Auto-Injector Safety Pin Mechanism for Single-Handed Activation
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Solution Overview
Problem
Existing auto-injectors have a complex structure with multiple parts, requiring multiple operations for use, which complicates assembly and usage.
Innovation Solution
An auto-injector design with a simplified structure featuring a tubular housing, a medicinal substance container, an activation member, a plunger, a trigger housing, a safety pin module, and elastic members that allow for a single-handed operation to inject medicinal substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking device and safety cap are separately provided to prevent unintentional operation, then safety is improved, but device complexity increases and the number of operations required increases
Solution Approach 1:
The patent combines the locking device and safety cap into a single integrated safety mechanism. The safety cap serves dual functions: it protects the needle during transport and acts as the locking mechanism that prevents unintentional activation. When the cap is removed, it simultaneously unlocks the device and exposes the needle, eliminating the need for separate locking and capping operations.
2Reliability
If a locking device and safety cap are separately provided, then safety is improved, but ease of operation deteriorates due to multiple required operations
Solution Approach 1:
The safety cap and locking device are merged into a single component that performs both safety protection and activation locking functions simultaneously, reducing the number of discrete operations required.
Solution Approach 2:
The safety cap is pre-attached to the device in a way that its removal automatically triggers the unlocking mechanism and needle exposure in sequence, eliminating the need for separate manual operations for each safety function.
3Reliability
If multiple separate components are used for safety functions, then reliability is improved, but ease of manufacture deteriorates due to complicated assembly
Solution Approach 1:
The safety cap is designed as an integrated component that combines needle protection and activation locking functions, reducing the total number of parts that need to be manufactured and assembled while maintaining safety reliability.
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 simplified design reduces the number of parts and operations, making assembly easier and use more straightforward.
Implementation Method 1
a first elastic member pressing the activation member in a proximal direction
Implementation Method 2
a second elastic member installed within the trigger housing and pressing the plunger in the proximal direction
Data Source
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AI summary
Disclosed is an auto-injector including: a tubular housing forming an exterior; a medicinal substance container including a medicinal substance storage unit storing a medicinal substance and an injection needle infiltrating a skin and injecting the medicinal substance stored in the medicinal substance storage unit and fixed to the tubular housing; an activation member slidably installed along the tubular housing, the activation member having a proximal end portion protruding outside the housing in an initial position; a first elastic member pressing the activation member in a proximal direction; a plunger including a plunger rod that slides into the medicinal substance container and presses the medicinal substance, a trigger arm extending from the plunger rod to a distal end portion, and a trigger protrusion formed to protrude outward from the distal end portion of the trigger arm; a trigger housing surrounding an outer circumferential surface of the plunger; a safety pin module installed inside the tubular housing and including a safety pin inserted between the trigger arms to cause the trigger arm to flare outward in a radial direction to maintain locking of the trigger housing and the trigger arm; and a second elastic member installed within the trigger housing and pressing the plunger in the proximal direction, wherein, as the activation member pushes the safety pin module in a distal direction, locking of the trigger arm and a locking protrusion is released and the plunger is activated.