Dose Counter Assembly with Segmented Wheels
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Solution Overview
Problem
Current dry powder inhalers lack a reliable mechanism for users to accurately track the remaining doses, leading to potential misuse due to undercounting, which can result in the inhaler not dispensing medication when it is empty.
Innovation Solution
A dose counter assembly comprising a units dose display and a tens dose display, with a driver mechanism that aligns indicia at a common viewing area, ensuring accurate and reliable counting, preventing undercounting by disengaging drive transmission when the end of the count sequence is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dose counter mechanism is added to track remaining doses, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The dose counter is divided into two independent wheels: a first count wheel with primary drive teeth and a second count wheel with secondary drive teeth. The first wheel tracks units doses while the second wheel tracks tens doses, allowing each to operate independently with simpler tooth geometries that mesh at specific intervals, thereby achieving accurate multi-digit counting without requiring a single complex counter mechanism.
Solution Approach 2:
A kick wheel is introduced as an intermediary component between the first and second count wheels. The kick wheel receives rotational input from the first wheel and transmits it to the second wheel only at specific intervals (when the first wheel completes a full rotation), enabling the second wheel to advance only when appropriate and preventing undercounting while maintaining mechanical simplicity.
2Productivity
If drive transmission is continuously engaged, then productivity is improved, but reliability deteriorates due to potential undercounting
Solution Approach 1:
The drive transmission from the first count wheel to the second count wheel is made periodic rather than continuous. The kick wheel engages with the secondary drive teeth only periodically (every time the first wheel completes a full rotation), allowing the counting mechanism to operate at full speed during active counting while automatically disengaging to prevent erroneous advances when the inhaler is empty or the count sequence ends, thus ensuring reliability.
Solution Approach 2:
The counter mechanism incorporates implicit feedback through the periodic engagement of the kick wheel with the secondary drive teeth. The system automatically detects when the first wheel has completed a full rotation and only then transmits motion to the second wheel, providing built-in verification that prevents undercounting and ensures accurate dose tracking without requiring external monitoring.
Data Source
AI summary
There is provided a dose counter assembly for use with a medicament dispenser, the dose counter assembly comprising: a) a units dose display means comprising a first count indicia and one or more driver teeth; b) a tens dose display means comprising a second count indicia; and c) a driver, wherein the first count indicia and second count indicia align at a common viewing area to collectively display a count sequence.