Locking Tab Washer for Torque-Independent Bolt Retention
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Solution Overview
Problem
Existing locking tab washers in aircraft engines require precise orientation of the bolt head for satisfactory alignment of locking tabs, leading to potential over or under-torquing issues.
Innovation Solution
A locking tab washer design with circumferentially spaced locking tabs and a retaining feature that allows the bolt to be torqued to a predetermined degree regardless of its rotational orientation, ensuring secure locking without over or under-torquing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If locking tabs are aligned with bolt head flats for satisfactory locking, then locking reliability is improved, but bolt head orientation precision requirement increases
Solution Approach 1:
The locking tabs are designed to be bendable rather than rigid, allowing them to dynamically adapt to the bolt head orientation after torquing. The tabs can be bent towards the bolt head to establish locking, providing tolerance for orientation variations while maintaining reliable locking.
Solution Approach 2:
The spacing between locking tabs is set at integer multiples of fifteen degrees (e.g., 0°, 45°, 90°, 135°), which creates multiple potential locking positions. This parameter configuration allows the system to accommodate a range of bolt orientations while ensuring at least one tab will align satisfactorily with the bolt head flats.
2Measurement precision
If bolt head is oriented at specific angles for locking alignment, then locking accuracy is improved, but operation complexity increases
Solution Approach 1:
The locking tabs are positioned and dimensioned to automatically align with the bolt head flats during the torquing process. The bendable nature of the tabs allows them to self-adjust and establish locking without requiring the operator to precisely control the bolt head orientation, making the operation simpler and more forgiving.
Solution Approach 2:
The locking tabs are pre-positioned at specific circumferential spacings (multiples of fifteen degrees) and pre-bent in the first direction relative to the axis. This preliminary configuration ensures that regardless of the initial bolt orientation, at least one tab will be in a satisfactory position to establish locking after torquing, eliminating the need for precise angular alignment during installation.
3Stability of the object's composition
If locking tabs are made rigid for stable locking, then locking stability is improved, but adaptability to bolt orientation variations decreases
Solution Approach 1:
The locking tabs are designed with bendability, transforming them from rigid to dynamic elements. This allows the tabs to adapt to variations in bolt orientation during installation while maintaining stable locking once bent into position. The dynamic characteristic enables tolerance for orientation variations, and the stable bent position provides reliable locking.
Solution Approach 2:
The tabs are configured with specific geometric parameters including circumferential spacing at integer multiples of fifteen degrees and pre-bending in the first direction relative to the axis. These parameter changes enable the tabs to accommodate a range of orientations while maintaining locking stability once engaged.
Data Source
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AI summary
A locking tab washer (70) for rotatably locking a bolt (40) fastened to a component (50, 60) in an aircraft engine has a body with an opening (73) and at least four locking tabs (74) positioned about the opening (73) and circumferentially spaced apart from one another at integer multiples of a common angle relative to the center of the opening (73). The locking tabs (74) are bendable towards to rotatably lock the bolt (40). The locking tab washer (70) also has a retaining feature positioned about the opening (73) and operable to rotatably retain the locking tab washer (70) to the component (50, 60).