Adaptive Draft Shield for Electronic Scale Weighing Chamber

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Solution Overview

Problem

High-precision electronic scales face challenges in measurement accuracy due to external influences like air movement, buoyancy, and temperature fluctuations, leading to increased measurement times and potential damage from uncontrolled loading forces, especially when handling small loads in microgram or submicrogram ranges.

Innovation Solution

An automated loading system for electronic scales with a draft shield that adapts to the dimensions of the goods to be weighed, featuring a transfer device and a drive mechanism for controlled positioning and loading, minimizing direct force contact and optimizing the weighing chamber's volume to reduce settling time for external parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the weighing chamber volume is reduced to improve measurement speed, then measurement time is reduced, but measurement precision may be compromised

Engineering Contradiction:
Improvemeasurement timeVSAvoidweighing accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The draft shield creates a localized controlled environment within the weighing chamber, providing stable atmospheric conditions (temperature, humidity, air pressure) specifically where the load carrier is positioned. This localized control allows for faster measurements while maintaining precision by concentrating the stable environment exactly where needed rather than requiring the entire chamber to be large and fully stabilized.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If manual loading with tweezers is used to place small loads, then loading precision is improved, but measurement repeatability deteriorates due to varying mechanical forces

Engineering Contradiction:
Improveloading precisionVSAvoidmeasurement repeatability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system replaces manual mechanical loading with an automated transfer device that uses a lifting movement mechanism. The load carrier is lifted vertically into the weighing chamber without requiring manual manipulation, thereby eliminating the varying mechanical forces introduced by different operators using tweezers. This automation ensures consistent, repeatable loading conditions while maintaining precision through controlled, force-minimizing transfer.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the weighing chamber is kept open for quick loading, then loading speed is improved, but measurement accuracy deteriorates due to air movement and external influences

Engineering Contradiction:
Improveloading speedVSAvoidweighing accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The draft shield is pre-positioned within the weighing chamber before loading begins. The transfer device is pre-configured to lift the load carrier vertically into the chamber. This preliminary preparation allows the chamber to remain effectively closed during weighing (maintaining accuracy) while enabling rapid, automated loading through the pre-arranged transfer mechanism, thus resolving the contradiction between speed and precision.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If multiple measurements are performed consecutively, then productivity is improved, but measurement time increases due to repeated settling periods

Engineering Contradiction:
Improvethroughput of measurementsVSAvoidtotal measurement time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The automated transfer device enables continuous operation by rapidly transferring load carriers into and out of the weighing chamber. The draft shield maintains stable atmospheric conditions throughout, allowing consecutive measurements to be performed without repeated long settling periods. The system keeps the weighing environment continuously stabilized while automating the loading/unloading cycle, thereby increasing throughput without proportionally increasing total measurement time.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP1912047B2Electronic scale
Publication Date: 2019.09.25 METTLER TOLEDO GMBH
  • EP1912047B2 patent drawingFigure 1
  • EP1912047B2 patent drawingFigure 2~3
  • EP1912047B2 patent drawingFigure 4A~5

AI summary

The machine (1) has a transfer device (6) movable relative to a load carrier (3). A wind deflector (16) surrounds a weighing chamber (15) that adapts to a dimension of goods to be weighed. A locking unit (13) opens and closes a feeding opening (14), and a drive actuates the locking device. The drive has an actuating unit (12), and works together with the actuating unit. A transmitting unit (18) causes a lifting movement of the transfer device relative to the load carrier. The actuating unit is formed for positioning the transfer device and/or the carrier in a set of defined positions. An independent claim is also included for a method for feeding an electronic weighing machine.