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.

Abstract: In order to provide for accurate setting of a preload force on an accelerometer force responsive pendulum and to provide for rigid support for the pendulum, a pendulum support assembly is constructed with a flexure member that is attached at one end to the accelerometer frame. The flexure receives the preload force from a preload pin at the other end and has one pendulum axle bearing attached to it between the attachment point and the preload pin. In addition, the flexure includes a hinge portion located next to the attachment point that serves to make the flexure a statically determinate beam so that the preload force on the bearing can be accurately determined.

Abstract: To increase the effectivity of warnings and to decrease nuisance warnings in a ground proximity warning system having several modes of operation, the switching from one mode to another is done as a function of time. In addition, in a ground proximity warning system where a warning signal is generated in accordance with a predetermined relationship between flight parameters, one or more of these parameters can be varied as a function of time in order to, for example, increase the altitude above ground as a function of time from take-off that a terrain clearance warning may be generated or to decrease as a function of time, the radio altitude below which a negative take-off after a climb warning may be generated.

Abstract: The present invention relates to an impingement cooling apparatus for use in the removal of heat from a heat liberating device. The apparatus includes a housing on which the device is secured and a stack of plates fitted within the housing. One of the plates is an impingement orifice plate adjacent the housing where the device is located. The orifice plate has a region that is characterized by coolant flow impingement orifices passing therethrough. The orifice plate also has a coolant drainage return adjacent the impingement orifice region.

Abstract: An electro-hydraulic control structure having a control input positioning a flapper relative to a nozzle to generate a control output pressure is provided with a squeeze film damper which utilizes the flapper, or an extension thereof, as the movable element of the squeeze film damper. Preferably the flapper is pivoted and forms with the nozzle exhaust passageway a tapered gap receiving a small portion of the nozzle flow which acts as the damping fluid. The majority of the nozzle flow passes through a hollow portion of the flapper located downstream of the nozzle.

Abstract: This invention relates to a self-priming screw pump lubrication system. The system 10 includes a central feed tube which communicates at one end with lubricant in a reservoir or sump and at the other end to the central region of an assembly that includes a horizontally disposed rotating shaft. The shaft having thereon threaded portions of opposite pitch mounted within a pair of mating sleeves which sleeves are biased away from each other at the central region of the assembly. The other ends of the sleeves are in abutting relationship with the outer races of a pair of angular contact bearings to be lubricated. Each of the inner races of the bearings are mounted on the rotary shaft. Lubricant slingers are mounted on the rotating shaft at a point remote from the bearings and cooperate with the lubricant that has been drawn upward through the central feed tube and delivered to and past the bearings, whereupon the slingers propel the lubricant back to the reservoir for reuse.

Abstract: The present invention is directed to a fuel supply system for a fuel burner of the type that requires for proper operation an excess flow of fuel to be provided to the burner with that excess being recirculated. The fuel system further requires that sufficient fuel is added to the system to make up for that amount of fuel which is fired or burned. The fuel supply system includes a fuel pump which selectively draws from a fuel supply the make-up fuel flow and from a return path the excess fuel flow for recirculation. At any given moment all fuel flow from one inlet line and the other inlet line is positively closed.

Abstract: The invention relates to an electro-hydraulic control system for a power drive unit having a wobbler controlled variable displacement hydraulic motor wherein the electro-hydraulic control system causes the displacement of the hydraulic motor to match a load to be driven by a power drive unit output shaft coupled to the motor. The system results in the hydraulic motor displacement matching the load as a combined function of the input command signal, the actual wobbler position, as well as the velocity and position of the power drive unit output shaft.

Abstract: An electrical distribution system has parallel connected generators powered by variable speed engines. Loads connected with each generator are interconnected through an electrical distribution bus. Constant speed drives have inputs connected with the engines and outputs directly connected with the generators. The connections between the constant speed drive outputs and the generators are characterized by the absence of overrunning clutches used in prior systems. An improved electrical protective circuit senses a flow of electrical power from the distribution bus to a generator, driving the generator as a motor. If the power flow to the generator is excessive, the bus tie breaker is opened disconnecting the generator from the bus.

Abstract: This invention relates to a shorted diode protection system for a brushless alternating current generator of the type having an energizeable exciter field winding. The system includes a circuit arrangement for sensing the voltage difference across the exciter field and pairing the voltage difference with generator load current to thereby provide an output signal that falls within a predictable range of values over a normal generator load current range. The output signal is of such a nature that it falls within a higher range of values upon the occurrence of a shorted diode. Another circuit arrangement is responsive to the output signal such that whenever the output signal exceeds a preset value over the normal load current range, an output is generated that operates to cause the interruption of the exciter field.

Abstract: This invention relates to an energy absorbing ratchet for a bidirectional no-back apparatus which includes in combination a fixed support, a rotatable input member and a rotatable output member. The input member includes an input plate which has integral therewith a pair of release pins. An output plate is coupled to the output member. The input plate and the output plate have a torque transmission device coupled therebetween. The fixed support has an energy absorbing means coupled to a ratchet ring. The ratchet ring is positioned between the input and the output plate. The output plate has thereon a pair of moveably mounted pawl members for cooperative engagement with the ratchet ring to thereby engage the ratchet ring when the no-back apparatus is at rest, and whenever a backdriving load is delivered from the output member to the output plate. The pawl members are released from the ratchet ring by the cooperative engagement with the release pins upon bidirectional rotation of the input member.