Patent ID: 7118177

Claim:
A chair comprising: a support structure for supporting a seat and a backrest, in which the backrest comprises a bearing portion and two connecting portions for connecting the backrest to the support structure, wherein the bearing portion is a surface for bearing a user's back and is provided with at least one weakened area which allows a relative elastic deformation between two adjacent backrest sections, characterized in that said weakened area has the shape of a line which extends on the surface of the backrest, wherein the two connecting portions each comprise a reaction portion housed within a box element that is fixed relative to the support structure and each of the box elements contain an elastic element, and the backrest is tiltable rearwards relative to a resting position under a rearwards thrust applied by the user and elastically returns to the resting position when said rearwards thrust ceases, characterized in that the rearwards tilting of the backrest is formed in part by an elastic deformation of the bearing portion and in part by a displacement of at least a part of the connecting portion relative to the support structure.