Annular Dose Counter Mechanism for Aerosol Dispensers
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Solution Overview
Problem
Existing aerosol dispensers with dose counters, such as inhalers, often make it difficult for users to accurately determine the number of doses remaining due to the design limitations of axial straight scales.
Innovation Solution
A dose counting mechanism featuring an annular dose counter with teeth along its perimeter, a rotatable actuator, and a ratchet mechanism that prevents backward counting, allowing for precise indication of remaining doses through a radial scale on the entire perimeter, ensuring accurate dose tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an axial straight scale is used for dose indication, then the device structure is simple, but the measurement precision of remaining doses is insufficient
Solution Approach 1:
The patent transforms the dose indication from a one-dimensional axial straight scale to a two-dimensional annular scale. The dose counter is configured as an annular structure with dose markings distributed along its perimeter, allowing the indicator to traverse a circular path. This dimensional change enables the use of the entire perimeter for dose indication, significantly improving measurement precision while maintaining reasonable device complexity.
2Reliability
If the dose counter can rotate freely in both directions, then the mechanism is simple, but the reliability of dose counting is compromised due to potential backward rotation
Solution Approach 1:
The patent implements a ratchet mechanism that prevents the dose counter from rotating in the wrong direction. The ratchet teeth are configured to engage with a ratchet arm, allowing rotation only in the intended direction (toward lower dose numbers). This preliminary anti-action ensures that even if external forces or mechanical tolerances cause potential backward rotation, the ratchet mechanism blocks such movement, maintaining reliable dose counting without requiring complex active control systems.
Data Source
AI summary
A dose counting mechanism for an aerosol dispenser is presented where the dose counting mechanism has a first body structure, a second body structure rotatably attached to the first body structure, an annular dose counter provided with a plurality of teeth along its perimeter, the dose counter being arranged coaxially with the first body structure and the second body structure, each of the first body structure and the second body structure being rotatable relative to the dose counter, a rotatable actuator that meshes with the teeth of the dose counter, the actuator being configured to follow the perimeter of the dose counter when the second body structure is rotated relative to the first body structure, and a rotator that rotates concurrently with one of the first body structure and the second body structure and that engages with the actuator when rotation of the first body structure relative to the second body structure is initiated.