Low-Profile Load Cell With Double-Bending Flexural Member
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Solution Overview
Problem
Low-profile load cell assemblies face limitations in accuracy due to small signal noise and unacceptable settling time, along with parasitic noise issues, which affect their ability to measure weights accurately.
Innovation Solution
The design incorporates a load cell body with a spring element and a two-dimensional flexural member, featuring cutout windows and an adapter that assumes a primary and secondary double-bending configuration, enhancing strain measurement accuracy and compensating for parasitic modes, while maintaining a low profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a low-profile load cell assembly is used, then the device height is reduced, but measurement accuracy deteriorates due to small signal noise and parasitic noise
Solution Approach 1:
The load cell body is segmented into distinct functional zones: a spring element region with first cutout windows for primary strain measurement, and a flexural member region with second cutout windows for parasitic mode compensation. This segmentation allows independent optimization of each region's function while maintaining overall low profile
Solution Approach 2:
The flexural member acts as an intermediary element between the spring element and the adapter, providing mechanical coupling while introducing secondary double-bending configuration that compensates for parasitic noise modes, thereby improving measurement accuracy without increasing device height
2Length of stationary object
If a low-profile load cell assembly is used, then the device height is reduced, but settling time increases to unacceptable levels
Solution Approach 1:
The patent optimizes geometric parameters of the spring element and flexural member, including the dimensions and positioning of cutout windows, to tune the mechanical response characteristics. This achieves faster settling time by optimizing the ratio of stiffness to mass distribution while maintaining low profile
3Productivity
If strain sensing gages are bonded to the spring element, then weight measurement capability is achieved, but parasitic noise affects measurement accuracy
Solution Approach 1:
The patent extracts and separates the parasitic noise compensation function into a distinct flexural member with second cutout windows, while the spring element with first cutout windows handles primary weight measurement. This extraction allows targeted compensation for parasitic modes without interfering with primary measurement function
Solution Approach 2:
The load cell employs a composite structural design combining spring element and flexural member with different geometric configurations and cutout patterns, creating a composite mechanical system that simultaneously achieves weight measurement and parasitic noise compensation functions
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 configuration improves measurement accuracy and reduces parasitic noise, enabling precise weight measurement with high sensitivity and reduced settling time, capable of weighing items up to 40 kg with an accuracy of 1/3000 divisions within a range of 50 grams to 15,000 grams.
Implementation Method 1
the spring element adapted such that responsive to a downward force exerted on the adapter, the beams assume a primary double-bending configuration having an at least partial double-bending behavior
Implementation Method 2
at least one strain-sensing gage, bonded to the spring element, the strain-sensing gage adapted to measure a strain in the spring element
Data Source
AI summary
A load cell assembly, including an adapter adapted to receive a vertical load, and having loaded and unloaded dispositions a load cell body including a spring element having a first cutout window defined by a top beam and a bottom beam, the window transversely disposed through the body, the spring element adapted such that responsive to a downward force exerted on a top face of the adapter, the beams assume a primary double-bending configuration a strain-sensing gage, attached to the spring element, the strain-sensing gage for measuring strain in the spring element; and an at least two-dimensional flexural member having a second cutout window, the second cutout window being transversely disposed through the body; the adapter disposed in mechanical relation to the flexural member such that, in the loaded disposition of the adapter, the flexural member assumes a secondary, substantially double-bending configuration.