Chair having ergonomic lumbar support cushion

Claim 1

A chair back for use with a chair comprising: (a) a lumbar support portion positioned to engage a chair occupant's lumbar region, said lumbar support portion having a pocket with a front face; (b) a lumbar cushion completely disposed within said pocket and situated approximately complementary to a chair occupant's lumbar region, said cushion including (i) a unitary, open-cell elastically-resilient cushion of foam positioned within a flexible, air-impermeable envelope, (ii) an air inlet/outlet conduit leading into said foam through .an opening in said envelope; (iii) a valve structure for controlling gas pressure within said foam for adjusting firmness of Said lumbar support in the chair and accessible to a chair occupant, said valve structure including (1) guide tube secured to said opening in said air inlet/outlet conduit; (2) an air impermeable plug manually slidable within said guide tube between an open position allowing flow of air and a resiliently biased closed position stopping flow of air; (3) a manually actuable member disposed within said guide tube and secured to said plug for moving said plug between said open and closed positions; (4) an outer flange forming part of said guide tube secured by its face to a side of said chair back; (5) a fixed, closed inner end wall having a central bore therethrough; (6) a manually-moveable outer end wall, said plug being disposed downstream of said fixed inner end wall and including a fixed, outwardly-projecting pin which extends through said bore and is fixed to said manually-moveable outer wall; and (7) a coil spring positioned between said outer end wall and said inner end wall.