Injection Device Anti-Remounting Axial Stop Mechanism
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Solution Overview
Problem
Existing injection devices allow users to mistakenly remount the cover cap, leading to incorrect assumptions about the sterility of the needle, which can result in faulty applications and potential deformation of safety mechanisms, causing permanent locking issues.
Innovation Solution
The injection device incorporates a mechanism that prevents the cover cap from being remounted on the housing, ensuring the needle protective cap is not detached and reattached, thus maintaining the sterility of the needle and preventing deformation of safety mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cover cap can be removed and remounted on the housing, then the user can easily store or protect the device, but the needle sterility cannot be guaranteed and safety mechanisms may be permanently deformed
Solution Approach 1:
The needle protective cap is extracted as a separate removable component that can be detached from the housing. When the cover cap is removed, the needle protective cap is also removed and carried away, ensuring the needle remains protected and sterile. This extraction principle prevents the needle from being exposed to contamination while allowing easy device storage.
Solution Approach 2:
The mechanism includes preliminary anti-action through the axial stop and axial mating stop configuration. When the cover cap is removed, the axial mating stop moves to a position where it contacts the axial stop, creating a mechanical barrier that prevents remounting. This preliminary prevention mechanism ensures needle sterility is maintained by making remounting physically impossible.
2Ease of operation
If the cover cap can be remounted on the housing, then the device can be protected during storage, but the release safety device mechanism may be permanently deformed causing locking issues
Solution Approach 1:
The mechanism employs preliminary anti-action by positioning the axial stop and axial mating stop such that removal of the cover cap creates an immediate mechanical interference condition. The axial mating stop moves to contact the axial stop, creating a physical barrier that prevents any attempt at remounting, thereby protecting the release safety device from permanent deformation.
Solution Approach 2:
The axial stop and axial mating stop are pre-configured in specific positions within the housing. When the cover cap is removed, these pre-positioned stops automatically engage to prevent remounting before any damage can occur to the safety mechanism. This preliminary arrangement ensures the safety device remains functional.
3Reliability
If a mechanism prevents the cover cap from being remounted, then needle sterility is guaranteed, but the device complexity increases
Solution Approach 1:
The anti-remounting mechanism applies local quality by implementing the axial stop and axial mating stop only in the specific region where the cover cap interfaces with the housing. This localized approach ensures needle sterility through a targeted mechanical prevention system rather than a complex overall device redesign, minimizing added complexity while maintaining reliability.
Data Source
AI summary
An injection device for distributing a liquid product, in particular a medicament, includes: a) a housing with a longitudinal axis (L) and a product container, in particular a syringe, provided in the housing, the product container including a displaceable plunger, where the plunger can be displaced along the longitudinal axis (L) in a distal direction using a propulsion member to distribute the product contained in the product container; b) a cover cap which is mounted on the distal end of the housing and which can be removed from the housing; and c) a mechanism which prevents the cover cap from being remounted on the distal end of the housing.