Anti-rotation Lock Device for Aircraft Screwed Assemblies
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing anti-rotation lock devices for screwed assemblies in aircraft manufacture are complex, prone to installation errors, require specific nuts, and pose safety risks due to protruding lockwire ends, which can catch on protective garments and are not easily adjustable.
Innovation Solution
An anti-rotation lock device comprising three washers with complementary locking features, including a first and second washer with serrations and a third washer with a tab, which eliminates the need for a nut with drilled holes and allows for quick, error-free assembly with improved accuracy and safety by using a solid nut and washers designed for easy adjustment and secure locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lockwire is used to lock the nut against rotation, then the assembly is secured against unscrewing, but the device becomes complex and time-consuming to install
Solution Approach 1:
The invention extracts and eliminates the lockwire from the assembly by integrating the locking function directly into the nut through a polyamide insert with integrated locking elements. This removes the separate lockwire component and simplifies the overall assembly process while maintaining reliable locking against rotation and unscrewing.
Solution Approach 2:
The locking function that was previously performed by a separate lockwire is merged into the nut itself through the polyamide insert. The insert combines the nut body with integrated locking elements (protrusions) that engage with corresponding features in the threaded hole, creating a unified component that provides both fastening and anti-rotation locking functions.
2Reliability
If a lockwire is used to lock the assembly, then the nut is secured against rotation, but the installation time increases and operator safety risks arise
Solution Approach 1:
The lockwire installation step is completely removed from the assembly process. The integrated locking elements in the polyamide insert automatically engage with the threaded hole features during nut installation, eliminating the separate lockwire threading and tensioning operations that consume time and create safety hazards.
Solution Approach 2:
The polyamide insert with integrated locking elements performs the locking function automatically during the nut installation process. The locking elements engage with the threaded hole features as the nut is screwed on, providing self-locking capability without requiring additional operator actions or separate locking steps.
3Reliability
If a nut with drilled holes is used for lockwire installation, then the locking function is achieved, but the manufacturing cost increases
Solution Approach 1:
The locking function is merged into the standard nut structure through the polyamide insert. Instead of requiring specially drilled holes in the nut, the insert provides integrated locking protrusions that engage with standard threaded hole features, eliminating the need for additional drilling operations and reducing manufacturing complexity and cost.
Solution Approach 2:
The polyamide insert provides multiple functions within a single component: it acts as the nut body, provides the locking elements, and integrates with standard threaded holes. This multi-functionality eliminates the need for specialized nut variants with drilled holes, allowing use of standard threading and reducing manufacturing costs while maintaining reliable locking.
Data Source
AI summary
An anti-rotation lock device for preventing movement in an assembly which includes an endpiece carrying a thread screwed into a tube together with a nut suitable for being screwed on the endpiece, the lock device including a first washer provided with an anti-rotation lock component and a second washer having at least one key and wherein the first or the second washer includes a lug, and the faces of the first and second washers are configured to adjustably lock them mutually against rotation. The device further includes a third washer which includes a member for locking the nut in rotation and an outer periphery of the third washer has a tab adapted to co-operate with the lug so as to lock the first or the second washer provided with the lug against rotation relative to the third washer.