Abstract: A seat device for supporting a sitting person includes: a first movably supported partial seat for supporting the person and a second partial seat for supporting the person, which is movably supported independently of the first partial seat and which can be combined with the first partial seat to form a whole seat. In order to enable better sitting, for each partial seat a pivot bearing spring device is provided, said pivot bearing spring device having a first pivot axis extending in a longitudinal direction, about which the respective partial seat can be pivoted while sprung with a first spring constant, and a second pivot axis extending in a transverse direction, about which the respective partial seat can be pivoted while sprung with a second spring constant, wherein each partial seat is associated with the respective pivot bearing spring device by means of a lever arm.

Abstract: The invention relates to a dimensionally-stable leg part that can be allocated to a seat device, which leg part is respectively allocated to a left or right upper leg of a person from the knee to the hip and is in close contact with the upper leg form, wherein the leg part contacts flat to the outside of the hip, on the underside of the thigh at least on the distal end, and at least inside and outside on the knee. The invention is further directed to seat devices, particularly vehicle seat devices and vehicle seat extraction systems having said leg parts. In addition, the invention relates to a seat device, preferably a vehicle seat device or vehicle seat extraction system having a U-shaped support device for the back underneath the shoulder having lateral support for the chest, which solely surrounds the adjacent back and chest.