Drug Delivery Coupling Assembly With Curved Force-Fit Protrusion
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Solution Overview
Problem
Drug-delivery devices require a mounting arrangement and coupling assembly that are both reliable and cost-effective for manufacturing, while ensuring accurate and precise mechanical coupling, especially for pen-type injectors used by non-medical professionals.
Innovation Solution
A mounting arrangement featuring a housing part with a recess and a plug element, where the side wall of the recess has a protrusion for force-fit engagement, facilitating a reliable mechanical coupling with reduced mechanical stress and allowing for easy insertion and adjustment, and a coupling assembly with multiple protrusions for increased stability and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a force-fit engagement with an inclined protrusion is used, then the mechanical coupling reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
The protrusion is designed with a curved longitudinal profile instead of a straight cylindrical shape. This curvature allows the protrusion to be inserted into the recess with reduced mechanical stress while maintaining a secure force-fit engagement, resolving the contradiction between reliability and complexity by using a geometrically optimized shape that achieves both goals
Solution Approach 2:
The inclination angle of the protrusion's longitudinal profile is optimized to balance insertion ease and coupling strength. By adjusting this geometric parameter, the design achieves reliable mechanical coupling without requiring overly complex manufacturing processes, thus resolving the contradiction between reliability and manufacturing complexity
2Manufacturing precision
If a force-fit engagement is used to ensure precise positioning, then the positioning accuracy is improved, but the mechanical stress on components increases
Solution Approach 1:
The curved longitudinal profile of the protrusion distributes the insertion force along a gradual arc rather than concentrating it at a single point. This geometric optimization achieves precise positioning through force-fit engagement while significantly reducing peak mechanical stress on the components, thereby resolving the contradiction between positioning accuracy and mechanical stress
3Stability of the object's composition
If multiple protrusions are added to increase stability, then the coupling stability is improved, but the manufacturing cost increases
Solution Approach 1:
Instead of adding multiple symmetric protrusions around the coupling interface, the design uses a single asymmetrically positioned protrusion with an optimized curved profile. This asymmetric design achieves the required coupling stability through precise geometric engagement while minimizing the number of features to manufacture, thus resolving the contradiction between stability and manufacturing cost
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 solution enables a robust, easy-to-use, and cost-effective mechanical coupling suitable for high-precision drug-delivery devices, ensuring accurate dosing and stability, even for disposable devices, by reducing mechanical stress and enhancing friction forces through the use of inclined and designed protrusions.
Implementation Method 1
a longitudinal section of the protrusion is arranged adjacent to the longitudinal end section and has a constant radial distance relative to the longitudinal axis. This enables to increase a friction force of the force-fit engagement by increasing a contact surface between the protrusion and the plug element
Data Source
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AI summary
A mounting arrangement for a drug-delivery device is proposed, the mounting arrangement comprising: a plug element (2) with a longitudinal axis (L) and a housing part (8) having a recess (10) with a side wall (12) which is adapted to receive the plug element (2). At least one of the plug element (2) or the side wall (12) of the recess are provided with a protrusion (16) for fixing the plug element (2) in a given position relative to the housing part (8) by a force-fit engagement. Furthermore, a coupling assembly is proposed, the coupling assembly comprising the plug element (2) and the housing part (8) being mechanically coupled to each other.