Load-Indicating Washer With Deformable Probe
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Solution Overview
Problem
Existing methods for tensioning fastening components like nuts and bolts, such as using torque wrenches, are often inaccurate due to high frictional resistance, leading to potential under-loading or over-loading, which can result in mechanical failure and safety issues.
Innovation Solution
A load-indicating device featuring a washer with a tubular body and a probe that deflects when the load reaches a predetermined tension, allowing for reliable and accurate tensioning without the need for torque wrenches, using a washer that compresses and provides visual or mechanical indicators for correct tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque wrenches are used to tension fastening components, then the tightening process can be performed, but the tensioning accuracy is poor due to high frictional resistance consuming up to 90% of the applied effort
Solution Approach 1:
The patent introduces a load-indicating washer as an intermediary device between the fastening components. This washer includes a deformable element that directly senses the clamping load and provides visual indication, thereby mediating the transmission of force information without being significantly affected by frictional losses in the threading interface.
Solution Approach 2:
The patent replaces the mechanical torque-based tensioning system with a direct load-indication system. Instead of relying on torque application and friction-overcoming mechanics, the system uses a deformable element within the washer that physically responds to the actual clamping load, substituting the indirect torque measurement with direct load sensing.
2Reliability
If torque wrenches are used for tightening, then fastening components can be tensioned, but the operator cannot reliably determine when correct tension is achieved due to unpredictable frictional variations
Solution Approach 1:
The load-indicating washer incorporates a visual feedback mechanism through its deformable element. As the clamping load increases, the deformable element changes its physical state or position, providing real-time visual feedback to the operator about the actual load applied, enabling reliable determination of when correct tension is achieved regardless of frictional variations.
Solution Approach 2:
The washer itself performs the function of indicating the load status. The deformable element within the washer automatically responds to the applied load and provides indication without requiring external measurement devices or complex monitoring systems, making the fastening system self-indicating.
3Measurement precision
If traditional washers are used without load indication, then the assembly is simple, but there is no way to verify if the correct tension has been applied to fastening components
Solution Approach 1:
The patent merges the load-indication function directly into the washer structure itself. The deformable element is integrated within the washer body, combining the structural support function of the washer with the load-indication function, rather than requiring separate indication devices or mechanisms.
Solution Approach 2:
The deformable element provides visual indication through color changes or visual transitions. As the element deforms under load, its color or visual appearance changes, providing an intuitive and easily observable indication of the tension status without requiring complex instrumentation.
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
Ensures consistent and accurate tensioning of fastening components, preventing mechanical failure and enhancing the safety and longevity of assemblies by providing a clear indication of when the required tension is achieved.
Implementation Method 1
the washer deflects to compress the hole against the probe when the load on the washer reaches a predetermined tension
Data Source
Figure 1~4b
Figure 5a~5b
Figure 6
AI summary
The present invention provides a load-indicating device for use with structural assemblies that have fastening components such as nuts and bolts. The load-indicating device comprising a washer having a tubular body defining a bore extending therethrough, the body comprising at least one hole extending at least partially through the body; and a probe configured to be disposed within the at least one hole and operable to provide an indication of the compression on the washer, such that, in use, the washer deflects to compress the hole against the probe when the load on the washer reaches a predetermined tension.