Direct Tension Indicating Washer Anti-Rotation Base
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Solution Overview
Problem
Direct tension indicating washers fail to provide a clear visual indication of proper bolt tension on irregular or rough installation surfaces due to smudging or smearing of the indicating material, caused by rotation and surface irregularities during assembly.
Innovation Solution
A direct tension indicating apparatus comprising a direct tension indicating washer and a base washer with an anti-rotation feature, such as tabs and notches or pins and openings, to prevent rotation and ensure clean emission of the indicating material at the outer diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a direct tension indicating washer is used on a rough or irregular installation surface, then the washer can indicate bolt tension, but the indicating material becomes smudged or smeared instead of emitting cleanly
Solution Approach 1:
A base washer is introduced as an intermediary component between the rough installation surface and the direct tension indicating washer. The base washer provides a smooth, flat bearing surface that prevents the indicating material from contacting surface irregularities, thereby eliminating smudging while still allowing the indicating washer to function properly
Solution Approach 2:
The system is divided into two separate functional components: the base washer that handles surface contact and provides a smooth bearing surface, and the direct tension indicating washer that performs the indication function. This segmentation allows each component to optimize its specific function without interference from surface irregularities
2Adaptability or versatility
If the direct tension indicating washer rotates during assembly on irregular surfaces, then the washer may align with surface irregularities, but the indicating material smears instead of emitting cleanly from the outer diameter
Solution Approach 1:
The base washer acts as a mediator that prevents rotation of the indicating washer by providing a stable, flat interface. This eliminates the harmful effect of rotation-induced smearing while preserving the ability to indicate tension at the correct threshold
Solution Approach 2:
The base washer is installed first to establish a stable, non-rotating foundation before the indicating washer is placed. This preliminary action prevents rotation from occurring during the subsequent tightening process, ensuring clean material emission
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents smearing and ensures clear visual indication of proper bolt tension by maintaining the direct tension indicating washer's position, improving the visibility and reliability of the tension indication even on irregular surfaces.
Implementation Method 1
protuberances 12 are compressed as the bolt is tensioned. When the desired bolt tension is achieved, indicating material 64 emerges from channel 62
Data Source
AI summary
A direct tension indicating washer apparatus includes a direct tension indicating washer; a base washer; and an anti-rotation feature to prevent rotation of the direct tension indicating washer relative to the base washer.