hayner

Claim 1

A FLOW-CONTROL, HYDRAULIC, SERVO VALVE HAVING FEEDBACK, COMPRISING: A SOURCE OF FLUID UNDER PRESSURE; PILOTVALVE MEANS INCLUDING A VARIABLE PRESSURE CHAMBER COUPLED TO SAID SOURCE OF FLUID, SAID CHAMBER HAVING A NOZZLE TO PRODUCE A FLUID JET-STREAM ALONG AN AXIS, AND A MOVABLE PILOT-VALVE MEMBER ADAPTED TO MOVE ALONG SAID AXIS IN OPPOSITION TO SAID JET-STREAM TO VARY THE PRESSURE IN SAID CHAMBER IN ACCORDANCE WITH AN INPUT SIGNAL; CONTROL VALVE MEANS COUPLED TO SAID CHAMBER AND HAVING AN OUTPUT CONTROL OUTLET, SAID CONTROL VALVE MEANS BEING ADAPTED TO CONTROL THE APPLICATION OF FLUID UNDER PRESSURE THROUGH SAID OUTLET IN ACCORDANCE WITH VARIATIONS IN PRESSURE FROM SAID CHAMBER; A RESTRICTED-ORIFICE MEANS COUPLED TO SAID OUTLET FOR DEVELOPING A DIFFERENTIAL-PRESSURE ACROSS SAID ORIFICE VARYING IN ACCORDANCE WITH THE VELOCITY OF FLOW OF SAID FLUID; AND FEEDBACK-PRESSURE MEANS COUPLING SAID DIFFERENTIAL-PRESSURE AND SAID MOVABLE PILOT-VALVE MEMBER TO VARY ITS POSITION IN ACCORDANCE WITH SAID DIFFERENTIAL PRESSURE AND PROVIDE SAID FEEDBACK TO PRODUCE AN OUTPUT FLUID VELOCITY VARYING ONLY WITH SAID INPUT SIGNAL.