SEAT SPRING SYSTEM

摘要

A seat suspension system, which includes a height adjustment valve for positioning a seat at a desired height in response to manual positioning of a height adjustment lever by controlling the amount of hydraulic fluid supplied to a cylinder having a piston therein coupled to the seat, provides damping of vertical motion of the seat by an accumulator coupled to the cylinder via a conduit so as to receive the hydraulic fluid from the cylinder and two different valves disposed in the conduit. A manually adjustable flow control valve has an adjustable orifice within the conduit for providing the seat with a nominal amount of damping. The damping of the suspension system is increased beyond the nominal amount in response to seat velocity in a downward direction by the second valve which responds to the pressure of hydraulic fluid flowing from the cylinder to the accumulator so as to restrict the flow of the fluid by an amount dependent upon the fluid pressure and thereby the rate of change of downward movement of the seat. At the same time the second valve is generally unresponsive to the pressure of fluid flowing in an opposite direction from the accumulator to the cylinder so as to be unidirectional in nature.