Lordosis-support backrest for a vehicle seat

A lordosis-support backrest for an automotive vehicle seat, said backrest comprising:

• a frame;
• a plurality of resiliently yieldable substantially vertically extending tension wires connected to said frame;
• a selectively deformable and shiftable back-bracing element mounted on said wires for displacement up and down thereon, said back-bracing element comprising:
• upper and lower members guided on said wires,
• flexible means connected between said upper and lower members for bulging toward a person seated on said seat upon movement of said upper and lower members toward one another,
• a first drive mechanism, a rack connected to said back-bracing element and first drive means connected to said rack for displacing said back-bracing element along said guide wires;
• and
• a second drive mechanism including a rack displaceable on said back-bracing element, a rocker lever articulated to said rack and respective substantially rigid links connecting spaced-apart locations on said lever with said upper member and said lower member respectively, and second drive means connected with said rack of said second drive mechanism for displacing the same to move said upper and lower members apart and together,
• at least one of said drive means including:
• a motor,
• a flexible shaft connected to and driven by said motor,
• a transmission including a worm and wormwheel driven by said shaft, and
• a pinion connected to said transmission and meshing with a respective one of said racks for actuating the respective drive mechanism.