on the user is less than about 81 mm Hg. 
     
     
         13 . The chair of  claim 10 , wherein the cutouts include a set of cutouts having at least two cutouts. 
     
     
         14 . The chair of  claim 13 , wherein at least one cutout of the set of cutouts being positioned near a back edge of the unitary body. 
     
     
         15 . The chair of  claim 10 , further comprising a low-friction interface extending across a top surface of the unitary body, the low-friction interface positioned between the top surface of the unitary body and a fabric cover and the low-friction interface comprising a low-friction fabric. 
     
     
         16 . A support surface comprising:
 a one-piece, unitary body formed of a single density substrate; and   a cutout on a bottom surface of the support surface, the cutout to provide a controlled structural collapse of the support surface by varying a stiffness in a cross-section of the support surface.   
     
     
         17 . The support surface of  claim 16 , wherein the cutout is geometric shaped, such as a shape selected from the group consisting of a dome, an elongated dome, a flat-topped dome, an ellipsoid, a semi-ellipsoid, a sphere, an elongated sphere, a semi-sphere, an elongated semi-sphere, a pyramid, a flat-topped pyramid, a box, a rectangular prism, a cone, a flat-topped cone, a cylinder, and a tapered cylinder. 
     
     
         18 . The support surface of  claim 16 , wherein the cutout includes a set of cutouts having at least two cutouts, and at least one of the cutouts being positioned adjacent a back edge of the unitary body. 
     
     
         19 . The support surface of  claim 16 , further comprising a low-friction interface extending across a top surface of the unitary body, the low-friction interface positioned between the top surface of the unitary body and a fabric cover. 
     
     
         20 . The support surface of  claim 19 , wherein the low-friction interface comprises a first close-knit fabric surface and a second close-knit fabric surface provided on the first close-knit fabric surface, the first and second close-knit fabric surfaces being positioned face to face such that the primary stitch direction of the first close-knit fabric surface is arranged perpendicular relative to the primary stitch direction of the second close-knit fabric surface.