Vehicle seat backrest with flexural joint motion-control

A vehicle seat, comprising:

• a foundation adapted for attachment to a vehicle floor;
• a seat bottom mounted on the seat foundation;
• a support frame extending upwardly from the seat bottom;
• a deformable seat shell adapted to assume various shapes between an initial lordosis position and a final kyphosis position in response to a variable rearward load applied by the torso of a passenger seated on the seat bottom;
• and
• first and second shell mounts, each shell mount having a stationary mount coupled to the support frame at a fixed location and first and second movable joints coupling the deformable seat shell to the stationary mount, wherein each of the first and second joints is configured for movement about respective first and second pivot axes during shape-changing deformation of the deformable seat shell, and wherein at least one of the joints is a flexural joint configured for bending movement about one of the pivot axes.