Slim Drug Delivery Device Axial Drive Mechanism
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Solution Overview
Problem
Existing drug delivery devices with spring-driven mechanisms are often bulky and complex due to their multi-layer designs, which complicates manufacturing and user experience.
Innovation Solution
A compact drug delivery device design where components are rearranged axially instead of concentrically, utilizing a piston rod, drive tube, and drive spring with a scale drum and spline connection to allow for a slimmer and more reliable device structure, enabling easier dose setting and expelling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a multi-layer concentric design is used in spring-driven drug delivery devices, then the device can accommodate all necessary components (drive spring, scale drum, drive tube, piston rod), but the device diameter increases making it bulky and less user-friendly
Solution Approach 1:
The patent transitions from a conventional concentric (radial) component arrangement to an axial arrangement, effectively changing the dimensional organization of components. The drive spring, scale drum, drive tube, and piston rod are arranged sequentially along the longitudinal axis rather than concentrically around a central axis, reducing the device diameter while maintaining all necessary functions
Solution Approach 2:
The device is divided into distinct axial segments where each component (drive spring assembly, scale drum assembly, drive tube assembly, piston rod assembly) occupies a specific axial position. This segmentation allows for optimized space utilization and simplified manufacturing of individual modules that can be assembled in sequence
2Adaptability or versatility
If more features are added to the drug delivery device, then the device functionality is improved, but the number of components increases leading to larger dimensions and bulk
Solution Approach 1:
The axial arrangement framework supports multiple features and functionalities within a compact diameter. The drive spring provides both dosing and expelling functions, the scale drum integrates dose setting and display, and the axial configuration itself enables accommodation of additional features without increasing diameter, making the device versatile yet compact
3Volume of moving object
If a compact axial design is implemented, then the device diameter is reduced improving slimness, but the manufacturing process becomes more complex due to rearranged components
Solution Approach 1:
The design is segmented into modular axial sections that can be manufactured independently and then assembled. This modularity simplifies the manufacturing of individual components while the standardized axial interface between segments facilitates assembly, offsetting the initial design complexity with manufacturing and assembly simplicity
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 design results in a more compact and cost-effective drug delivery device with fewer layers, enhancing user experience and manufacturing efficiency while maintaining reliable operation.
Implementation Method 1
a spring which is strained during dose setting, the stored energy subsequently being used to expel the set dose of drug from a cartridge
Data Source
AI summary
A drug delivery device comprises a housing (201) and an expelling assembly with a piston rod (220), a drive tube (260) with an outer surface and a scale drum (270) arranged between the drive tube and the housing, the scale drum being coupled to the housing and the drive tube outer surface. The device further comprises a drive spring (255) arranged between the housing and the drive tube, and setting means (280) allowing a user to simultaneously set a dose amount to be expelled and strain the drive spring correspondingly by rotation of the drive tube. The scale drum is coupled to the drive tube via a spline connection, wherein the drive spring is arranged proximally of the spline connection when the spline connection is in its proximal-most position.