Blood Bag Swing Position Encoding for Automatic Calibration

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Solution Overview

Problem

Current swing devices for blood bags require cumbersome manual calibration and are prone to position estimation errors due to mechanical and electromagnetic disturbances, making accurate and automated position determination challenging.

Innovation Solution

Integrate a position encoding device into the drive device to encode the rotary position of the rotatable shaft member, allowing for automatic calibration and reliable position determination of the tray with respect to the stand, using a digital two-phase Hall-effect encoder to count positional increments and determine the tray's position indirectly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a Hall sensor is used to directly observe the tray position, then the position can be measured, but the calibration process becomes cumbersome and non-automatable

Engineering Contradiction:

Improvetray position measurementVSAvoidcalibration process

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the direct mechanical position measurement approach (Hall sensor on stand interacting with magnet on tray) with an indirect measurement approach using a position encoding device on the rotatable shaft member. This substitution transforms the measurement system from direct mechanical interaction to indirect encoding, enabling automatic calibration while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a position encoding device as an intermediary element that encodes the rotary position of the shaft member. This intermediary allows the control device to determine tray position indirectly through encoder values, avoiding the need for direct Hall sensor measurement and enabling automated calibration procedures.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a Hall sensor is used to measure tray position, then position data can be obtained, but the measurement is prone to errors from mechanical and electromagnetic disturbances

Engineering Contradiction:

Improveposition estimationVSAvoidposition measurement

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the Hall sensor-based magnetic field measurement system with a position encoding device that provides digital output signals. This substitution eliminates susceptibility to electromagnetic radiation interference and mechanical disturbances, significantly improving measurement reliability while maintaining position estimation accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If manual calibration is performed to ensure precise position estimation, then accuracy is improved, but the process becomes time-consuming and difficult to automate

Engineering Contradiction:

Improveposition estimation accuracyVSAvoidcalibration time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables the system to perform self-calibration automatically through the control device, which processes encoder values from the position encoding device. This self-service capability eliminates the need for manual calibration operations, reducing calibration time while maintaining precise position estimation through automated procedures.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent implements a feedback mechanism where the control device continuously receives encoder values from the position encoding device and uses this feedback to determine and adjust tray position. This closed-loop feedback system enables automatic calibration and maintains measurement precision without manual intervention.

Inventive Principle:

Principle #23Feedback

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 easy and reliable position observation of the tray, reduces component count, and eliminates the need for manual calibration, providing robust signal processing and precise tray positioning for operations like weighing.

Implementation Method 1

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

Methodology Applied

Scientific EffectPosition encoding:

Implementation Method 2

the position of the tray is observed by for example using a Hall sensor which is placed on the stand and interacts with a magnet, such as a toroidal magnet, placed on the swing

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS12629459B2Swing device for moving a blood bag and method for operating a swing device

Publication Date: 2026.05.19 FRESENIUS KABI DEUTSCHLAND GMBH

AI summary

A swing device for moving a blood bag includes a stand, a tray for receiving the blood bag, the tray being pivotable with respect to the stand, an electromotive drive device operatively coupled to the tray for causing a rocking movement of the tray with respect to the stand, and a control device for controlling operation of the drive device. The drive device includes a rotatable shaft member which is rotatable for driving the rocking movement of the tray. The drive device also includes a position encoding device configured to encode a rotary position of the rotatable shaft member of the drive device, wherein the control device is configured to determine a position of the tray with respect to the stand based on an encoder value indicative of the rotary position of the rotatable shaft member.