Abstract: A velocity compensated contacting ring system includes a first dielectric material, a plurality of concentric spaced conductive rings and a first ground plane. The first dielectric material includes a first side and a second side. The plurality of concentric spaced conductive rings are located on the first side of the first dielectric material. The conductive rings include an inner ring and an outer ring. The first ground plane is located on the second side of the first dielectric material. A width of the inner ring is greater than a width of the outer ring and the widths of the inner and outer rings are selected to substantially equalize electrical lengths of the inner and outer rings.

Abstract: A fiber optic rotary joint is provided that is unaffected by variations in the optical properties of a fluid that fills its internal cavity. The rotary joint includes a housing defining the internal cavity, first and second optical collimation arrays on opposite sides of the internal cavity, and a reversion prism between the optical collimation arrays. Further, the rotary joint includes an interface optical element proximate at least one of the first and second optical collimation arrays and the reversion prism. Each interface optical element includes an optically-flat surface adapted to contact the fluid such that optical signals that are oriented normal to the optically-flat surface can be transmitted without refraction, thereby rendering the optical signals immune to variations in the fluid's optical properties. A reversion prism assembly, an optical collimation assembly and a method of aligning an optical collimation array utilizing alignment pins are also provided.

Abstract: The present invention provides several improvements in a slip ring (36) that is adapted to provide electrical contact between a rotor (42) and stator (40). In one aspect, a brush tube (39) is crimped around the upper marginal end portions of a plurality of individual fibers (38) inserted therein. In another aspect, a collimator tube (41) extends downwardly beyond the end of the brush tube to limit lateral movement of the fibers in the bundle when the rotor rotates. In yet another arrangement, a spring (55, 56) is arranged to bear against a current-carrying conductor to adjustably vary the force by which the lower ends of the fibers are urged to move toward the rotor.

Abstract: A compact actuator (20) is arranged to selectively move an airfoil surface (27) relative to a support (27) relative to a support (21). The actuator includes a gear reduction unit (24) mounted on the support. The gear reduction unit has a ring gear (25) adapted to be rotated about a longitudinal axis (x—x), and a pinion (26) mounted on the ring gear. All bearings for the pinion gear are physically located within the gear reduction unit. The pinion gear engages a rack (23) attached to the airfoil surface such that rotation of the pinion gear will move the airfoil surface relative to the support.

Abstract: An electrohydraulic actuator (10) includes a fluid-powered actuator (11) having a piston (15) in a cylinder (16). The piston divides the cylinder into two opposed chambers (18, 19). The actuator includes a fixed-displacement reversible motor-driven pump (13) having a first port communicating with one of the chambers and having a second port communicating with the other of the chambers in a closed hydraulic system. A pre-charged accumulator (14) communicates with the pump first port. One of the actuator chambers is maintained at a fixed pre-charged pressure of the accumulator, and the operation of the pump controls the pressure in, and volume of, the other chamber.

Abstract: The invention provides a method for controlling an electromechanical servomechanism (20) for moving an output member relative to a variable load (38). The servomechanism includes: a motor (37) having at least one coil (32A, 32B or 32C) adapted to be supplied with current and having a rotor (33) with an output shaft (35); a mechanical transmission (36) arranged between the output shaft and the load, the transmission having a mechanical friction related to the load; a servoamplifier (30) arranged to supply current to the motor coil in response to an input signal (in line 29); a command signal (in line 21) for commanding the position of the load; a load position feedback signal (in line 23) compared (in summing point 22) to the command signal and arranged to produce an error signal (in line 24); and means (28) for generating an offset signal (in line 26) that is summed (in summing point 25) with the error signal to modify the servoamplifier input signal (in line 29).

Abstract: A torque motor (20) has a base (21), four polepieces (22A, 22B, 22C, 22D) extending away from the base, the polepieces being separated from one another and being arranged at the corners of an imaginary polygon (27), each polepiece terminating in a pole (23A, 23B, 23C, 23D); a coil (24A, 24B, 24C, 24D) surrounding each of the polepieces; an armature (26) pivotally mounted on the base, the armature having a portion arranged to move toward and away from an associated one of the poles, respectively, to define a variable-reluctance air gap (gA, gB, gC, gD) therebetween; a permanent magnet (29) mounted on one of the base and armature and polarized in a direction parallel to the pivotal axis of the armature; and wherein at least a portion of the torque motor is formed by a MEMS technique; whereby the coil may be selectively energized to cause the armature to pivot about its axis.

Abstract: A torque motor (20) has a base (21), four polepieces (22A, 22B, 22C, 22D) extending away from the base, the polepieces being separated from one another and being arranged at the corners of an imaginary polygon (27), each polepiece terminating in a pole (23A, 23B, 23C, 23D); a coil (24A, 24B, 24C, 24D) surrounding each of the polepieces; an armature (26) pivotally mounted on the base, the armature having a portion arranged to move toward and away from an associated one of the poles, respectively, to define a variable-reluctance air gap (gA, gB, gC, gD) therebetween; a permanent magnet (29) mounted on one of the base and armature and polarized in a direction parallel to the pivotal axis of the armature; and wherein at least a portion of the torque motor is formed by a MEMS technique; whereby the coil may be selectively energized to cause the armature to pivot about its axis.

Abstract: A propellant supply device (10) is provided for a vehicle (11) having a main propulsion motor (12) and having an attitude control system (11) including a plurality of thrusters (14A, 14B, 14C, . . . , 14F). The improved device comprises: a pressure vessel (15); first and second movable walls (20, 21) operatively arranged within the pressure vessel and dividing the interior space therewithin into three separate sealed chambers (22, 23, 24) from each of which fluid may be supplied; a first fluid (e.g., a first bipropellant) in one of the chambers; a second fluid (e.g., a second bipropellant) in a second of the chambers; and a third fluid (e.g., ammonia) in a third of the chambers, the third fluid being a volatile liquid having a liquid phase and a gaseous phase, and wherein all three chambers are pressurized to the vapor pressure of the third fluid.

Abstract: A displacement control device (1) is adapted to move a member (23) relative to a body (7). The displacement control device includes a drive means (2, 3) and an emergency actuator(8) arranged mechanically in series with the member. The actuator includes a housing (16) and a spring (14) arranged to act between the housing and the member. The improvement comprises: the actuator including a toggle linkage (9) acting between the housing and the spring, the toggle linkage having two pivotally-connected links (10, 11) that are adapted to be selectively moved between a collapsed position at which the links are arranged at an acute included angle, and an extended position at which the links are arranged at an obtuse included angle slightly less than 180°. The toggle linkage is arranged such that the spring will be more greatly compressed when the links are in the extended position than when the links are in the collapsed position.

Abstract: A servoactuator (20) is operatively arranged to control the movement of an output member (21) in either of two directions in response to a command signal. The servoactuator includes an electric motor (25); a first transmission mechanism (34); a hydrostatic second transmission mechanism (35); a transfer mechanism (36) operatively arranged to selectively couple the motor output shaft to the output member either through the first transmission mechanism to impart a high-speed low-force drive to the output member, or through the second transmission mechanism to impart a low-speed high-force drive to the output member; at least one feedback transducer (29, 32); and a servo control loop (30, 33) closed about the motor, controller, transmission mechanisms, transfer mechanism, feedback transducer and output member for selectively controlling at least one of the position, velocity or force of the output member as a function of the command signal.

Abstract: A pressure-control device (20) includes a controllable variable-displacement reversible hydraulic motor (21) having a pressure port (22) and a return port (23); a source of pressurized fluid (Ps); a fluid return (R); and a pressure regulating valve (24) operatively interposed between the source, return and pressure port. The pressure regulating valve is operatively arranged to maintain a predetermined pressure at the pressure port regardless of the direction of flow through the pressure port.

Abstract: A torque motor (20) has a base (21), four polepieces (22A, 22B, 22C, 22D) extending away from the base, the polepieces being separated from one another and being arranged at the corners of an imaginary polygon (27), each polepiece terminating in a pole (23A, 23B, 23C, 23D); a coil (24A, 24B, 24C, 24D) surrounding each of the polepieces; an armature (26) pivotally mounted on the base, the armature having a portion arranged to move toward and away from an associated one of the poles, respectively, to define a variable-reluctance air gap (gA, gB, gC, gD) therebetween; a permanent magnet (29) mounted on one of the base and armature and polarized in a direction parallel to the pivotal axis of the armature; and wherein at least a portion of the torque motor is formed by a MEMS technique; whereby the coil may be selectively energized to cause the armature to pivot about its axis.

Abstract: A servoactuator (20) is operatively arranged to control the movement of an output member (21) in either of two directions in response to a command signal. The servoactuator includes an electric motor (25); a motor controller (24); a first transmission mechanism (34); a hydrostatic second transmission mechanism (35); a transfer mechanism (36) operatively arranged to selectively couple the motor output shaft to the output member either through the first transmission mechanism to impart a high-speed low-force drive to the output member, or through the second transmission mechanism to impart a low-speed high-force drive to the output member; at least one feed-back transducer (29, 32); and a servo control loop (30, 33) closed about the motor, controller, transmission mechanisms, transfer mechanism, feedback transducer and output member for selectively controlling at least one of the position, velocity or force of the output member as a function of the command signal.

Abstract: A skewed roller brake assembly (20) has a main axis of rotation (x—x), has a first plate (21) adapted to be rotated about the main axis, has a second plate (22) adapted to be rotated relative to the first plate about the main axis, and has an intermediate plate (23) positioned between the first and second plates. The first and second plates are adapted to be axially loaded with respect to one another. The intermediate plate has a plurality of slots (25). Each slot is bounded by a first wall (26) that is arranged at a first angle (&thgr;1) with respect to a radius from the main axis. A cylindrical roller (25) is arranged in each slot for rolling engagement with the first and second plates about the axis of the roller such that the roller axis (y—y) is parallel to the first wall when the first and second plates are rotated relative to one another in one angular direction.

Abstract: A tandem electrohydrostatic actuator (70) broadly includes a first piston (22) operatively arranged in a first cylinder (23), and a second piston (24) operatively arranged in a second cylinder (25). The pistons are coupled to move together. The first piston has a small extend area (35) and a large retract area (36). The second piston has a large extend area (38) and a small retract area (39). The large areas (36, 38) of the pistons are equal to one another and the small areas (35, 39) of the pistons are equal to one another. A reversible fixed-displacement first pump (45) has equal inlet and outlet flows supplied to the small areas of the first and second pistons, respectively. A reversible fixed-displacement second pump (40) has equal inlet and outlet flows supplied to the large areas of the first and second pistons, respectively. The total volume of the fluid in the actuator remains constant at all positions of the pistons.

Abstract: A servoactuator (20) is operatively arranged to control the movement of an output member (21) in either of two directions in response to a command signal.

Abstract: A compound differential planetary gear assembly (50) includes a sun gear (52), a plurality of planet gears (53) engaging the sun gear, a plurality of first ring gears (54), and a plurality of second ring gears (55). Each of the second ring gears has a number of teeth that is different from the number of teeth of the first ring gears. The first and second ring gears are arranged alternately in an axial stack. Each planet gear has a constant gear-tooth cross-section along the length of the stack, with its gear teeth in meshing engagement with the teeth of the first and second ring gears. Loads transmitted between the first and second ring gears and the planets act in alternate directions along the length of the stack.

Abstract: A tandem electrohydrostatic actuator (70) broadly includes a first piston (22) operatively arranged in a first cylinder (23), and a second piston (24) operatively arranged in a second cylinder (25). The pistons are coupled to move together. The first piston has a small extend area (35) and a large retract area (36). The second piston has a large extend area (38) and a small retract area (39). The large areas (36, 38) of the pistons are equal to one another and the small areas (35, 39) of the pistons are equal to one another. A reversible fixed-displacement first pump (45) has equal inlet and outlet flows supplied to the small areas of the first and second pistons, respectively. A reversible fixed-displacement second pump (40) has equal inlet and outlet flows supplied to the large areas of the first and second pistons, respectively. The total volume of the fluid in the actuator remains constant at all positions of the pistons.

Abstract: A torque motor (20) has a base (21), four polepieces (22A, 22B, 22C, 22D) extending away from the base, the polepieces being separated from one another and being arranged at the corners of an imaginary polygon (27), each polepiece terminating in a pole (23A, 23B, 23C, 23D); a coil (24A, 24B, 24C, 24D) surrounding each of the polepieces; an armature (26) pivotally mounted on the base, the armature having a portion arranged to move toward and away from an associated one of the poles, respectively, to define a variable-reluctance air gap (gA, gB, gC, gD) therebetween; a permanent magnet (29) mounted on one of the base and armature and polarized in a direction parallel to the pivotal axis of the armature; and wherein at least a portion of the torque motor is formed by a MEMS technique; whereby the coil may be selectively energized to cause the armature to pivot about its axis.