Safety Needle Cover Mechanism for Prefilled Injection Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Prefilled injection devices pose a risk of accidental needle pricks due to the unprotected needle before and after use, and there is a need to prevent further injections once the dose is completed.
Innovation Solution
A medical injection device with a needle cover that moves between storage, injection, and safety positions, where the needle is only accessible for injection and then securely covered, using a plunger mechanism to transition the needle cover from injection to safety position after the full dose is administered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the needle is left free and unprotected before and after injection, then the device is easy to operate and the needle is accessible for injection, but the risk of accidental needle pricks increases and user safety deteriorates
Solution Approach 1:
The needle cover is pre-positioned to cover the needle in the storage state, and is designed to be automatically or manually retracted before injection to expose the needle. This preliminary protective action eliminates accidental prick risks during storage and transport while ensuring needle accessibility when needed.
Solution Approach 2:
The needle cover is designed as a dynamic component that can move between different positions: covering the needle in storage, exposing the needle during injection, and potentially returning to cover or being locked in a safe position after injection. This dynamic behavior resolves the contradiction between protection and accessibility.
2Ease of operation
If the needle cover can be moved freely between positions, then the device is flexible and easy to operate, but the risk of incomplete injection or premature locking increases
Solution Approach 1:
The device incorporates a feedback mechanism where the plunger's position or movement triggers the needle cover to transition to the safety position only after the injection is complete. This feedback ensures that the needle is protected only when the full dose has been delivered, preventing premature locking while maintaining operational flexibility.
Solution Approach 2:
The needle cover system is designed to automatically transition to the safety position based on the injection status, eliminating the need for manual intervention to ensure proper sequencing. The device self-regulates to prevent incomplete injections or premature needle coverage.
3Reliability
If a safety mechanism is added to prevent accidental pricks and ensure complete injection, then safety and reliability are improved, but the device complexity increases
Solution Approach 1:
The safety mechanism is merged with the existing plunger and needle cover components. The plunger's axial movement, which is necessary for injection, is coupled with the needle cover's radial or axial movement to trigger the safety position. This integration adds safety functionality without requiring entirely separate mechanical systems.
Solution Approach 2:
The needle cover serves multiple functions: protecting the needle during storage, exposing it for injection, and providing a safety lock after injection. By making the needle cover multi-functional, the design avoids adding separate components for each function, thereby limiting the increase in device complexity.
Data Source
AI summary
A medical injection device for supporting a medical container, the medical container comprising a barrel adapted to contain a composition and a needle extending from a distal end of the barrel, wherein the medical injection device comprises: a body configured to receive at least a part of the medical container, a plunger axially movable relative to the body along an axis of the body, needle cover movable relative to the body along the axis, the needle cover being configured to move successively between storage position wherein the needle cover covers the needle, an injection position wherein the needle cover exposes at least partially the needle, a safety position wherein the needle cover covers the needle and is prevented from moving back to the injection position.