Inhaler Dose Counter with Dual-Stroke Ratchet

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Solution Overview

Problem

Existing dose counters for pressurized aerosol inhalers are unreliable and prone to miscounting, lack durability, and fail to accurately track the remaining doses due to manufacturing variations and mechanical complexities.

Innovation Solution

A dose counter mechanism featuring a fixed ratchet member and a counter member with inclined surfaces that advance during both the outward and return strokes of the trigger, ensuring precise counting and resilience to handle variations in valve stem travel, constructed from robust materials like plastics to withstand wear and tear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dose counter mechanism is implemented to track medicament doses, then the patient can determine the amount of medicament remaining, but the counter may miscount or fail to accurately track doses due to manufacturing variations and mechanical complexities

Engineering Contradiction:

Improvedose counting accuracyVSAvoidcounter mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The counter mechanism is divided into separate functional components: a ratchet member with teeth for unidirectional advancement, a trigger member that interacts with inclined surfaces, and a counter member with distinct first and second regions. This segmentation allows each component to perform its specific function reliably, reducing the overall complexity while maintaining accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using a complex mechanism that counts during the outward stroke, the invention uses the return stroke to complete the counting action. The ratchet member is fixed and the counter member is advanced during the return movement, inverting the traditional approach and simplifying the mechanism while improving reliability.

Inventive Principle:

Principle #13The other way round (Inversion)

2Strength

If the counter mechanism is made sturdy to withstand being carried in pockets or bags, then the counter will not alter the count during transport, but the mechanism may become more complex and difficult to manufacture

Engineering Contradiction:

Improvemechanical durabilityVSAvoidmanufacturing simplicity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The counter mechanism is designed as a simple, robust assembly that can be easily manufactured from standard materials. The ratchet member, trigger member, and counter member are constructed to be durable yet simple in form, allowing for cost-effective production while maintaining the strength needed to withstand normal handling and transport conditions.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If the counter must compensate for manufacturing variations in valve stem travel length, then accurate counting is maintained, but the mechanism becomes more complex and less reliable

Engineering Contradiction:

Improvedose counting precisionVSAvoidmechanical reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The counter mechanism is designed to accommodate variations in valve stem travel by using inclined surfaces that engage at different points during the return stroke. The ratchet teeth are positioned to engage with these inclined surfaces, allowing the mechanism to compensate for parameter variations in stroke length while maintaining reliable and precise counting without adding complexity.

Inventive Principle:

Principle #35Parameter changes

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 provides a reliable, durable, and accurate count of medicament doses, preventing miscounting and ensuring the counter returns to the correct position even if the trigger stroke is interrupted, thus maintaining the integrity of the dose tracking.

Implementation Method 1

the counter member being resiliently biased towards the ratchet and trigger members

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8740014B2Dose counter for dispensers

Publication Date: 2014.06.03 KINDEVA DRUG DELIVERY LP

AI summary

A dose counter for use with an inhaler comprising a container for medicament equipped with a reciprocal actuation means to dispense a dose of medicament therefrom, the dose counter comprising: a fixed ratchet member, a trigger member constructed and arranged to undergo reciprocal movement coordinated with the reciprocal movement between the actuation means and the container, said reciprocal movement comprising an outward stroke and a return stroke, a counter member constructed and arranged to undergo a predetermined counting movement each time a dose is dispensed, the counter member being biased towards the ratchet and trigger members and being capable of counting motion in a direction generally orthogonal to the direction of reciprocal movement of the trigger member, the counter member comprising: a first region for interaction with the trigger member which comprises at least one inclined surface which is engaged by the trigger member during its outward stroke causing the counter member to undergo counting motion, and a second region for interaction with the ratchet member which comprises at least one inclined surface which is engaged by the ratchet member during the return stroke of the trigger member causing the counter member to undergo further counting motion to complete said predetermined counting movement.