Inhaler Dose Counter Resilient Flex Prevention
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Solution Overview
Problem
Inhalers, particularly breath-actuated pressurized metered dose inhalers (pMDIs), face issues with reliability due to mechanical blocking mechanisms that can deform or fail under repeated use, leading to inaccurate dose counting and potential misuse from premature disposal.
Innovation Solution
An inhaler design featuring a dose counting mechanism, a dispensing mechanism with a loading member and resetting member, and a prevention mechanism with engaging members that resiliently flex under load to ensure the dispensing mechanism is fully reset before allowing further actuation, preventing partial resets and ensuring accurate counting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical blocking mechanism is used to prevent premature actuation, then the inhaler can block movement of components, but the small components are subjected to significant forces that cause deformation or damage under repeated use
Solution Approach 1:
A resilient member acts as an intermediary between the blocking mechanism and the rigid component. This resilient member absorbs and distributes the significant forces generated during blocking operations, preventing direct transmission of high stress to small components. The resilient member deforms elastically under load and returns to its original shape, enabling repeated blocking cycles without component damage or deformation.
2Productivity
If the resetting member allows partial reset, then the inhaler can be operated more quickly, but the dispensing mechanism may not be fully reset leading to inaccurate dose counting and potential misuse
Solution Approach 1:
The prevention mechanism provides feedback by detecting whether the resetting member has completed its full reset行程. The first and second engaging members are positioned such that they prevent actuation if the resetting member is in any position other than the fully reset position. This feedback mechanism ensures that the system only allows operation when properly reset, preventing inaccurate dose counting while maintaining operational efficiency through clear go/no-go signals.
3Force
If the engaging members are made rigid to hold the load, then the blocking force is sufficient, but the components may be deformed or damaged under the forces
Solution Approach 1:
The resilient member changes its physical parameters (shape, density, or material properties) to optimize the balance between blocking force and structural integrity. By selecting appropriate material properties such as elastic modulus and yield strength, the resilient member can generate sufficient blocking force through elastic deformation while remaining resistant to permanent damage. This parameter optimization allows the engaging members to withstand repeated high-force blocking operations without deformation or failure.
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 design enhances the reliability and consistency of medicament delivery by ensuring the dispensing mechanism is fully reset, reducing the risk of inaccurate dosing and counting, and preventing accidental actuation, thus improving patient safety and inhaler performance.
Implementation Method 1
at least one of the first and second engaging members is configured to resiliently flex, under load, into abutment with a substantially rigid component of the inhaler
Data Source
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AI summary
An inhaler for delivery of a medicament by inhalation is disclosed. The inhaler comprises a dose counting mechanism comprising a counter. The inhaler further comprises a dispensing mechanism, the dispensing mechanism being configured, on actuation, to dispense a dose of medicament and to adjust the counter. The inhaler further comprises a resetting member configured for movement in a first direction between a first position and a second position to reset the dispensing mechanism, and a prevention mechanism comprising a pair of first and second engaging members. If the movement of the resetting member in the first direction is reversed before it reaches the second position, the first and second engaging members prevent further actuation of the dispensing mechanism until the resetting member is again moved in the first direction. At least one of the first and second engaging members is configured to resiliently flex, under load, into abutment with a substantially rigid component of the inhaler. Preferably the dose counting mechanism counter indicates the number of remaining doses in, or the number of dispensed doses from, the inhaler.