Syringe Safety Shield Trigger Lock Mechanism
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Solution Overview
Problem
Existing needle shielding systems for syringes require activation force that is dependent on the injection movement, which may not be suitable for patients with limited strength or those requiring partial injections, as they do not allow independent activation of the shielding mechanism after partial use.
Innovation Solution
A syringe assembly with a safety shield that is longitudinally movable between retracted and activated positions, featuring a spring-urged mechanism and dual locking systems, allowing independent activation of the shield from the injection movement, with a trigger button that engages and disengages specific areas to control the shield's position, ensuring the needle is covered in the activated state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shielding device is activated by a user after injection (active type), then the needle is protected from needle stick injuries, but the activation force is dependent on the injection movement which limits usability for partial injections or patients with limited strength
Solution Approach 1:
The syringe assembly incorporates a dynamic locking mechanism with a trigger button that can transition between locked and unlocked states, allowing the safety shield to be activated independently of injection movement. The trigger button engages with locking surfaces on the safety shield to maintain it in a retracted position during injection, but can be manually depressed to release the lock and allow spring-driven activation of the shield.
Solution Approach 2:
The activation mechanism is segmented into separate functional components: a trigger button for manual release, a spring for providing activation force, and a safety shield with distinct locking surfaces. This segmentation allows the shielding function to be decoupled from the injection movement, enabling independent activation while maintaining reliability.
2Productivity
If the safety shield is locked in the retracted position during injection, then the needle remains accessible for medication delivery, but the user must manually release the locking mechanism which complicates the operation
Solution Approach 1:
The trigger button is designed to be passively engaged by the user's finger during normal handling, allowing accidental or intentional release without requiring deliberate manual manipulation. The spring mechanism automatically drives the safety shield to the activated position once the lock is released, eliminating the need for complex manual release procedures while maintaining needle accessibility during injection.
3Ease of operation
If a spring is used to urge the safety shield towards the activated position, then the activation force is provided automatically, but the locking mechanism becomes more complex
Solution Approach 1:
The complex locking mechanism is extracted and simplified by using a single trigger button that interacts with distinct locking surfaces on the safety shield. The spring force is extracted as a separate activation mechanism that operates independently once the simple trigger lock is released. This separation reduces overall complexity while maintaining automatic activation capability.
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
Enables safe and independent activation of the needle shield, allowing for safe handling post-injection, even after partial use, without exposing the user to needlestick injuries, and provides a secure locking mechanism to prevent accidental exposure.
Implementation Method 1
a spring urging said safety shield towards said activated position
Data Source
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AI summary
A syringe assembly for use in medication delivery comprising: a syringe barrel (12) having a needle (11) at a distal end (122) of the barrel (12); a body (2) defining an enclosure, said barrel (12) extending at least partially within said enclosure; a safety shield (3) for the needle (11), longitudinally movable with respect to the body (2) between a retracted position and an activated position; a spring (4) urging said safety shield (3) towards said activated position; a first locking mechanism (31) for locking the safety shield (3) in the retracted position, wherein the first locking mechanism (31) is manually releasable by a user so as to let the safety shield (3) reach the activated position, the first locking mechanism (31) comprising a trigger button (20) on the body (2), and a first engaging area (21) on the safety shield (3); the trigger button (20) presenting a default state and a depressed state; the first locking mechanism (31) being configured such that: ∘ when the safety shield (3) is in the retracted position and the trigger button (20) is in the default state, the trigger button (20) engages the first engaging area (21); ∘ when the trigger button (20) is in the depressed state, the trigger button (20) does not engage the first engaging area (21).