Abstract: A capacitive differential pressure transducer for sensing the difference in pressure between at least two fluids includes first and second halves of a housing separated by a diaphragm which acts as a common capacitive plate to the capacitive differential pressure transducer with each housing half being identical and containing an interior chamber which is filled with a force transmitting fluid, a sensing capacitive plate located within the chamber and cooperating with the common capacitive plate, a fastening mechanism for holding the sensing capacitive plate tight against its housing half, sealing devices for sealing in the force transmitting fluid and terminals for connecting the common capacitive plate and the sensing capacitive plate to a sensing circuit.

Abstract: A vehicle propulsion system is provided with an auxiliary hydraulic drive having a variable displacement motor connected to ground engaging wheels by a clutch. A multiple position control has a first position which causes clutch engagement and positions a motor displacement member in a position which permits fluid drive of the motor. The control has a second position which causes clutch disengagement and positions the motor displacement member in a zero displacement condition which prevents fluid drive of the motor. Preferably the control is responsive to motor output speed and reduces motor displacement as speed increases.

Abstract: To provide for accurate determination of azimuth in a borehole survey apparatus, a downhole probe is provided with two or more sections connected by torsionally rigid, flexible joint assemblies with provisions for generating signals that represent the relative inclination and azimuth of one probe section from another. These signals are combined with inclination signals obtained from a set of accelerometers in one of the probe sections in a signal processing unit to generate signals that represent the direction and depth of the borehole.

Abstract: This invention relates to a pulse width modulated inverter circuit having an output signal with reduced harmonic content. The inverter circuit includes a first circuit that provides a filtered fundamental pulse width modulated signal. A second circuit is electrically coupled to the first circuit to receive the signal and sum therewith a controlled signal and the filtered fundamental pulse width modulated signal. The second circuit thereby providing the output signal with reduced harmonic content.

Abstract: A fluidic servovalve is disclosed comprising a pilot stage valve having a pilot output for supplying a control fluid dependent upon a movable element, a boost valve responsive to the control fluid for supplying an output fluid, and a fluidic mechanical feedback connected from the output of the boost valve to the pilot stage valve, the fluid mechanical feedback having a ball-type motor responsive to the output fluid acting against it for positioning the movable element.

Abstract: A pilot stage for use in pilot pressure control applications includes a magnetic torque motor having an output torque in response to an input current, a flapper operated by the magnetic torque motor and responsive to the output torque, the magnetic torque motor being arranged to apply a resultant spring rate to the flapper, and first and second nozzles responsive to the output torque applied to the flapper for providing a differential output pressure proportional to input current, the first and second nozzles having a size sufficiently large to swamp out the resultant spring rate applied to the flapper so that the first and second nozzles apply a feedback force to the flapper sufficient by itself to substantially balance motor torque.

Abstract: A protection circuit for a semiconductor device such as a field effect transistor is disclosed having an oscillator which is connected to both the gate turn on circuitry and to the drain-source circuit of the field effect transistor for sensing the voltage of the drain-source circuit and for turning off cyclically the field effect transistor upon the simultaneous occurrence of a gate turn on signal to the gate of the transistor and high drain-source voltage.

Abstract: This invention relates to a panel air chiller for use with a portable food storage unit. The panel air chiller includes in combination first and second spaced apart parallel panels that have thermal insulation disposed between and in contact with the panels. The thermal insulation material has formed therein at least a first and a second chamber between the panels thereby establishing passageways between the panels and through the thermal insulation material. Located in the first chamber is a means to extract heat from air passing thereover to thereby cool the air. At least one return air opening is provided through one of the panels to communicate with the portable storage unit. A fan is coupled to the space between the panels and to the first chamber to thereby draw air through the return air opening coupled to the portable storage unit.

Abstract: For use on a vehicle having a split torque transmission, the split torque transmission including first and second throughputs and a summing junction connected to the first and second throughputs and having a transmission output dependent upon the first and second throughputs, each throughput having an input connected to an output of the engine of the vehicle, the system including a sensor adapted to sense the output of the engine, and a controller connected to the sensor and adapted to control the second throughput dependent upon the engine output, the second throughput being controlled from a negative value cancelling the first throughput to a positive value so that the transmission output is varied from idle to a predetermined value.

Abstract: This invention relates to a drive circuit coupled to electrical devices, which may be semiconductors, connected in parallel in a circuit network. The electrical devices have distinct total on-time periods when they are simultaneously energized. The circuit network has a source of power coupled through the parallel connected devices to a load. The drive circuit includes a signal source coupled respectively through a time adjustable circuit to a first electrical device and to a second electrical device. The time adjustable circuit is adjusted such that the total on-time of the first electrical device matches the total on-time of the second electrical device to thereby ensure equal power at all times through the electrical devices to the load. The invention allows a number of parallel devices to act as a single switch.

Abstract: A frequency detector for detecting the frequency of vibration of an apparatus is disclosed having a first vibration sensor for providing a first output having a first frequency response to the vibration, a second vibration sensor for providing a second output having a second frequency response to the vibration where the first and second frequency responses envelope the desired frequency of vibration for the apparatus, a difference sensor connected to the first and second vibration sensors for providing a third output dependent upon the difference between the first and second outputs, and a load which is responsive to the third output.

Abstract: A tape cassette particularly adapted for use with a dual capstan magnetic tape deck that does not utilize pinch rollers, includes a pair of capstan actuators that respond to a central loading knob which serves to move the tape away from the capstans when the cassette is loaded or unloaded into the tape deck. In addition, the cassette includes a pair of tape guide actuators that respond to the loading knob by rotating and forcing the tape away from the magnetic head and tape guide pins of the tape deck during the loading or unloading operation. This single knob controls both the capstan actuators and the tape guide actuators. The capstans and reels are arranged such that a large angle of wrap, 165.degree. or more, around the capstans is provided in order to effectively drive the tape without the need for pinch rollers.

Abstract: This invention relates to electrical aircraft engine start and generating system for use in an aircraft having an engine driven torque converter coupled to an alternator which provides AC power for conversion to DC and AC power. The system includes a reversible AC to DC converter controllably electrically coupled to the alternator and a controller unit to provide DC power in a generating mode. The reversible AC to DC converter is capable of receiving externally supplied DC power to be converted to AC power to drive the alternator as a motor in a start mode. A DC to AC converter is controllably electrically coupled to the controller unit and the DC power output during the generating mode. The reversible DC to AC converter in the start mode is mutually controllably electrically coupled to the externally supplied DC power.

Abstract: A gear pump having a pair of intermeshing gears which operate in a housing and which are supported by a pair of bearing blocks which are biased towards the side faces of the gears for effecting a seal. There is interposed, between each bearing block and the adjacent side faces of the gears, a flexible plate which on its outer side is pressure-loaded by pump-delivery pressure admitted to an area of the plate confined by a linear seal element that includes part-circular portions extending around the gear axes at a radial distance appreciably smaller than the radius of the root circle of the gear teeth.

Abstract: The invention relates to a fault current detection, isolation and clearing system for use in an integrated power generating and distribution arrangement having multiple generators electrically connected to loads and to a distribution bus through circuit breakers. The system includes a power control logic unit and circuit breaker condition detection units which have their outputs electrically coupled to the power control logic unit. Fault current detection circuits are coupled to the electrical connections of the generating and distribution arrangement and have outputs electrically coupled to the power control logic unit. The power control logic unit has an output which is controllingly electrically connected to the circuit breakers to control the circuit breakers and clear faults from the generating and distribution arrangement as a function of circuit breaker conditions and fault currents detected.

Abstract: This invention relates to a current transformer support assembly for use in an electromotive machine that includes an armature slideably secured to the electromotive machine housing. The armature end windings have radially disposed neutral armature conductors. The support assembly includes an arcuate shaped support member secured internally of the housing within a recessed region of the housing. The arcuate shaped support member is provided with at least one well shaped opening in which a secondary current transformer winding is positioned. A neutral armature assembly is provided that includes an arcuate strap secured in a mating manner to the support member. The neutral armature assembly has a neutral lead which acts as a primary for the current transformer. The neutral lead is secured to the strap and passes through a central opening in the current transformer winding for electrical connection to a neutral armature winding. The current transformers so mounted are completely supported by the housing.

Abstract: During a take-off or missed approach phase of operation the aircraft's maximum barometric altitude is retained in a memory element and compared to the aircraft's current altitude, and if the aircraft's current barometric altitude should be below the maximum altitude by a predetermined amount based on the aircraft's radio altitude, a voice warning is generated indicating that the aircraft is descending. Landing gear and flaps are monitored by the system and if the gear or flaps are down, an additional voice warning is generated indicating that the gear or flaps are down.

Abstract: This invention relates to an actuating mechanism for a pump inlet closure valve and includes in combination a pump housing which projects into a fuel tank and has an opening to allow passage of fuel from the tank into the pump housing. A pump inlet closure valve sleeve is positioned within the pump housing and is mounted for movement in a predetermined path. A pump is positioned within the valve sleeve. A fixed pump housing seal is located in the path of the valve sleeve as well as within and between the pump and the housing. A valve actuating mechanism includes a handle which is pivotally secured to the pump housing and slideably moveable in a direction parallel to the path of the valve sleeve. The handle is mechanically coupled to the valve sleeve whereby initial manual movement of the handle causes the valve sleeve to move into a position blocking the opening to the fuel tank.

Abstract: The invention relates to a force limiting assembly that includes a force transmitting reciprocating output member carried by an actuator member mounted at one end for rotation in a force limiting assembly housing. A power input member is secured to the actuating member in the housing. The assembly is provided with a release mechanism secured to the assembly housing and mechanically releasably secured to the actuating member to thereby permit the actuating member to move axially into the housing. The axial movement into the housing occurs only when an axial force present in the actuating member, which force is directed towards the housing, exceeds a preset value which results in the sudden release and movement of the actuating member and the power input member into locking cooperation with a portion of the assembly housing.

Abstract: This invention relates to a hydraulic control system for an aircraft starter-drive mechanism that includes a generator that can be driven as a motor drivingly connected through a differential, which is mutually connected to first and second hydraulic units and to an engine drive shaft during a start mode. The hydraulic control system includes a control valve arrangement, cooperatively coupled to the first and second hydraulic units, and operative in the starting mode to control flow between the hydraulic units, to thereby divide the delivery of rotary power from the generator/motor to the engine drive shaft through the differential and the hydraulic units.