Low Friction Dose Encoder on Pen Injection Thread
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Solution Overview
Problem
Existing pen-type drug delivery devices face challenges in accurately determining the relative position of components during dose setting and delivery, leading to potential errors in insulin administration, especially for self-administering patients with diabetes who need to adjust insulin doses based on individual blood glucose levels.
Innovation Solution
A drug delivery device featuring a conductive track pattern on the thread features of one component and contacts on the other, allowing for precise determination of the relative position without significant additional resistance, enabling accurate dose setting and delivery while minimizing frictional forces during axial movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conductive track pattern is formed on the thread features to enable position detection, then measurement precision is improved, but frictional resistance during axial movement increases
Solution Approach 1:
The conductive track pattern is extracted and formed only on specific portions of the thread features (the engaging faces) rather than the entire surface. This selective placement allows position detection functionality to be added while minimizing the additional frictional resistance, as the conductive material is applied only where contacts are made during rotation, not across the full axial movement path.
Solution Approach 2:
The thread features are given different local properties: the engaging faces have conductive track patterns for position detection, while other portions maintain their original mechanical properties for low-friction axial movement. This local differentiation allows the system to simultaneously achieve precise position measurement and minimal friction during the axial movement phase.
2Strength
If the body component and sleeve engage through thread features with engaging faces, then mechanical coupling is improved, but friction during axial movement increases
Solution Approach 1:
The thread features are segmented into distinct functional zones: engaging faces that provide mechanical coupling strength through threaded engagement, and non-engaging surfaces that minimize friction during axial movement. The conductive track pattern is applied only to the engaging faces, separating the position detection function from the friction-generating axial movement surfaces.
Data Source
AI summary
A drug delivery device comprises a body component located concentrically within a sleeve, wherein the body component comprises body component thread features and the sleeve comprises sleeve thread features that engage with the body component thread features such that the body component is caused to rotate within the sleeve as the body component and the sleeve component move axially with respect to one another by force of an engaging face of the sleeve thread features against an engaging face of the body component thread features causing sliding of the engaging face of the sleeve thread features over the engaging face of the body component thread features. One of the body component and the sleeve constitutes a first part and the other of the body component and the sleeve constitutes a second part. A conductive track pattern is formed on the thread features of the first part and plural contacts are formed on the second part such as to contact the conductive track pattern as the body component rotates within the sleeve.