Dosage Limiting Mechanism Using Gear Guidances
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Solution Overview
Problem
Existing medication administration devices lack a reliable and simple mechanism to prevent dosage settings beyond the remaining amount of medication in the cartridge, posing safety risks and inefficiencies.
Innovation Solution
A dosage limiting mechanism using two gear guidances to return a stop wheel from a tilted to a non-tilted position without the need for elastic elements, ensuring that dosage settings do not exceed the available medication, and allowing for accurate dose adjustment and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a limiting mechanism is added to prevent dosage settings beyond the remaining amount of medication, then safety and reliability are improved, but device complexity increases
Solution Approach 1:
The limiting mechanism is integrated into the existing dosage-setting mechanism by combining the stop wheel with the dosage-setting sleeve and coupling sleeve. The stop wheel is rotatably received in the coupling sleeve and meshes with the dosing sleeve, creating a unified structure that limits dosage settings without requiring separate independent components. This merging approach adds safety functionality while minimizing increases in overall device complexity.
Solution Approach 2:
The gear guidances automatically return the stop wheel to its non-tilted position during both dose increase and decrease movements without requiring external intervention or additional actuating mechanisms. The gear guidances utilize the existing rotational movements of the dosing sleeve to self-correct the stop wheel position, making the system self-regulating and reducing the need for complex control mechanisms.
2Device complexity
If elastic elements are used to return the stop wheel to its non-tilted position, then the mechanism is simpler, but reliability decreases due to wear and failure of elastic components
Solution Approach 1:
The patent replaces elastic elements (springs) with a gear guidance mechanism that uses rigid gear teeth engagement to return the stop wheel to its non-tilted position. The gear guidances consist of gear teeth on the stop wheel meshing with corresponding gear teeth on the coupling sleeve, creating a deterministic mechanical system that eliminates wear-prone elastic components while maintaining reliability through precise gear engagement.
Solution Approach 2:
The gear guidance acts as an intermediary mechanism between the stop wheel and the dosage-setting sleeve. Instead of directly using elastic elements to push the stop wheel back, the gear teeth serve as an intermediate transmission element that converts the rotational movement of the dosing sleeve into a controlled return movement of the stop wheel, eliminating the need for elastic recovery elements.
3Device complexity
If the stop wheel is allowed to remain tilted after dosage setting, then the mechanism is simpler, but measurement precision is lost as the position cannot be accurately reset
Solution Approach 1:
The gear guidance provides automatic feedback control for the stop wheel position. As the dosing sleeve rotates during dosage setting or correction, the gear teeth engagement continuously monitors and adjusts the stop wheel position, automatically returning it to the non-tilted position when appropriate. This feedback mechanism ensures accurate position resetting without requiring additional sensors or control systems, maintaining measurement precision through passive mechanical feedback.
Data Source
AI summary
Dosing device for an administration device with a limiting mechanism containing: a dosing sleeve with a first stop and a stop wheel with a second stop means adapted to continually and proportionally follow a movement of the dosing sleeve during dosing movements. During an ejection movement, there is no relative movement between dosing sleeve and stop wheel. The first stop and the second stop each describe a path curve by their movements such that the two path curves intersect in one point and the stops contact one another and tilt the stop wheel, thereby blocking the dosing movement of the dosing sleeve. The stop wheel comprises first and third sloped surfaces that may form first and second gear guidances with a clutch thereby returning the stop wheel to a non-tilted position during up or down dosing movements when the stops do not contact another.