Drug Delivery Safety Mechanism With Automatic Needle Cover
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Solution Overview
Problem
Existing drug delivery devices, particularly semi-reusable autoinjectors, pose a risk of needle stick injuries due to the need for users to manually handle and detach the reservoir unit, exposing them to the needle before and after injection, and require additional components for needle protection that complicate design and disposal.
Innovation Solution
A safety mechanism for drug delivery devices with a reusable drive unit and disposable reservoir unit, featuring a cap with an elastically deformable holding member that securely covers the needle before and after injection, allowing easy attachment and detachment without additional handling steps, using a mechanical drive and gear element to ensure needle protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the reservoir unit is manually handled and detached from the drive unit, then the user can attach and detach the reservoir unit, but the user is exposed to the needle before and after injection increasing the risk of needle stick injuries
Solution Approach 1:
The needle cover is pre-positioned to automatically cover the needle when the reservoir unit is detached from the drive unit. This preliminary action ensures that the needle is covered before the user can accidentally contact it, eliminating the need for additional manual steps to protect the user during detachment.
2Object-affected harmful factors
If additional needle protection components are added to the device, then the needle is protected from accidental contact, but the device complexity increases
Solution Approach 1:
The needle cover function is merged with the existing reservoir unit structure. The holding member that secures the reservoir unit to the drive unit is integrated with the needle cover, so that a single component serves both the securing function and the needle protection function, avoiding additional separate components.
Solution Approach 2:
The holding member is designed to perform multiple functions: it secures the reservoir unit to the drive unit during injection and simultaneously acts as a needle cover when the reservoir unit is detached. This multi-functionality eliminates the need for separate needle protection components.
3Object-affected harmful factors
If the needle cover is designed to stay attached to the reservoir unit, then the needle remains covered after injection, but the user cannot easily detach the reservoir unit from the drive unit
Solution Approach 1:
The holding member is designed with elastic deformability, allowing it to dynamically change its state. When detachment force is applied, the holding member deforms to release the reservoir unit from the drive unit. After detachment, the holding member returns to its original position, maintaining the needle cover function.
Solution Approach 2:
The holding member's mechanical properties are designed to change under different conditions: it maintains a secure attached state during normal operation but transitions to a released state when sufficient detachment force is applied. This parameter change enables both secure attachment and easy detachment while maintaining needle protection.
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 mechanism ensures the needle is securely covered throughout the injection process, preventing accidental needle contact and simplifying user handling, while reducing waste and resource consumption by allowing for easy disposal of the reservoir unit.
Implementation Method 1
The holding member is adapted to hold the cap on the distal end portion when the holding member is in an undeformed state and to release the cap from the distal end portion when the holding member is in a deformed state
Implementation Method 2
the actuation member is adapted to elastically deform the holding member of the cap in a circumferential direction, when the reservoir unit reaches the end position, such that the cap can be separated from the distal end portion
Data Source
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AI summary
The present invention relates to a safety mechanism for a drug delivery device for dispensing a liquid drug from a reservoir through a needle, the safety mechanism comprising a drive unit and a reservoir unit adapted to hold the reservoir and releasably attachable to the drive unit. The drive unit comprises a drive unit housing defining a longitudinal axis, a plunger movable inside the drive unit housing in a dispensing direction to dispense the liquid drug and a mechanical drive, preferably a compression spring, arranged inside the drive unit housing for moving, when loaded, the plunger in the dispensing direction. The reservoir unit comprises a reservoir unit housing and a cap releasably attachable to a distal end portion of the reservoir unit housing, wherein the cap comprises a deflectable holding member adapted to hold the cap on the distal end portion. The reservoir unit is insertable into the drive unit housing from a distal end of the drive unit housing until it reaches an end position within the drive unit housing. According to the invention the drive unit housing comprises an actuation member adapted to elastically deform the holding member of the cap in a circumferential direction, when the reservoir unit reaches the end position, such that the cap is released from the distal end portion.