Medicament Delivery Cassette With Force-Activated Cap Release
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Solution Overview
Problem
Existing medicament delivery devices pose a risk of user injury and contamination due to the premature removal of the cap before insertion into the base unit, particularly in auto-injectors where the cap prevents the needle cover from being pressed, leading to increased risk of needle exposure.
Innovation Solution
A cassette design with a connection mechanism that locks the cap to the body and requires a distal force for disconnection, ensuring the cap cannot be removed before attachment to the base unit, utilizing interfaces like cam or screw threads to generate this force during mounting, allowing safe and controlled detachment post-attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cap is made removable before insertion into the base unit, then the user can access the medicament delivery member, but the user is at risk of injury from the needle and contamination of the medicament delivery member
Solution Approach 1:
The cap is pre-attached to the body in a connected state that prevents premature removal. The connection is designed to be disconnected only after the cassette is inserted into the base unit, ensuring the medicament delivery member remains protected until the proper time. This preliminary configuration prevents user injury and contamination by maintaining the cap in place during handling and insertion.
Solution Approach 2:
The connection between cap and body transitions from a locked state during insertion to a disconnectable state after insertion. The base unit generates a distal force that causes the body to move relative to the cap, disconnecting the connection. This dynamic state change allows the cap to be securely attached during critical phases while enabling removal after safe insertion, resolving the contradiction between protection and accessibility.
2Reliability
If the cap is securely locked to the body, then premature removal is prevented, but the cap cannot be removed when needed after insertion
Solution Approach 1:
The connection mechanism dynamically changes its state based on the insertion phase. During insertion, the connection maintains a locked state for reliable retention. After insertion, when the base unit generates a distal force, the connection transitions to a disconnectable state, allowing cap removal when needed. This dynamic behavior resolves the contradiction between secure retention and operational flexibility.
Solution Approach 2:
The system preliminarily maintains the cap in a locked state during the insertion phase, then transitions to allow removal. The connection is arranged to be disconnected by a distal force generated during the mounting sequence, ensuring the cap remains secure until the proper time when removal is needed for medicament delivery.
3Reliability
If a connection mechanism is added between cap and body, then premature cap removal is prevented, but the device complexity increases
Solution Approach 1:
The base unit's drive mechanism, which already exists for medicament delivery, is utilized to generate the distal force that disconnects the cap connection. The mounting sequence itself provides the force needed to transition the connection state, eliminating the need for separate actuators or complex control systems. This self-service approach prevents premature removal while minimizing added complexity.
Solution Approach 2:
The existing interface between the body and base unit serves multiple functions: it provides structural support, enables force transmission, and triggers the cap connection disconnection. The distal force generated during normal mounting operations is repurposed to disconnect the cap, making the connection mechanism part of the overall system's existing functionality rather than adding separate complexity.
Data Source
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AI summary
A cassette (12) for a medicament delivery device (10) having a base unit (14), the cassette (12) comprising a longitudinal axis (16) defining a proximal direction (18) and a distal direction (20); a body (22) for accommodating a medicament container (44); a medicament delivery member (46); and a cap (24) connected to the body (22) by means of a connection (40), the cap (24) enclosing a proximal end (42) of the body (22); wherein the connection (40) is arranged to be disconnected by means of a distal force acting in the distal direction (20) on the body (22) relative to the cap (24) when the cassette (12) is attached to the base unit (14). A medicament delivery device (10) comprising a cassette (12) is also provided.