Telescopic Thrust Reverser Locking Rod Vibration Isolation
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Solution Overview
Problem
The existing locking device for aircraft thrust reverser cowls is subjected to severe vibrations due to differing frequencies and vibration levels among the cowls, motor, and mast, leading to reduced longevity and instability, especially when the yoke joint is fastened on the motor, which can cause tilting and require additional angular stops.
Innovation Solution
The locking device incorporates a telescopic connecting rod with support fingers and a centering pin system, allowing free displacement in the closed configuration to avoid transmitting vibrations and using elastic return elements for stabilization, along with a fuse element to prevent damage during opening or closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the connecting rod is rigidly linked to both cowls and the motor/mast, then structural strength is improved, but vibration transmission increases and longevity decreases
Solution Approach 1:
The patent applies the dynamics principle by introducing a dynamic support system where support fingers can freely displace within slots during flight. This allows the connecting rod to move relative to the motor/mast, absorbing vibrations while maintaining structural integrity. The support fingers are constrained by slot walls during opening/closure operations, providing rigidity when needed, but are free to move during flight to isolate vibrations.
2Adaptability or versatility
If the yoke joint is fastened on the motor, then adaptability is improved, but stability deteriorates due to tilting and vibration
Solution Approach 1:
The patent uses support fingers as an intermediary element between the connecting rod and the motor/mast. These support fingers transmit support forces during flight while allowing relative movement to accommodate vibrations and prevent tilting. The support fingers act as a mediator that decouples the rigid connection, enabling the yoke joint to be fastened on the motor without compromising stability.
3Stability of the object's composition
If additional angular stops are added to prevent tilting, then stability is improved, but device complexity increases
Solution Approach 1:
The support fingers serve multiple functions: they provide support during flight, allow vibration isolation, and prevent tilting through their interaction with the slot walls. By making the support fingers multi-functional, the patent eliminates the need for separate angular stops, maintaining stability without increasing device complexity.
4Manufacturing precision
If the connecting rod is rigidly connected, then manufacturing precision is improved, but vibration transmission increases
Solution Approach 1:
The patent applies dynamics by allowing the support fingers to move freely within the slots during flight operations. This dynamic capability enables the system to maintain precise manufacturing tolerances for the connecting rod geometry while simultaneously isolating vibrations through the permitted relative movement between the support fingers and slot walls.
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 solution effectively reduces vibration transmission, enhances longevity, and stabilizes the connecting rod during flight, ensuring reliable engagement and disengagement of the cowls while preventing damage to the motor or cowls.
Implementation Method 1
a stabilizing spring which is arranged in a compressed state between the movable rod and the tubular element of the connecting rod
Implementation Method 2
a fuse element which is designed to yield beyond a certain force in case of blocking of the connecting rod during the opening or the closure of the movable cowls
Data Source
AI summary
The present disclosure provides a device for locking a first cowling and a second cowling of a thrust reverser of an aircraft propulsion assembly. The cowlings are mounted such that each cowl pivots around a longitudinal axis between a closed flight position and an open maintenance position. The locking device includes a telescopic connecting rod having at least one sliding shaft, a locking mechanism on a proximal end of a shaft on the second cowling, and a connecting rod support. The connecting rod support or the tubular element includes two walls each delimiting a hole, and the tubular element of the connecting rod or the connecting rod support has two support fingers which each extend longitudinally on a side of the tubular element into a hole. The holes engage with the support fingers when the cowlings are open and allow free movement of the support fingers in a closed-cowlings configuration.