Patent ID: 8684460

Claim:
A backrest structure for a seat comprising; a backrest frame which has a support structure and a front side facing a back of a seat user; a backrest cushion at the backrest frame; a lumbar support mounted on the front side of the backrest frame for supporting the back of a seat user; an adjusting device for adjusting the position of the lumbar support perpendicular to the extension plane of the backrest frame; and a curving element arranged on the front side of the backrest frame between the lumbar support and the backrest cushion, wherein the curving element is secured to the support structure and the adjusting device acts on the curving element in order to adjust a curvature of the curving element, wherein the curving element is mounted to the support structure in front of the adjusting device and comprises at least one fastening section via which the curving element is secured to the supporting structure, and wherein at least one connecting element is connected to the curving element and the support structure, the at least one connecting element connecting the curving element to the support structure in addition to a connection via the fastening section and the at least one connecting element applying a pre-tensioning force to the curving element in a direction towards the support structure and away from the backrest cushion arranged in front of the curving element in order to maintain the curving element in such a contact with the support structure to minimize movement of the curving element against the support structure and the adjusting device.