Abstract: A method for monitoring quality of a hydraulic fluid in an electro-hydraulic (EH) valve is disclosed. The method includes applying predetermined signal to a solenoid coil, surrounding a pusher pin in EH valve, to facilitate oscillation of a pusher pin in EH valve to change static friction between the pusher pin and a cavity of EH valve, to dynamic friction. EH valve includes a housing defining the cavity having an end wall. Cavity slidably receiving the pusher pin having a first end and a second end. The hydraulic fluid is received between the first end of the pusher pin and the end wall. The oscillation of the pusher pin generates an acoustic wave that propagates through the hydraulic fluid. The method further includes determining the quality of the hydraulic fluid based on one or more characteristics of the acoustic wave detected by an acoustic sensor positioned on the end wall.

Abstract: A straddle-type vehicle including left and right front wheels effectively prevents deterioration of a travel feeling caused by vibrations occurring in the left and right front wheels. The straddle-type vehicle includes a body frame, left and right front wheels, a link mechanism configured to connect the left and right front wheels with the body frame, a shock absorber configured to damp vibrations in the same phase occurring in the left and right front wheels, and a damper configured to damp vibrations in opposite phases occurring in the left and right front wheels. The damper is configured such that its damping force increases at least in a certain frequency range as the frequency of the vibrations in the opposite phases increases.

Abstract: A servomechanism has a jet pipe mounted by a flexure pivot driven by an electromagnet to control the position of the jet pipe. A fixed seal tube surrounds the armature and keeps the coil isolated and dry. The flexure pivot has two parts that can move with respect to one another. The jet pipe can be fixed with respect to one part and movable with respect to the other such that when the electromagnet armature moves pivotal motion is imparted to the jet pipe. A multi-port jet receiver receives media from the jet pipe in different orifices dependent upon armature position. That in turn can extend or retract an actuator, such as a piston, depending upon which receiver orifice receives greater pressure. A feedback mechanism can link the actuator to the jet pipe to provide feedback input used to improve the accuracy of the device.

Abstract: Systems for powering vehicles using compressed air and vehicles involving such systems are provided. In this regard, a representative system includes: a power source configured to power an air compression system, the air compression system comprising at least one air compressing piston; a compressed air storage system, comprising at least two storage tanks configured to store compressed air from the air compression system; a valve configured to control release of air from the compressed air storage system into a rotor system; the rotor system comprising a first air jet configured to direct the released air into a plurality of paddles located about a circumference of at least one rotor, thereby turning the at least one rotor.

Abstract: A fuel metering unit including a pump having a rotor with a plurality of slots. The pump also includes a pivotally movable cam ring coaxially arranged with respect to the rotor. Vanes are slideably disposed in the slots for maintaining contact with the cam ring during movement thereof. A servovalve has a motor and nozzles operatively connected to the pump such that increased flow through the first nozzle pivots the ring of the pump toward maximum while increased flow through the second nozzle pivots the ring toward minimum. An arm extends between the nozzles for varying fluid flow therethrough. The arm couples to the motor such that the motor moves the arm. A flow meter connects to the pump and an end of the arm for applying a force against the arm to assist in maintaining position of the arm.

Abstract: A fuel metering unit including a pump having a rotor with a plurality of slots. The pump also includes a pivotally movable cam ring coaxially arranged with respect to the rotor. Vanes are slideably disposed in the slots for maintaining contact with the cam ring during movement thereof. A servovalve has a motor and nozzles operatively connected to the pump such that increased flow through the first nozzle pivots the ring of the pump toward maximum while increased flow through the second nozzle pivots the ring toward minimum. An arm extends between the nozzles for varying fluid flow therethrough. The arm couples to the motor such that the motor moves the arm. A flow meter connects to the pump and an end of the arm for applying a force against the arm to assist in maintaining position of the arm.

Abstract: A variable displacement hydrostatic pump (11) having its displacement varied by a controller (17) in response to movement of a manual control lever (95) from a neutral position (FIG. 1). The vehicle has at least one other device (125,127) which provides an electrical output signal (133) indicating when operation of the pump (11) is "acceptable", in terms of either vehicle performance or operator safety. Associated with the control lever (95) is an input shaft (103) defining at least one stop surface (121,123). A solenoid assembly (109) has a moveable plunger (111), disposed adjacent the stop surfaces, and moveable between a retracted position (FIG. 4a) and an extended position (FIGS. 2 and 4), engaging one of the stop surfaces, when the output signal (133) indicates that operation of the pump is not acceptable.

Abstract: A driving device comprises a source of hydraulic fluid under pressure, a working arrangement (6) having a working chamber (7) intended for receiving hydraulic fluid and a working member (8) adapted to be put in motion on respective fluid supply to and fluid evacuation from the working chamber. Conduits (20, 29, 30) are provided for respective supply to and evacuation from the working chamber (7) of hydraulic fluid. A valve (16) is adapted to, in a first state, direct fluid to the working chamber and, in a second state, allow evacuation of fluid from the working chamber. An apparatus (17) are provided for returning the working member to a starting position. These apparatus comprise an ejector arrangement adapted to generate a negative pressure evacuating the working chamber as a consequence of flow of fluid through the ejector arrangement. The hydraulic fluid source is constituted by a high pressure washing unit known per se or of an arbitrary nature.

Abstract: A servovalve apparatus for use in fluid systems which comprises an elongate flexible valve element having a fixed end and a free, moveable end, and a conductive coil which surrounds at least a portion of the valve element adjacent its fixed end. An armature is secured to the valve element so as to be adjacent the conductive coil. Two permanent magnets, are provided adjacent the armature on opposite sides thereof, the magnets being positioned such that one magnet presents a north magnetic pole facing the armature and the other magnet presents a south magnetic pole facing the armature. A recieving plate is provided adjacent the free end of the valve element, the receiving plate having one or more channels formed therein for receiving fluid, and a bore for delivering fluid.

Abstract: A pneumatic control valve (10) including a valve body (12) with fixed aperture plate (14), a movable redirector (18) and a force motor (26). The force motor (26) supports the redirector (18) adjacent to the aperture surface (16) of the fixed aperture plate (14) and is operable to move the redirector (18) back and forth along a line (28) without contacting the aperture surface. The aperture surface (16) has a plurality of apertures (70,72,74,76,78) with metering edges (124,126,128,130,132,134,136,138). The redirector (18) has redirector cavities (102,104,106,108) with metering edges (140,142,144,146). The force motor (26) deflects the redirector (18) to positions in which one or more of the cavities in the redirector connect two or more of the apertures (70,72,74,76,78) and direct fluid from some apertures and into other apertures. The location, length and shape of the metering edges can be varied as required to obtain desired fluid flow characteristics.

Abstract: A multiplexed hydraulic control system which avoids the use of a rotary multiplexer and thereby allows for random selection of the multiplexed outlet ports and variable dwell times for the respective ports. A single hydraulic input is multiplexed among a plurality of hydraulic outputs. A control system provides two types of signals: (1) modulation signals selected from a plurality of multiplexed input signals for producing a modulating hydraulic flow, and (2) selector signals for operating on the multiplexer means to route the modulated signal to the appropriately selected channel.

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: A servovalve apparatus for use in fluid systems which comprises a flexible fluid conduit and a conductive coil which surrounds at least a portion of the conduit adjacent its upstream end. An armature is secured to the flexible conduit so as to be adjacent the conductive coil. Two permanent magnets, preferably formed of a rare earth metal material, are provided adjacent the armature on opposite sides thereof, the magnets being positioned such that one magnet presents a north magnetic pole facing the armature and the other magnet presents a south magnetic pole facing the armature. A receiving plate is provided adjacent the downstream end of the flexible conduit, the receiving plate having one or more channels formed therein for receiving fluid from the conduit.

Abstract: A hollow cylindrical amplifier driven actuator spool has first and second vortex chambers divided by an internal piston. A shaft is attached to the pistion and extends out the cylinder. Fluid logic controls the fluid flow in the vortex chambers so that the resulting chamber pressure causes the piston to accelerate. The use of beam deflection amplifiers for fluid control in connection with a push-pull vortex amplifier arrangement results in a device with low fluid flow leakage.

Abstract: In one form of the present invention, a plurality of serovalves are connected to a common manifold. The manifold transmits fluid pressure from the servovalves to a modulator piston which controls the fluid pressure applied to a hydraulic actuator piston. The servovalves are designed such that, if the fluid pressure provided by any one of them to the manifold falls below a threshold, then the servovalve disconnects itself from the manifold, allowing control of the modulator piston to be assumed by the remaining, functioning servovalves. The present invention can be used in control surface actuators of short takeoff and landing (STOL) aircraft.

Abstract: A fluid control device comprising a pivotable member which has a planar major face and is mounted so as to enable pivotal motion about an axis parallel to the major face. The pivotable member including a fluid jet channel which directs a fluid jet towards a fluid receiving channel defined in a receiving member. The pivotable member is pivotally rotated about the axis by a device operable to pivot the pivotable member. This device may be an electromagnet disposed with its poles adjacent and parallel to the major face of the pivotable member. The motion of the pivotable member alters the relative positions of the fluid jet channel/channels and the fluid receiving channel/channels and thereby the quantity of fluid received by the fluid receiving channel/channels.

Abstract: In one form of the present invention, a plurality of serovalves are connected to a common manifold. The manifold transmits fluid pressure from the servovalves to a modulator piston which controls the fluid pressure applied to a hydraulic actuator piston. The servovalves are designed such that, if the fluid pressure provided by any one of them to the manifold falls below a threshold, then the servovalve disconnects itself from the manifold, allowing control of the modulator piston to be assumed by the remaining, functioning servovalves. The present invention can be used in control surface actuators of short takeoff and landing (STOL) aircraft.

Abstract: A shear-type, fail-fixed servovalve is disclosed which includes a piston whose piston head is movably disposed in one chamber of a multi-chamber housing. A piston rod is attached to the piston head and extends into the other chambers. Two passages extend through the piston rod and communicate with the chamber on opposite sides of the piston head. A pair of input orifices are located proximate each other at one end of the piston rod, each corresponding to one passage. An angularly movable jet pipe emits fluid directed at the input orifices. The jet pipe has a null angular position disposed at a predetermined offset angle with respect to the axis of the piston rod, and directs fluid towards the pair of orifices. Means responsive to a selectively variable control signal for changing the angular position of the jet pipe is provided which is effective to produce a magnified linear piston displacement by varying the relative amounts of fluid supplied to the input orifices.

Abstract: The servovalve includes a primary jet of fluid. A variable control signal is adapted to vary the angular position of the primary jet from its maximum recovery position. A first fluid path is adapted to supply fluid to a servopiston at a variable pressure determined at least in part by the control signal. A second fluid path is adapted to receive a predetermined portion of the primary jet fluid when the control signal reaches a predetermined value. The second fluid path terminates in the vicinity of the primary jet and is adapted to direct a secondary jet of fluid at the primary jet to deflect the primary jet toward the input orifice of the second fluid path. The resultant positive fluid feedback in the second fluid path causes the primary jet to latch in a first angular position relative to the maximum recovery position when the control signal reaches a predetermined value.

Abstract: A power boost mechanism for converting pilot linear throttle input commands to rotary motion and providing amplification of output torque to an engine fuel control and having an output shaft adapted for connection to an engine power lever assembly. An input member is movable in response to a throttle input command and power boost structure responsive to movement of the input member causes rotation of the output shaft. The mechanism further includes feedback structure associated with the output shaft and responsive to movement thereof for returning said power boost structure to a null position independently of said input member, structure automatically enabling direct operation of the output shaft by said input member when the power boost structure is inoperative, and structure responsive to a malfunction in the engine fuel control causing limited rotation of the output shaft without movement of said input member.

Abstract: A single-stage servovalve has a movable member operatively arranged to selectively divide a continuously-discharged fluid jet between two receiver passages. The hydraulic output of the valve is the differential between the conditions in the receivers. In the event of a hard-over failure of the control system of which the servovalve is a part, a jet deflector surface becomes operative to create a substantially balanced hydraulic condition in the receiver passages, thus terminating control.

Abstract: A power boost mechanism for converting pilot linear throttle input commands to rotary motion and providing amplification of output torque to an engine fuel control and having an output shaft adapted for connection to an engine power lever assembly. An input member is movable in response to a throttle input command and power boost structure responsive to movement of the input member causes rotation of the output shaft. The mechanism further includes feedback structure associated with the output shaft and responsive to movement thereof for returning said power boost structure to a null position independently of said input member, structure automatically enabling direct operation of the output shaft by said input member when the power boost structure is inoperative, and structure responsive to a malfunction in the engine fuel control causing limited rotation of the output shaft without movement of said input member.

Abstract: A pilot stage valve is disclosed having a control mechanism for moving an actuating arm in response to an input signal, a jet pipe moved by the actuating arm for issuing a jet of fluid, a sandwich constructed receiver having a first receiver plate and a second receiver plate, each having a groove in the surface thereof facing each other with a splitter plate between the first and second receiver plates, the first and second grooves receiving a differential amount of fluid dependent upon the position of the jet pipe with respect to the splitter plate, the grooves being connected to respective outlet ports.

Abstract: A simplified fail-fixed electrohydraulic servovalve for operating with a source of fluid under pressure, and a piston translatably disposed within a bore. The piston has a rod side face area which is less than its head side face area and translates in a first direction for electrical input signals above a first predetermined percent of a maximum rated input signal. At a second percent of the rated input signal, determined by the ratio of the piston rod side face area to the piston head side face area, the piston position is fixed. For electrical input signals greater than the second percent of the rated input signal the piston translates in the second direction. Any input signal below the first percent causes the piston to be fixed in place.

Abstract: A blind pressure pilot apparatus provides a supportive base having a pressure responsive bourdon tube mounted on the base for sensing pressure within a connected test vessel. A pair of indicating arms are movably mounted on the bourdon tube upon a shaft mount which is attached to the bourdon tube and generates a rotation of the shaft responsive to pressure changes in the bourdon tube and the test vessel. Changes in pressure produce pivotal movement of each indicating arm which arms can be spaced to cover a desired span. A gap sensor is mounted upon the supportive base and provides a gap having a continuous stream of instrumentation gas flowing across the gap. During pivotal movement, each of the indicating arms generates an arcuate path, a portion of which intersects the gap and flowing stream of instrumentation gas. During such interruption, the flow of instrumentation gas is halted, which can produce desirable signals for operating valves, and performing like pneumatic instrumentation tasks.

Abstract: A fluidic driver amplifier for a servovalve has its controllably directed fluid jet differentially divided by a divider element which moves with a main valve piston in a manner to equalize the differential pressure received from the jet when the piston reaches the commanded position. In order to permit use of a small, low-leakage, fluidic driven amplifier, without the disadvantage of reduced speed of response, a derivative piston is linked to move with the main piston and displace fluid in a chamber containing a spring-centered secondary valve piston. When displaced, the secondary piston admits pressurized fluid into the main valve chamber in a positive feedback sense to aid the fluidic driver in positioning the main piston. The secondary piston is displaced only when the main piston is in motion and therefore has no effect once the main piston reaches the commanded position.

Abstract: A fail-fixed servovalve is provided for use in a digital control system. The servovalve is comprised of a deflecting means which deflects a jet pipe in response to an electrical input signal. Fluid flowing through the jet pipe causes a spool to translate within a sleeve, thereby allowing pressurized fluid to flow through selected ports within the sleeve to control the movement of an output piston. The output of the servovalve is essentially linear over the primary range of digital input currents with the output being zero when the input current is either zero or in excess of the maximum rated current for the servovalve.

Abstract: The instant invention relates to an electrically operated control which operates the displacement setting mechanism of a variable displacement pump and allows the displacement mechanism to be manually operated when the electrically operated control is disabled.

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.

Abstract: In fluid jet transfer valves comprising two opposing jet tube openings with high pressure fluid flowing out of one opening towards the other, the end surfaces of the jet tubes are provided with a novel shape which allows the tube ends to seal tightly together when they are coaxially aligned with each other and also to be deflected apart without binding. The shape of the end surface on one of the tubes is an inverted reproduction of the surface on the opposing tube so that when the tubes are coaxially aligned with each other and pressed together a tight seal will be formed. The end surfaces on the tubes are shaped so that the tubes may be freely moved laterally relative to each other without binding. The tilt of the end surfaces of the two tubes is minimized so that small lateral closure forces will generate much larger axial seating forces and so that the lateral opening forces created by escaping high pressure fluid are minimized.

Abstract: Pressurized motive fluid flow passes through a single fluidic vortex orifice to opposite chambers of a differential area, double acting, linear servo-cylinder. While shifting in one direction the vortex orifice severely restricts the flow to the fluid chamber of the motor which is contracting in size so as to permit rapid movement of the piston in that direction, and whenever the piston is moving in an opposite direction the vortex orifice allows substantially unrestricted fluid flow to the same chamber which is now expanding in size, so that the piston can shift rapidly in this opposite direction.

Abstract: A variable displacement axial piston pump has a rocker cam for controlling the output of the pump. The rocker cam is driven by a fluid motor member. A valve with a follow-up device regulates pressure fluid flow to the fluid motor member to move the rocker cam. Both the fluid motor member and a part of the follow-up device are rigidly secured to and movable with the rocker cam to provide precise positioning of the rocker cam.

Abstract: A fuel supply and distribution system is provided for a gas turbine engine wherein a plurality of flow dividing valves disposed about a manifold are positively controlled through an actuator which interconnects the flow dividing valves by linkage means extending through the manifold thus preventing sticking or seizing of the pressure regulating valves on account of contaminant particulate matter in the fuel.

Abstract: Method and apparatus for the electric hydraulic control of a hydraulic actuator, said control comprising a redundant servovalve circuit with switching and monitoring logic. The apparatus has a plurality of electrohydraulic servovalves each controlled by separate electrical input channels and connected to a central pressure medium source. The control further has a control spool triggered by the servovalve to control the actuator and a hydraulic logic system for monitoring errors in the servo output signal. The positioning land of the control spool is acted upon on the one side by one group of signals consisting of the combined output signals of the same sign from one selected group of servovalves and is acted upon on the other side by the central pressure medium supply while the remaining sevovalve signals are applied separately to a hydraulic logic system including a comparator and alarm means.