US Patent 8251448 Dynamic chair back lumbar support system

A chair back according to embodiments of the present invention includes a rigid support member for reclinable attachment to a base, a flexible frame member having a flexible frame and a mesh, the mesh at least partially spanning the frame, and a seat attachment member moving in synchronization with the rigid support member at a different rate than the rigid support member during reclining of the rigid support member, wherein a first portion of the flexible frame member is affixed to the rigid support member, wherein a second portion of the flexible frame member flexes freely, wherein the seat attachment member contacts at least part of the second portion of the flexible frame member, wherein the first portion moves with the rigid support member and the second portion moves with the seat attachment member such that a curvature of the second portion increases as the rigid support member reclines.