Autoinjector Protective Means Prevents Accidental Activation
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Solution Overview
Problem
Autoinjectors with small round flanges fail to prevent accidental activation during drop tests due to the inability of the medical container to abut against abutment protrusions, leading to potential unintended triggering of the injection mechanism.
Innovation Solution
Incorporation of protective means with auto-engaging shapes between the locker and the housing, which increase the contact area and prevent the locker from inadvertently unlocking during impacts, ensuring the autoinjector remains in a deactivated state even when dropped 'cap upward'.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a small round flange is used on the medical container, then interference with the safety shield mechanism is avoided, but the ability to abut against abutment protrusions is lost
Solution Approach 1:
The patent introduces a protective means as an intermediary element between the locker and the housing. This protective means has an auto-engaging shape that couples to the locker and engages with the housing, serving as a mediator to provide the necessary abutment function that the small round flange cannot provide. The protective means transfers the abutment force from the housing to the locker, preventing accidental activation while maintaining compatibility with small round flanges.
2Ease of operation
If the medical container is allowed to move freely during a drop, then no interference with injection mechanism occurs, but accidental activation may be triggered
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring the protective means with an auto-engaging shape that is designed to counteract the harmful effects of dropping. The protective means is positioned and shaped in advance to engage with the housing and prevent the locker from moving during a drop, thereby preventing accidental activation before it can occur.
3Reliability
If abutment protrusions are provided in the housing, then medical container movement is prevented, but small round flanges cannot abut against them
Solution Approach 1:
The protective means serves as an intermediary that bridges the gap between the housing and the small round flange. Instead of requiring the small round flange to directly abut against the abutment protrusions, the protective means engages with both the housing and the locker, transferring the abutment function to an element that can accommodate small round flanges.
4Ease of operation
If the locker is designed to rotate and move away from the abutment surface during normal use, then injection activation is enabled, but inadvertent unlocking may occur during drops
Solution Approach 1:
The protective means is designed with differentiated local qualities: it has an auto-engaging shape that provides strong engagement with the housing to prevent accidental unlocking during drops, while simultaneously allowing controlled rotation and movement during normal activation. The local geometry of the protective means enables it to be restrictive in one context (drops) and permissive in another (normal use).
Data Source
AI summary
The autoinjector includes a housing configured to receive a medical container having a barrel defining a reservoir for containing a medical product, and said barrel having a distal end provided with a needle and an opened proximal end configured to receive a plunger rod for pushing a stopper arranged inside the barrel. The autoinjector also includes a needle cover coupled to and movable with respect to said housing between a first extended position, a retracted position, and a second extended position, an injection mechanism configured to move the plunger rod distally inside the barrel in order to expel the medical product contained inside the barrel, and a holder movable with respect to the housing between a passive position wherein the holder does not trigger the injection mechanism and an active position wherein the holder triggers the injection mechanism. A locker is coupled to the holder and is movable with regard to the housing between a locking position, thereby preventing the holder from moving to the activated position, and an unlocking position, allowing the holder to move to the activated position. Protective means are configured to prevent the locker from inadvertently damaging and passing by the first abutment surface if the autoinjector falls down onto a floor, proximal end first.