a vibration compensating vehicle seat suspension combines the vertical movement of the parallelogram suspension with the pivoting of the knee - pivot suspension . three embodiments all include a horizontal pivot for pivoting of the seat , and a sublinkage for simultaneous vertical movement of the seat . a first embodiment includes a horizontal pivot and a vertical slide for sliding of the pivot . a rocking lever which rocks due to pivoting of the seat causes sliding of the pivot . a second preferred embodiment includes a horizontal pivot and a linkage for vertical movement of the front of the seat . a third preferred embodiment includes a horizontal pivot , a vertical slide , and a spring for biasing the pivot .