Injection Device Spring-Driven Dose Dial with Limiter

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Solution Overview

Problem

Existing drug delivery devices require high dispensing forces from users and lack effective indication of set doses, often leading to overdosing or underdosing, especially for visually impaired users, and do not prevent doses exceeding the medication amount remaining in the cartridge.

Innovation Solution

A drug delivery device with a spring-driven mechanism that includes a rotatable dose dial member, a limiter for preventing excessive dose setting, and dual display members for clear dose indication, allowing for low-force dispensing and accurate dose management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a rigid cartridge holder is used to secure the cartridge, then the cartridge is firmly held in place, but the device requires high dispensing forces from the user

Engineering Contradiction:

Improvecartridge holding stabilityVSAvoiddispensing force

Core Design Contradiction:

Stability of the object's compositionVSForce

Solution Approach 1:

The cartridge holder is divided into a proximal portion and a distal portion that can move relative to each other. The distal portion is displaceable in the axial direction to create expansion movement, which reduces the force needed for dispensing while maintaining secure cartridge holding through the segmented structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cartridge holder transitions from a rigid, fixed structure to a dynamic structure where the distal portion can move axially. This dynamic capability allows the holder to expand during dispensing, reducing the force required while maintaining stability during dosing.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If a single dose indicator is used, then the device structure is simple, but visually impaired users cannot accurately identify the remaining dose

Engineering Contradiction:

Improveindicator structure complexityVSAvoiddose indication accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

Two different dose indicators are provided with distinct characteristics (first indicator and second indicator). Each indicator has local quality differences in terms of visual presentation, allowing users with visual impairments to distinguish between them and accurately determine the remaining dose through tactile or visual differentiation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The solution adds another dimension to dose indication by providing two separate indicators instead of relying on a single visual indicator. This dimensional addition (having both first and second indicators) enables visually impaired users to perceive dose information through multiple senses or modalities.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If no dose limiting mechanism is used, then the device operation is simple, but users may set doses exceeding the medication amount remaining in the cartridge

Engineering Contradiction:

Improvedose setting simplicityVSAvoiddose safety

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The limiter provides feedback to the user during dose setting by preventing the dose dial member from being rotated beyond the available medication amount. This feedback mechanism maintains operational simplicity while ensuring reliability, as the user naturally receives information about the maximum settable dose through the mechanical limitation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The limiter is pre-configured to prevent excessive dose setting before it can occur. By having the limiter in place beforehand, the system proactively prevents the harmful action of overdosing while maintaining simple operation, as the user cannot accidentally exceed the limit.

Inventive Principle:

Principle #9Preliminary anti-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

The device enables low-force dose dispensing while preventing overdosing by limiting set doses to the available medication amount and providing clear, dual-display dose indication, improving user safety and accuracy.

Implementation Method 1

Methodology Applied

Scientific EffectSpring energy storage and release: Spring

Data Source

PatentEP2983756B1Injection device

Publication Date: 2019.06.19 SANOFI SA(FR)

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AI summary

The invention refers to an injection device comprising a housing (10), containing a cartridge (170) with an amount of liquid to be dispensed, a drive sleeve (41), which is rotationally constrained to the housing (10) during dose setting and spring driven rotatable relative to the housing (10) during dose dispensing, a dose dial member (60) for setting a dose to be dispensed, which is rotatable relative to the housing (10) during dose setting and during dose dispensing, and which is rotationally coupled to the drive sleeve (41) during dose dispensing. The device further comprises a last dose protection mechanism (41, 50, 60) for preventing the setting of a dose, which exceeds the amount of liquid left in the cartridge (170), with a limiter (50), which is interposed between the drive sleeve (41) and the dose dial member (60). Further, the device comprises two different display members (110, 120), each indicating the set dose.