| 摘要 |
1,091,308. Automatic deceleration control. CRANE CO. Dec.30, 1965, No.55295/65. Heading G3R. [Also in Division F2] The rate of deceleration during landing of a multi-wheeled aircraft is regulated to prevent skidding by brake-control, the speed of wheel W7 being detected by transducer coil 22 associated with frequency-sensing circuit 17, 18, and rectifying and wave-shaping net 28, 30, 26, whereby the square waveform signal developed at terminal 34 has a frequency proportional to wheel-speed. A series of pulses of corresponding frequency is produced at terminal 40 by differentiation by capacitor 38 and resistor 42 which are connected to transistor amplifier 36. These pulses are integrated by circuit components 46, 48, 50, so that the potential at terminal 47 decreases with decrease of frequency. The current passing through transistor 52 decreases with reduced speed permitting partial discharge of capacitors 58, 59, to render transistor 64 conductive, the bias potential established by diodes 61, 62, representing the maximum deceleration rate. Transistors 68, 70, then conduct to energize coil 72 of a pilot valve for relaxing the brake. The pilot valve by-passes fluid under pressure around the brake cylinder in proportion to the strength of the applied signal. In the absence of a signal to coil 72, the braking effort is controlled by adjustment of a brake-pedal valve. Brake application before the wheels are loaded is prevented by a signal through rectifier 76 and switch 100. The first wheel to roll supplies potential to a central memory unit comprising capacitor 80 so that, if one or more wheels are not loaded after the switch 100 is operated, locked wheel protection is still provided. The potential across capacitor 80 is supplied by the fastest wheel. If wheel-lock occurs, the signal at terminal 34 is removed, and capacitor 89 discharges whereby capacitor 80 renders transistor 90 conductive. The resultant potential-drop across resistor 77 is amplified by transistors 81, 70, to energize coil 72 and remove the brake. After deceleration ceases, the brake pressure is prevented from returning to the level which caused the incipient skidding. For this purpose, each time a valve-controlling signal is developed by transistor 70, the charge on capacitors 101, 102, is increased, As the control signal decreases transistor 98 conducts to maintain energization of coil 72. Hence the brake pressure continues to be relaxed to an extent dependent upon the rate control signal. |
