Dose Dial Add-On Coupling for Easy Mounting and Secure Engagement
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Solution Overview
Problem
Existing drug delivery devices lack efficient and secure mounting mechanisms for user-mountable add-on devices, particularly for those with impaired dexterity, and do not effectively automate dose logging and monitoring.
Innovation Solution
The solution involves a drive portion that can be mounted on the dose setting member in a rotationally non-engaged state, allowing easy and secure attachment, with a biased rotationally sliding engagement that locks into place when aligned with a drive groove, and includes a sensor system to detect dose amounts using magnetic fields from dipole magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional mechanical coupling with multiple engaging spline structures is used, then the rotational coupling between add-on device and dose setting member is secure, but the mounting becomes difficult and time-consuming, especially for users with impaired dexterity
Solution Approach 1:
The coupling mechanism is divided into two functional parts: a mounting portion that provides axial alignment and a drive portion with flexible drive structures that engage the drive groove. This segmentation allows the mounting operation to be simplified while maintaining secure rotational coupling through the flexible drive structures.
Solution Approach 2:
The drive structures are designed to be flexible and capable of deforming elastically. This parameter change from rigid to flexible allows the drive structures to automatically adjust during mounting, engaging the drive groove without requiring precise rotational alignment, thereby simplifying the mounting process while ensuring reliable coupling.
2Reliability
If a rigid mechanical coupling structure is used, then the rotational engagement is precise and reliable, but the mounting process requires complex alignment procedures and multiple engaging structures
Solution Approach 1:
The coupling is segmented into a mounting portion for axial positioning and a drive portion for rotational engagement. This reduces the complexity of the overall structure by separating functions, allowing each part to be optimized independently.
Solution Approach 2:
The drive structures are designed to be flexible rather than rigid, allowing them to deform and adapt during the engagement process. This dynamic characteristic simplifies the coupling structure by eliminating the need for multiple rigid alignment features while maintaining reliable engagement.
3Strength
If multiple spline structures are used for rotational coupling, then the torque transmission is secure, but the mounting time increases and user effort increases
Solution Approach 1:
The drive structures are designed with elastic flexibility, allowing them to deform during mounting and automatically engage the drive groove without requiring multiple alignment attempts. This reduces mounting time while maintaining sufficient torque transmission capability through the flexible engagement.
Solution Approach 2:
The flexible drive structures automatically self-align and engage with the drive groove during the axial mounting process, eliminating the need for manual rotational alignment. This self-service mechanism reduces both mounting time and user effort while ensuring secure torque transmission.
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 arrangement facilitates easy, secure, and efficient operation of add-on devices, enabling accurate dose setting and logging, even for users with impaired dexterity, by ensuring reliable rotational coupling and dose detection.
Implementation Method 1
the sensor means comprises a plurality of magnetometers arranged non-rotational relative to the housing in a mounted state and adapted to determine magnetic field values from the plurality of dipole magnets
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
An assembly comprising a drug delivery device and an add-on device adapted to be releasably mounted thereon, the drug delivery device comprising a rotatable dose setting member with an outer surface and at least one axially oriented drive groove. The add-on device comprises a drive portion adapted to be mounted in engagement with the dose setting member and comprises a drive structure adapted to engage a drive groove and being biased in a radially inwards direction. This arrangement allows the drive structure to rotationally slide on the dose setting member outer surface and into engagement with the drive groove(s).