Sensing Washer Attachment Monitoring for Bolt Tightening Stress
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Solution Overview
Problem
Existing methods for inspecting the attachment state of objects fastened by bolts and nuts are labor-intensive, costly, and prone to human error, particularly when visual inspection is difficult or requires expensive image analysis software.
Innovation Solution
A management system using a sensing washer with a strain sensor and RFID tag that detects stress between a bolt and nut, transmitting data wirelessly for analysis by a management processing device to determine suitable or unsuitable attachment states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If visual inspection with match marks is used to confirm attachment state, then inspection can be performed with simple tools, but inspection time increases and labor costs rise
Solution Approach 1:
The patent replaces the mechanical visual inspection method with a sensor-based detection system. Strain sensors, pressure sensors, or acoustic emission sensors automatically detect attachment state, eliminating the need for manual visual inspection with match marks and significantly reducing inspection time while maintaining simplicity in the overall system.
Solution Approach 2:
The attachment structure performs self-inspection through integrated sensors that continuously monitor its own state. The sensors detect strain, pressure, or acoustic emissions generated by the attachment components themselves, enabling automatic detection without external inspection equipment or personnel.
2Measurement precision
If image analysis software is used to automate inspection, then inspection accuracy improves, but system cost increases significantly
Solution Approach 1:
The patent replaces complex image analysis software systems with straightforward sensor-based detection. Strain sensors, pressure sensors, or acoustic emission sensors provide direct physical measurements of attachment state, achieving high accuracy without requiring expensive computer vision algorithms or image processing capabilities.
Solution Approach 2:
The patent uses relatively inexpensive sensor components that can be easily replaced if needed, rather than investing in expensive proprietary image analysis software systems. The sensors provide sufficient measurement precision at a fraction of the cost of automated visual inspection systems.
3Measurement precision
If close-up visual inspection is performed to detect loosening, then inspection detail is sufficient, but inspection safety decreases due to access to high places
Solution Approach 1:
The attachment structure performs self-monitoring through integrated sensors that continuously detect attachment state without requiring external inspection. The sensors detect strain, pressure, or acoustic emissions at the attachment site, providing detailed information while eliminating the need for inspectors to access hazardous high places.
Solution Approach 2:
The patent replaces manual visual inspection requiring physical access with remote sensor-based detection. Sensors mounted on or near the attachment components transmit data wirelessly or through conduits, allowing detailed monitoring of attachment state without exposing personnel to safety risks.
4Reliability
If multiple inspectors are deployed to cover all attachment points, then inspection coverage improves, but labor costs and coordination complexity increase
Solution Approach 1:
Each attachment point is equipped with its own sensors that autonomously monitor its state. The distributed sensor network independently detects local conditions, eliminating the need for multiple inspectors and complex coordination protocols while ensuring complete coverage of all attachment points.
Solution Approach 2:
The patent divides the inspection system into independent sensor units at each attachment point. Each sensor operates autonomously and can be individually addressed or aggregated, providing comprehensive coverage without requiring centralized human coordination. The segmented approach allows parallel monitoring of multiple locations simultaneously.
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
Accurately assesses attachment states quickly and cost-effectively, reducing labor and minimizing errors, while enabling remote monitoring and eliminating the need for manual match marks.
Implementation Method 1
a strain sensor that detects a value equivalent to stress of stress applied to the strain element
Implementation Method 2
a communication unit that communicates a value equivalent to stress and identification information of the sensing washer with a management processing device
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Suitable states and unsuitable states of attachment of attachment objects can be accurately comprehended, and inspection work can be performed in a short time at low costs. In a management system for an attachment state of an attachment object, a sensor that is capable of detecting a value equivalent to stress such as a resistance value or the like corresponding to stress that is being loaded, a washer storage unit 32 that stores identification information of a sensing washer 30, and a washer control unit 31 that transmits the value equivalent to stress and the identification information of the sensing washer 30 via a communication unit, are provided in the sensing washer 30 that is interposed between a bolt 60 and a nut 70 that attach an attachment object 90 to a structural object 80, and a management processing device 10 acquires the value equivalent to stress and the identification information of the sensing washer 30 from the sensing washer 30 via a reader 20, and presents the stress value corresponding to the value equivalent to stress that is acquired as relational information with respect to a reference value for stress by nut tightening that is stored in a storage unit 12.