Drive Unit Mount for Conveying Scale Weighing Accuracy

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Solution Overview

Problem

Existing scale technologies face challenges in minimizing the mechanical and metrological influence of the motor drive unit on the transport device, leading to deformation, corner load errors, and inaccurate weighing signals due to off-centre motor arrangements and vibrations.

Innovation Solution

A mount for the drive unit is placed between the load cell and the transport device, allowing the weight force to be introduced into the load cell through a receptacle, which is designed to be rigid and stable, reducing eccentric loads and enabling a modular, easy-to-use design with electromagnetic compatibility and IP protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the motor drive unit is arranged on the transport device, then the transport device can be driven, but the motor mass deforms the transport device and causes shocks

Engineering Contradiction:
Improvedrive capabilityVSAvoidtransport device deformation
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The system is divided into separate functional modules: the drive unit is separated from the transport device and positioned on a separate support structure. This segmentation allows the heavy motor mass to be isolated from the transport device, preventing deformation while maintaining drive capability through the transmission mechanism.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the motor is arranged off-centre to the load cell, then the transport device can be decoupled from the drive unit, but corner load errors occur and weighing signals are falsified

Engineering Contradiction:
Improvedecoupling capabilityVSAvoidweighing accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The support structure is designed with an asymmetric configuration where the drive unit is positioned at a specific offset distance from the load cell center. This controlled asymmetry allows decoupling of the drive unit from the transport device while maintaining accurate weight measurement by optimizing the moment arm and force transmission path.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

A rigid support structure acts as an intermediary between the load cell and the drive unit. This mediator transmits the weight force from the transport device through the drive unit to the load cell while maintaining structural stability and preventing falsification of weighing signals despite the off-center arrangement.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Power

If vibrations from the floor are present, then the drive unit can operate, but large moments are created at load introduction that falsify weighing signals

Engineering Contradiction:
Improvedrive operationVSAvoidweighing signal accuracy
Core Design Contradiction:
PowerVSMeasurement precision

Solution Approach 1:

The support structure is designed with vibration-damping features and rigid connections that preemptively counteract floor vibrations before they can create large moments at the load introduction point. This prior cushioning protects the weighing signal from falsification while allowing the drive unit to operate normally.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 solution reduces mechanical loads on the transport device, stabilizes the scale, minimizes vibrations, and ensures accurate weighing by centering the drive unit's weight, enhancing service life and safety while allowing for quick assembly and disassembly, and protecting against electromagnetic interference and moisture.

Implementation Method 1

the load cell experiences the weight force to be detected over a force introduction area and in the direction of an imaginary force introduction axis

Methodology Applied
Scientific EffectWeight force detection: Force

Implementation Method 2

introduce the weight force from the transport device through the receptacle into the load cell

Methodology Applied
Scientific EffectForce transmission: Force

Data Source

PatentEP1952102B1Holding fixture for the drive unit of a conveying device
Publication Date: 2013.10.23 WIPOTEC WIEGE UND POSITIONIERSYSTEME GMBH
  • EP1952102B1 patent drawingFigure 1

AI summary

The invention relates to a holding fixture (4) for the drive unit of a conveying device (5) that conveys goods (G) to be weighed, whereby in order to transfer the weight to be measured, the holding fixture (4) is placed between the conveying device (5) and the weigh cell (2) that measures the weight.