Injection Drive Mechanism Configurable Dose Limits
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Solution Overview
Problem
Existing injection devices lack a mechanism to ensure a minimum and maximum dose threshold for medicament delivery, which is crucial for therapeutic efficacy, especially in combination drug therapies, and do not allow for easy configuration of dose sizes without modifying multiple components.
Innovation Solution
A drive mechanism with a blocking structure and clutch system that allows for configurable minimum and maximum dose settings by interchanging specific components, enabling the device to dispense only pre-defined doses and permit a 'priming' operation, suitable for both disposable and reusable devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a minimum and maximum dose function is implemented, then therapeutic efficacy is improved, but device complexity increases
Solution Approach 1:
The drive mechanism is divided into modular components: an inner body with a blocking structure, a display member with dose indicators, and a dose member with a clutch system. The blocking structure includes segmented blocking elements that can be selectively positioned to enforce minimum and maximum dose thresholds, allowing the complexity to be localized to specific components rather than the entire device.
Solution Approach 2:
The blocking structure is pre-configured with blocking elements positioned at specific locations along the axial direction to correspond with minimum and maximum dose values. This preliminary arrangement of blocking elements allows the dose limits to be enforced automatically without requiring complex real-time calculations or additional control systems during operation.
2Adaptability or versatility
If dose settings are made configurable, then adaptability to different therapeutic needs is improved, but device complexity increases
Solution Approach 1:
Different portions of the inner body are assigned different functions: the blocking structure for dose limiting, the outer thread for drive engagement, and the blocking thread for clutch control. This local differentiation allows each component to be optimized for its specific function while maintaining overall simplicity, as the adaptability is achieved through localized modifications rather than system-wide complexity.
Solution Approach 2:
The inner body serves multiple functions simultaneously: it provides the blocking structure for dose limits, engages the display member through external threading, and controls the clutch mechanism through the blocking thread. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while achieving configurability for different therapeutic needs.
3Measurement precision
If a blocking structure with multiple blocking elements is used, then dose control precision is improved, but manufacturing complexity increases
Solution Approach 1:
Multiple blocking elements are integrated into a single blocking structure formed as one piece on the inner body. This merging of multiple dose-control features into a unified structure simplifies manufacturing compared to assembling separate components, while still providing precise control over minimum and maximum doses through the different blocking elements positioned at specific axial locations.
4Ease of operation
If a clutch system is implemented, then operational control is improved, but device complexity increases
Solution Approach 1:
The clutch system acts as an intermediary mechanism between the dose member and the drive mechanism. The blocking thread on the inner body engages with the clutch to control the transition between dose setting and dispensing modes. This intermediary clutch system provides clear operational control by mechanically enforcing the distinction between setting and dispensing phases without requiring complex electronic controls or multiple separate mechanisms.
Data Source
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AI summary
The present invention relates to a drive mechanism for an injection device for setting and dispensing of a dose of a medicament, the drive mechanism comprising: - an inner body (20) fixable inside a housing (10) of the injection device (1), the inner body (20) comprising an elongated shaft (20a) extending in an axial direction (z), wherein the elongated shaft (20a) comprises an outer thread (21) and a blocking structure (40) on an outer circumference, - a tubular-shaped display member (160) having an inner thread (163) engaged with the outer thread (21) of the inner body (20), and - a dose member (70; 270) axially displaceable relative to at least one of the inner body (20) and the display member (160) between a dose setting position (S) and a dose dispensing position (D), - a blocking ring (180; 280; 380) axially engageable with the dose member (70; 270), rotationally fixed to the display member (160) and comprising at least one blocking element (182, 282; 382) to axially engage with the blocking structure (40) for blocking an axial displacement of the dose member (70) from the dose setting position (S) towards the dose dispensing position (D).