Aircraft Preloading Tool for Strut Positioning
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Solution Overview
Problem
Preloading an aircraft assembly for attachment of a preloading linkage is a difficult and time-consuming operation, and accurately achieving the required preloading distance is challenging.
Innovation Solution
A method employing a variable length preloading tool is used to move the main strut between default and preloaded positions, allowing for precise adjustment of link attachment joints to match the preloading distance, with a high displacement ratio for increased accuracy and ease of installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a preloading linkage is fitted to reduce down-lock spring size and mass, then the spring energy requirement is reduced, but the assembly process becomes difficult and time-consuming
Solution Approach 1:
The patent applies preliminary action by pre-setting the main strut to the correct preloaded position using a dedicated tooling fixture before the preloading linkage is installed. This preliminary positioning ensures that when the linkage is fitted, the attachment joints are already at the correct distance, eliminating the need for time-consuming adjustment operations during assembly.
Solution Approach 2:
The patent introduces a dedicated tooling fixture as an intermediary device that temporarily holds the main strut in the correct preloaded position. This fixture acts as a mediator between the default position and the required preloaded position, enabling accurate positioning without requiring complex manual adjustment operations during the actual assembly process.
2Adaptability or versatility
If manual adjustment methods are used to set the preloading distance, then flexibility is maintained, but manufacturing precision and accuracy are difficult to achieve
Solution Approach 1:
The dedicated tooling fixture serves as an intermediary that provides precise geometric references for positioning the main strut. The fixture incorporates fixed dimensional references that directly establish the correct preloaded distance between attachment joints, eliminating the need for manual measurement and adjustment while ensuring consistent precision across all assemblies.
Solution Approach 2:
The patent replaces manual measurement and adjustment mechanical operations with a fixed tooling fixture system. Instead of using rulers, calipers, or manual positioning devices that require operator skill and time, the fixture mechanically enforces the correct geometry through its rigid structure and fixed reference features, substituting human judgment with precise mechanical constraints.
3Ease of manufacture
If the main strut is manually repositioned to achieve preloading distance, then the preloading linkage can be fitted, but the operation is time-consuming and prone to errors
Solution Approach 1:
The tooling fixture performs the repositioning action in advance, before the preloading linkage is installed. By pre-setting the main strut to the correct position and securing it with the fixture, the actual linkage installation becomes a simple bolt-on operation without requiring time-consuming manual repositioning or adjustment during the assembly process.
Data Source
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AI summary
A method (40) of preloading an aircraft assembly (1) involving a step of operating an extendible preloading tool (20) to move a main strut (15) to decrease the distance between first and second link attachment joints (C2, C3) for attachment of a preloading linkage (12b).