Parallel Guide for Gravimetric Instruments
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Solution Overview
Problem
Existing gravimetric measuring instruments face challenges in achieving precise corner load accuracy due to limitations in adjusting the parallelism of guide diaphragm springs, leading to corner load errors under non-centric loading conditions, which are difficult to correct with current adjustment methods.
Innovation Solution
A parallel guide design featuring a fixed parallel leg with upper and lower end regions connected via bending points, ball joints, or annular constrictions, allowing for precise adjustment of corner load errors by pivoting about defined axes, eliminating the need for adjustment screws and improving temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If adjustment screws are used to correct corner load errors, then corner load accuracy can be improved, but device complexity increases and temperature stability deteriorates
Solution Approach 1:
The patent removes adjustment screws entirely from the parallel guide structure. Instead of adding adjustable elements, the invention extracts the adjustment function into a separate calibration process that uses the load cell's electrical output to drive piezoelectric actuators, thereby simplifying the mechanical structure while maintaining adjustment capability.
Solution Approach 2:
The patent replaces manual mechanical adjustment screws with an automated electro-mechanical system. Piezoelectric actuators convert electrical calibration signals into precise mechanical adjustments of the parallel guide's geometry, eliminating the need for manual screw adjustments and improving temperature stability.
2Measurement precision
If manufacturing precision is increased to reduce corner load errors, then corner load accuracy improves, but manufacturing costs increase
Solution Approach 1:
The patent performs corner load calibration after the parallel guide is assembled and mounted in the weighing instrument. By conducting calibration in the final installed position rather than during component manufacturing, the system achieves high accuracy without requiring extremely tight manufacturing tolerances on individual parts.
Solution Approach 2:
The patent uses the load cell's measurement output as feedback to guide the calibration process. The system measures corner load errors electrically and uses this information to drive piezoelectric actuators that automatically correct the parallel guide's geometry, achieving high accuracy through measurement-driven adjustment rather than precision manufacturing.
3Measurement precision
If manual test and adjustment processes are used to achieve required corner load accuracy, then measurement precision improves, but time consumption increases
Solution Approach 1:
The patent accelerates the calibration process by using piezoelectric actuators that can rapidly adjust the parallel guide's geometry in response to electrical signals. This electro-mechanical acceleration replaces slow manual adjustment operations, achieving high-precision corner load calibration much faster than traditional manual methods.
Solution Approach 2:
The patent enables the parallel guide to self-calibrate using its own measurement output. The load cell measures corner load errors, and this measurement directly drives the piezoelectric actuators that correct the error, creating an automated self-adjusting system that eliminates time-consuming manual intervention.
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
The design achieves precise corner load accuracy with minimal zero-point shift and simplified adjustment processes, enhancing the accuracy and reliability of gravimetric measurements while reducing manufacturing costs and temperature-dependent errors.
Implementation Method 1
the upper end region and the lower end region can be pivoted relative to one another about at least one pivot axis
Implementation Method 2
guided vertically at the top and bottom by diaphragm springs
Data Source
Figure 1
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Figure 5
AI summary
The invention relates to a parallel guide that can be used in a gravimetric measuring instrument and comprises a fixed parallel limb which is vertically arranged in the operating state of the parallel guide and has an upper end region and a lower end region. The fixed parallel limb surrounds a mobile parallel limb having a central longitudinal axis extending vertically during operation. The parallel guide also comprises a first parallel guiding element fixed to the upper end region, and a second parallel guiding element fixed to the lower end region, said guiding elements enabling the mobile parallel limb to be connected to the fixed parallel limb and guided in a vertically mobile manner. The mobile parallel limb can be connected to a load receiver and to a load cell in such a way as to transmit a load. The upper end region and the lower end region are interconnected by means of at least one pair of bending points and/or at least one ball-and-socket joint and/or at least one annular constriction, the end regions being mutually pivotable about at least one pivoting axis in order to correct a corner load error.