Weighing Cell Eccentric Loading Error Correction
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Solution Overview
Problem
Eccentric loading errors in weighing cells with parallel guiding mechanisms lead to inaccuracies in weight measurements due to geometrical deviations and internal material stresses, requiring frequent recalibration and maintenance, especially in high-accuracy scales like analytical balances.
Innovation Solution
A processor-controlled weighing cell with a test weight actuating device and motor-operated actuating units that position test weights at multiple support points to determine and correct eccentric loading errors, allowing for automatic adjustment and reducing the need for manual recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual calibration and adjustment of the parallel guiding mechanism is performed, then measurement precision can be restored after eccentric loading errors occur, but loss of time increases due to frequent maintenance interventions
Solution Approach 1:
The weighing cell performs automatic self-calibration by using its own measuring sensor to detect eccentric loading errors and activate motor-operated actuating units that adjust the parallel guiding mechanism. This self-service capability eliminates the need for external manual calibration, thereby maintaining measurement precision while minimizing maintenance time and human intervention.
Solution Approach 2:
The system performs preliminary detection of eccentric loading errors during normal operation and automatically initiates correction before measurement precision deteriorates beyond acceptable limits. The processor unit continuously monitors weight measurements and triggers adjustment operations proactively, preventing accumulated errors rather than reacting to failed measurements.
2Measurement precision
If the parallel guiding mechanism is made highly precise to eliminate eccentric loading errors, then measurement precision improves, but device complexity increases due to stricter manufacturing tolerances
Solution Approach 1:
The invention replaces static geometric precision with dynamic adjustment capability. Instead of requiring the parallel guiding mechanism to maintain absolute parallelism through complex manufacturing, the system uses motor-operated actuating units to dynamically correct positional deviations during operation. This transforms a manufacturing precision problem into a controllable actuation problem.
Solution Approach 2:
The system substitutes mechanical precision requirements with an automated detection and correction system. The measuring sensor and processor unit detect eccentric loading errors, and motor-operated actuators perform corrections, replacing the need for highly precise mechanical manufacturing with an automated feedback control system.
3Ease of operation
If motor-operated actuating units are added for automatic correction, then ease of operation improves through automated calibration, but device complexity increases due to additional components
Solution Approach 1:
The motor-operated actuating units serve multiple functions: they adjust the position of the parallel guiding mechanism during calibration, maintain measurement precision during operation, and can potentially perform other positioning tasks. This multi-functionality justifies the added complexity by consolidating several operations into a single versatile component.
Solution Approach 2:
The invention merges the calibration function with the normal operation function. The same motor-operated actuating units that perform calibration also maintain measurement precision during weighing operations. The measuring sensor serves both to detect load weight and to detect eccentric loading errors, combining multiple detection functions in one component.
Data Source
AI summary
Eccentric loading errors of a weighing cell (1) with a parallel guiding mechanism are determined and corrected or at least reduced. The weighing cell has a test weight actuating device (14), by which at least one test weight (15) is positioned successively on at least three test weight support points (16, 17, 18, 19, 20) of the test load receiver (4) that do not lie in a straight line. A processor unit (21) uses a control signal (S1) to position the test weight on the support points. A test weighing signal (T) is generated for each support point, and from these, eccentric loading errors are ascertained. A device for correcting the eccentric loading errors uses control signals (S2) from the processor unit to make a geometrical-mechanical change in the parallel guiding mechanism, using a first and a second actuating unit.