Proportional flow metering valve

Claim 1

A SERVOMECHANISM COMPRISING: A PILOT MEMBER; A SECOND MEMBER HAVING A SURFACE DISPOSED IN FLUID SEALING RELATION WITH THE SURFACE OF SAID PILOT MEMBER; FLUID PRESSURE MEANS INCLUDING A FLUID PRESSURE CHAMBER FOR EFFECTING RELATIVE MOVEMENT OF SAID MEMBERS IN ONE DIRECTION ALONG A DIRECT LINE PARALLEL TO SAID SURFACES; MEANS TO EXERT FORCE ON SAID MEMBERS FOR URGING THE LATTER IN THE OPPOSITE DIRECTION OF RELATIVE MOVEMENT THEREOF; THERE BEING A FLUID PASSAGE COMMUNICATING A FLUID INLET TO A FLUID OUTLET THROUGH PORTS IN ONE OF SAID SURFACES AND THE OTHER SURFACE HAVING MEANS FOR PROGRESSIVELY AND SIMULTANEOUSLY COVERING ONE PORT AND UNCOVERING THE OTHER PORT IN RESPONSE TO RELATIVE MOVEMENT OF SAID MEMBERS ALONG SAID DIRECTION LINE AND IN SUCH MANNER THAT THE PRESSURE IN SAID CHAMBER IS DECREASED IN RESPONSE TO RELATIVE MOVEMENT OF SAID MEMBERS IN SAID ONE DIRECTION AND INCREASED IN RESPONSE TO RELATIVE MOVEMENT OF SAID MEMBERS IN SAID OPPOSITE DIRECTION; AND MEANS FOR ADJUSTING SAID PILOT MEMBER TO VARY THE EFFECTIVE AREA OF SAID PORTS INDEPENDENTLY OF THE RELATIVE MOVEMENT OF SAID MEMBERS.