Abstract: Inertial measurement of the angular rotation and translational motion of a structure can be provided by a pair of vibrating accelerometers aligned in a side-by-side arrangement with their force sensing axes in the same direction and vibrated to and away from each other along an axis normal to their force sensing axes.

Abstract: Apparatus for measuring inertial specific force and angular rate of moving body by means of a plurality of accelerometers mounted on mutually perpendicular axes, each accelerometer being mounted for vibratory movement along its respective axis. The apparatus further includes a drive for vibrating each accelerometer to produce output signals and a signal processor for deriving from the accelerometer output signals the specific force and angular rate for the respective axes. Enhanced performance is achieved by utilizing pairs of accelerometers vibrating along each axis combined with a preseparation circuit that separates the components of the accelerometer output signal having specific force information from components having angular rate information.

Abstract: The age old problem of monitoring a liquid level in a reservoir has continued to cause problems. If the level is too low, the component will malfunction due to lack of lubricant; on the other hand, if the level is too high, the component can overheat. The present system overcomes the problem of the level being too high by providing an automatic vent for draining excess liquid from the reservoir. When the engine is in the nonoperating mode, the spring moves the spool of the valve to the open position. In the open position, excess liquid is vented from the reservoir establishing the predetermined liquid level. When the engine is operating, a portion of the air from the compressor enters the chamber forcing the spool to the closed position preventing liquid from being vented from the reservoir. In the closed position, contaminants are also prevented from entering the reservoir.

Abstract: The invention relates to a swashplate leveling and holddown mechanism wherein an axially sliding leveling mechanism is biased into engagement with a swashplate of an axial piston variable displacement hydraulic unit to position the swashplate in a zero displacement position when there is no control input to the hydraulic unit. The leveling mechanism has a pair of contact points, one positioned on each side of the swashplate tilt axis in a manner that both contact points positively engage the swashplate when it is centered to its zero displacement position. Such mechanism requires no spring adjustment and has no backlash. Furthermore, the axial bias on the leveling mechanism helps seat the swashplate in its support bearings. Utilized in conjunction with the leveling mechanism is an axially biased control input which operates on the opposite side of the swashplate to further hold the swashplate in its support bearings.

Abstract: A method of making a segmented externally finned tube with at least one fin free area for use in a heat exchanger. The method includes the steps of providing a tape of thermally conductive material with spaced reliefs along one longitudinal edge thereof and slitting the tape from that edge partially across its length between the reliefs. The slit portions of the tape are bent to form an angle with respect to the remainder of the tape which is then used to helically wrap a thermally conductive tube. The area of the reliefs provide fin free areas.

Abstract: A water leak control circuit in combination with a water heater having an inlet and a drain. The water leak control circuit simultaneously detects leaks, actuates an alarm, shuts off a water supply to the water heater, drains the heater, while releaseably maintaining the alarm activated, the water supply shut off and the heater drained, all of which is accomplished by means of leak responsive circuit.

Abstract: This invention relates to a compact high efficiency furnace having a cylindrical combustion chamber and a fin and tube type heat exchanger substantially parallel, transverse to the furnace air flow, and closely spaced in the air flow direction with no other major heat exchange being utilized. Condensation of fluids from the combustion gases occurs at the fin and tube type heat exchanger, whereby a high efficiency furnace results. The fins and tubes of the heat exchanger are of different materials, requiring that the combustion gas temperature at the heat exchanger inlet be limited.

Abstract: A thin valve plate for use in an axial piston hydraulic unit wherein valve plate ports are provided with slot shaped extensions passing through the valve plate to provide limited initial fluid communication between cylinder block ports and valve plate ports and wherein the thickness of the valve plate is no greater than one half the width of the slots. Furthermore, such valve plate facilitates economical manufacture wherein the slots and valve plate ports can be stamped in a hardened steel disk.

Abstract: An electromotive machine has a stator provided with multiple sets of windings, each independently, electrically coupled to an electrical means, to establish separate power channels between the windings and the electrical means that allow for the simultaneous independent transmission of power through the channels when the machine is in operation. The electromotive machine may take either the form of a motor or a generator.

Abstract: This invention relates to a motor control system for a brushless DC motor having an inverter responsively coupled to the motor control system and in power transmitting relationship to the motor. The motor control system includes a motor rotor speed detecting unit that provides a pulsed waveform signal proportional to rotor speed. This pulsed waveform signal is delivered to the inverter to thereby cause an inverter fundamental current waveform output to the motor to be switched at a rate proportional to said rotor speed. In addition, the fundamental current waveform is also pulse width modulated at a rate proportional to the rotor speed.A fundamental current waveform phase advance circuit is controllingly coupled to the inverter.

Abstract: The present invention is directed to a two stage hydraulic servo amplifier wherein the boost stage valve comprises two separate valve members, each individually controlling one of a pair of controlled outputs and wherein the position of each valve member is modulated by inputs from a pilot stage acting against separate biasing forces for each valve member.

Abstract: The present invention provides an improved control system for a driven cable reel mounted on a vehicle wherein the reel is adapted to pay-in and pay-out electrical cable to supply power to the vehicle, such as a mine car. The control system modifies the torque supplied by the reel drive so as to maintain a relatively constant tension on the cable. The improved control system has a first or basic output which provides higher torque when the reel is paying in cable and provides lower torque when the reel is paying out cable, the difference in drive torque being necessary to compensate for the reversal of frictional characteristics during paying in and paying out of the cable. The control system further provides a transient condition output signal to modulate the drive of the cable reel in a manner which compensates for acceleration and deceleration of the cable reel to reduce cable slack and prevent a sudden increase in cable tension which could cause cable breakage.

Abstract: The invention relates to a torsionally stiff door adapted to be mounted for pivotal movement at points on a line parallel to an edge of the door and to be latched at a point along an opposing edge of the door. The door is intended for use in an environment where one side of the door is subject to loading over that surface. The door is also subject to highly directional point loading on the other side of the door. The surface loading and the point loading tend to torsionally bend the door about lines passing through the points, which lines intersect at the latch. The door is fashioned of a pair of spaced apart panels which form respectively one side of the door and the other side of the door.

Abstract: The invention is directed to a multi-motor actuation system for a power drive unit. The system includes three independently hydraulically controlled motors adapted to be drivingly coupled to a power drive unit output. Two of the said motors are normally active at all times and the third motor acts as a back-up motor to provide redundancy for the two normally active motors. A hydraulic failure detection mechanism is controllingly coupled to the three independently hydraulically controlled motors. The hydraulic failure detection mechanism is responsive to any failure of one of the normally active hydraulically controlled motors to thereby cause the third motor to be coupled to the power drive unit. The failure detection mechanism is additionally responsive to a failure of both normally active hydraulically controlled motors to cause the third motor to take over the functions of both of the normally active hydraulically controlled motors.

Abstract: In order to provide an aircraft navigation computer display unit for use in an aircraft with limited cockpit panel space, the display unit is provided with a housing configured in a rectangular cross-section and includes a cathode ray tube assembly secured in an upper quadrant of the housing, a power supply secured directly below the CRT assembly and a group of circuit boards vertically orientated in the remaining half of the housing in tracks that permit the removal of the circuit boards from the front of the housing. The display unit also includes a front panel assembly having data entry and function switches enclosed therein and an opening aligned with the CRT. The front panel additionally includes a plastic filter secured to a shoulder of the front panel assembly in front of the CRT wherein the filter is located approximately 0.010 inch from the CRT when the front panel is secured to the housing.

Abstract: In order to vary the brightness of the display produced by a cathode ray tube, a digital brightness control circuit is provided that utilizes a source of cathode control voltage connected to the cathode of the cathode ray tube, a brightness selector circuit which is connected to a digital counter, and a resistance network connected to the counter and the cathode control voltage source which is effective to vary in discrete increments the brightness of the cathode ray tube.

Abstract: In a structure utilizing a pair of accelerometers vibrating in a direction normal to their force sensing axes, a circuit utilizing voltage-to-frequency converters is utilized to convert the analog output signals from the accelerometers to digital signals representing the translational motion and the angular rate rotation of the structure.

Abstract: This invention relates to a triangle wave generator for producing a constant amplitude triangle wave signal having a frequency proportional to an input voltage signal. The triangle wave generator is comprised of a square wave signal generating circuit to provide a square wave signal having a frequency proportional to the input voltage signal.A biased amplifier circuit is provided which has an input and an output. The input of the biased amplifier circuit receives the input voltage signal and the biased amplifier output is coupled to a switching circuit.The switching circuit is coupled to the square wave signal generating circuit to receive the square wave signal and provide a pair of square wave signals to positive and negative input terminals of a differential integrator. One of the pair of square wave signals is the complement of the other.The differential integrator provides the constant amplitude triangle wave signal which has constant amplitude and has a frequency proportional to the input voltage.

Abstract: An apparatus for inertially determining the rate of angular rotation and translational motion of a structure is provided which utilizes a pair of vibrating accelerometers vibrating along a single axis with their force sensing axis located normal to the axis of vibration and rotated 90.degree. from each other. Signals from the vibrating accelerometers can be processed to provide indications of angular rotation about two axes and translation motion about two axes. Two of the sets of vibrating accelerometers can be combined to provide a three axis inertial reference system.

Abstract: In an inertial system for sensing the angular rotation and translational motion of a structure utilizing a pair of accelerometers in a back-to-back arrangement vibrating substantially linearly along an axis normal to their force sensing axes, a mechanism utilizing a parallelogram structure is used to impart the vibratory motion to the accelerometers.