US Patent 7681952 Chair with tiltable backrest

A chair having a base adapted to support the chair on a support surface, and a seat and backrest mounted on the base that includes a flexible backrest and a relatively simple tilt mechanism for tilting the backrest relative to the seat. The tilt mechanism includes a pair of dual cantilevered U-shaped springs mounted on opposite sides of the base and in communication with the backrest. The backrest is mounted to the tilt mechanism such that a rearward thrust applied by the user deflects an outer end of each U-shaped spring downwardly to enable rearward tilting of the backrest relative to the seat. Upon removal of the rearward thrust, the backrest elastically returns to its initial position under the biasing force of the U-shaped springs.