Abstract: An electrohydraulic servovalve including a tailoring circuit coupled to provide a predetermined input signal to the motor of the valve. The predetermined signal functions to control the flow of fluid from the valve to effect a desired result. The electrohydraulic servovalve includes a housing defining round flow ports with a spool valve for metering flow through the ports. The spool valve substantially overlaps the round flow ports. The tailoring circuit includes a plurality of amplifiers each of which has a different gain. A command signal is applied to the amplifier and the output from the amplifiers is summed to provide an input signal to the motor of the electrohydraulic servovalve.

Abstract: Pressure gain compensation for a single-stage servovalve of the jet pipe type. The pressure gain compensation is provided by a separate reciprocally mounted spool having a feedback wire connected between the spool and the ejector jet. The spool has a differential pressure applied across the ends thereof from the receptors disposed opposed the ejector jet. Movement of the spool applies a force feedback to the ejector jet which is proportional to the pressure differential across the receptors and is opposite the force applied to the ejector by the torque motor to thereby compensate for pressure gain.

Abstract: The shaft of a linear actuator driven by a force motor preferably electromagnetic or hydraulic has a bifurcated arm positioned with one of the bifurcations on each side of the shaft and with the opposite end of the arm securely affixed to a torsion bar. The torsion bar has both ends thereof rigidly secured to a frame member. The bifurcations on the arm end contact a hub which defines a pair of side walls that are threadably received upon the end of the shaft. As the shaft reciprocates, a force is generated by the torsion bar colinear with the shaft axis motion which is proportional to the displacement of the shaft.

Abstract: A coupling device for interconnecting a drive shaft and a driven shaft which is maintained under fluid pressure to provide a tensile preload and which is specifically adapted for utilization with hydromechanical or electrohydraulic servovalves.

Abstract: An electrohydraulic servovalve having a pair of linear, variable, differential transducers (LVDT) affixed thereto in side by side relationship. A spool valve driven by the electrohydraulic servovalve is connected to the movable core in each of the LVDTs so that as the spool valve moves, each of the LVDTs develops a position output signal representative of the position of the spool. The connecting mechanism between the driven spool valve and the LVDT cores is a rod which is attached to the spool and includes a pair of flanges at the opposite end defining a groove therebetween. A pair of plates spaced apart at the center define a slot centrally thereof. The plates at the slot are spaced apart so that the width of the two plates plus the space between them is greater than the width of the groove in the rod. The outermost flange is formed so that it will fit through the slot in the plates. The two cores of the LVDTs include rods which are in turn permanently affixed at each end of the plates.

Abstract: An electrohydraulic servovalve including a second stage piston slidably mounted within a housing and movable responsive to application of pressure signals thereacross to control the flow of fluid under pressure from a source to a load in response to electrical input signals applied to the servovalve. The electrical signals are applied to a torque motor which has a driven member affixed thereto which generates the pressure signals applied to the spool. A mechanical feedback member is connected between the driven member and the spool. The mechanical feedback member is part of an assembly which is removably attached to the driven member. The removable attachment includes a tang extending radially from the driven member which receives a holder to which the feedback member is permanently affixed. The holder includes opposed flanges one of which receives the tang through an indexing opening provided therein.