DTI Washer Horseshoe Protuberances Visual Tension Indication
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Solution Overview
Problem
Existing direct tension indicating (DTI) washers lack a practical method to visually confirm the 'snug' tight condition before final tightening, and they often provide premature or inaccurate visual indications of bolt tension due to the placement of elastomeric material against unpredictable surface conditions, leading to variability in tension measurements.
Innovation Solution
The development of a DTI washer with U-shaped horseshoe protuberances and varying height protuberances that encapsulate and control the indicating material, ensuring it emits only when the bolt is adequately tightened, providing a clear visual indication of both snug and final tension stages, and protecting the material during handling and use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If elastomeric indicating material is placed against joint member surfaces in existing DTI washers, then visual indication of bolt tension is provided, but the indication is premature or inaccurate due to unpredictable surface conditions
Solution Approach 1:
The patent introduces a controlled release mechanism as an intermediary between the bolt tension force and the elastomeric indicating material. The indicator material is encapsulated within a matrix that prevents premature contact with unpredictable joint member surfaces. The release occurs only when the matrix itself deforms under controlled tension, ensuring accurate and reliable visual indication regardless of surface conditions.
Solution Approach 2:
The elastomeric indicating material is pre-positioned within a protective matrix structure before installation. The matrix is designed to remain intact during handling and installation, preventing premature emission of the indicator material. The material is released only when the matrix deforms at a predetermined tension level, ensuring the indication occurs at the correct moment rather than during unpredictable surface contact.
2Ease of operation
If indicating material is emitted early to show tension, then visual confirmation is provided, but it gives premature indication before adequate tightening is achieved
Solution Approach 1:
The patent designs the matrix material to undergo a specific deformation parameter change at a predetermined tension level. The matrix remains rigid during handling and installation, then transitions to a deformed state that releases the indicator material only when the bolt tension reaches the desired level. This controlled parameter change ensures the visual indication occurs at the precise moment of adequate tightening.
Solution Approach 2:
The system provides visual feedback through the elastomeric material emission, but this feedback is gated by the matrix deformation condition. The matrix acts as a feedback control mechanism that only allows indicator material release when the tension parameter reaches the predetermined threshold, ensuring accurate tension measurement while providing clear visual confirmation.
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 allows for accurate and repeatable visual confirmation of bolt tension, ensuring that the joint is properly snugged and fully tightened, overcoming the limitations of existing DTI washers by delaying the emission of the indicating material until the correct tension is achieved and ensuring it is against a predictable surface, thus providing reliable and consistent results.
Implementation Method 1
The horseshoe protuberances are struck and partially sheared from the annular body to leave one or more corresponding indentations in the second face of the annular body. An indicating material is initially encapsulated and contained within the area on the first face defined by each of the horseshoe protuberances.
Implementation Method 2
providing a clear visual indication of both snug and final tension stages
Data Source
AI summary
A direct tension indicating (DTI) washer. The DTI washer has an annular body and one or more U-shaped horseshoe protuberances. The annular body includes a central hole, a circumference, an outer edge, a first face, and a second face opposite from the first face. The horseshoe protuberances each have a height, an apex closest to the central hole, and an opening directed toward the outer edge. The horseshoe protuberances are integral with the annular body and struck and partially sheared from the annular body to project from the first face of the annular body and leave one or more corresponding indentations in the second face of the annular body. The horseshoe protuberances may be radially offset from their corresponding indentations. An indicating material is initially encapsulated and contained within the area on the first face defined by each of the horseshoe protuberances.