Abstract: A new pilot valve for spool-type valves and cartridge-type valves is disclosed. In both types of valve, the valve body (spool or cartridge) is provided with a cylindrical bore and first and second radial bores on opposite sides of a land on the valve body. The valve body is slidable within the axial bore of a valve housing. The valve housing is provided with a pressure inlet port, at least one service port, and usually at least one pressure return port, the ports being axially spaced apart. In a central position, a land of the valve body isolates the pressure inlet port from the pressure inlet port and/or the service port, one of the radial bores is in fluid communication with the pressure inlet port, and the other radial bore is in fluid communication with either a pressure return port or service port. A control rod is inserted in the cylindrical bore of the valve body and rotatable therein.

Abstract: A servo valve assembly having torque feedback includes a housing and a valve spool disposed for axial translation therein. The valve spool has a plurality of lands alternating with three reduced diameter regions which cooperate with axially spaced apart inlet, return and service ports in the housing. The servo mechanism includes a piston integrally formed with the valve spool. An axial bore extends through the spool and receives a control rod having an axially extending flat which cooperates with radial passageways in the valve spool. At the end of the control rod is a torque motor which rotates bi-directionally and provides an input signal to which the servo valve assembly responds. Between the torque motor and the valve housing is a torque feedback assembly. The assembly includes a pair of cantilever spring arms each fixed at one end, the opposite ends of each of the cantilever arms coupled to a respective pair of pistons which are in communication with respective service ports.

Abstract: A new pilot valve for spool-type valves and cartridge-type valves is disclosed. In both types of valve, the valve body (spool or cartridge) is provided with a cylindrical bore and first and second radial bores on opposite sides of a land on the valve body. The valve body is slidable within the axial bore of a valve housing. The valve housing is provided with a pressure inlet port, at least one service port, and usually at least one pressure return port, the ports being axially spaced apart. In a central position, a land of the valve body isolates the pressure inlet port from the pressure return port and/or the service port, one of the radial bores is in fluid communication with the pressure inlet port, and the other radial bore is in fluid communication with either a pressure return port or service port. A control rod is inserted in the cylindrical bore of the valve body and rotatable therein.

Abstract: An axial bore which extends through the spool and receives a control rod. Channels formed in the control rod cooperate with radial passageways in the valve spool. A pair of torsion rods extend axially from the control rod. One is coupled to a stepping or torque motor, the other is coupled to a rotatable drive member. An assembly for converting axial motion to rotary motion couples the valve spool to the drive member. In the preferred embodiment, this assembly takes the form of a rotatable threaded member secured to the end of the torsion rod and receiving a complementarily threaded end portion of the valve spool. One alternate embodiment comprises a pair of threaded rods extending from the spool, which drives a centrally disposed gear through a pair of complementarily threaded pinion gears. In another alternate embodiment a pressure control valve is achieved. Output fluid from the spool valve is applied to opposite sides of a threaded piston, which is spring biased by opposed compression springs.

Abstract: A transversal filter which utilizes a charge transfer delay line in combination with a plurality of source-follower pairs or their equivalent to tap the delay line and a plurality of transistors fabricated and disposed to proportionately weight, polarize, error-compensate and differentially sum the tapped signals in a single operation.