Magnetic Encoder for Medication Delivery Device

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Solution Overview

Problem

Existing medication delivery devices, such as infusion pumps, face challenges in accurately detecting the amount of medication dispensed, which affects accuracy, product life, energy efficiency, and manufacturability, while also increasing part count and cost.

Innovation Solution

The implementation of a low-resolution magnetic encoder in medication delivery devices, which includes a series of magnets fixed to an encoder hub and mechanically coupled to a drive gear, aligned with a magnetic Hall Effect sensor to provide rotational feedback and accurately measure the rotational position of the drive gear, thereby detecting the amount of medication dispensed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mechanical switches or spring loaded electrical connections are used to detect medication dispensed amount, then the detection function is achieved, but the device complexity and part count increase

Engineering Contradiction:

Improvemedication delivery detection accuracyVSAvoidpart count

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical switches and spring-loaded electrical connections with a magnetic encoder system consisting of a magnet, encoder hub, and magnetic sensor. This substitution eliminates direct mechanical contact and complex electrical connections while maintaining accurate detection of drive gear rotation and medication dispensed amount.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the drive gear and the sensor. The magnet coupled to the encoder hub creates magnetic field variations that the magnetic sensor detects, allowing indirect measurement of rotation without mechanical contact or complex electrical connections.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If traditional mechanical encoding methods are used, then rotational position detection is achieved, but energy efficiency decreases due to increased friction

Engineering Contradiction:

Improverotational position detectionVSAvoidenergy efficiency

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces mechanical encoding mechanisms that rely on physical contact and friction with a magnetic encoding system. The magnetic sensor detects rotor position through magnetic field variations without mechanical contact, eliminating friction-induced energy losses while maintaining precise rotational position detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If high precision encoding mechanisms are used, then medication delivery accuracy improves, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvemedication delivery accuracyVSAvoidmanufacturability

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces complex mechanical encoding mechanisms with a simplified magnetic encoding system consisting of a magnet, encoder hub, and magnetic sensor. This substitution reduces manufacturing complexity while maintaining accurate detection of drive gear rotation and medication dispensed amount through non-contact magnetic field sensing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the essential function of rotational position detection from complex mechanical encoding mechanisms and implements it through a simpler magnetic field-based system. This extraction eliminates unnecessary mechanical components while preserving the core measurement capability.

Inventive Principle:

Principle #2Taking out (Extraction)

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 enhances the accuracy of medication delivery, improves energy efficiency by reducing friction, and simplifies the production process, leading to a more cost-effective and reliable medication delivery system.

Implementation Method 1

a magnetic Hall Effect sensor to provide rotational feedback indicative of a detected magnetic field

Methodology Applied

Scientific EffectHall Effect: Hall Effect

Data Source

PatentUS20250177641A1Medication delivery device

Publication Date: 2025.06.05 BECTON DICKINSON & CO

AI summary

A medication delivery device comprising a base plate engaging a cover to form an interior, the interior including a pump drive mechanism for driving medication through the device, a drivetrain engaged to the pump drive mechanism, a magnetic encoder including an encoder hub mechanically coupled to the drivetrain, the encoder hub including a magnet, and a sensor that measures a magnetic field from the magnet to determine a rotational position of the drivetrain.