Autoinjector Planetary Gear Delay Mechanism
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Solution Overview
Problem
Current autoinjectors face challenges such as accidental triggering during transport or use, difficulty in ensuring complete fluid delivery, proper needle depth control, and user safety, particularly for elderly or disabled individuals, along with issues related to needle safety and the need for reliable indicators to prevent premature device removal.
Innovation Solution
The autoinjector design incorporates a locking mechanism to prevent accidental activation, a flexible actuator sleeve with radial and lateral deformation for secure needle insertion and retraction, and a delay device to ensure complete fluid delivery, combined with visual and tactile indicators to inform the user of injection completion, enhancing user safety and ease of use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reliable locking means are included to prevent accidental triggering, then safety is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is segmented into multiple independent components: a locking element with locking and unlocking positions, a control element for actuating the locking element, and a trigger element with a predefined activation force. This segmentation allows each component to perform its specific function reliably while keeping the overall design manageable and not excessively complex.
2Reliability
If the injection time is extended to ensure complete fluid delivery, then reliability of fluid delivery is improved, but user convenience deteriorates
Solution Approach 1:
The device includes an indication element that automatically signals to the user when the injection is complete. This self-service feature eliminates the need for the user to manually time or monitor the injection process, providing clear feedback when it is safe to remove the device, thus maintaining reliability of fluid delivery while improving user convenience.
3Reliability
If the needle remains inserted after injection to ensure complete fluid delivery, then fluid delivery reliability is improved, but user safety deteriorates
Solution Approach 1:
The retraction mechanism is pre-configured to automatically activate after the injection is complete, as signaled by the indication element. This preliminary preparation ensures that the needle retracts promptly after fluid delivery is complete, eliminating the need for the user to manually operate the device and ensuring both complete fluid delivery and user safety.
4Measurement precision
If a planetary gear set is used for time delay mechanism, then precision of delay timing is improved, but device complexity increases
Solution Approach 1:
The planetary gear set acts as an intermediary mechanism between the trigger element and the retraction mechanism. It provides precise time delay through its inherent mechanical gear ratios while translating the trigger activation into controlled retraction motion. This intermediary approach achieves accurate timing without requiring complex electronic controls or multiple separate mechanical components.
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 ensures reliable and safe autoinjection with complete fluid delivery, proper needle placement, and user safety, addressing the challenges of accidental triggering and user error, while being cost-effective and easy to manufacture.
Implementation Method 1
a delay device in the form of a planetary gear set (16, 17)
Implementation Method 2
a flexible actuator sleeve with radial and lateral deformation for secure needle insertion and retraction
Data Source
Figure 1
Figure 2a~2f
Figure 3a~3c
AI summary
The invention relates to an autoinjector comprising a lower body (10) that receives a barrel, said barrel containing fluid product and comprising a plunger and a needle, such as a pre-filled syringe (A). The autoinjector comprises: injection means (5, 8) for injecting the fluid product through the needle when the needle is in the injection position; a barrel movement device (2, 4, 9) for retracting the needle from the user's body following injection of the fluid product; and a trigger (19) actuated by the injection means, actuating the barrel movement device (2, 4, 9) following injection of the fluid product in order to retract the needle. The autoinjector also comprises a time delay device (15, 16, 17) which can delay the actuation of the barrel movement device (2, 4, 9) by the trigger (19) following injection of the fluid product by a pre-determined time, in order to delay the retraction of the needle by said pre-determined time after the end of the injection.