Landing Gear Axle Nut Safety Socket Trigger Mechanism
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Solution Overview
Problem
The existing methods for tightening axle nuts on aircraft landing gear often result in costly repairs due to the accidental omission of spacers and washers, which can lead to improper installation and damage, as these components are difficult to detect visually or by feel, causing aircraft downtime and regulatory fines.
Innovation Solution
A socket wrench configuration with a rotatable gear hub, trigger mechanism, and ball bearings that disengages torque application when the distance between the axle and nut differs from a predetermined distance, indicating missing spacers or washers, allowing for easy detection and correction of the issue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard socket wrench is used to tighten the axle nut, then the tightening operation can be performed, but the mechanic cannot detect missing spacers or washers, leading to improper installation and potential damage
Solution Approach 1:
The socket incorporates a trigger mechanism with a spring-loaded indicator that provides immediate feedback to the mechanic. When the axle end is at the correct distance from the nut (indicating proper spacer and washer installation), the trigger remains engaged. If components are missing and the distance is incorrect, the trigger disengages and visually alerts the mechanic, ensuring detection of improper installation conditions
Solution Approach 2:
The trigger mechanism acts as an intermediary between the axle-nut assembly and the mechanic. Instead of relying on the mechanic's direct measurement or visual inspection, the trigger translates the physical distance relationship into a clear mechanical signal (engaged/disengaged position), making the detection of missing components straightforward and reliable
2Reliability
If the mechanic carefully inspects each component before installation, then missing spacers or washers can be detected, but this increases the time required for the wheel change operation
Solution Approach 1:
The socket is pre-configured with the trigger mechanism and spring system before the tightening operation begins. The trigger is positioned and spring-loaded in advance to automatically sense the correct axle-to-nut distance, eliminating the need for time-consuming manual inspections during the wheel change process
Solution Approach 2:
The socket wrench performs the verification function automatically through its self-activating trigger mechanism. As the mechanic applies the socket and tightens the nut, the trigger automatically engages or disengages based on the physical dimensions of the assembly, providing self-verification without requiring additional manual checking steps
3Reliability
If a complex detection system is added to the socket to detect missing components, then installation correctness can be ensured, but the device complexity and cost increase
Solution Approach 1:
The socket incorporates a localized trigger mechanism at the specific point where dimensional verification is needed (the opening facing the axle end). Rather than making the entire socket complex, only the critical verification zone contains the trigger and spring components, keeping the rest of the socket simple and straightforward
Solution Approach 2:
The trigger mechanism exploits the physical parameter of distance (axle end to nut distance) to detect improper installation. By designing the trigger with specific dimensions and spring tension, it automatically responds to dimensional variations caused by missing components, converting a physical parameter change into a detectable mechanical state without complex electronics or sensors
Data Source
AI summary
A socket and a method for tightening a nut on an axle are disclosed. The socket includes a socket body having a first end and a second end. The first end of the socket body has a rotatable gear hub. The second end is configured to accommodate the nut. The socket includes a socket body insert fixed substantially within the socket body. The socket also includes a trigger movable between a triggered position and a non-triggered position, wherein the trigger is configured to move to the triggered position when a distance between the axle and nut is different than a predetermined trigger distance. The socket further includes a reset pin operably connected to the trigger to reset the trigger to the non-triggered position when depressed. The socket also includes a reset spring positioned between the reset pin and the gear hub to bias the reset pin towards the second end.