Dose Setting Mechanism Vibration Damping Intermediate Element
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Solution Overview
Problem
Existing dose setting mechanisms in drug delivery devices often produce unpleasant sounds due to vibrations and play between the inner and outer sleeves, leading to uncomfortable chatter sounds during dose setting and cancellation.
Innovation Solution
Incorporating an elastically deformable intermediate element between the inner and outer sleeves to minimize relative movement and absorb vibrations, thereby reducing sound feedback and amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the inner and outer sleeves are directly connected without intermediate elements, then the structure is simple, but vibrations and play between the sleeves produce unpleasant chatter sounds during dose setting
Solution Approach 1:
The patent introduces intermediate elements (damping elements, elastic elements, or fluid-filled chambers) between the inner and outer sleeves to act as mediators that absorb vibrations and reduce play. These intermediaries prevent direct rigid contact between the sleeves, thereby eliminating the chatter sounds while maintaining structural simplicity.
Solution Approach 2:
The patent changes the physical parameters of the connection between sleeves by introducing elements with specific damping characteristics, elastic properties, or fluid viscosity. This modifies the vibration transmission characteristics and reduces the harmful chatter sounds without significantly complicating the overall structure.
2Object-affected harmful factors
If intermediate elements are added to reduce play and dampen vibrations, then sound characteristics are improved, but the device complexity increases
Solution Approach 1:
The patent employs flexible damping elements or thin film structures that can be integrated into the existing sleeve design. These flexible components provide vibration damping and play reduction while maintaining a compact form factor and minimal impact on overall device complexity.
Solution Approach 2:
The patent uses composite material structures for the intermediate elements, combining materials with different damping characteristics to achieve optimal vibration reduction. This allows effective sound characteristic improvement while keeping the intermediate elements compact and the overall device complexity manageable.
3Object-affected harmful factors
If the sleeves are rigidly connected to eliminate play, then vibration damping is improved, but the mechanism becomes less sensitive to tolerance deviations
Solution Approach 1:
The patent employs dynamic connection elements that can adapt their stiffness or damping characteristics based on operating conditions. This allows the system to maintain rigid connection characteristics when needed for vibration damping while remaining compliant enough to accommodate normal manufacturing tolerances without excessive stress or binding.
Solution Approach 2:
The patent incorporates pre-compressed springs or pre-loaded damping elements that anticipate and compensate for tolerance variations before they cause problems. This beforehand cushioning ensures consistent vibration damping performance while being tolerant of manufacturing variations in sleeve dimensions and alignment.
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 intermediate element effectively dampens vibrations and sound production, making the dose setting mechanism less sensitive to tolerance deviations and providing improved sound characteristics by constantly interconnecting the sleeves and compensating for positional deviations.
Implementation Method 1
Incorporating an elastically deformable intermediate element between the inner and outer sleeves to minimize relative movement and absorb vibrations
Implementation Method 2
The intermediate element effectively dampens vibrations and sound production
Data Source
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AI summary
The present invention is directed at a dose setting mechanism for a drug delivery device, comprising an outer sleeve (10) and an inner sleeve (9) located at least partially within the outer sleeve (10) wherein the outer sleeve (10) is rotationally fixed to the inner sleeve (9). To reduce noise excitations of the dose setting mechanism, at least one intermediate element (23) is at least partially located in a clearance (14) between the inner sleeve (9) and the outer sleeve (10) in such way that it reduces the relative movement of the inner sleeve (9) and the outer sleeve (10) along a play (22, 24) between the inner sleeve (9) and the outer sleeve (10). The invention is further directed to a pen-type injector equipped with a respective dose setting mechanism.