Weigh-in-motion scale plate thickness and load cell positioning
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Solution Overview
Problem
Existing weigh-in-motion scales are inaccurate and unrepeatable when measuring heavier loads due to complex and bulky configurations of load cells and their placement, limiting their ability to handle larger weights effectively.
Innovation Solution
A weigh-in-motion scale design featuring a slightly thicker bending plate and altered lateral placement of load cells, coupled with a Wheatstone bridge circuit, allows for accurate measurement of heavier loads by increasing the thickness of the upper flexibly-deformable metal plate and optimizing the positioning of strain gauges, enabling improved deformation detection and signal generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the thickness of the bending plate is increased and load cells are repositioned laterally, then the measurable weight capacity improves, but the device complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the thickness of the bending plate from the prior art specification to an optimized range (0.604-0.756 inches), and by changing the lateral positioning parameters of the load cells relative to the plate edges. These parameter adjustments enable the plate to withstand heavier loads (up to 15 Tonnes/axle) while maintaining measurement accuracy, directly resolving the contradiction between measurable weight capacity and device complexity.
2Measurement precision
If the thickness of the upper flexibly-deformable metal plate is increased, then the accuracy of heavier load measurement improves, but the device becomes bulkier
Solution Approach 1:
The patent optimizes the plate thickness parameter within a specific range (0.604-0.756 inches) rather than simply increasing it indefinitely. This controlled parameter change achieves the necessary structural strength for accurate heavy load measurement while minimizing the volume increase, preventing the device from becoming excessively bulky.
3Measurement precision
If the lateral positions of load cells are changed, then the deformation detection accuracy improves, but the ease of manufacture decreases
Solution Approach 1:
The patent specifies precise lateral positioning parameters for load cells (distance B from longitudinal edges at 52-54% of the half-width) to optimize deformation detection accuracy. While these positions require precision during manufacturing, the patent maintains ease of manufacture by providing clear dimensional specifications and using standard manufacturing tolerances that accommodate these positioning requirements without excessive complexity.
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 design achieves a 50% improvement in measurable weight capacity, allowing for accurate weighing of up to 15 Tonnes/axle, compared to the previous 10 Tonnes/axle, with enhanced accuracy and reliability.
Implementation Method 1
strain gauges, which provide a changing resistive value, associated with the bending of the upper, flexibly-deformable metal plate
Implementation Method 2
A Wheatstone bridge circuit generates output signals, which are indicative of, and preferably proportional to, the force applied to the upper, flexibly-deformable metal plate
Data Source
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AI summary
The present invention provides an improved weigh-in-motion scale. A slight increase in the thickness of a an upper, flexibly-deformable metal plate e.g., having a thickness of about 0.604 inches to about 0.756 inches in a thin, flexibly-deformable plate system coupled with a change in the transverse locations of the load cells each of the strain gauge channels is spaced e.g., by an amount of about 52 % to about 54 % of the distance from the center line of the bottom or lower metal plate to the respective longitudinal edge of the bottom or lower metal plate, provides the improved weigh-in-motion scale, which is capable of weighing substantially heavier loads than previously known weigh-in-motion scales. In use, as weight is applied to the wcigh-in-motion scale, the upper flexibly-deformable metal plate elastically bends. The strain gauges thus provide a changing resistive value proportional to the bending of the flexible element and the weight applied, to generate signals to the Wheatstone bridge circuit, which then provides output signals from the Wheatstone bridge circuit, which are proportional to the force applied to the upper flexibly-deformable metal plate.