Abstract: This invention provides brake clamping and declamping in response to a position feedback controlled brake actuator in which an electric torque motor drives a rotating member of a reciprocating drive mechanism to axially move another member into out of engagement with a brake pressure plate of a multi-disk brake assembly. A microprocessor controller receives electric signals indicative of (i) a pilot's command for braking, (ii) a command for brake release and antiskid braking, (iii) the position of the torque motor rotor at any instant, and (iv) the initiation of brake clamping of the multi-disk brake. The controller generates a feedback control signal to the torque motor which adjusts the motor rotor position, in revolutions, to increase or decrease brake clamping in accordance with the pilot signal and to effect brake release in accordance with an overriding antiskid signal.

Abstract: The invention is directed to a system for increasing and/or extending the operation service life of an aircraft brake disk stack by selectively limiting the number of brake assemblies which comprise the aircraft landing gear configuration and which are put into operation during the time the aircraft is on the ground and subject to low speed taxi braking cycles while also providing that all of the brake assemblies of the total available on the aircraft are operational during other portions of the landing and takeoff cycle of the aircraft.

Abstract: This invention provides for heating a brake assembly electrically to prevent it from freezing. More specifically this invention provides for heating electrically an aircraft multi-disk brake assembly.An electric resistance heating element 12 is adapted to form a heater 10 to provide heating to a brake stack 44. Heat may be transferred either directly to the brake stack 44 or indirectly by first heating a member of the brake assembly 36. This member in turn transfers heat to the brake stack.The heater 10 may be formed to fit within the cavity formed by a torque tube 26 wherein the heater abuts a substantial portion of the torque tube 26.Signals from a thermocouple may be used for activation and deactivation of the heater 10.

Abstract: A control circuit for regulating the application and release of brake force in an electric brake. A pulse width modulator presents an output signal of regulatable duty cycle to power drivers connected to the electric motors of the brake. A control circuit regulates the direction of current flow through the motors to achieve either brake application or brake release. The output of the pulse width modulator is set by the position of the brake pedal or by a signal which is a function of the correlation betwen brake torque and the position of the brake pedal, whichever is larger.

Abstract: An antiskid brake control wherein sensitive deceleration detectors present output signals to a valve driver for releasing brake pressure. The deceleration detector output is also passed to a modulator which acts as a memory circuit to keep the average brake pressure near the skid level and also provides for a controlled reapplication of brake pressure following the release. A constant current discharge circuit is connected to the modulator to provide a linear discharge of the modulator capacitor. A fast recovery circuit is interconnected between the deceleration detector and modulator to rapidly discharge the modulator capacitor in the event that no outputs from the deceleration detector have been sensed for a predetermined period of time. The control system includes gain control circuitry to provide for at least three distinct system gains.

Abstract: A circuit incorporated in a braking system for allowing a pilot to select a desired rate of deceleration and to cause the aircraft, upon landing, to achieve and maintain the selected deceleration rate. Fundamentally, the circuit includes a selector switch for selecting the desired rate of deceleration and uses a linear decelerometer signal having an output corresponding to the instantaneous rate of actual deceleration of the aircraft. Comparator circuitry compares the actual and desired rates of deceleration and provides an error signal to high and low rate circuits which charge a storage capacitor which in turn, through a buffer and power drive circuitry, regulates the associated control valve. When the difference between the actual and desired rates exceeds a particular level, the high rate circuit controls the charging of the capacitor.

Abstract: An antiskid brake control system for a wheeled vehicle having a second order lead network in parallel connection with a deceleration detector. The deceleration detector includes both a current threshold level and a voltage threshold level, the deceleration rate of a wheel having to exceed both thresholds to result in a brake control signal to the modulator and brake control valves. The lead network, deceleration detector, and a modulator all feed a summing circuit which includes a switching circuit providing the system with two distinct characteristic gains. Also included is a circuit for linearly discharging certain capacitors in the system. Also included are locked wheel, touchdown protection, and low speed drop-out circuitry to regulate the application and release of antiskid control and touchdown and upon the occurrence of preselected vehicle activities.

Abstract: A circuit incorporated with an antiskid system for testing the operability of the system. A multivibrator may be actuated to energize converter circuitry with a signal indicative of a particular wheel speed. The entire antiskid system is then caused to function as though the vehicle wheels are actually spinning and the vehicle is moving. The major subcircuits of the antiskid system are connected to logic circuitry which senses their operation and produces an output signal to a lamp which is illuminated when the subcircuits are properly operative. When the multivibrator operation is ceased, changes in operation of the various subcircuits is again sensed by the logic circuitry which, if such subcircuits are operating properly, deenergizes the lamp.

Abstract: A circuit for converting AC signals from a wheel speed transducer to a varying DC level indicative of the instantaneous rotational speed of the wheel of a vehicle. The invention includes a squaring circuit receiving a sinusoidal input from a wheel speed transducer and producing a fixed amplitude square wave of a frequency equivalent to that of the sinusoidal input. A pulsing circuit receives the square wave signal and produces a series of fixed duration pulses of a frequency double that of the sinusoidal signal. These pulses are applied to an integrator which produces a DC output of an amplitude characteristic of the frequency of the sinusoidal input. The integrator has a characteristic phase lag associated therewith resulting in a tendency of the phase of the superimposed AC output, caused by cyclic changes in the frequency of the transducer output, to lag the phase of the associated wheel speed change.

Abstract: An improvement is provided for use in a wheeled vehicle having anti-skid circuitry associated with the wheels thereof. Fundamentally, the invention comprises a comparator connected to the anti-skid circuitry which products an output signal when anti-skid signals exceed a particular level for a predetermined period of time. The output of the comparator is operative for removing the application of the anti-skid control circuit from the anti-skid valves and for applying in its place a rudimentary anti-skid control circuit comprising a multivibrator of predetermined duty cycle. Thus, under all conditions, braking effort remains with the vehicle operator but under certain conditions is modulated at a predetermined rate by the multivibrator. Provisions are also made for returning the anti-skid system to normal operation in conjunction with the brake system when the output of the anti-skid system drops below the aforesaid particular level.

Abstract: An anti-skid and brake control system for use on an aircraft wherein the output signals from standard anti-skid circuitry are combined with the signals from a brake pedal transducer to create braking signals. The braking signals are applied to current controlled hydraulic valves for regulation of the application and release of brake pressure. The brakes utilized are dual cavity brakes with corresponding cavities of all brakes being interconnected to the same hydraulic line. Shut-off valves are interposed in the hydraulic lines and are operative to enable the brake valves to regulate brake pressure when either brake pedal of the aircraft has been depressed a fixed amount. Biasing circuitry is presented to affect the brake signal in such a manner as to overcome a dead band within the response characteristics of the brake valves utilized.