Auto-injector Cassette Shuttle Lock Cap Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge is to prevent accidental removal of the removable cap from the cassette unit in auto-injectors with a reusable drive unit and separate cassette unit, which exposes the needle tip to contaminants and potential contamination, especially before the cassette unit is docked for use.
Innovation Solution
The auto-injector incorporates a shuttle lock control mechanism that moves between 'cassette unused', 'unlocked', and 'used' positions, ensuring the cap remains locked until the cassette unit is docked, featuring a radial arrangement of socket through holes and locking legs with blocking elements to control cap locking and unlocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the removable cap is made easily detachable for convenient access, then the ease of operation is improved, but the risk of accidental removal exposing the needle tip to contaminants increases
Solution Approach 1:
A locking mechanism acts as an intermediary between the cap and the cassette unit housing. The locking legs with blocking elements provide a controlled interface that prevents accidental removal while maintaining intentional accessibility. The shuttle lock control mediates the transition between locked and unlocked states, ensuring safe operation.
Solution Approach 2:
The cap is pre-locked to the cassette unit housing before use through the locking mechanism. This preliminary locking action prevents accidental removal during transport and storage. The user must intentionally activate the shuttle lock control to unlock the cap before the cassette unit is docked, ensuring protection against contamination until ready for use.
2Reliability
If the locking mechanism is made complex to prevent accidental removal, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The locking mechanism is segmented into distinct functional components: locking legs with blocking elements for physical retention, and a shuttle lock control for operational management. This segmentation allows each component to perform its specific function efficiently while maintaining overall system reliability without excessive complexity.
Solution Approach 2:
The locking mechanism is designed to be self-latching through the interaction of locking legs and blocking elements. Once engaged, the mechanism maintains its locked state automatically without requiring continuous external input. The shuttle lock control provides a simple user interface that leverages the self-servicing nature of the mechanical locking components.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
There is provided a cassette unit suitable for use with an auto-injector. The cassette unit comprises a cassette unit housing and a removable cap that in a capping position fits over and thereby, acts to close off, a needle projection aperture of the housing. The cassette unit housing has one or more first engagement features arranged for reversibly engaging one or more second engagement features of the removable cap for reversible lock engagement of the removable cap to the housing; and a shuttle lock control defining one or more blocking elements for selectively blocking movement of said first engagement features relative to said second engagement features. The shuttle lock control is axially movable relative to the cassette unit housing between a first 'cassette unused' position; a second 'cassette unlocked' position; and after replacement of the removable cap, a third 'cassette used' position, locating intermediate the first and second positions.