Patent ID: 7625044

Claim:
A chair backrest, comprising: a support structure constituted by a single piece of injected plastic material, including a bearing section having a front surface against which a user's back is to bear, the bearing section having an opening that extends in a lumbar region of said front surface, the backrest comprising a lumbar support panel movably positioned in said opening, the lumbar support panel having a front surface against which a lumbar region of the user's back is to bear and having an outer perimeter that is connected to the edge of said opening by means of an elastic element that tends to thrust the support panel towards a position in which the front surface of the lumbar support panel projects anteriorly relative to the front surface of said bearing section, wherein the support structure and the lumbar support panel are made of a first relatively rigid plastic material and wherein the elastic element is made of a second relatively flexible injected elastic material.