Autoinjector Needle Guard Axial Locking Mechanism
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Solution Overview
Problem
Current autoinjectors are complex, costly, and environmentally impactful due to their multi-component design and material usage, which complicates manufacturing, assembly, and storage, especially when requiring low temperatures.
Innovation Solution
A compact autoinjector design with a simplified mechanism using a housing, a pre-filled syringe, and a needle guard that moves axially between storage, dispensing, and lock-out states, featuring a drive chassis with trigger arms and a lock-out spring to engage and disengage the needle guard, reducing the number of components and enhancing protection against accidental needle pricks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-component design is used in autoinjectors, then the device can achieve reliable needle protection and dispensing functionality, but the manufacturing complexity, assembly complexity, and material usage increase
Solution Approach 1:
The patent combines multiple functions into the needle guard component, which integrates needle protection, state indication (through position changes between storage, dispensing, and lock-out states), and engagement mechanisms (via clip arms that interact with the housing). This merging reduces the number of separate components while maintaining reliable needle protection functionality.
Solution Approach 2:
The needle guard serves multiple functions: it protects the needle in the storage state, enables dispensing when moved to the dispensing state, and provides lock-out protection after use. The clip arms provide both mechanical engagement and state indication functions. This multi-functionality reduces overall device complexity while maintaining reliability.
2Reliability
If a multi-component design is used in autoinjectors, then the device can achieve reliable dispensing functionality, but the manufacturing and assembly costs increase
Solution Approach 1:
The drive chassis integrates the dispensing mechanism with the needle guard engagement system. The trigger arms on the drive chassis interact with the clip arms to both secure the needle guard in the storage state and enable reliable dispensing functionality. This merging reduces manufacturing steps and assembly complexity compared to separate components.
3Reliability
If a multi-component design is used in autoinjectors, then the device can achieve reliable needle protection, but the storage and transportation requirements become more complex
Solution Approach 1:
The needle guard integrates needle protection with compact positioning features (clip arms that engage with housing cut-outs) and state indication capabilities. This merging allows reliable needle protection in a more compact configuration, reducing storage volume compared to separate protection mechanisms.
Solution Approach 2:
The needle guard can be positioned in different axial states (storage, dispensing, lock-out) within the housing, effectively nesting the protection mechanism within the existing device volume. This eliminates the need for additional external protection components, reducing storage and transportation requirements.
4Device complexity
If a simplified mechanism is used in autoinjectors, then the material usage and manufacturing complexity are reduced, but the reliability of needle protection may be compromised
Solution Approach 1:
The needle guard is segmented into functional regions: the main body for needle coverage, clip arms for engagement and state indication, and interaction surfaces with the housing. This segmentation allows a simple overall design while maintaining reliable needle protection through specific engineered features at critical locations.
Solution Approach 2:
The needle guard automatically transitions between storage, dispensing, and lock-out states through user interaction, with the clip arms self-engaging with the housing cut-outs. This self-service mechanism provides reliable needle protection without requiring additional active components or complex control systems.
5Volume of stationary object
If a compact design is used in autoinjectors, then the storage and transportation efficiency is improved, but the mechanism complexity may increase
Solution Approach 1:
The needle guard and drive chassis are nested within the housing, with the needle guard axially movable between storage, dispensing, and lock-out states. The clip arms nest within the housing structure when engaged. This nesting achieves compact storage volume without increasing mechanism complexity, as the components utilize existing structural spaces.
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 solution minimizes material usage, reduces manufacturing and assembly complexity, and decreases storage and transportation costs while providing effective needle protection and user safety through a compact, efficient design.
Implementation Method 1
a lock-out spring arranged between the needle guard and the inner body, the lock-out spring being configured to bias the needle guard towards the distal end of the housing
Implementation Method 2
a respective one of the one or more trigger arms is configured to engage a respective one of one or more clip arms of the needle guard on moving the needle guard in the proximal direction between the dispensing state and the lock-out state
Implementation Method 3
a drive spring arranged between the drive chassis and the distal end of the housing, the drive spring being configured to bias the drive chassis towards the pre-filled syringe
Data Source
AI summary
An autoinjector includes a needle guard mounted axially moveable in the housing for movement between a storage state, a dispensing state and a lock-out state in which states the needle guard adopts different axial positions relative to the housing, with the needle guard being configured to be axially moved in a proximal direction between the dispensing state and the lock-out state.