Actuator Lock Nut Assembly for In Situ Torque Adjustment
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Solution Overview
Problem
Existing actuator assemblies require disassembly and replacement of components to check and adjust lock nut torque, leading to increased maintenance time and risk of Foreign Object Debris (FOD) in safety-critical applications like helicopter rotors.
Innovation Solution
A lock nut assembly with a lock nut retaining and release mechanism that allows in situ torque checking and adjustment, featuring a lock nut and a mechanism with an axially movable pin to engage and disengage with the nut, enabling torque adjustment without dismounting the actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lock nuts are used in helicopter rotor actuators, then the torque can be maintained as designed, but the nuts require regular disassembly for torque checking and adjustment, increasing maintenance time and FOD risk
Solution Approach 1:
The lock nut assembly incorporates a movable retaining mechanism that transitions between locked and unlocked positions, enabling dynamic access for torque adjustment without permanent disassembly. The retaining member can be moved axially to release the lock nut, allowing maintenance personnel to check and adjust torque while the actuator remains installed on the helicopter.
Solution Approach 2:
The assembly is divided into separable components including the lock nut, retaining member, and actuator body. This segmentation allows the retaining mechanism to be independently moved or removed, facilitating torque checking without requiring complete disassembly of the actuator assembly.
2Reliability
If conventional lock nuts are used in helicopter rotor actuators, then the torque can be maintained as designed, but disassembly is required for torque checking, increasing the risk of Foreign Object Damage
Solution Approach 1:
The movable retaining mechanism allows the lock nut to be accessed and adjusted without removing it from the actuator assembly. By enabling the retaining member to move axially between engaged and disengaged positions, the system eliminates the need for complete disassembly, thereby reducing the risk of Foreign Object Damage during maintenance operations.
3Ease of operation
If a lock nut retaining and release mechanism is added, then in situ torque checking becomes possible, but the device complexity increases
Solution Approach 1:
The retaining function is extracted as a separate, movable mechanism distinct from the lock nut itself. The retaining member can be independently actuated to release the lock nut, simplifying the overall design compared to integrated solutions while enabling easy torque checking without complex multi-component systems.
Solution Approach 2:
The retaining mechanism is designed to be manually operable by maintenance personnel using simple tools or direct hand operation. The axial movement of the retaining member is self-contained within the assembly, requiring no external equipment or complex actuation systems, thus balancing ease of operation with minimal added complexity.
Data Source
AI summary
A lock nut assembly for an actuator, the lock nut assembly comprising a nut configured to be mounted to a bracket of the actuator for axial movement relative to the bracket, and a lock nut retaining and release mechanism configured to be fixedly mounted to the bracket and axially movable between a first engaged position in which the lock nut retaining and release mechanism engages with the nut to prevent rotation of the nut and a second unlocked position in which the lock nut retaining and release mechanism is not engaged with the nut and the nut can be rotated relative to the bracket.