Thrust Reverser Guide Rail End-of-Travel Stop
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Solution Overview
Problem
Thrust reversers for aircraft nacelles face issues with cowl deformation or dislocation due to the absence or failure of control cylinders, leading to inadequate support for axial loads and potential dislocation of secondary rails during operation or maintenance.
Innovation Solution
A thrust reverser design featuring a primary axial guide rail with a rear end-of-travel stop that can support significant axial loads without additional mass, preventing secondary rail dislocation, and includes a movable device for easy maintenance and safety features to ensure proper operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a lightweight secondary rail structure is used to guide the outer portions of the cowls, then the device complexity and weight are reduced, but the rail cannot withstand high axial loads applied during cylinder failure events
Solution Approach 1:
The patent introduces an intermediary component (reinforcement element or structural coupling) between the secondary rail and the primary axial guide rail. This intermediary allows the lightweight secondary rail to benefit from the high strength of the primary rail when axial loads are applied during cylinder failure, enabling the secondary rail to withstand high axial loads without compromising its lightweight design
2Ease of operation
If control cylinders are used to move the cowls backward for thrust reverser operation, then the ease of operation is improved, but the reliability deteriorates due to potential cylinder absence or failure during flight
Solution Approach 1:
The patent implements beforehand cushioning by designing the rail system with inherent load-bearing capacity and structural reinforcement that prepares the system to withstand axial loads even before a cylinder failure occurs. The primary and secondary rails are configured with appropriate strength and connectivity to the nacelle structure, creating a passive safety mechanism that activates automatically upon cylinder failure without requiring additional active components
3Strength
If the primary rail is designed with high resistance to support the whole mass and stresses, then the strength is improved, but the weight of the stationary structure increases
Solution Approach 1:
The patent applies local quality by concentrating the high strength requirements specifically in the primary axial guide rail where axial loads are transmitted to the nacelle structure, while allowing the secondary rail to be lightweight since it only needs to guide the outer portions during normal operation. This localized strengthening approach ensures the primary rail has the necessary strength without unnecessarily increasing the weight of the entire rail system
Data Source
AI summary
The present disclosure relates to a thrust reverser for a turbojet engine nacelle, including cowls that move backwards to open the thrust reverser. Each cowl includes a primary axial guide rail that receives most of the loads of the cowl, and secondary rails guiding an outer portion of each cowl. The thrust reverser includes a rear end stop for each cowl is arranged on the primary axial guide rails.