A control rod connects the crank on the thrust lever to the autothrottle brake housing which turns the thrust lever resolver. The resolver angle (TRA) is the primary input to the electronic engine control (EEC) for setting engine thrust.
There is one interlock actuator for each thrust lever. The interlock actuators are mounted at the bottom of the control stand. Each actuator has a clevis mounting that attaches the actuator to the control stand structure and a rod end that attaches to the interlock crank assembly. The interlock crank assembly has a roller that contacts an interlock stop on the autothrottle brake housing. The interlock stop physically prevents the reverse thrust lever movement to the full reverse thrust position until the thrust reverser sleeve has deployed approximately 60 percent.
The interlock actuator is a linear actuator with a 28v dc motor. Internally, the actuator has a brake, spur reduction gear drive train, ball screw and nut assembly, load limit clutch and stroke limit switches. Positive mechanical stops in the unit prevent overtravel of the actuator if a limit switch malfunctions.
EFFECTIVITY
BEJ ALL
The actuator weighs approximately 2.5 pounds (1.1 kilograms).
There is a separator bar clamped to the wire bundles from the two interlock actuators; this bar is to prevent the left side interlock actuator connector connected to the control stand electrical panel connector for the right side interlock actuator connector.
Functional Description
When you move the reverse thrust lever to command reverse thrust, the thrust lever movement causes the autothrottle brake assembly to turn until the interlock stop engages the roller on the interlock crank assembly. The roller on the crank assembly prevents any further movement of the autothrottle brake assembly in the reverse thrust direction. It stops the assembly at the reverse thrust interlock position.
When the thrust reverser sleeves get near the extended position (approximately 60 percent deployment), the electronic engine control (EEC) provides electrical power to electromagnetically release the internal brake and the motor starts. Actuator operation will continue until the extend limit switch is actuated which interrupts the electrical power to the motor. Spring force causes the brake to engage which prevents overrun of the actuator.
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TRAS -REVERSE THRUST LEVER INTERLOCK ACTUATOR
The interlock actuator extends the rod end which turns the interlock crank assembly roller away from the interlock stop. The roller no longer blocks the movement of the autothrottle brake assembly. The pilot can now move the reverse thrust lever to increase the reverse thrust from idle to the maximum reverse thrust position.
There is no interlock actuator limit when you command forward thrust. When the polarity of the electrical power input is reversed, the actuator operates in the retract direction which continues until the retract limit switch is reached. If the limit switches malfunction, the load limit clutch slips to prevent damage to the actuator when it engages the mechanical stops.
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本文链接地址：777 AMM 飞机维护手册 发动机排气 Engine Exhaust PW 777 AIRCRAFT MAINTENANCE MANUAL(41)
