Automatic Thrust Reverser Latch Using Pressure Differential
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Solution Overview
Problem
Existing latches for thrust reversers in turbofan propulsion systems are inefficient in preventing deflections due to pressure differences, particularly during engine operation, and are difficult to deploy for inspection and servicing as they often require human intervention and may not be accessible to ground support personnel.
Innovation Solution
An automatic locking mechanism that includes a pneumatic actuator, bellows, and centrifugal clutch, which latch and unlatch based on pressure and temperature changes within the core compartment, allowing the thrust reverser to maintain structural integrity during flight and open for maintenance without human intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing latches are used to reinforce the IFS by latching to the pylon or engine, then structural strength is improved, but device complexity and difficulty of operation increase due to requiring manual intervention
Solution Approach 1:
The latch system automatically engages and disengages based on pressure differential detection, eliminating the need for manual operation. The system serves itself by using the pressure difference between core compartment and bypass duct as the actuating force for both engagement and disengagement of the latch mechanism.
Solution Approach 2:
The patent replaces manual mechanical operation with an automated system that uses pneumatic pressure differentials to actuate the latch. The mechanical system is substituted with a pressure-driven automatic control system that responds to flight conditions.
2Reliability
If existing latches are used to prevent deflections, then reliability is improved, but ease of operation worsens due to inaccessibility to ground support personnel
Solution Approach 1:
The latch system automatically engages during flight conditions when pressure differential exists and disengages when pressure equalizes, providing reliable protection without requiring ground personnel intervention. The system is self-actuating based on detected flight conditions.
Solution Approach 2:
The system changes its state based on pressure parameter changes. When pressure differential exceeds a threshold during flight, the latch engages; when pressure equalizes during ground operations, the latch disengages. This parameter-based control provides both reliability and accessibility.
3Device complexity
If manual latching mechanisms are used, then device complexity is reduced, but productivity decreases due to requiring human intervention for each operation
Solution Approach 1:
The system automatically performs the latching and unlatching operations based on detected pressure conditions, eliminating the need for repeated manual interventions. This self-service capability significantly improves operational efficiency despite the added complexity of the automatic actuation system.
Solution Approach 2:
The latch mechanism is pre-configured to automatically engage when flight conditions are detected (pressure differential exists), preparing the system in advance for potential deflection events without requiring real-time manual intervention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The automatic locking mechanism effectively prevents thrust reverser deflections during increased pressure conditions and allows for easy access during maintenance, enhancing safety and operational efficiency by eliminating the need for manual latching and unlatching.
Implementation Method 1
a pneumatic actuator, which receives pressurized air from the bypass air duct and uses the pressure differential between the core compartment and the bypass air duct to drive a locking pin into a locking slot
Implementation Method 2
The latch may latch automatically responsive to the temperature of the air inside a core compartment between the engine and the first thrust reverser half
Implementation Method 3
The locking mechanism may comprise a centrifugal clutch
Data Source
AI summary
A nacelle may include a pylon and a thrust reverser having an inner fixed structure. A locking mechanism may automatically engage and prevent relative movement between thrust reverser halves. A bumper may be coupled to the inner fixed structure. The locking mechanism may limit deflections between the thrust reverser and the pylon in response to a burst duct. A locking mechanism in the inner fixed structure may include a pressure relief door and an arrestor which hooks onto a retaining bar in a pylon bracket. The locking mechanism may allow the thrust reverser halves to be opened for access to the engine.