Patent ID: 7320503

Claim:
A backrest with a support area extending from a first and lower end region to a second and top end region for supporting the back of a user, said backrest comprising: at least one mounting element for mounting the backrest to a backrest bracket, said at least one mounting element being arranged between the end regions at a distance from the first end region and at a distance from the second end region of the support area, and at least one extended structure with a tension element at the front side of the structure and a pressure element at its rear side, both the tension element and the pressure element extending from the first end region of the support area to the second end region of the support area, whereby the tension element connects the first end region of the support area to the second end region of the support area thereby transmitting tensile forces, and the pressure element is in the extension direction non-displaceably connected to the tension element as well in the first end region of the support area as in the second end region of the support area, the pressure element between the first end region and the second end region is arranged at a distance from the tension element and can take thrust forces, between the end regions the tension element and the pressure element are connected to one another by means of spacers, which spacers keep the distance between the pressure element and the tension element and allow a relative movement between the tension element and the pressure element in the extension direction of the structure, and the spacers together with the tension element and the pressure element in a cross section in the extension direction form a polygon structure, said structure having angles that are deformed by loading.