Medicament Delivery Sub-Assembly With Axial Coupling Lock
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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 plastic particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protrusions are used to restrict axial movement of the coupling member, then the coupling member is prevented from moving axially, but the protrusions are prone to breakage and generate plastic debris causing operation failure
Solution Approach 1:
The invention removes the protrusions from the main body and replaces them with axial engagement elements formed on the coupling member itself. This extraction eliminates the source of plastic debris generation while maintaining the axial restriction function through the engagement between the axial engagement element and the corresponding feature on the main body.
Solution Approach 2:
The invention introduces axial engagement elements as intermediary structures that mediate the axial restriction function. These elements are formed on the coupling member and engage with corresponding features on the main body, providing a reliable mechanical interface that prevents axial movement without relying on fragile protrusions.
2Adaptability or versatility
If the coupling member is made rotatable relative to the main body, then the holding member can switch between holding and releasing positions, but axial dislocation may occur during transportation causing unintentional plunger rod actuation
Solution Approach 1:
The invention merges the axial restriction function with the rotational coupling mechanism by forming axial engagement elements directly on the coupling member. This integration ensures that the axial restriction and rotational movement work together seamlessly, preventing dislocation during transportation while maintaining the ability to switch between holding and releasing positions.
Solution Approach 2:
The axial engagement elements are pre-formed on the coupling member to establish the axial restriction before the device is put into service. This preliminary configuration ensures that the coupling member maintains its predetermined relative position with the main body during transportation, preventing unintentional actuation before the device is activated.
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
Ensures reliable maintenance of the sub-assembly's position during transportation and assembly, preventing operation failures by eliminating the need for protrusions that can break, thus enhancing the device's operational reliability.
Implementation Method 1
The main body and the coupling member are configured such that the first and second axial engagement elements are engaged with each other to restrict a movement of the coupling member relative to the main body in a proximal direction
Implementation Method 2
a biasing member configured to bias the plunger rod
Data Source
AI summary
The present disclosure relates to a sub-assembly 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 disclosure applies a coupling mechanism 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 present disclosure can prevent unintentional release of the engageable releasing means reliably.