Auto-injector Locking Clip Subassembly Assembly
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Solution Overview
Problem
Existing drug delivery devices, such as auto-injectors, face challenges in secure assembly and needle protection mechanisms, which can lead to accidental needle exposure and improper device usage.
Innovation Solution
A drug delivery device design featuring a subassembly locking mechanism using a C-shaped locking clip and rib/ groove configuration, along with a needle shield system, ensures secure assembly and automatic needle protection after use, preventing accidental exposure and ensuring proper device operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is added to secure subassemblies, then assembly reliability is improved, but device complexity increases
Solution Approach 1:
The device is divided into separate subassemblies (first subassembly with syringe holder and second subassembly with drive assembly) that can be assembled and locked independently. The locking clip provides a localized securing mechanism without requiring complex integration across the entire device.
Solution Approach 2:
The locking clip acts as an intermediary component between the first and second subassemblies. It provides a simple mechanical interface that secures the subassemblies together without requiring complex bonding or integration mechanisms.
2Object-affected harmful factors
If a needle shield system is implemented, then safety is improved, but device complexity increases
Solution Approach 1:
The needle shield is pre-positioned to cover the needle before use. The cap and needle cover are assembled in a predetermined configuration that automatically provides protection, eliminating the need for additional active shielding mechanisms during operation.
Solution Approach 2:
The needle shield function is merged with the cap and needle cover components. These elements serve both as protective shields and as structural parts of the device housing, reducing the need for separate dedicated shielding components.
3Reliability
If multiple locking features (ribs and grooves) are added, then assembly security is improved, but manufacturing complexity increases
Solution Approach 1:
The locking features are segmented into discrete ribs on one component and corresponding grooves on another component. This segmentation allows each feature to be manufactured independently using standard molding or machining processes, simplifying production despite the increased number of features.
Data Source
AI summary
A drug delivery device includes a first subassembly having a cap, a needle cover, a syringe holder configured to receive a syringe assembly, a cassette body, and a lower housing shell, with the cap receiving at least a portion of the needle cover, a second subassembly, including a drive assembly configured to move a stopper of a syringe assembly, and a motor body, with the motor body receiving at least a portion of the drive assembly and the cassette body of the first subassembly configured to receive at least a portion of the motor body, and a locking clip configured to secure the first subassembly to the second subassembly upon assembly of the first subassembly to the second subassembly.