Drug Delivery Device Push-Pull Mechanism Dose Setting
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Solution Overview
Problem
Existing drug delivery devices for administering pre-set doses of medicinal products, such as heparin or insulin, face challenges in being easy to use, accurate, inexpensive to produce, and robust, while also requiring a simple internal structure and minimal mechanical parts.
Innovation Solution
A drug delivery device with a housing, a movable piston, and a push-pull element that converts proximal displacement into rotational and axial movements of the piston rod, allowing for intuitive dose setting and dispensing through a mechanism involving coupling elements, guide and stop elements, and a guiding sleeve, enabling easy handling and reliable dose administration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional drug delivery device uses multiple mechanical parts for dose setting and dispensing, then the device can achieve reliable dose administration, but the device complexity increases and manufacturing cost rises
Solution Approach 1:
The patent combines the dose setting and dose dispensing functions into a single push-pull element that performs both operations. The push-pull element integrates the functions of a separate dose setting mechanism and a separate dispensing mechanism, reducing the total number of mechanical parts while maintaining reliable dose administration through its dual-function design
Solution Approach 2:
The push-pull element is designed as a multi-functional component that can both set the dose (by pulling to rotate the piston rod) and dispense the dose (by pushing to move the piston). This universal component replaces multiple specialized parts, reducing device complexity while preserving the reliability of dose delivery
2Ease of manufacture
If the device uses a simple structure with minimal parts, then the manufacturing cost decreases and assembly is easier, but the ease of operation and user-friendliness may be compromised
Solution Approach 1:
The device is segmented into modular components (housing, container, piston, piston rod, push-pull element, coupling elements) that can be manufactured separately and assembled simply. This segmentation enables cost-effective manufacturing while maintaining ease of operation, as each component has a specific function and the assembly follows a straightforward configuration
Solution Approach 2:
The push-pull element provides self-service functionality where a single user action (pushing or pulling) automatically performs the required operation (dispensing or dose setting). The coupling elements between the push-pull element and piston rod automatically convert the linear motion into rotational motion for dose setting, eliminating the need for complex user manipulation or additional actuating mechanisms
3Ease of operation
If the device uses a single push-pull element for both dose setting and dispensing, then the ease of operation improves, but the reliability of the mechanism may deteriorate due to increased functional demands on fewer parts
Solution Approach 1:
The coupling elements between the push-pull element and piston rod provide dynamic functionality that adapts to the operational mode. During dose setting, the coupling elements enable rotational movement of the piston rod; during dose dispensing, they transmit linear force to the piston. This dynamic adaptability allows a single push-pull element to reliably perform both functions without compromising mechanical stability
Solution Approach 2:
The coupling elements act as intermediaries between the push-pull element and the piston rod/piston system. These intermediary components facilitate the conversion of motion types (linear to rotational for dose setting, linear to linear for dispensing) and ensure reliable force transmission, maintaining mechanical stability while enabling intuitive single-element operation
Data Source
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AI summary
The invention provides a drug delivery device for dispensing of a dose of a medicinal product, comprising: a housing (12, 20;120) having a proximal end and a distal end, a container (16) comprising the medicinal product, a piston being retained in the container (16), a push-pull element (50; 150), wherein the push-pull element (50;150) is displaceable in proximal direction for setting of a dose and wherein the push-pull element (50; 150) is displaceable in distal direction for dispensing of a dose, a piston rod (40;140) being coupled with the housing (12, 20;120) and having a distal end (42) to interact with the container's piston (18), the piston rod (40;140) being further coupled with the push-pull element (50;150), coupling elements for converting a proximal displacement of the push-pull element (50;150) into a rotational movement of the piston rod (40; 140) and for converting a distal displacement of the push-pull element (50;150) into an axial movement of the piston rod (40) with respect to the housing (12, 20; 120).