Dispensing Indicator Mechanism for Accurate Dose Tracking
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Solution Overview
Problem
Existing dispensing devices, such as aerosol inhalers, face challenges in providing accurate and reliable indication of the number of doses remaining or dispensed, often leading to unexpected empty containers due to inadvertent indicator movement or inconsistent actuation forces.
Innovation Solution
A drive mechanism featuring a rotatable drive member with a convex surface and a driven member with concave surfaces and protrusions, which engages to prevent unintended rotation and display dispensing indicia, ensuring accurate dose tracking without additional resistive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an indexing device is provided to prevent inadvertent movement of the indicator member, then the reliability of dose indication is improved, but the device complexity increases
Solution Approach 1:
The indexing device is segmented into discrete elements: the drive member with convex surface, the driven member with concave surfaces and protrusions, and the engagement member. Each element performs a specific function in the sequence of preventing inadvertent movement while allowing intentional advancement. This segmentation allows the complex function to be achieved through simple, well-defined components working together.
Solution Approach 2:
The engagement member acts as an intermediary between the drive member and driven member. It selectively engages with the protrusions on the driven member, mediating the transfer of rotational motion only when intentional actuation occurs. This intermediary mechanism prevents direct engagement that would cause inadvertent movement while allowing controlled advancement when needed.
2Reliability
If the indicator member is designed to move only upon a predetermined number of actuations greater than one, then the reliability of dose indication is improved, but the actuation force becomes inconsistent
Solution Approach 1:
The mechanism dynamically transitions between two states: locked (when engagement member engages protrusions) and unlocked (when convex surface slides along concave surfaces). During the locked state, the indexing device prevents movement regardless of actuation force. During the unlocked state, the indicator advances smoothly. This dynamic behavior ensures that actuation force remains consistent whether the indicator is being advanced or is immobilized, resolving the contradiction between reliability and force consistency.
3Reliability
If the convex surface slides along the concave surfaces to prevent rotation, then inadvertent movement is prevented, but additional resistive force is generated during actuation
Solution Approach 1:
The interaction between convex and concave surfaces is segmented into discrete engagement points (protrusions) and sliding intervals. During sliding intervals, the surfaces move smoothly with minimal friction. During engagement points, the protrusions are temporarily held by the engagement member, preventing inadvertent movement. This segmentation allows the system to achieve reliable prevention of inadvertent movement without generating continuous resistive force during actuation.
Data Source
AI summary
An indicating device includes a drive member and a driven member. The driven member is non-rotatably immobilized by the successive engagement of a convex surface on the drive member with a plurality of concave surfaces on the driven member. The driven member further includes a plurality of protrusions that are successively received in a recess of the drive member as an engagement member engages the driven member and rotates the driven member. The driven member has dispensing indicia. In another aspect, an indicating device includes an indicator member having dispensing indicia. A stop member is selectively engaged with successive ones of a plurality of stop surfaces on the indicator member such that the indicator member is non-rotatable. Methods for indicating the amount of substance that have been dispensed from or remain in a container are also provided.