US Patent 10470574 Chair having synchronized backrest and seat movements

A chair includes a seat and a backrest connected to a leg assembly. The front part of the seat is mounted on the leg assembly via a pivot link about an axis. The backrest is connected to the seat by a flexible intermediate part fixed to the leg assembly in the vicinity of the pivot of the seat for the purpose of a pivoting movement of the intermediate part by elastic deformation about an axis. The rear part of the seat is supported by the intermediate part, for example with at least one coupling element.