Drug Delivery Drive Member Track Geometry for Dose Precision
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Solution Overview
Problem
Existing drug delivery devices face challenges in reliably setting and dispensing precise doses of medication, particularly in fixed-dose devices where the absolute size of the dose is predetermined, and in ensuring efficient mechanical advantage and minimizing medicament dripping after dispensing.
Innovation Solution
A drive member with a combined axial and rotational movement capability, featuring a track with inclined sections that redirect axial loads into rotational movements, coupled with a bias track for torque generation, allows for reliable dose setting and dispensing while minimizing medicament loss through controlled piston rod movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a drive member with combined axial and rotational movement is used, then mechanical advantage is enhanced and dose dispensing precision is improved, but device complexity increases
Solution Approach 1:
The drive member integrates both axial and rotational movement capabilities into a single component. The track structure combines inclined sections for torque generation with bias track sections for directional control, merging multiple functions (axial movement, rotational movement, torque generation) into one integrated element that drives the piston rod while maintaining precise dose dispensing
Solution Approach 2:
The track on the drive member is segmented into distinct functional sections: inclined sections for generating rotational torque and bias track sections for controlling axial movement direction. This segmentation allows each portion to optimize its specific function while working together to achieve precise dose dispensing without requiring separate complex mechanisms
2Force
If inclined sections on the track are used to redirect axial loads into rotational movements, then mechanical advantage is enhanced, but manufacturing complexity increases
Solution Approach 1:
The track incorporates inclined sections with specific angular orientations that convert axial loading into rotational torque through geometric curvature. These inclined surfaces are designed with optimized angles to maximize mechanical advantage while maintaining manufacturability through standard machining processes for conical or inclined surfaces
3Reliability
If the drive member is designed for reliable dose setting and dispensing, then dosing reliability is improved, but the device structure becomes more complex
Solution Approach 1:
The drive member design incorporates features that provide mechanical feedback during operation, ensuring reliable dose setting and dispensing. The interaction between the drive member's track structure and the piston rod creates inherent mechanical feedback that confirms proper engagement and movement, enhancing dosing reliability without requiring additional electronic or mechanical feedback systems
Solution Approach 2:
The drive member serves multiple functions simultaneously: it converts axial motion to rotational motion, generates torque through inclined sections, controls piston rod movement direction through bias tracks, and ensures reliable dose dispensing. This multi-functionality reduces the need for separate dedicated components for each function, thereby managing structural complexity while improving reliability
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 reliable and precise dose dispensing in fixed-dose devices with enhanced mechanical advantage and reduced medicament dripping, ensuring accurate and efficient operation of drug delivery devices.
Implementation Method 1
a track (12) having a contact face (120) for transmitting a driving load from an actuating member to the drive member (1). The track (12) is designed such that during dose setting and dispensing an axial load exerted by an actuating member is redirected into a rotational load onto the drive member (1)
Data Source
Figure 1
Figure 2~3
Figure 4A
AI summary
A drive member (1) for driving a piston rod (5) in a drug delivery device (4) is provided. The drive member (1) is configured to be driven in a rotational movement by an actuating member. The drive member (1) comprises a track (12) for transmitting a driving load from the actuating member to the drive member (1). The track (12) comprises both sections running in a distal and sections running in a proximal direction of the drive member (1). Moreover, a drug delivery device (4) comprising such a drive member (1) is provided.