Lockable Variable Nozzle Section for Thrust Reverser
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Solution Overview
Problem
Existing thrust reverser systems for turbojet engines lack independent actuation of the nozzle section during takeoff, requiring complex linkages and limiting aerodynamic optimization and fuel efficiency.
Innovation Solution
A simple and reliable locking system using a locking pawl with an elastic return mechanism and a pin to mechanically link or unlink the movable nozzle section to the thrust reverser cowl, allowing independent operation of the nozzle and thrust reverser without complex linkages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-rod actuator is used to drive both the thrust reverser cowl and the variable nozzle section, then the device complexity is reduced, but the ability to independently actuate the nozzle section during takeoff is lost
Solution Approach 1:
The system divides the actuation mechanism into two independent parts: a single-rod actuator for driving the thrust reverser cowl, and a separate locking mechanism (locking pawl and pin) for the variable nozzle section. This segmentation allows the nozzle section to be independently locked or unlocked from the cowl actuation, enabling independent actuation during takeoff while maintaining simplicity through the shared actuator for thrust reversal operations.
2Adaptability or versatility
If complex linkages are used to enable independent actuation of the nozzle section, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The locking pawl and pin act as intermediary elements between the single-rod actuator and the variable nozzle section. When the locking pin engages the locking pawl, it creates a mechanical linkage that couples the nozzle section to the cowl actuation. When disengaged, it allows independent movement. This intermediary mechanism provides the needed adaptability without requiring complex continuous linkages.
3Ease of operation
If the locking pawl is held in the disengaged position by a pin mounted on a fixed structure, then the ease of operation is improved, but the reliability may be affected by the additional component
Solution Approach 1:
The locking mechanism is designed to be self-actuating through the elastic return means. When the pin is in the engaged position, the spring automatically pushes the locking pawl into the engaged position with the cleat, maintaining the locked state without requiring additional actuators or complex control systems. The system serves itself by using the elastic energy stored in the spring to maintain the locking state.
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
Enables independent actuation of the nozzle section during takeoff, optimizing aerodynamic performance and reducing fuel consumption by allowing the nozzle section to be adjusted without activating the thrust reversal function.
Implementation Method 1
a locking pawl (202) mounted so as to move against an elastic return means between an engagement position in which it secures the drive of the section of the nozzle and the inversion cowl
Data Source
Figure 1~8
Figure 9~12
AI summary
The present invention relates to a thrust reverser (1) including at least one translatably movable cowl (3, 4) capable of alternately shifting between a closed position in which same ensures the aerodynamic continuity of the nacelle and which covers the deflecting means, and an open position in which same opens a passage in the nacelle and uncovers the deflecting means, said thrust reverser likewise including at least one variable nozzle section (3, 3a) arranged in the extension of the movable thrust-reversing cowl (4) and provided with at least one locking means (201) capable of engaging with a complementary locking means (202) of the movable reversing cowl so as to optionally mechanically link the movable nozzle section to the movable reversing cowl.