US Patent 10172465 Chair with activated back flex

A chair back that includes a back support, an upright frame, and at least one flex wing. The back support is substantially flexible and has a first side portion and a second side portion. The upright frame is substantially rigid and has a first frame side and a second frame side. The flex wing is located between the first frame side and the first side portion, where the flex wing includes a front portion coupled to the first side portion, a back portion coupled to the first frame side, and a web portion interconnecting the front portion and the back portion. The flex wing flexes during engagement by a user.