Aerosol Dispenser Locking Mechanism Eliminates Leaf Spring
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Solution Overview
Problem
Existing aerosol dispensers, such as inhalers, face complexity in design and assembly due to the use of pre-stressed leaf springs for locking mechanisms, making it difficult to indicate when the liquid cartridge is empty and potentially allowing users to dispense empty doses.
Innovation Solution
A locking mechanism for aerosol dispensers that uses a spindle and movable element to incrementally move along a threaded connection, applying a radial force to a locking element that bends and prevents rotation, eliminating the need for a pre-stressed leaf spring, thereby simplifying assembly and indicating the remaining doses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-stressed leaf spring is used for the locking mechanism, then the locking function is achieved, but the design and assembly complexity increases
Solution Approach 1:
The patent removes the pre-stressed leaf spring from the locking mechanism, extracting the problematic component that caused design and assembly complexity. The locking function is achieved through a simplified arrangement where the movable element itself performs the locking action by engaging with the housing wall when it reaches the final position, eliminating the need for separate spring components.
Solution Approach 2:
The movable element serves dual functions: it indicates the number of remaining doses and simultaneously performs the locking function. When the movable element reaches the final position, it automatically engages with the housing wall to prevent further rotation, making the system self-sufficient without requiring external spring mechanisms.
2Reliability
If a pre-stressed leaf spring actuated by axial movement of a push rod is used, then the locking mechanism functions, but the assembly process becomes more complex
Solution Approach 1:
The patent eliminates both the pre-stressed leaf spring and the push rod actuation mechanism. The locking function is achieved directly through the rotational movement of the movable element along the spindle, which naturally engages with the housing wall at the final position, simplifying the assembly process by removing multiple components and their associated assembly steps.
Solution Approach 2:
Instead of using axial movement of a push rod to actuate the spring, the patent inverts the mechanism by using direct rotational movement of the movable element along the spindle to achieve the locking function. The movable element's rotation itself creates the engagement with the housing wall, reversing the traditional actuation approach.
3Loss of information
If the liquid cartridge is empty, then the user should be indicated, but the user may be left with the impression that liquid has been dispensed
Solution Approach 1:
The movable element serves as a visual indicator that changes position along the spindle to indicate the number of remaining doses. When the liquid cartridge is empty, the movable element reaches the final position where it engages with the housing wall, providing a clear visual cue to the user that the cartridge is empty, preventing the misconception that liquid remains.
Solution Approach 2:
The movable element simultaneously performs the dosing indication function and the locking function. As it rotates along the spindle to indicate remaining doses, it automatically provides the empty cartridge indication and triggers the locking mechanism when it reaches the final position, eliminating the need for separate indication systems.
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 more robust and simplified locking mechanism that effectively prevents further dispensing when the cartridge is empty, ensuring users are aware of the remaining doses without increasing design complexity.
Implementation Method 1
the movable element is configured to apply a radial force onto the locking element causing the locking element to bend in the radial direction
Data Source
AI summary
A locking mechanism for an aerosol dispenser is presented having a first body structure, a second body structure rotatably attached to the first body structure, a spindle rotatably attached to the second body structure, the spindle having an actuator rotationally cooperating with the first body structure such that rotation of the first body structure relative to the second body structure causes rotation of the actuator and of the spindle, a movable element arranged around the spindle, the spindle being rotatable relative to the movable element, wherein rotation of the spindle causes movement of the movable element along the spindle from an initial position to a final position, and a locking element, wherein in the final position the movable element applies a radial force onto the locking element causing the locking element to bend in the radial direction thereby preventing rotation between the first body structure and the second body structure.