Seat assembly with movable inner seat back

A seat assembly for supporting an occupant above a floor of a motor vehicle, said seat assembly comprising:

• a seat cushion having opposite front and rear ends;
• an adjuster mechanism operatively coupled between the floor of the motor vehicle and the seat cushion, said adjuster mechanism allowing selective adjustment of said seat cushion relative to the floor among a plurality of vertical positions;
• and
• a seat back having:
• an outer frame, said outer frame having spaced apart side members, and wherein the spaced apart side members include bolsters formed thereon, at least one of said side members comprising a tower defining a belt exit for a seat belt, said tower being adapted to withstand loads associated with the weight of the occupant against said seat belt during a sudden deceleration of the vehicle;
• and
• an inner frame, said inner frame including a lumbar support formed thereon, said inner frame being slidably engaged with said side members for movement along a path defined by said side members, said inner frame of seat back being connected to said rear end of said seat cushion for movement of said inner frame relative to said outer frame along said path in response to corresponding adjustment of said seat cushion among said plurality of vertical positions wherein said lumbar support moves vertically relative to said bolsters that remain fixed in position.