Autoinjector Locking Mechanism Prevents Accidental Triggering
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Solution Overview
Problem
Current autoinjectors face challenges in preventing accidental triggering, ensuring reliable and complete fluid delivery, maintaining needle safety, and providing user feedback on injection completion, particularly for elderly or disabled users, while being cost-effective and easy to manufacture.
Innovation Solution
The autoinjector design incorporates a locking mechanism with a flexible actuator sleeve that requires a specific force for activation, a delay device for post-injection retention, and visual/tactile indicators to signal injection completion, ensuring safe and complete delivery of the fluid while preventing needle exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is implemented to prevent accidental activation, then reliability is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is segmented into modular components: a cover that can be removed to unlock the device, and an internal lock that engages with the actuator sleeve. This segmentation allows the locking function to be distributed across simple, independent parts rather than a single complex mechanism, reducing overall device complexity while maintaining reliability.
Solution Approach 2:
The device is prepared in a locked state during manufacturing and transport, with the cover serving as a preliminary protective barrier. This preliminary locking action prevents accidental activation before the device is ready for use, and the lock is designed to be easily disengaged only after the cover is intentionally removed by the user.
2Reliability
If the locking mechanism is made more secure, then reliability is improved, but ease of operation deteriorates
Solution Approach 1:
The locking function is extracted into a separate removable cover that can be easily taken off by the user. This separates the security function from the activation mechanism, allowing the lock to be secure during transport while being simple to disengage when needed. The cover acts as an independent element that can be removed without requiring complex manipulation of the internal locking components.
Solution Approach 2:
The locking system transitions from a static locked state to a dynamic unlocked state through the simple action of removing the cover. This dynamic approach allows the device to adapt between secure transport mode and easy-to-use injection mode, with the locking mechanism responding to the user's intentional action of cover removal rather than requiring complex unlocking procedures.
3Reliability
If the injection time is extended to ensure complete fluid delivery, then reliability is improved, but loss of time increases
Solution Approach 1:
The device incorporates visual feedback through a window that allows the user to observe the piston moving and the fluid being delivered. This feedback mechanism provides real-time confirmation that the injection is progressing and completing, allowing the user to understand the actual duration needed without relying on fixed timing instructions. The feedback ensures complete delivery while minimizing unnecessary waiting time.
4Ease of manufacture
If manual instructions are provided for post-injection retention time, then ease of manufacture is improved, but reliability deteriorates
Solution Approach 1:
The device provides its own timing function through the visible piston movement and fluid delivery process observed through the window. Instead of relying on external manual instructions that require user comprehension and execution, the device itself communicates the timing information through its operation. The user can see when the injection completes and naturally understands when to remove the device, eliminating the need for separate timing instructions while ensuring consistent retention time.
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 enhances user safety by preventing accidental triggering, ensuring complete fluid delivery, and providing clear feedback on injection completion, while maintaining cost-effectiveness and ease of manufacturing.
Implementation Method 1
a spring (12) forcing said actuator sleeve (11) to return from its activated position to its second projected position
Implementation Method 2
said flexible leg (110) is adapted to deform radially when said actuator sleeve (11) is moved from its initial projected position to its activated position, and to deform laterally when said actuator sleeve (11) is moved from its activated position to its second projected position
Data Source
Figure 1
Figure 2a~2f
Figure 3a~3c
AI summary
Auto-injector comprising an outer casing (1022), a reservoir, a piston rod (1005), an injection spring (1008), a moving element (1004; 1006), said piston rod (1005) being movable relative to said moving element (1004; 1006) during the injection phase, an audible and/or tactile indicator device (1500) comprising a key (1120), said key comprising a rod portion (1120) extending inside the piston rod (1005), and a head portion (1122), said moving element comprising at least one deformable tab (1510; 1520), said head portion (1122) of said key (1120) cooperating before injection with said at least one deformable tab (1510; 1520), said piston rod (1005), at the end of injection, exerting via said shaft part (1121) of said key (1120) a pull on said head part (1122) of said key (1120), causing the displacement of said key (1120) relative to said at least one deformable leg (1510;1520), thus allowing a radial deformation of said at least one deformable leg (1510; 1520) and an axial displacement of said moving element (1004; 1006) under the effect of said injection spring (1008), said displacement generating an audible and/or tactile indication for the user.