Planar Load Cell With Segmented Cutout Windows
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Solution Overview
Problem
Planar load cell assemblies face challenges in achieving high accuracy weight measurement due to low amplitude signals and sensitivity to off-center loading, which results in compromised performance and durability.
Innovation Solution
The design incorporates a load cell body with contiguous cutout windows and flexure beams connected by bases, featuring a series arrangement of measuring beams and flexure beams, with strain gauges attached to the measuring beams to enhance accuracy and reduce noise, using a magnesium alloy with a lower elastic modulus than aluminum for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If planar load cell assemblies use conventional design, then manufacturing is simpler, but measurement precision deteriorates due to low amplitude signals and parasitic noise
Solution Approach 1:
The load cell body is segmented into multiple functional regions through contiguous cutout windows that divide the body into distinct measurement zones. These windows create separate flexure beam regions, measuring beam regions, and loading element regions, allowing each segment to perform its specific function optimally while reducing parasitic noise from other areas.
Solution Approach 2:
Different regions of the load cell body are given different structural qualities through the cutout window design. The flexure beams have specific thickness and geometry for flexibility, the measuring beams have optimized dimensions for strain gauge attachment, and the loading element has a hole for load application. This local differentiation enhances measurement precision while managing overall complexity.
2Reliability
If planar load cell assemblies use conventional design, then device complexity is lower, but reliability deteriorates due to sensitivity to off-center loading
Solution Approach 1:
The contiguous cutout windows segment the load cell body into multiple load paths, creating redundant structural routes for force transmission. When off-center loading occurs, the segmented structure distributes stresses more evenly across the flexure beams and measuring beams, preventing localized failure and improving reliability under varying load conditions.
Solution Approach 2:
The flexure beams are designed with specific geometric properties and material characteristics that provide inherent stress distribution capabilities before loading occurs. The cutout window geometry is optimized to create stress-relief zones that cushion against concentrated off-center loads, protecting the measuring beams from damage before failure can occur.
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 enhances the accuracy and durability of weight measurements by reducing parasitic noise and improving sensitivity, allowing for precise and reliable load cell operations within a nominal load capacity.
Implementation Method 1
strain gages, attached to the beams
Implementation Method 2
When the weight on the platform is removed, the metallic load cell body is designed to return to an original, unstressed condition
Data Source
AI summary
An assembly including a load cell body having contiguous cutout windows, each formed by a pair of cutout lines and connected by a cutout base, the second window being transversely bounded by the first window, the third window being transversely bounded by the second window; measuring beams, disposed along edges of the body, each defined by a respective line of the first pair of cutout lines; first and second arrangements, each having a pair of flexure beams connected by first and second bases, respectively; a loading element, extending from the second base; and strain gages, attached to the beams.