Shape-changing support, such as for seating

Abstract

A compliant back for a seating unit includes a rigid upright defining a track, and a flexible back shell configured to support a seated user's upper body, including a top pivot pivotally connected to a top section of the back shell and a pivot/slide member slidably connected to the track of the back shell. A biasing device is operably coupled to the pivot/slide member that biases the pivot/slide member toward a position where the flexible back shell protrudes forwardly to a shape chosen to optimally support a seated user.

We claim:  
     
         1 . A back construction for a seating unit comprising: 
 a back frame including a rigid upright having top and bottom connections;    a flexible back shell configured to support a seated user's upper body, including a pivot member pivotally connected to one of the top and bottom connections and a pivot/slide member slidably connected to the other of the top and bottom connections; and    a spring operably coupled to a pivot/slide member that biases the pivot/slide member back shell toward a position where the flexible back shell protrudes forwardly for optimal lumbar support to a seated user.    
     
     
         2 . A back construction for a seating unit comprising: 
 a back frame including a rigid upright having top and bottom connections;    a flexible back shell configured to support a seated user's upper body, the shell being pivotally attached to the back frame at the top connections and movably attached to the back frame at the bottom connection; and    an energy mechanism being positioned so as to operably act upon the back shell and cause the flexible back shell to protrude forwardly for lumbar support to a seated user.    
     
     
         3 . The back construction defined in  claim 2 , wherein the bottom connection includes a sliding connector.  
     
     
         4 . The back construction defined in  claim 2 , wherein the energy mechanism includes one of a spring and bladder.  
     
     
         5 . A support apparatus comprising: 
 a shell having a front surface, and including relatively stiff top and bottom sections separated by a flexible middle section, the middle section including edge strips connecting the top and bottom sections, the edge strips being made of a longitudinally stiff but bendable plastic;    a horizontal cross section through the middle section being forwardly concave so that the front surface on a center area of the middle section is positioned rearward of the edge strips, and a vertical cross section through the middle section being forwardly convex so that the front surface on the center area of the middle section is forward of the top and bottom sections;    an energy mechanism positioned vertically on the front surface and across the center area and having top and bottom ends attached to the top and bottom sections; the energy mechanism being movable to a constricted position where the top and bottom ends are pulled toward each other causing the top, bottom, and center sections to move toward a first vertical shape; the energy mechanism being movable to a relaxed elongated position where the top and bottom ends are allowed to extend from each other causing the top, bottom, and center sections to move toward a different second vertical shape;    whereby, by constricting and relaxing the energy mechanism, the shell is flexed between the first and second vertical shapes.    
     
     
         6 . The support apparatus defined in  claim 5 , wherein the first vertical shape is a more curved vertical shape and the second vertical shape is a more planar vertical shape.