Air-sprung seat for vehicles

Claim 1

A pneumatically sprung seat for vehicles comprising a seating surface, said seating surface being borne by a seat frame, said seat frame being carried by an air-spring unit that is variable in its springing force, said air-spring unit comprising a first chamber having a constant volume of air, said first chamber being open at each end, the upper end of said chamber communicating with a second chamber, said second chamber being airtight and having deformable walls, said second chamber being attached at one end to said seat frame and the other end being attached to said first chamber, said second chamber being adapted to increase and decrease in volume in accordance with the movement caused by weight applied to said seating surface, the other end of said first chamber communicating with an airtight fluid chamber adapted to receive a body of liquid and a volume of air above said body of liquid communicating with the interior of said first chamber, said fluid chamber being provided with a piston, means to adjust and maintain the position of said piston to vary the volumE of said chamber and thereby regulate the compression space of the air above the liquid in said fluid chamber.