Direct Tension Indicating Washer Protuberance Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Direct tension indicating washers with small or low protuberances relative to indentation depth fail to reliably expel indicating material due to insufficient deformation of the indentation cavity, leading to unpredictable and insufficient ejection of material.
Innovation Solution
The protuberance is redesigned with four planar and perpendicular walls, formed using a wider punch to create a higher and weaker structure that deflects more easily, causing greater interior deformation of the indentation and predictable ejection of indicating material, with a volume ratio of indicating material to compression resistance optimized between 0.7×10−6 cc per lb and 0.9×10−6 cc per lb.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If protuberances are made small or low relative to indentation depth, then the washer structure is more compact, but the indicating material is not reliably expelled
Solution Approach 1:
The patent changes the geometric parameters of the protuberance by adding four perpendicular walls to create a box-like structure. This structural parameter change allows the protuberance to deflect more easily and generate sufficient compression force to reliably eject indicating material, even when the overall protuberance size is small relative to indentation depth.
2Ease of operation
If protuberances have low compression resistance, then they deflect more easily to expel indicating material, but they may deform too much or fail structurally
Solution Approach 1:
The patent optimizes the wall thickness and height parameters of the four-sided protuberance structure. The walls are designed to be thin enough to allow easy deflection and material ejection, yet sufficiently thick to maintain structural integrity and prevent excessive deformation or failure under compression loads.
3Quantity of substance
If indicating material volume is increased to ensure sufficient ejection, then the indication is more prominent, but the compression resistance increases making ejection harder
Solution Approach 1:
The patent optimizes the volume of indicating material to fall within a specific range that balances two competing requirements: sufficient volume to provide prominent visual indication after ejection, and limited volume to maintain manageable compression resistance that allows reliable ejection through the channel.
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
This design ensures a reliable and predictable 'squirt event' by effectively expelling more indicating material, enhancing the indication of proper bolt tension and allowing for detection of bolt tension loss over time.
Implementation Method 1
the compression of the small protuberances 12 sometimes does not result in sufficient deformation of the indentation 16 cavity to eject indicating material 64
Implementation Method 2
when the DTI protuberances 12 get too small, or low, relative to the indentation 16 depth under them, when used to expel indicating material 64
Data Source
AI summary
A direct tension indicating washer including a first surface having a protuberance formed thereon; a second surface having an indentation formed opposite the protuberance; an indicating material positioned in the indentation; and a channel leading from the indentation to an outer diameter of the direct tension indicating washer; wherein the protuberance has four walls, each of the walls being substantially perpendicular to the first surface.