Drive-Shaft Position Encoding for Blood Bag Swing Devices

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Solution Overview

Problem

Current swing devices for mixing blood with anticoagulant require cumbersome manual calibration and are prone to position estimation errors due to mechanical and electromagnetic disturbances, making them difficult to automate.

Innovation Solution

A swing device with a position encoding device that indirectly measures the tray's position using a rotatable shaft member's rotary position, allowing for automatic calibration and robust signal processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a Hall sensor and magnet are used to directly observe tray position, then position measurement is possible, but manual calibration is cumbersome and position estimation is prone to errors due to mechanical and electromagnetic disturbances

Engineering Contradiction:
Improvetray position measurement accuracyVSAvoidcalibration procedure complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the direct mechanical position observation system (Hall sensor and magnet on the swing) with an indirect measurement system using a position encoding device on the drive shaft. This substitution eliminates the need for manual calibration and reduces susceptibility to mechanical and electromagnetic disturbances during operation.

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

Solution Approach 2:

The patent introduces a position encoding device as an intermediary element that measures the rotary position of the drive shaft rather than directly measuring the tray position. This intermediary measurement approach provides more stable and accurate position information without being affected by disturbances in the blood bag mixing process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a Hall sensor and magnet are used to directly observe tray position, then position measurement is possible, but the system is prone to errors due to electromagnetic radiation during donation process

Engineering Contradiction:
Improveposition estimation reliabilityVSAvoidelectromagnetic radiation interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The position encoding device serves as an intermediary that measures drive shaft position indirectly, isolating the measurement system from electromagnetic radiation and mechanical disturbances occurring during the blood bag mixing process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the position measurement function from the directly disturbed environment (tray and blood bag area) and relocates it to the drive shaft, where measurement conditions are more stable and less susceptible to electromagnetic interference and mechanical disturbances.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If direct position observation using Hall sensor is used, then position data is available, but significant effort and time is spent on adjustment and calibration during manufacturing

Engineering Contradiction:
Improvedevice manufacturing efficiencyVSAvoidcalibration time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent replaces the calibration-dependent Hall sensor system with a position encoding device that provides inherent reference positions, eliminating the need for time-consuming manual calibration procedures during device manufacturing and setup.

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

Solution Approach 2:

The position encoding device is pre-configured with reference position markings on the drive shaft, allowing the system to automatically determine tray position without requiring preliminary manual calibration adjustments during manufacturing or setup.

Inventive Principle:
Principle #10Preliminary action

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 accurate, automated position determination of the tray with reduced components and manual effort, enhancing reliability and ease of use.

Implementation Method 1

the drive device comprises a position encoding device configured to encode a rotary position of the rotable shaft member of the drive device

Methodology Applied
Scientific EffectPosition encoding:

Implementation Method 2

An electromotive drive device is operatively coupled to the tray for causing a rocking movement of the tray with respect to the stand

Methodology Applied
Scientific EffectElectromotive drive: Electromagnetic Induction

Data Source

PatentEP4169542B1Swing device for moving a blood bag and method for operating a swing device
Publication Date: 2025.09.17 FRESENIUS KABI DEUTSCHLAND GMBH
  • EP4169542B1 patent drawingFigure 1~2
  • EP4169542B1 patent drawingFigure 3
  • EP4169542B1 patent drawingFigure 4~5

AI summary

A swing device (1) for moving a blood bag (2) comprises a stand (11), a tray (10) for receiving the blood bag (2), the tray (10) being pivotable with respect to the stand (11), an electromotive drive device (12) operatively coupled to the tray (10) for causing a rocking movement of the tray (10) with respect to the stand (11), and a control device (14) for controlling operation of the drive device (12). The drive device (12) comprises a rotatable shaft member (126) which is rotatable for driving said rocking movement of the tray (10). The drive device (12) further comprises a position encoding device (13) configured to encode a rotary position of the rotatable shaft member (126) of the drive device (12), wherein the control device (14) is configured to determine a position of the tray (10) with respect to the stand (11) based on an encoder value indicative of the rotary position of the rotatable shaft member (126).