Autoinjection Device Safety Latch and Needle Shrouding Mechanism
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Solution Overview
Problem
Reusable autoinjection devices require simple and consistent loading, priming, firing, and unloading processes, while ensuring safety against inadvertent operation and effective needle shrouding after use.
Innovation Solution
An autoinjection device with a housing and drive mechanism that includes a moveable front body portion, a drive member, and trigger mechanism, featuring a safety latch and lockout mechanism to prevent accidental operation, and a contact element with lobes to facilitate injection by compressing the skin on either side of the needle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the autoinjection device is designed for reuse with manual loading and priming, then environmental sustainability is improved, but the risk of inadvertent operation and user error increases
Solution Approach 1:
The device requires the front body portion to be moved rearwardly before the drive member can be primed, establishing a preliminary action sequence that prevents inadvertent operation. The safety latch means must be released before the drive member can be actuated, creating a deliberate multi-step process that reduces user error while managing complexity through structured operation sequences.
2Ease of operation
If the front body portion is made moveable for loading and priming, then ease of operation is improved, but the risk of accidental firing increases
Solution Approach 1:
The safety latch means acts as an intermediary between the moveable front body portion and the drive member. It mediates the interaction by requiring deliberate release before the drive member can be primed, allowing easy loading and priming operations while preventing accidental firing through this intermediate safety mechanism.
3Reliability
If a safety latch mechanism is added to prevent inadvertent operation, then reliability is improved, but device complexity increases
Solution Approach 1:
The safety latch means is merged with the existing moveable front body portion and drive member mechanisms. The latch integrates with the longitudinal movement system, combining safety functionality with the loading and priming operations rather than adding completely separate components, thereby improving reliability while minimizing increases in overall device complexity.
4Ease of operation
If the drive member is made easily releasable for priming, then ease of operation is improved, but the risk of premature injection increases
Solution Approach 1:
The moveable front body portion must be actuated rearwardly as a preliminary action before the drive member can be primed. This preliminary movement initiates the priming sequence but does not complete it, requiring additional deliberate actions to actually inject. This structured sequence enables easy priming operation while preventing premature injection through the multi-step process.
Data Source
AI summary
An autoinjection device includes a main body 12 in the front end of which is slideably mounted a drawer or front body portion 14. The drawer can be opened to remove or insert a syringe. Closing the drawer while pressing a multifunction button 22 primes the drive mechanism 54, 58 by latching it against trigger latch 66. Pressing the button 22 again while urging the front end causes the drawer to release the trigger latch 66. After the injection the drawer shrouds the used needle and can be released only by pressing the button 22.