Segmented Stopper Assembly for Post-Sterilization Electronics
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Solution Overview
Problem
Existing medical injection devices face challenges in sterilizing components with integrated electronics due to high-temperature manufacturing processes, which can degrade temperature-sensitive materials and affect dosing precision, alignment, and container closure integrity.
Innovation Solution
A stopper design with a shell and insert configuration, where the insert contains electronic components, allowing assembly post-sterilization, and features like snap-fit elements, stepped interfaces, and venting channels to ensure proper alignment and air expulsion, maintaining dosing precision and container integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature sterilization is applied to components with integrated electronics, then sterilization effectiveness is improved, but temperature-sensitive materials are degraded and dosing precision is affected
Solution Approach 1:
The stopper is divided into two separate components: a shell that can withstand sterilization and an insert containing electronics that is assembled after sterilization. This segmentation allows each component to be treated according to its specific requirements, resolving the contradiction between sterilization effectiveness and protection of temperature-sensitive materials.
Solution Approach 2:
The shell is sterilized in advance before the insert is assembled into it. This preliminary sterilization action ensures that the sterilization process is completed before any temperature-sensitive electronic components are introduced, eliminating the risk of thermal damage while maintaining sterilization effectiveness.
2Reliability
If high-temperature sterilization is applied to components with integrated electronics, then sterilization effectiveness is improved, but container closure integrity is affected
Solution Approach 1:
The stopper assembly is segmented into a sterilizable shell and a post-assembled insert. This allows the shell to undergo high-temperature sterilization without exposing the electronic insert to damaging temperatures, thereby maintaining both sterilization effectiveness and container closure integrity.
Solution Approach 2:
The shell is sterilized before the insert is installed. This preliminary action ensures that the sterilization process occurs when only heat-resistant materials are present, preventing thermal degradation that would compromise container closure integrity while still achieving effective sterilization.
3Ease of manufacture
If insert is inserted into shell cavity, then assembly is completed, but air and fluid may be trapped in the cavity
Solution Approach 1:
The convex surface at the closed end of the shell cavity provides a visual and tactile indicator of proper insert insertion. When the insert is correctly positioned, the convex surface ensures complete insertion while allowing trapped air and fluid to be expelled through the cavity design, preventing harmful entrapment.
Solution Approach 2:
The cavity design with inwardly tapering sidewalls and a convex surface at the closed end creates a mechanism that extracts or expels trapped air and fluid during the insertion process. The geometry of the cavity forces air and fluid out as the insert is pushed in, preventing harmful entrapment.
4Strength
If snap-fit feature is used to retain insert, then retention is achieved, but insertion force may cause radial deflection
Solution Approach 1:
The retention mechanism is segmented into a snap-fit feature that provides strong retention while allowing controlled deflection. The snap-fit design enables the insert to be retained securely without requiring excessive insertion force that would cause radial deflection and misalignment.
Solution Approach 2:
The snap-fit feature utilizes flexible deformation of the shell material during insertion. The shell temporarily deforms to accommodate the insert, then springs back to retain it securely. This flexibility allows strong retention while minimizing permanent radial deflection and maintaining alignment precision.
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 ensures effective sterilization of electronic components while maintaining dosing precision, alignment, and container closure integrity, enhancing the functionality of medical injection devices.
Implementation Method 1
the closed end of the shell in the cavity defines a convex surface configured to be contacted and deflected by the insert upon insertion into the cavity, and wherein the closed end of the shell is made of an elastic and/or plastic deformable material
Implementation Method 2
The cavity may comprise an interior step element, and the insert may comprise a corresponding step element configured to abut the interior step element of the shell and distribute at least a portion of the force from the plunger rod to the interior step element
Implementation Method 3
The cavity may define a snap-fit feature extending into the cavity, the snap-fit feature configured to retain the insert in the cavity by being deflected or deformed by the insert during insertion of the insert into the cavity until the snap-fit feature relaxes into a corresponding depression in the insert
Data Source
AI summary
A stopper for use in a cartridge or syringe of a medical device is configured to be disposed within a container closure system. The stopper comprises a shell comprising a closed end and an open end with sidewalls extending between the closed end and the open end along a longitudinal axis of the shell. The open end defines a cavity and the sidewalls define an exterior surface sized and shaped to fit inside the container closure system. An insert is configured to be inserted into the cavity, receive a force from a plunger rod, and distribute the force to the shell in order to advance the shell into the container closure system. The closed end of the shell in the cavity defining a convex surface configured to be contacted and deflected by the insert upon insertion into the cavity includes an elastic and/or plastic deformable material.