Dose Setting Mechanism With Rotational Stop For Drug Delivery
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Solution Overview
Problem
Existing dose setting mechanisms for drug delivery devices lack a cost-effective and easy method to prevent users from selecting doses greater than a predefined maximum, which can lead to improper medication administration.
Innovation Solution
A dose setting mechanism featuring an inner housing with a helical groove and a dial sleeve that includes rotational stop members to prevent dialing beyond a pre-defined maximum dose, ensuring accurate and safe dosing through a threaded engagement and complementary stop features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a dose setting mechanism allows unlimited dose selection, then ease of operation is improved, but safety deteriorates due to risk of overdose
Solution Approach 1:
The patent applies preliminary anti-action by incorporating a rotational stop member that prevents the dial sleeve from rotating beyond a predetermined angle corresponding to the maximum safe dose. This mechanical constraint is built into the device structure beforehand, automatically blocking the harmful action of dose selection beyond the safe limit without requiring user awareness or intervention.
2Object-affected harmful factors
If a rotational stop member is added to prevent overdose, then safety is improved, but device complexity increases
Solution Approach 1:
The patent merges the rotational stop function with the existing dial sleeve structure. The stop member is integrated into the dose setting mechanism assembly, combining the dose display/selection function of the dial sleeve with the dose limitation function of the stop member. This integration prevents overdose while minimizing additional complexity by using a simple mechanical interface rather than a separate complex control system.
3Manufacturing precision
If a helical groove and threaded engagement are used for dose setting, then manufacturing precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent segments the dose setting mechanism into distinct functional components: the dial sleeve with external threading for user rotation, the helical groove as a separate engagement feature, and the rotational stop member as an independent safety component. This segmentation allows each component to be manufactured and assembled separately, improving overall manufacturability while maintaining the precision of the threaded engagement that ensures accurate dose correspondence.
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 mechanism effectively restricts users from selecting doses beyond the predefined limit, enhancing safety and accuracy in medication administration while simplifying assembly and manufacturing processes.
Implementation Method 1
a dial sleeve rotatably engaged with the helical groove of the inner housing
Implementation Method 2
the first rotational stop member prevents the user from selecting a dose greater than a pre-defined maximum selectable dose
Data Source
AI summary
A dose setting mechanism of a drug delivery device and a respective method of assembling said dose setting mechanism. The dose setting mechanism includes an inner housing having a helical groove along an external surface of the housing. The inner housing includes a rotational stop member near one end of the helical groove. The dose setting mechanism also includes a dial sleeve rotatably engaged with the helical groove of the inner housing. When a user rotates the dial sleeve to select a dose, the rotational stop member prevents the user from selecting a dose greater than a pre-defined maximum selectable dose.