Capsuled Load Cell Eccentric Calibration Adjustment
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Solution Overview
Problem
Encapsulated load cells in gravimetric measuring instruments face challenges with corner load accuracy due to encapsulation influences and manufacturing tolerances, leading to off-center errors and requiring complex signal processing for compensation.
Innovation Solution
A gravimetric measuring instrument with a flexible, tubular enclosure and an adjustment area that allows for corner load adjustment within the encapsulation, using deformation points and lever mechanisms to correct corner load errors without opening the encapsulation, and incorporating a signal processing unit for data correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the load cell is encapsulated to protect from moisture and dirt, then reliability is improved, but corner load accuracy deteriorates due to encapsulation influences
Solution Approach 1:
The patent applies preliminary action by performing corner load adjustments before the load cell is encapsulated. The adjustment area is designed to be accessible only during the manufacturing process, allowing corner load errors to be corrected while the parallel guide is still adjustable. Once encapsulated, the parallel guide is fixed and can no longer be adjusted, but the preliminary adjustment ensures optimal corner load accuracy is achieved before the protective encapsulation is applied.
2Measurement precision
If the parallel guide is adjusted to correct corner load errors, then measurement precision is improved, but device complexity increases due to adjustment mechanisms
Solution Approach 1:
The patent applies segmentation by separating the adjustment function from the main load cell structure. The adjustment area is created as a distinct region on the parallel guide with deformation points that can be selectively modified. This segmentation allows corner load adjustment to be performed through localized modifications rather than requiring complex overall adjustment mechanisms, simplifying the device while maintaining precision.
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with a simpler approach using deformation points. Instead of requiring multiple adjustment screws, levers, or mechanical components, the solution uses localized deformation of the parallel guide material at specific points to achieve corner load correction. This substitution of mechanical systems with material deformation reduces device complexity while maintaining measurement precision.
3Reliability
If the load cell is encapsulated, then protection from environment is improved, but ease of operation deteriorates as adjustment is no longer possible
Solution Approach 1:
The patent applies preliminary action by ensuring all necessary corner load adjustments are performed before the encapsulation process. The adjustment area is designed to be accessible during manufacturing but becomes inaccessible after encapsulation. This timing of the adjustment action resolves the contradiction by making adjustment possible when needed (before encapsulation) while maintaining protection after encapsulation.
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
Enables precise corner load adjustment and compensation for manufacturing tolerances, allowing for easy replacement of encapsulated load cells without recalibrating the entire device, while minimizing temperature increases and material stresses within the encapsulation.
Implementation Method 1
The strain gauges stretched or compressed by the deformation of the deformation body as a result of a load on the movable parallel leg have a changed electrical resistance value compared to the unloaded state of the movable parallel leg, which is a measure of the applied load.
Implementation Method 2
With EMFC load cells, the weight of the load is transferred either directly or by one or more force transmission levers to an electromechanical measuring sensor, which emits an electrical signal corresponding to the weight of the load
Implementation Method 3
A vibrating string is tensioned by the load, the change in frequency of which in turn represents a measure of the load applied.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The instrument (100) has a flexible tubular-shaped encapsulation unit (118), whose front side (119) is attached to a fixed parallelogram leg (114). An adjustment region (121) is formed at a movable parallelogram leg (115) and/or the fixed leg, and allows adjustments of a distance between one of the flexure pivots (116) of an upper parallel-guiding member (113) to one of the flexure pivots of a lower parallel-guiding member (112). An adjustment-setting area (127) arranged outside the encapsulation unit is mechanically connected to the adjustment region to allow modification in the region.