Thrust Reverser Lock Pin-Capturing Member Design
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Solution Overview
Problem
Aircraft engine thrust reverser systems face challenges in preventing accidental deployment due to the complexity and weight added by redundant locking mechanisms, which can lead to increased wear and cost.
Innovation Solution
A pin-capturing member with a unique slot design and a biasing mechanism that allows the pin to move from a released to a captured position without reversing direction, reducing the need for over-stow processes and minimizing contact with the pin-capturing member during normal operation, thereby reducing wear and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant locking mechanisms are used to prevent accidental deployment, then reliability is improved, but device complexity and weight increase
Solution Approach 1:
The locking mechanism is divided into distinct functional segments: the pin-capturing member with its slot structure, the pin itself, and the biasing mechanism. This segmentation allows each component to perform its specific function efficiently, reducing overall system complexity while maintaining reliability through distributed functionality rather than redundant overlapping mechanisms.
Solution Approach 2:
The design inverts the traditional locking approach by using a biasing mechanism that naturally maintains the locked position, with unlocking requiring a specific action to overcome the bias. This inversion simplifies the locking logic while maintaining safety, as the default state is locked and requires deliberate intervention to unlock.
2Reliability
If redundant locking mechanisms are used to prevent accidental deployment, then reliability is improved, but weight increases
Solution Approach 1:
The design extracts the essential locking function from complex redundant mechanisms and implements it through a simplified pin-capturing member and biasing mechanism combination. By taking out only the necessary components to achieve reliable locking, the weight is minimized while maintaining the critical safety function.
Solution Approach 2:
The biasing mechanism provides self-service by automatically maintaining the locked position without requiring additional actuators or complex control systems. The spring-loaded or elastomeric biasing element continuously applies force to keep the pin engaged, eliminating the need for powered locking mechanisms and reducing overall system weight.
3Reliability
If traditional locking mechanisms are used, then reliability is improved, but wear increases due to repeated contact
Solution Approach 1:
The biasing mechanism performs preliminary action by pre-loading the pin into the captured position before any operational forces are applied. This preliminary positioning ensures that the pin is already engaged and protected from wear-causing movements, extending the service life of the locking components.
Solution Approach 2:
The slot in the pin-capturing member features curved surfaces that guide the pin smoothly into the captured position. These curved surfaces distribute contact forces more evenly and reduce stress concentrations, minimizing wear on both the pin and the slot walls during repeated locking cycles.
4Reliability
If over-stow processes are used to capture the pin, then reliability is improved, but the number of mechanical parts increases
Solution Approach 1:
The design extracts the over-stow process from the locking mechanism entirely, replacing it with a direct capture approach where the pin moves straight into the slot without requiring reverse motion or additional positioning steps. This elimination of the over-stow process reduces the number of mechanical parts and simplifies the overall system.
Solution Approach 2:
The pin movement is made continuous and direct, moving from the released position straight into the captured position within the slot without interruption or reversal. This continuous action eliminates the need for additional mechanical components that would be required to manage discontinuous or reversible motion sequences.
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 prevents inadvertent deployment of the thrust reverser while reducing wear and weight by allowing the pin to move directly into the captured position without reversing direction, thus eliminating the need for additional seals and mechanical parts, resulting in a more efficient and cost-effective locking system.
Implementation Method 1
The aircraft engine thrust reverser lock also includes a spring that contacts the pin-capturing member body to bias the body in a first direction of rotation about the rotational axis.
Data Source
Figure 1~3
Figure 2A
Figure 2B
AI summary
An aircraft engine thrust reverser lock system (100) includes a pin- capturing member (102). The pin-capturing member includes a body that is rotatable about an axis defined by a pivot (104) extending through the body. The body includes an interior surface that defines a slot (150). The slot has an opening that is sized to receive a pin (110) into the slot. One side of the slot includes a protruded sidewall surface that protrudes into the slot toward an another sidewall surface of the slot. The protruded sidewall surface defines an apex (206) between the open and closed ends of the slot. Between the apex and the closed end of the slot, the protruded sidewall surface faces the rotational axis.