Looseness Detection Sensor Using Resonance Frequency Shift
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Solution Overview
Problem
Existing methods for detecting looseness in bolts, such as visual marking displacement checks and ultrasonic wave inspections, are unsuitable for hard-to-reach locations, require skilled personnel, and are costly and dangerous, lacking a suitable method for inspecting looseness in bolts tightening two or more parts.
Innovation Solution
A looseness detection sensor system using a non-conductive film with a conductive film attached, which receives a high-frequency signal and changes resonance frequency based on the position of loosened bolts, allowing for detection and specification of loosened bolts through a high-frequency sweep, resonance frequency detection, and comparison.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If visual inspection methods (marking displacement check) are used, then inspection can be performed with simple equipment, but inspection is not suitable for hard-to-reach locations and requires skilled personnel
Solution Approach 1:
The patent replaces mechanical/visual inspection methods with an electromagnetic field-based sensor system. The sensor uses high-frequency signals and resonance frequency detection to identify loosened bolts, eliminating the need for visual line-of-sight and skilled manual inspection while maintaining detection capability.
Solution Approach 2:
The patent introduces a non-conductive film with conductive patterns as an intermediary element attached to the bolted joint. This intermediary translates mechanical bolt loosening into detectable electrical resonance frequency changes, enabling remote and automated detection without direct visual inspection.
2Measurement precision
If ultrasonic wave inspection method is used, then detection accuracy is improved, but inspection cost increases and operations become dangerous in hard-to-reach locations
Solution Approach 1:
The patent uses a inexpensive non-conductive film with conductive patterns that can be attached to the structure once and used for multiple inspections. This disposable-like element eliminates the need for expensive portable ultrasonic equipment while providing accurate detection results.
Solution Approach 2:
The patent replaces the ultrasonic wave-based mechanical inspection system with an electrical resonance frequency measurement system. This substitution maintains high detection accuracy while eliminating the costs and safety risks associated with deploying personnel to hard-to-reach locations with heavy equipment.
3Device complexity
If traditional inspection methods are used, then no additional components are required, but automation capability is lost and skilled personnel are needed
Solution Approach 1:
The non-conductive film with conductive patterns serves multiple functions: it acts as a mechanical element attached to the bolted joint, an electrical resonance circuit element for detection, and a permanent marker for the specific joint location. This multi-functionality enables automation while adding minimal complexity to the system.
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
Enables effective and safe detection of looseness in bolts tightening two or more parts, suitable for hard-to-reach locations, reducing costs and eliminating the need for skilled personnel, while providing quantitative inspection results.
Implementation Method 1
a shape in which a resonance frequency of a high-frequency signal confined in the non-conductive film is different according to a position of a loosened bolt
Data Source
AI summary
A sensor for detecting looseness of a plurality of bolts and nuts fixing parts includes: a non-conductive film attached to a surface of the part, which is one of the parts, including holes H from which the bolts are inserted; and a conductive film attached to the non-conductive film, configured to receive supply of a high-frequency signal, and having a same planar shape as that of the non-conductive film, wherein the planar shape is a shape in which a resonance frequency of the high-frequency signal confined in the non-conductive film is different according to a position of a loosened bolt, and the planar shape of the conductive film is a shape in which a distance between a bolt and an end portion of the conductive film is different for each of the plurality of bolts.