Force Measurement Device Mechanical Amplification
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Solution Overview
Problem
Force measurement devices, such as load cells, face limitations in sensitivity and resolution due to the inherent limitations of mechanical and electrical amplification methods, resulting in high noise-to-signal ratios and relatively low accuracy, typically achieving a resolution of only 0.02-0.05% of the full scale.
Innovation Solution
The implementation of a force measurement device with a closed contour load sensing element and cantilever arms that undergo quasi-linear movement upon loading, allowing for mechanical amplification of deformation, which is then correlated with applied loads using digital encoders to enhance sensitivity and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrical signal amplification is used to improve measurement sensitivity, then the output signal level increases, but the noise-to-signal ratio increases and measurement precision deteriorates
Solution Approach 1:
The patent replaces electrical signal amplification with mechanical amplification of the elastic deformation itself. By using a lever mechanism with a mechanical amplification factor of 10, the deformation is amplified before measurement, eliminating the need for electrical amplification and its associated noise problems. This substitution of mechanical amplification for electrical amplification directly resolves the contradiction between improving sensitivity and avoiding noise amplification.
2Power
If analog electronics and signal conditioning hardware are used to amplify output signals, then the output voltage increases from mV to V, but device complexity and sources of error increase
Solution Approach 1:
The patent extracts and removes the analog electronics and signal conditioning hardware from the measurement system. By achieving sufficient output signal level through mechanical amplification of deformation, the complex electronic amplification chain is eliminated entirely. This extraction of unnecessary electronic components directly reduces device complexity while maintaining adequate output power.
3Measurement precision
If strain-gauges are used to measure deformation, then electrical property changes can be detected, but the inherent deformation remains too small for high precision measurement
Solution Approach 1:
The patent introduces a mechanical amplification dimension to the measurement system. By using a lever mechanism that provides 10x mechanical amplification, the small deformation in one dimension is transformed into a larger amplified deformation in another dimension. This allows the original small deformation to be measured with high precision through its amplified counterpart, effectively resolving the limitation of small deformation magnitude.
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 approach results in a force measurement device with a resolution 10 times more accurate than traditional strain-gauge based load cells, achieving improved sensitivity and accuracy through mechanical amplification of deformation, while eliminating the need for analog electronics and reducing noise-to-signal issues.
Implementation Method 1
a load sensing element which deforms elastically in proportion to applied load
Implementation Method 2
mechanical amplification of linear elastic deformation along the axis of loading by estimating the quasi-linear incremental displacement between two points on arcs inscribed due to angular movements of a pair of cantilever arms
Data Source
AI summary
The present invention relates to a force measurement device that includes mechanical amplification of linear elastic deformation along the axis of loading by estimating the quasi-linear incremental displacement between two points on arcs inscribed due to angular movements of a pair of cantilever arms located on opposite quadrants on a closed contour load sensing element to improve the sensitivity, and hence the resolution, of the force measurement device.