Dosage Limiting Mechanism with Intersecting Path Curves
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Solution Overview
Problem
Existing self-injection devices with dosage-limiting mechanisms require significant space and complex coupling mechanisms, which are cumbersome and inefficient in preventing dosage settings beyond the remaining product amount in the cartridge.
Innovation Solution
A compact dosage-setting device with a limiting mechanism featuring a threaded nut and guide element, where a dosing sleeve with a grippable element allows setting and correcting dosages independently of the conveying unit, using a coupling device and reverse rotation lock to prevent excessive dosage settings, and a limiting mechanism with intersecting path curves to block further movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dosage-limiting mechanism is implemented in self-injection devices, then dosage safety is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent combines the dosage-setting function and the dosage-limiting function into a single integrated mechanism. The dosing sleeve with its toothing directly interacts with the stop wheel with corresponding toothing, eliminating the need for separate coupling mechanisms between dosage-setting and limiting components. This integration maintains dosage safety while reducing device complexity.
Solution Approach 2:
The dosing sleeve serves multiple functions: it allows dosage selection by rotation, transmits rotational movement to the stop wheel through meshing toothing, and enables dosage correction by reversible rotation. The stop wheel simultaneously limits dosage settings and tracks administered dosage through its interaction with the dosing sleeve. This multi-functionality reduces the number of separate components needed.
2Reliability
If a dosage-limiting mechanism is implemented in self-injection devices, then dosage safety is improved, but device space requirements increase
Solution Approach 1:
The stop wheel is positioned within the housing and interacts with the dosing sleeve in a nested arrangement. The dosing sleeve rotates within the same spatial envelope as the stop wheel, allowing both components to occupy overlapping or adjacent spaces rather than requiring separate dedicated spaces. This nesting approach minimizes the overall device footprint while maintaining dosage-limiting functionality.
3Ease of operation
If the dosing sleeve can be rotated independently of the conveying unit, then ease of dosage setting is improved, but device complexity increases
Solution Approach 1:
The patent extracts the dosage-setting function from the conveying unit, allowing the dosing sleeve to rotate independently to select dosage without moving the piston rod or triggering product ejection. The coupling between dosage-setting and conveying is established only when needed, through the engagement of the dosing sleeve's toothing with the stop wheel's toothing. This separation improves ease of operation while the simple meshing toothing keeps the coupling mechanism uncomplicated.
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 effectively prevents dosage settings beyond the remaining product in the cartridge, ensuring safe and accurate administration while minimizing space and complexity, allowing for precise dosage control and easy correction of over-set dosages.
Implementation Method 1
The dosing device has a threaded rod (8), the outside thread of which is engaged with an inside thread of a threaded nut (7)
Implementation Method 2
The two path curves intersect in at least one point or come so close together that the stop means strike against one another, whereby a blocking of the movement and the dosing movement is effected
Data Source
AI summary
Dosing device for an administration device with a limiting mechanism, comprising a first limiting means with a first stop means, a second limiting means with a second stop means, wherein the second limiting means follows movements of the first limiting means during dosing movements with a defined transmission ratio, and wherein the first and the second stop means each describe a path curve by their movements in such a manner that the two path curves intersect in at least one point or come so close together that the stop means contact one another in a stop position, whereby a blocking of the movement of the limiting means relative to each other during dosing movements can be effected in that the respective path curves described by the first and second stop means are closed and can be run through preferably multiple times by the first stop means, by the second stop means or by both stop means until the stop means contact one another at the stop position.