Medicament Delivery Guard Locking Mechanism
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Solution Overview
Problem
Medicament delivery devices face challenges in securely locking the delivery member guard before use, leading to accidental exposure or injury during assembly, as existing mechanisms may not adequately prevent distal movement until proper assembly is ensured.
Innovation Solution
A sub-assembly comprising a body with a longitudinally extending delivery member guard, a latch, and a lock member that moves between locked and unlocked positions, preventing axial movement of the guard until proper assembly is confirmed, ensuring safety by allowing proximal movement only after correct alignment and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is provided to prevent distal movement of the delivery member guard, then safety is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is divided into separate functional components: a lock member with a distally directed surface, a latch with a proximally directed surface, and a biasing member. This segmentation allows each component to perform its specific function while keeping the overall mechanism manageable and understandable.
Solution Approach 2:
The locking mechanism is designed to be self-actuating through the interaction between the distally directed surface of the lock member and the proximally directed surface of the latch. When the lock member moves distally, it automatically engages the latch without requiring additional actuation steps, making the system self-service and reducing operational complexity.
2Reliability
If the delivery member guard is locked in position, then accidental exposure is prevented, but ease of operation is reduced
Solution Approach 1:
The lock member is positioned and configured before use with the biasing member pre-loaded to exert proximal force on the latch. This preliminary action ensures that the locking mechanism is ready to engage automatically when needed, eliminating the need for complex activation sequences and maintaining ease of operation.
Solution Approach 2:
The locking and unlocking actions are designed to occur rapidly through the relative movement of the lock member and latch surfaces. The biasing member provides the necessary force to quickly engage or disengage the latch, allowing the system to skip intermediate states and transition directly between locked and unlocked positions, thereby maintaining operational simplicity.
3Reliability
If a lock member with distally directed surface and latch with proximally directed surface are used, then locking reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The locking reliability is achieved through the directional surfaces (distally directed surface of the lock member and proximally directed surface of the latch) rather than through tight dimensional tolerances. The geometric orientation and interaction of these surfaces provide the locking function, allowing for more relaxed manufacturing precision requirements compared to mechanisms that rely on precise fit-ups or clearance gaps.
Data Source
AI summary
A sub-assembly for a medicament delivery device cassette unit, the sub-assembly having a body extending along a longitudinal axis from a proximal end to a distal end; a delivery member guard coaxially attached to the body and being axially movable relative to the body along the longitudinal axis; a latch adjacent to the delivery member guard and axially movable relative to the body; and a lock member attached to the body; the lock member is movable relative to the latch between a locked position and an unlocked position; the lock member has a distally directed surface facing a proximally directed surface of the latch in the locked position; and wherein the distally directed surface of the lock member is further apart from the proximally directed surface of the latch in the unlocked position than in the locked position.