Auto-injector Needle Cover Lever Actuation Integration
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Solution Overview
Problem
Existing drug delivery devices, such as auto-injectors, often require complex assembly and lack efficient mechanisms for needle protection and user-friendly operation, particularly in preventing unintended needle contact and ensuring proper actuation.
Innovation Solution
A drug delivery device with a housing containing a syringe assembly, a drive assembly, and a needle cover that moves between pre-use, actuation, and post-use positions, using a lever actuation member and a spring mechanism to facilitate automatic needle deployment and protection, allowing for easy user operation while preventing unintended actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a needle cover mechanism is added to protect the cannula, then safety is improved, but device complexity increases
Solution Approach 1:
The needle cover is merged with the lever actuation member into a single integrated component. The lever actuation member serves dual functions: it acts as the actuating lever for the drive assembly and simultaneously serves as the needle cover that protects the cannula. This integration eliminates the need for separate needle cover and actuation mechanisms, thereby improving safety while avoiding additional complexity.
Solution Approach 2:
The lever actuation member is designed to perform multiple functions: (1) it serves as the actuating lever that triggers the drive assembly, (2) it functions as the needle cover protecting the cannula, and (3) its movement coordinates both the actuation sequence and needle exposure/treatment sequence. This multi-functionality resolves the contradiction by consolidating safety and actuation functions into one component.
2Ease of operation
If automatic needle deployment is implemented, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The device is pre-configured with the lever actuation member in a locked position that automatically prevents premature actuation. When the user pulls the lever, the drive assembly is pre-loaded and immediately deploys the needle and administers the injection automatically. This preliminary preparation enables automatic deployment with a simple user action, improving ease of operation while the automation sequence is managed by the pre-configured mechanical system.
Solution Approach 2:
The drive assembly is designed to automatically execute the injection sequence once triggered by the lever actuation member. The system self-manages the needle deployment, drug delivery, and needle retraction without requiring additional user interventions. The lever simply initiates the process, and the mechanical system completes the entire injection sequence autonomously, balancing automation with simplicity.
3Device complexity
If the lever actuation member is integrated with the needle cover, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The lever actuation member is designed with distinct functional segments: a lever portion for user actuation, a contact surface for engaging the drive assembly, and a needle cover portion for protecting the cannula. This segmentation allows each portion to be optimized for its specific function while maintaining overall integration, thereby reducing the integrated component's complexity without significantly increasing manufacturing precision requirements.
Solution Approach 2:
Different portions of the lever actuation member have different geometric and material properties optimized for their local functions. The lever portion has ergonomic shaping for user interaction, the contact surface has precise geometric features for mechanical engagement, and the needle cover portion has dimensions tailored to fit and protect the cannula. This local optimization allows the integrated component to achieve multiple functions with moderate overall manufacturing precision requirements.
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 device ensures safe and efficient drug delivery with automatic needle protection, reducing the risk of needle contact and simplifying user interaction, while maintaining compactness and the ability to inject high viscosity drugs.
Implementation Method 1
The drive member may be a compression spring
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3~4
AI summary
A drug delivery device includes a housing, a syringe assembly comprising a barrel, a stopper, and a cannula,withat least a portion of the syringe assembly positioned within the housing, a drive assembly configured to move the stopper within the barrel upon actuation of the drive assembly, with at least a portion of the drive assembly positioned within the housing, a lever actuation member moveable between a locked position where actuation of the drive assembly is prevented and a released position where actuation of the drive assembly is allowed, and a needle cover having a pre-use position where the cannula is positioned within the needle cover, an actuation position where the needle cover is configured to actuate the drive assembly, and a post- use position where the cannula is positioned within the needle cover. The needle cover is configured to engage the lever actuation member and move the lever actuation member to the released position when the needle cover is in the actuation position.