Luer-Snap Syringe Connection Mechanism for Secure Hub Attachment
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Solution Overview
Problem
Existing luer fitting mechanisms for connecting needle hubs to syringes, such as luer lock and luer slip, often result in breakage or insecure attachment, leading to usability issues like broken male conical tips or 'pop-offs' during attachment and detachment.
Innovation Solution
A syringe with a luer snap mechanism that uses a rotatable arm and latch system to create a snap-fit connection between the needle hub and syringe barrel without relative rotation, providing tactile and audible feedback for secure attachment and easy disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If luer lock mechanism is used to connect needle hub to syringe, then connection strength is improved, but device complexity increases and risk of breakage occurs due to required twisting force
Solution Approach 1:
The connection mechanism is divided into separate functional elements: a collar with internally threaded portion, a male conical fitting, and external lugs. This segmentation allows each component to perform its specific function while reducing overall complexity and preventing breakage of integrated structures.
Solution Approach 2:
The connection mechanism transitions from a static friction-fit to a dynamic threaded engagement system. The externally threaded collar rotates to engage with internally threaded portions, providing progressive tightening and secure connection without requiring excessive twisting force that could cause breakage.
2Reliability
If luer lock mechanism with twisting force is applied to attach needle hub, then secure connection is achieved, but harmful factors increase due to potential breakage of male conical tip
Solution Approach 1:
The design incorporates externally threaded collars with controlled thread engagement that distribute the tightening force progressively. This prevents sudden stress concentration that could cause the male conical tip to break off during attachment.
Solution Approach 2:
The externally threaded collar acts as an intermediary between the user's twisting force and the male conical fitting. It provides a controlled engagement interface that protects the fragile conical tip from direct high-stress twisting forces.
3Ease of operation
If luer slip fitting is used for connection, then ease of operation is improved, but connection strength deteriorates leading to pop-offs during use
Solution Approach 1:
The design merges the simplicity of luer slip fitting with the security of threaded connection. The collar provides both a friction-fit interface for easy attachment and threaded engagement for secure, leak-proof connection, eliminating the pop-off problem of pure friction-fit systems.
4Ease of operation
If repeated twisting force is applied to detach needle hub from luer lock, then disconnection is achieved, but device complexity increases and breakage risk persists
Solution Approach 1:
The detachment mechanism inverts the attachment process by using reverse rotation of the externally threaded collar. This simple inverse action provides easy disconnection without requiring complex release mechanisms or tools.
Data Source
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AI summary
Syringes (100) having a snap-fit mechanism for attaching a needle hub (120) to a syringe barrel in a snap-fit relationship and packaged medical device comprising a syringe with a snap-fit mechanism and a needle hub mare provided. An exemplary syringe includes a barrel (150) with a collar (130) and a rotatable arm (140) which allows connection of a needle hub to the barrel in a snap-fit relationship. Additional features of the collar and rotatable arm may also permit disconnection of the needle hub from the barrel without the use of relative rotation of the needle hub and barrel. In a specific configuration, the syringe utilizes a torsional snap-fit element to connect the needle hub to the barrel in a snap-fit rotation. In a more specific configuration, the syringe utilizes a collar with differing interior surfaces which permit snap-fit assembly and disassembly of the needle and the barrel.