Patent ID: 7806478

Claim:
A task chair capable of forward and rearward synchronized movement, the task chair comprising: a base assembly; a linkage supported by the base assembly to pivot about an axis in relation to the base assembly; a seat assembly pivotally retained relative to the linkage; and a back assembly pivotally retained relative to the linkage; wherein the linkage comprises a bracket and a resiliently deflectable assembly retained relative to the bracket, wherein the resiliently deflectable assembly has a first end and a second end, and wherein the bracket has a force-bearing portion that engages the resiliently deflectable assembly of the linkage whereby the linkage and the seat and back assemblies pivotally retained relative to the linkage can pivot in relation to the base assembly; wherein the force-bearing portion is slidable relative to the bracket and longitudinally between the first and second ends of the resiliently deflectable assembly to adjust the effective location of force applied to the resiliently deflectable assembly by the force-bearing portion; and wherein the resiliently deflectable assembly of the linkage comprises a leaf spring stack with a plurality of leaf springs of sequential lengths and wherein the force-bearing portion of the bracket is disposed to engage a longest leaf spring of the leaf spring stack wherein the leaf spring stack is disposed in a leaf spring housing with an elongated tail disposed to a side of the leaf spring stack adjacent a shortest leaf spring of the leaf spring stack, wherein the leaf spring stack is retained by the leaf spring housing at a proximal end of the leaf spring stack, wherein the leaf spring stack is free at a distal end of the leaf spring stack, and wherein the elongated tail has an interior wall that tapers from a proximal end adjacent to the proximal end of the leaf spring stack toward a distal end adjacent to the distal end of the leaf spring stack.