Patent ID: 7721758

Claim:
A valve ( 1 ), comprising: a body ( 2 ); a bushing ( 3 ) slidably mounted on said body; a valve spool ( 4 ) slidably mounted on said bushing; said bushing and spool having respective control edges ( 5 ) that are adapted to cooperate with one another as a function of the relative position between said bushing and spool to vary the size of a control opening therebetween; a first drive ( 11 ) operatively arranged to controllably move one of said bushing and spool relative to said body; and a second drive ( 12 ) operatively arranged to controllably move the other of said bushing and spool relative to said body; whereby said first and second drives may be selectively operated to move said bushing and spool simultaneously in opposite directions to increase the dynamic response of said valve.