A chair comprising a frame having a seat portion and a back portion is adapted to support the trunk of the body of an occupant. The frame is supported on a base. The chair includes a mechanism for allowing that part of the body portion supporting the upper trunk of the body of the occupant to tilt relative...http://www.google.sh/patents/US5114210?utm_source=gb-gplus-sharePatent US5114210 - Tilting chair with improved lumbar support
