Drug Delivery Device Dose Setting Mechanism
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Solution Overview
Problem
Administering injections poses risks and challenges for users and healthcare professionals, both mentally and physically, and existing drug delivery devices may not ensure safe operation.
Innovation Solution
The development of an improved drug delivery device featuring a mechanism unit with a dispense mechanism and a setting mechanism, which includes elements that interact to facilitate safe and precise drug dosing, such as a plunger rod, drive elements, and a user interface for dose setting and dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex mechanism unit with multiple interacting elements is used for dose setting and dispensing, then dosing precision and safety are improved, but device complexity increases
Solution Approach 1:
The mechanism unit is divided into distinct functional elements including a setting mechanism for dose selection and a dispense mechanism for dose delivery. These elements interact through defined coupling relationships (spline coupling, threaded engagement) that allow independent function while maintaining coordination, thereby achieving precise dosing without excessive overall complexity
Solution Approach 2:
The mechanism unit serves multiple functions through its interacting elements: the setting mechanism allows dose selection, the dispense mechanism delivers the dose, and the coupling between elements ensures proper coordination. This multi-functionality within a single integrated unit improves dosing precision while managing complexity through functional consolidation
2Measurement precision
If a splined coupling between mechanism elements is used to fix rotational position during dose setting, then dosing accuracy is improved, but the coupling must be released for dose dispensing which adds operational complexity
Solution Approach 1:
The coupling between mechanism elements transitions from a static splined coupling during dose setting to a dynamic state during dose dispensing where the coupling is released. This allows the system to adapt its mechanical constraints based on the operational phase, ensuring precision during setting while enabling movement during dispensing through controlled release mechanisms
3Reliability
If an electromechanical actuator is used to block or enable dose setting, then operational safety is improved, but device complexity increases
Solution Approach 1:
A mechanical blocking system is replaced with an electromechanical actuator that uses electrical signals to control the blocking and unblocking of dose setting. This substitution improves operational safety through more reliable and controllable actuation while reducing the complexity of mechanical linkages and springs required for blocking mechanisms
Data Source
AI summary
A drug delivery device includes a mechanism unit with a housing element, a first movable element that is movable with respect to the housing element, and an electromechanical actuator that, when operated, moves an actuator element between a first position and a second position. The mechanism unit is configured to: operatively couple with a drug reservoir unit, enable a dispense process for dispensing a drug dose, and enable setting a drug dose to be dispensed. Setting a drug dose involves movement of the first movable element in a first direction. The mechanism unit is configured to block movement of the first movable element in the first direction when the actuator element is in the first position to prevent setting a drug dose and to allow movement of the first movable element in the first direction when the actuator element is in the second position.