Abstract: An adjustable ergonomic back for a seat is disclosed. The back has a plurality of back cushions, each cushion having at least one adjustment area. It further comprises a structural shell having a plurality of voids therein. A plurality of thin flexible elements are located between the back cushions and the structural shell, each flexible element being attached to the structural shell. Each of the flexible elements has a front surface and a back surface, the front surface being in contact with a respective adjustment area of one of the plurality of back cushions. The back further has a plurality of actuators located between the flexible elements and the structural shell, each of the actuators being in contact with one of the respective back surfaces of the flexible elements and exerting a pressure on the back surface.

Abstract: An object of the present invention is to provide a compact base for a seat with a suspension for a vehicle driver, for use in buses, heavy vehicles or special use vehicles, including excavation vehicles or foresting equipment, in which the operator or driver is subject to vibrations. The present invention provides total independence of the suspension properties, including stiffness, damping and range of travel, with height adjustment. In order to accomplish this, the compact base for the seat is divided into parts including a suspension and a seat height adjustment mechanism. These parts have no common component including balloons, dampers or guiding systems. In this manner, the suspension properties of the seat are not affected by the seat height adjustment. Moreover, the invention provides a compact seat base through the use of structures and balloons that fit one within the other.