US Patent 9211824 Adjustable firmness vehicle seat

A vehicle seat includes a seat back and a seat for supporting an occupant. A cushion is coupled to the seat and has at least one inflatable upper bladder for selectively adjusting the firmness of the cushion. The seat further includes an inflatable lower bladder positioned beneath the upper bladder. The seat is configured such that a vehicle seat hip pivot point is maintained when adjusting the firmness of the cushion by increasing the pressure in the lower bladder when the pressure in the upper bladder is selectively decreased, and by decreasing the pressure in the lower bladder when the pressure in the upper bladder is selectively increased.