Patent attributes
A back portion (16) for a chair (10) includes a peripheral frame (34) defining an opening therein. A lumbar support portion (36) is disposed in the opening. The lumbar support portion (36) comprises a substantially rigid panel (207). Two hinge devices (214) are hingedly mounted on opposite sides of the peripheral frame (34). The lumbar support portion (207) is mounted on the peripheral frame by the two hinge devices (214). Each hinge device has a biasing device (226) associated with it to bias the hinge devices (214) forwardly relative to the peripheral frame (34). A cushion (540) may be mounted atop the lumbar support portion (207). The cushion has a first substantially planar sheet (542) of resiliently flexible material and a second substantially planar sheet (544) of resiliently flexible material. The first and second sheets are separated by a plurality of spaced webs (546) of resiliently flexible material.