A structural support shell for a tilt-back chair has a back portion, a seat portion, and a flexible compression zone extending between the back and seat portions in an integrally molded, one-piece unit. The chair has a base with a recline control pivoting recline control lever. The seat ...http://www.google.com.au/patents/US5842264?utm_source=gb-gplus-sharePatent US5842264 - Chair construction and method of assembly
