Hall Sensor Thickness Detection Linearizing Lever Arm
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Solution Overview
Problem
Conventional Hall thickness detection devices for sheet-like media experience inaccuracies due to non-linear changes in magnetic flux detected by Hall sensors, leading to errors in thickness calculation.
Innovation Solution
A Hall thickness detection device with a specific configuration including a mounting frame, reference shaft, floating roller assembly, detection block, and sensor, where the positional relationships and component sizes are optimized to ensure a linear change in detected magnetic flux, including a circular magnet with a detection block and sensor alignment, allowing for accurate thickness measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional Hall sensor is used to detect thickness, then the detection structure is simple, but the magnetic flux changes non-linearly causing large errors in detection results
Solution Approach 1:
The patent introduces a lever arm mechanism that converts the vertical displacement (one dimension) into rotational motion (another dimension). The detection block rotates around a pivot point, transforming the linear thickness measurement into an angular displacement that produces a linear magnetic flux change, thereby resolving the non-linearity issue while maintaining structural simplicity
Solution Approach 2:
The detection block acts as an intermediary between the floating roller and the Hall sensor. It converts the mechanical displacement into a controlled magnetic field variation by positioning the magnet at a specific distance from the sensor, ensuring linear relationship between thickness and magnetic flux while keeping the overall structure simple
2Measurement precision
If the magnet is positioned close to the Hall sensor, then the magnetic field sensitivity is high, but the linear detection range is limited
Solution Approach 1:
The patent employs a dynamic lever arm mechanism where the detection block rotates around a pivot point. This dynamic motion allows the magnet to maintain an optimal distance from the Hall sensor during measurement, preserving high magnetic field sensitivity while extending the linear detection range through controlled rotational movement rather than fixed positioning
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
The optimized configuration ensures a substantially linear change in detection data, enhancing the accuracy of thickness calculation and reducing errors in the detection process.
Implementation Method 1
a Hall sensor 05...detecting a sheet-like valuable document 02 entering a conveying passage, formed between a reference shaft 03 and a floating roller 04, may cause a floating roller 04 to move upward, which causes the magnet 01 also to move upward. Thus, a magnetic field sensed by a Hall sensor 05 is intensified.
Data Source
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AI summary
Disclosed is a Hall detection device for a thickness of a sheet medium, comprising a mounting rack, a reference shaft (1) and a floating wheel assembly (2), wherein the floating wheel assembly (2) comprises a bracket (21) and at least one floating wheel (22), one end of the bracket (21) being mounted on the mounting rack via a floating wheel rotary shaft (23) and the other end thereof being rotationally fitted with the floating wheel (22) so as to form a free end, a torsional spring (24) is provided between the floating wheel rotary shaft (23) and the bracket (21) so that the floating wheel (22) elastically bears against the reference shaft (1), and the bracket (21) is fixedly mounted with a detection block (3) and a sensor (4) for detecting a displacement amount of the detection block (3); and the connection line of the axial centres of the floating wheel (22) and the reference shaft (1) and the detection centres of the detection block (3) and the sensor (4) are located in one straight line, the distance from the axial centre of the floating wheel rotary shaft (23) to a point of tangency (a) of the floating wheel (22) and the reference shaft (1) is the same as the distance from the axial centre of the floating wheel rotary shaft to a surface detection central point (b) of the detection block (3), and an angle of 45 degrees is formed between the connection line from the point of tangency (a) to the axial centre of the floating wheel rotary shaft (23) and the orientation (p) of a sheet medium conveying path.