Auto-injector Interlock Mechanism for Accidental Activation Prevention
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Solution Overview
Problem
Current auto-injectors lack a mechanism to prevent accidental activation and ensure proper positioning against the injection site, leading to potential needle stick injuries and medicament wastage.
Innovation Solution
An interlock mechanism is introduced that allows the trigger button to be operated only when the auto-injector is pressed against the injection site, utilizing a detector spring and sliding detector means to prevent accidental activation, ensuring safe and proper use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the trigger button is always operable, then the device is easy to operate, but accidental activation may occur causing needle stick injuries and medicament wastage
Solution Approach 1:
A safety mechanism acts as an intermediary between the trigger button and the injection mechanism. This safety mechanism includes a safety lever that must be moved to a second position to enable the trigger button, preventing accidental activation while maintaining ease of operation when properly intended
2Object-affected harmful factors
If the trigger button is restricted to operate only when pressed against injection site, then accidental activation is prevented, but the device complexity increases
Solution Approach 1:
The safety mechanism is merged with the existing trigger button assembly and housing structure. The safety lever integrates with the trigger button mechanism, and the interlock features are combined with the housing and plunger assembly, reducing overall device complexity while achieving the positioning restriction function
3Object-affected harmful factors
If a safety mechanism is added to prevent accidental activation, then needle safety is improved, but the device complexity increases
Solution Approach 1:
The safety mechanism is segmented into distinct functional components: a safety lever that can be moved between positions, interlock features on the plunger assembly, and corresponding engagement features on the housing. This segmentation allows each component to perform its specific safety function while maintaining modularity and reducing overall complexity
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
The interlock mechanism enhances needle safety, reduces the risk of needle stick injuries, and ensures complete delivery of the medicament by preventing accidental activation and ensuring proper positioning during use.
Implementation Method 1
The detector means is slidable in longitudinal direction and biased by a detector spring into a position with the detector means protruding beyond the proximal end
Data Source
Figure 1~2
Figure 3~5B
Figure 5C~7
AI summary
The invention relates to an auto-injector with an interlock mechanism for defining an operation sequence of the auto-injector (1 ) in a manner to allow a lateral trigger button (16) to be operated only when a proximal end (P) of the auto-injector (1 ) is pressed against an injection site, wherein a detector means (18) is arranged inside an elongate housing (2) of the auto-injector (1 ) at the proximal end (P), the detector means (18) slidable in longitudinal direction and biased by a detector spring (19) into a position with the detector means (18) protruding beyond the proximal end (P), wherein a dog (16.2) is arranged at the trigger button (16) and wherein at least one longitudinal bar (18.1, 21 ) is provided, at least one of the bars (21 ) slidable in longitudinal direction and coupled to the detector means (18) for joint movement at least in distal direction (D), wherein a recess (21.1 ) for the dog (16.2) is provided in the bar (21 ) for allowing the trigger button (16) to be pressed when the detector means (18) is being pushed into the auto-injector (1 ) and wherein otherwise the dog (16.2) is engaged with the bar (21 ) in a manner to prevent the trigger button (16) from being pressed.