Composite Button Assembly for Quiet, Shock-Resistant Drug Delivery
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Solution Overview
Problem
Drug delivery devices, particularly those with spring-driven mechanisms, suffer from noise and accidental dose ejection due to unintentional shocks, and lack effective shock resistance and noise reduction mechanisms.
Innovation Solution
A button assembly with a shock-resistant mechanism, utilizing a material composite and an acceleration sensor to prevent axial movement upon shock, and a noise-damping mechanism using a material composite with different elasticity and sound transmission planes to reduce operating loudness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a spring-driven mechanism with clutch teeth is used for dose setting, then the device enables user variable dose selection, but noise is generated during clutch engagement that is transmitted along the device and perceived as too loud
Solution Approach 1:
A button assembly with a plate-like or sleeve-like button body is introduced as an intermediary element between the user's finger and the drive mechanism. This button body absorbs and dampens vibrations and noise generated during clutch engagement, preventing noise transmission along the device while still enabling effective force transmission for dose setting and injection actuation.
Solution Approach 2:
The button body is made from a material composite with specific damping properties that balance force transmission efficiency with noise and vibration attenuation. The composite material structure allows the button to function as both a force transmission element and a noise-damping element, resolving the contradiction between operational effectiveness and noise reduction.
2Adaptability or versatility
If the clutch allows relative axial movement between drive member and driven member during dose setting, then dose selection is enabled, but accidental shocks can cause unintended dose ejection
Solution Approach 1:
An acceleration sensor is integrated into the button assembly to detect shock events in real-time. When accidental shock is detected, the system can trigger feedback mechanisms such as visual indicators or auditory signals to alert the user, and potentially engage locking mechanisms to prevent unintended dose ejection while maintaining the ability to perform deliberate dose setting operations.
Solution Approach 2:
The button assembly with its damping material composite provides beforehand cushioning against shock forces. The material's viscoelastic properties allow it to absorb and dissipate shock energy before it can transmit to the drive mechanism, preventing accidental clutch engagement and unintended dose ejection while not interfering with intentional user actuation.
3Force
If a rigid button structure is used for force transmission, then efficient force transmission to the driven element is achieved, but shock forces are transmitted along the device causing accidental operation
Solution Approach 1:
The button body's material parameters are specifically selected to exhibit frequency-dependent mechanical properties. At low frequencies (intentional pressing), the material behaves relatively rigidly for efficient force transmission. At high frequencies (accidental shocks), the material becomes more compliant and dissipative, absorbing shock energy. This parameter change with frequency allows the same structure to serve both force transmission and shock protection functions.
Solution Approach 2:
A composite material structure combining materials with different mechanical properties is used in the button assembly. This composite structure provides the necessary rigidity for force transmission during normal operation while incorporating damping components that absorb and dissipate shock forces, preventing their transmission to the drive mechanism and elimination of accidental dose ejection.
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
Prevents accidental medication ejection and reduces noise by absorbing shock forces and damping vibrations, ensuring safe and quiet operation of drug delivery devices.
Implementation Method 1
a resilient member, wherein the plate-like button body or the sleeve-like button body is movable into a longitudinal direction relative to the support element against the tension of the resilient member
Implementation Method 2
the plate-like button body and/or the axially elongated member or the sleeve-like button body comprises a material composite with at least one third material component consisting of a third material and at least one fourth material component consisting of a fourth material different from the third material
Implementation Method 3
a shock deactivation mechanism preventing movement of the plate-like button body or the sleeve-like button body relative to the support element or preventing transmission of a shock force to the driven element
Data Source
AI summary
A button for a drug delivery device with a reduced operating loudness includes a plate-like button body forming a touch surface, wherein the plate-like button body is coupled by an axial supporting member to a noise-generating interface of the drug delivery device and movable into a longitudinal direction of the drug delivery device, wherein the plate-like button body includes a material composite with at least one first component consisting of a first material and at least one second component consisting of a second material different from the first material, wherein the at least one first component and the at least one second component are coupled via at least one coupling plane that is at least section wise slanted or perpendicular to the longitudinal direction. Further, the disclosure describes a button assembly for a drug delivery device which is shock resistant.