A spring loaded vehicle seat is of the kind having a seat frame and an underframe supports this seat frame by levers and a pneumatic spring so that the seat is maintained at a constant height. Valves control the flow of air to and from the spring to counteract the effect of vibrations. A switch mechanism controls the operation of the valves and a coupling device transmits vibrations of the seat to the mechanism. The coupling device is arranged so that movement of the mechanism after opening a valve lags behind the vibration of the seat.
