Inhalation Device Dosage Lever Cam Surface Triggering
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Solution Overview
Problem
Existing inhalation devices for powdered drugs face challenges in reproducible triggering forces and usability, with variations in airflow requirements due to component tolerances, leading to inconsistent dosing accuracy and potential for user errors like double dosing.
Innovation Solution
The inhalation device features a dosage lever that engages a cam surface tangentially, ensuring consistent triggering forces and a sealed dosing compartment to reduce airflow variations, along with a double-dosing prevention mechanism using a flap valve and locking mechanism to prevent empty reservoir use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dosage lever engages a cam surface of a trigger member to enable inhalation-triggered automatic metering, then dosing accuracy is improved through reproducible triggering forces, but manufacturing precision deteriorates due to sensitivity to component tolerances and assembly variations
Solution Approach 1:
The trigger member is segmented into distinct functional zones: a cam surface for inhalation-triggered release, a blocking edge for mechanical engagement, and a cam groove for guiding motion. This segmentation allows each element to be optimized independently, reducing the cumulative effect of tolerances while maintaining reproducible triggering forces for improved dosing accuracy
Solution Approach 2:
The cam surface is designed with a specifically shaped curved profile that compensates for manufacturing tolerances. The curved geometry ensures that variations in component dimensions result in minimal changes to the triggering force, thereby maintaining dosing accuracy despite imperfections in manufacturing precision
2Object-affected harmful factors
If sealing measures are implemented around the dosing slider passage opening, then moisture protection is improved, but device complexity increases due to additional sealing components and assembly steps
Solution Approach 1:
A flexible sealing lip is integrated directly into the dosing slider passage opening, forming a simple yet effective barrier against moisture. This thin-film sealing approach provides comprehensive moisture protection without requiring complex multi-component sealing assemblies, thereby minimizing the increase in device complexity
Solution Approach 2:
The sealing function is merged with the structural design of the dosing slider passage opening itself. The sealing lip is formed as an integral part of the passage structure, combining the functions of structural support and moisture barrier in a single element, thus avoiding additional sealing components and assembly steps
3Reliability
If a locking mechanism blocks the activation device after a pre-determined number of metering cycles, then reliability is improved by preventing double dosing and empty reservoir use, but device complexity increases due to additional locking components
Solution Approach 1:
The locking mechanism is designed to engage automatically after a pre-determined number of metering cycles, performing the safety function in advance before the reservoir becomes empty. The index and detection means predict when the reservoir will be depleted and trigger the lock proactively, preventing dosing errors without requiring complex real-time monitoring systems
Solution Approach 2:
The dosage lever serves multiple functions: it acts as the activation device for metering, engages with the cam surface for inhalation-triggered release, and interacts with the locking mechanism to prevent further dosing. This multi-functionality reduces the need for separate dedicated locking components, thereby minimizing the increase in device complexity while maintaining reliability
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
This design achieves reproducible triggering forces with minimal airflow variation, enhancing dosing accuracy and preventing double dosing, ensuring safe and efficient delivery of powdered medications.
Implementation Method 1
an inhalation-operated valve in an air duct (9) communicating with said powder channel, said inhalation-operated valve being operatively connected to said dosage lever so that said dosage lever is releasable by action of the valve initiated by the suction generated by the patient during inhalation
Implementation Method 2
a cyclone (16) forming a vortex flow in a powder groove (16a) leading from the powder reservoir (2)
Data Source
AI summary
The invention refers to an inhalation device for powdered drugs to be received by a patient by an inhalation-caused air stream, comprising at least one powder reservoir, metering means for repeatedly metering a powder dose from the reservoir, a transportation mechanism for moving said metering means from a filling position for receiving a powder dose into an emptying position for releasing said powder dose into a powder channel, at least one activating device for manual operation by the patient being operatively connected to said transportation mechanism such that upon operation a single powder dose is being metered, said activating device comprising a dosage key (5) acting on said transportation mechanism when actuated by the patient. According to the invention, said transportation mechanism furthermore comprises a dosage lever (6) acting on said metering means, said dosage lever (6) being locked in the inhalation position of said metering means after said dosage key (5) has been properly pressed down by the patient. The dosage lever (6) in the inhalation position engages a trigger member and is releasable by actuation of the trigger member. The trigger member comprises at least one cam surface and the dosage lever (6) engages the cam surface tangentially in said locked inhalation position.