Abstract: Two subassemblies located on the left and right of a seat provided or not with a massage system, each one provided with a bowed arc wire, a straight wire or a molded component, which under the forces exerted by the traction cables on the ends of the arc or on the middle of the straight wires, are respectively arching or relocating, pushing or pulling the back cover or the foam back pad of the seat at the lumbar region of the occupant, generating the lumbar variable pressure.

Abstract: An assembly comprising of spiral sub-assemblies, each provided with plastic rollers and connected to an output shaft of a gearbox attached to a swinging beam, is mounted to a seat frame with two vertical wires. Two adjustable cables are connected to the swinging beam-ends, and press the spiral assembly rollers against the seat-back cover by bending the vertical wires. The rotation of the spiral assemblies moves the contact points of the rollers with the seat-back cover up and down, creating a massage effect throughout the seat-back cover.