Abstract: An improved fluid amplifier (39) is operatively arranged in a flow path extending between a source (28, 31) of pressurized fluid (P.sub.s) and a fluid return (38) at a return pressure (R). The amplifier has at least one fluid connection (34 or 35) to a load. The amplifier has a movable mechanical member (24) operatively arranged to control the pressure at, and flow with respect to, the load. The mechanical member has a displacement range encompassing a null position and an off-null position. The improvement broadly includes a variable-impedance orifice (42 and/or 43) arranged in series with the amplifier in the low path. The impedance of the orifice is varied such that the impedance is a maximum when the mechanical member is in the null position and is a minimum when the mechanical member is in off-null position, such that flow from the supply to the return when the mechanical member is in the null position will be less than the maximum flow between the amplifier and the load.

Abstract: A fluid coupling (30) has a male half (32) and a female half (31). Each half has a poppet (35,42) arranged to move toward and way from a seat (34,43). The male half (32) has an outer sleeve (38) which is adapted to guide initial joinder of the female half distal end (46). After the two halves have been initially joined, the male half body (39) is extended relative to the sleeve (38) so as to move both poppets (35,42) off their respective seats and to permit flow through the coupling. The coupling has protrusions (76) provided with sharpened edges which are positioned to scrape ice adhering to facing surfaces when the coupling halves are joined and separated.

Abstract: A fluid-powered actuator (42) has a body (11) which includes an end wall (16) provided with a through-opening (21). A piston rod (44) has an inner portion (44A) arranged on one side of the end wall within a pressurizable working chamber (24) of the actuator, has a penetrant portion (44B) passing through the end wall opening, and has an outer portion (44C) arranged on the other side of the end wall. The rod is configured such that the transverse cross-sectional area of the penetrant portion is greater than the transverse cross-sectional area of the outer portion so as to define an annular surface (46) which faces away from the actuator chamber. The improvement provides a seal assembly (43) for containing fluid leaking from the actuator chamber.

Abstract: An improved communication system (10) includes a plurality of transceivers (A, B, C, D, etc.) adapted to communicate with one another via a common communication path. Each transceiver has its own unique identity code. The invention provides a cable (11) for temporarily enabling the mutual exchanging of identity codes between only two of the transceivers so as to establish a dedicated pair. Each transceiver has memory (12) for receiving and storing the identity code of the other transceiver of the pair, and for purging any previously-stored identity code. Each transceiver is arranged to identify all communications transmitted by it as having originated from it, and as being addressed to the other transceiver of the pair. Each transceiver is also arranged to accept communications only if addressed to it and if identified as having originated from the other transceiver of the pair.

Abstract: An electro-mechanical-hydraulic drive mechanism (10) for moving a lead (11) relative to a support (12) includes an electric motor-driven element (14) and a hydraulic reaction element (15). The two elements are arranged mechanically in series between the lead and the support. The motor-driven element may be operated independently of the reaction element to move the lead relative to the support when the reaction element is held at a fixed displacement. The two elements may be operated cooperatively to move the load when the motor-driven element is operated at a controlled velocity to pressurize the reaction element, and the reaction element is operated by controlling its pressure.

Abstract: A device (19) for generating a rotating force vector and an oscillatory couple includes a plurality of non-concentric eccentric masses (22A, 22B, 22C, 22D, 22E, 22F) co-rotating at the same angular speed; and means (24A, 24B, 24C, 24D, 24E, 24F) for individually controlling the angular position of each of the masses; whereby, by selectively controlling the angular position of each eccentric mass, the device may generate a desired rotating force vector and a desired oscillatory couple. In use, the device performs an improved method for opposing the propagation of vibration from a dynamically unbalanced rotating rotor through a supporting structure (12).

Abstract: An improved two-stage servovalve (70) has a pilot-stage and an output-stage. A torque motor (16) produces pivotal movement of a flapper (18) in response to a supplied electrical current. The pilot-stage produces a flow which is used to selectively displace a second-stage spool (61) relative to a body bore. The servovalve has a hydromechanical pressure feedback loop closed about the load and second-stage spool. The pressure feedback loop is intertwined with an electrical spool position feedback loop closed about the spool and driver. The command to the pressure loop is a function of the error of the spool position loop. The gain of the spool position loop dominates that of the pressure loop. The valve has pressure-flow characteristics approximating those of a "flow-control" servovalve but affords access to an electrical signal substantially proportional to the load pressure differential.

Abstract: A system for transducing a signal voltage into an optical signal, transmitting the optical signal via an optical fiber to a remote location in the form of light attenuation frequency and interpreting the light frequency at the remote location to the amplitude and wave form of the signal voltage. The electro optic modulator includes an elongated piezoelectric member which changes length when an electric field is imposed across it. A mirror is attached to a free end of the piezoelectric member and strains or alternately moves toward and away from a partially reflecting surface at the end of an adjacent optical fiber. Light is introduced into the fiber with a portion reflected back by the movable mirror and part by the end of the fiber. A detector at the second end of the optical fiber receives the reflected light.

Abstract: An adjustable converging-diverging nozzle (10) includes a body (11) having a flow passageway (14) therethrough. The passageway is configured to define an entrance section (18), a narrowed throat section (19), and an exit section (20). Two opposing vane members (12,13) are pivotally mounted on the body. Each vane member has a first surface (33,33') facing into the passageway to form a movable wall portion of the throat section. Each first surface is eccentric to the pivotal axis (38,38') of the associated vane member. A pair of actuators (42,43) are mounted on the body for selectively varying the angular positions of the associated vane members. The vane members may be moved to a closed position to reduce the orifice area of the throat section to zero, or may be moved to other angular positions to vary the magnitude and/or direction of the thrust vector of hot gas discharged through the nozzle. The invention also provides an improved method of operating the nozzle by selectively moving the vane member(s).

Abstract: A vibration isolator is operatively associated with a suspension having a spring (21) and a fluid damper (22) arranged in parallel with one another between two masses (23, 24) which are arranged to move relatively toward and away from one another. A restricted orifice (33) communicates the opposed damper chambers (30, 31). The vibration isolator includes a fluid pump (46) and an actuator (48) for operating the pump. The pump has a first chamber (51) communicating with the damper first chamber (30), and has a second chamber (52) communicating with the damper second chamber (31). The pump is selectively operated so as to create a pressure differential across the orifice to oppose and substantially cancel the dynamic force transmitted through the spring and damper and attributable to high-frequency relative vibration between the masses, while permitting the damper to damp low-frequency relative velocity between the masses.

Abstract: An electro-optic power cell for transducing incoming light energy from an optical fiber into electrical energy through a photo diode. An optical fiber extends into a first housing through a wall thereof. A lens in the housing abuts and is sealed to the end of the optical fiber to expand the light beam from the fiber and direct it to a photo diode in engagement with the output end of the lens. A second housing which contains an electrical socket is fastened to the first housing. Leads from the photo diode are connected to the electrical socket so that the electrical signal from the photo diode can be connected to an external electric receptacle. The optical path is hermetically sealed to prevent entry of contaminants. Several embodiments of the photo diode are described in order to perform different functions. One embodiment uses a segmented photo diode having the segments connected in series to increase diode output voltage.

Abstract: A lase diode light source (21) is arranged to emit light of a desired intensity (I1), which is transmitted via an optical conductor (22). Light exiting the fiber has an intensity (I.sub.2), and falls incident on the receiver surface of a photodiode (23). Such transmitted light provides both the power and control for operating a load (24). The load has a maximum impedance such that the maximum load input voltage required to produce the maximum desired load current does not exceed the forward conductive breakdown voltage of the photodiode.

Abstract: A fluid coupling device has a male section (20) and a female section (21). Each of the sections has two rotatable ball valve elements (30,31). A docking member (23,24) is mounted on each section to accomodate a misalignment of the flow passageways when the sections are brought together. When the sections are brought together, the ball valves automatically rotate sequentially from flow-preventing positions to flow-permitting positions.

Abstract: A device and method for modulating light intensity in response to a varying electrical signal which is particularly useful with optical fiber information sensing systems. The device includes a number of components positioned in seriatim in an elongated cavity in an insulating body. Means for receiving a light signal, such as from an optical fiber, is positioned at one end of the cavity. A lens receives the light and collimates it into a narrow collimated beam directed through the cavity. The beam is polarized, retarded by a wave plate to circular polarization and passed through a modulator material which is capable of rotating beam polarization in response to varying voltage signals imposed on the modulator through electrodes thereon. A mirror at the end of the modulator reflects the beam back through the system.

Abstract: A fluid coupling device has a male section (20) and a female section (21). Each of the sections has two rotatable ball-valve elements (30,31). A docking member (23,24) is mounted on each section to accommodate a misalignment of the flow passageways when the sections are brought together. When the sections are joined together, the ball valves automatically rotate sequentially from flow-preventing positions to flow-permitting positions.

Abstract: An improved energy-conserving servoactuator has at least one valve operatively associated with a double-acting fluid-powered actuator. When a load is applied to the actuator, the pressure in one actuator chamber will be greater than in the other. If the load is "opposing" with respect to the desired direction of actuator movement, fluid is supplied to the higher pressure chamber and is permitted to flow from the lower pressure chamber. However, if the load is "aiding" with respect to the desired direction of actuator movement, fluid in the higher pressure chamber is permitted to flow into the lower pressure chamber without drawing fresh fluid from the source.

Abstract: The second stage (10) of a fail-fixed flow-control servovalve has a five-lobed valve spool (12) slidably mounted in a body bore (19). At null, the end lobes (41,45) are substantially zero-lapped with respect to supply pressure slots (22,26), the middle lobe (43) is substantially zero-lapped with respect to a pair of return slots (23,24), and the intermediate control lobes (42,45) are both symmetrically underlapped with respect to their associated control slots (29,30). Stops (34,35) limit movement of the spool in either axial direction. When the spool is at null or in either hard-over position, deliberate flow with respect to the control slots is blocked, and relative leakage flows are controlled. Such leakage flows may be balanced such that there is substantially-zero net leakage flow with respect to each control slots. Alternatively, such leakage flows may be deliberately mismatched to provide for desired net leakage flows with respect to control slots.

Abstract: A fluid-powered actuator has a piston slidably mounted in a cylinder. The piston subdivides the cylinder into first and second end chambers. A plurality of solenoid valves are arranged to selectively inject fuel and oxidizer into either chamber, or to inject liquid oxidizer to react with a solid fuel. Upon contact with one another, the fuel and oxidizer undergo a hypergolic reaction, and the products of this reaction create a pressure sufficient to displace the piston. Alternatively, a mono-propellant fluid fuel may be injected into such chamber. Upon contact with a catalyst in the chamber, the fuel undergoes a disassociation reaction, and the products thereof may be used to displace the piston.

Abstract: A piezoelectric torque motor (10) includes a body (11), a pair of opposed nozzle assemblies (12,13) mounted on the body, a pair of piezoelectric actuators (14,15) extending upwardly away from the body, and a lever assembly (16) having an upper portion (95) engaging the upper ends of the actuators and having depending leg portions (96,98). A foot plate (94) is mounted on the lower marginal end portions of the lever legs, and is positioned between the nozzles. The piezoelectric actuators are supplied with differential voltages to cause swinging movement of the lever assembly between the nozzles. The improved torque motor may be used in the first- or pilot-stage of a two-stage electrohydraulic servovalve.

Abstract: An electro-mechanical actuator has a ferrous alloy armature movably mounted within a body chamber. Two axially-spaced permanent magnets are arranged radially inwardly of the chamber and partially define the chamber at the ends thereof. A coil surrounds the chamber. The body is formed of a magnetically-permeable material. Because of the high reluctance of the magnets, each magnet forms a short magnetic loop which passes through the adjacent air gap, and forms a long magnetic loop which encircles the coil and passes through the distant air gap. The armature has a bistable toggle-like movement, and may be latched proximate either end wall. If springs are added between the armature and the body, the improved actuator may be used as a proportional position of force transducer within an operating range of armature movement.