Medicament Delivery Sub-Assembly With Axial Locking Coupling
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Solution Overview
Problem
Existing medicament delivery devices face issues with unintentional actuation of the plunger rod during transportation due to disengagement of components, leading to potential breakage of protrusions and generation of plastic debris, which can cause operation failures.
Innovation Solution
A sub-assembly design featuring a plunger rod, biasing member, tubular main body, and rotatable coupling member with axial engagement elements that maintain a predetermined relative position, preventing axial movement and reducing the risk of component breakage and debris generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cartridge assembly is designed to be replaceable in an injector, then ease of operation is improved, but device complexity increases due to additional coupling mechanisms
Solution Approach 1:
The device is divided into two main separable components: a reusable injector body and a replaceable cartridge assembly. This segmentation allows the cartridge to be independently replaced without disposing of the entire device, improving ease of operation while managing complexity through modular design.
Solution Approach 2:
A coupling mechanism acts as an intermediary between the injector body and cartridge assembly, enabling secure attachment and detachment. This intermediary structure facilitates easy replacement while maintaining reliable connection during use, resolving the contradiction between operational ease and device complexity.
2Object-affected harmful factors
If the cartridge assembly includes a needle shield, then safety is improved, but device complexity increases
Solution Approach 1:
The needle shield is merged with the cartridge assembly as an integrated component rather than a separate attachment. This combination provides safety functionality while minimizing additional complexity, as the shield becomes part of the single replaceable unit that is already necessary for medicament delivery.
Solution Approach 2:
The needle shield is designed to automatically cover and protect the needle during cartridge handling and disposal. This self-service safety mechanism reduces the need for additional active safety components or complex control systems, maintaining simplicity while improving safety.
3Reliability
If the coupling mechanism is designed for secure attachment, then reliability is improved, but ease of operation deteriorates due to difficulty in detachment
Solution Approach 1:
The coupling mechanism incorporates dynamic elements that allow it to transition between a locked state during use and an unlocked state during detachment. This dynamic behavior enables secure attachment for reliable operation while facilitating easy detachment when needed, resolving the contradiction between reliability and ease of operation.
Data Source
Figure 1
Figure 2A~3B
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AI summary
The present invention relates to a sub-assembly (1) for medicament delivery device, which has an engageable releasing means, and a medicament delivery device including the sub-assembly. The engageable releasing means provides force for injecting medicament contained in the device when the engageable releasing means is released. For a conventional sub-assembly having an engageable releasing means, there is high possibility that the engageable releasing means is released during transportation of the sub-assembly to a final assembly location. To address this problem, particularly caused by unintentional external axial forces applied to the sub-assembly during transportation, the present invention applies a coupling mechanism (127, 144a) to securely hold in an axial direction components including the engageable releasing means. Therefore, the sub-assembly and the medicament delivery device according to the invention can prevent unintentional release of the engageable releasing means reliably.