Offset Dual-Axis Injection Device Drive Assembly

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Solution Overview

Problem

Pen-injector injection devices face challenges in maximizing internal space for additional components due to their concentric arrangement around a single longitudinal axis, limiting the incorporation of features like e-health telematics and compromising user experience under mechanical forces.

Innovation Solution

The design introduces a secondary longitudinal axis offset from the primary axis, allowing for additional internal space by positioning the medicament cartridge holder and worm gear rack around this new axis, enabling the incorporation of extra components such as e-health telematics and improving balance and user experience through a rotational to axial coupling mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If components are arranged concentrically around a single longitudinal axis, then space utilization is maximized and balance is improved, but additional internal space for extra components cannot be created

Engineering Contradiction:
Improveinternal spaceVSAvoidincorporation of additional components
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent transitions from a single longitudinal axis arrangement to a dual-axis configuration. The drive assembly is positioned around a second longitudinal axis that is offset from the first longitudinal axis of the housing. This dimensional change creates additional internal space while maintaining compact form factor, allowing incorporation of e-health telematics and other additional components.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If a concentric arrangement is used, then the device remains well-balanced under mechanical forces, but handling properties and user experience are compromised when additional components are added

Engineering Contradiction:
ImprovebalanceVSAvoidhandling properties
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

By introducing a second longitudinal axis offset from the first, the patent redistributes component mass in three-dimensional space. The drive assembly positioned around the offset axis creates a new balance configuration that maintains stability under mechanical forces while accommodating additional components, thereby improving handling properties and user experience.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Volume of moving object

If the drive assembly is positioned on an offset axis, then additional internal space is created, but device complexity increases

Engineering Contradiction:
Improveinternal spaceVSAvoidcomponent arrangement
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The offset dual-axis configuration utilizes the third dimension more effectively. By positioning the drive assembly around a second longitudinal axis offset from the housing's first longitudinal axis, the patent creates additional internal space without proportionally increasing device complexity. The concentric arrangement around the offset axis actually simplifies the mounting and integration of additional components compared to trying to fit them into a single-axis configuration.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration enhances the internal space within the device, allowing for the integration of additional features like e-health telematics, improves balance and user handling, and effectively delivers medicament doses while preventing over-torque and ensuring accurate dose delivery.

Implementation Method 1

a worm gear and means engageable between the drive shaft and the worm gear which, when engaged, rotationally locks the drive shaft and worm gear together, the worm gear being engaged in a rack, wherein rotation of said worm gear causes the rack to advance axially forward or backward with respect to said worm gear to provide an axial force for ejecting a dose of medicament from the injection device

Methodology Applied
Scientific EffectWorm gear mechanism: Worm Drive

Implementation Method 2

the drive assembly comprises a rotational to axial coupling, where the drive assembly is rotationally drivable by a torsion spring and is arranged to provide an axial force for ejecting the dose from the injection device

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP3509673B1Dose delivery mechanism
Publication Date: 2024.01.03 NORTON HEALTHCARE LTD
  • EP3509673B1 patent drawingFigure 1
  • EP3509673B1 patent drawingFigure 2
  • EP3509673B1 patent drawingFigure 3

AI summary

An injection device comprises a housing having a first longitudinal axis (L). The injection device further comprises a medicament cartridge holder and a drive assembly including a drive shaft. The drive shaft is arranged around the first longitudinal axis. The drive assembly is capable of providing an axial force for ejecting a dose of medicament from the injection device. The medicament cartridge holder and at least part of said drive assembly are arranged around a second longitudinal axis (LC) which is substantially parallel to but offset from the first longitudinal axis.