US Patent 7922247 Hydraulic adjustable seat

An adjustable chair and a tilt assembly for use therewith typically provides side to side tilting of the chair seat and preferably provides forward and backward tilting of the seat separately or in combination with the side to side tilting. A hydraulic system is provided for controlling the tilting movement. Progressive hydraulic valves are used to control the resistance to the tilting movement whereby the chair is useful for exercise while the user is seated and the rate at which the tilting occurs may be controlled. The seat may be locked in any tilted position or the user may shift weight on the seat to provide a continuous shifting of the tilt angle and tilt direction of the seat.