Lumbar support device

A lumbar support device, which includes an electric motor fixed on a seat frame, a lead screw operatively connected with said electric motor, a nut block in threaded engagement with said lead screw, an arm means operatively coupled to said nut block and a lumbar support plate provided at a free end of said arm means, such that a drive of said motor causes vertical movement of said nut block along said lead screw so as to simultaneously move said arm means, thereby displacing said lumbar support plate forwardly and backwardly relative to said seat frame,

• characterized in that the said arm means comprises:
• 1) an arm member rotatably supported upon said seat frame such as to be rotatable about a longitudinal axis of said seat frame, and operatively connected to said nut block so that vertical movement of said nut block causes said arm member to rotate, and
• 2) a wire member operatively connected to said arm member, said wire member comprising a first wire section which extends along a lower part of said seat frame and is operatively connected to said arm member so that said wire member rotates as said arm member rotates, and a second wire section which extends inwardly from said seat frame and terminates in a free end, said lumbar support plate being supported at said free end of said second wire section, whereby said lumbar support plate is rotated forwardly and backwardly with respect to the seat back frame as said wire member rotates.