Medical Connector Threading With Opposing Barb for Disconnection Resistance

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Solution Overview

Problem

Medical connectors with low friction between luer-lock elements risk accidental disconnection, especially when administering toxic fluids, and lack an indication for full engagement, leading to contamination risks and connector breakage.

Innovation Solution

A connector design featuring helical threads with vertical ribs and a stop mechanism that increase friction progressively during assembly, providing tactile feedback and resistance to disconnection, using tapered protrusions to enhance engagement and prevent over-tightening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If low friction materials are used for connector components, then ease of assembly is improved, but reliability deteriorates due to accidental disconnection risk

Engineering Contradiction:
Improveease of assemblyVSAvoidconnection security
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The connector is divided into multiple functional elements: a threaded portion for rotational engagement, a barb element for friction-based locking, and a stop element for axial positioning. This segmentation allows each element to perform its specific function optimally - the threaded portion enables easy assembly through standard threading, while the barb and stop elements provide reliability through mechanical interlocking and friction enhancement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple retention mechanisms into a single integrated connector structure. The barb element is integrated with the threaded portion, and the stop element is positioned to work with both the barb and threaded structures. This merging creates a composite retention system where the threaded engagement provides initial connection, the barb provides friction-based locking, and the stop prevents over-tightening, thereby achieving both ease of assembly and connection security simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If low friction materials are used for connector components, then ease of assembly is improved, but device complexity worsens due to lack of engagement indication

Engineering Contradiction:
Improveease of assemblyVSAvoidengagement indication mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The connector provides self-indicating engagement through its structural design. The barb element's friction-based retention creates a tactile sensation during assembly, and the stop element automatically engages with the mating connector's threaded portion to indicate full assembly and prevent over-tightening. This self-service mechanism eliminates the need for separate engagement indicators or complex feedback systems, maintaining ease of assembly while providing clear engagement indication.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If friction between luer-lock elements is low, then ease of operation is improved, but harmful factors worsen due to connector breakage and contamination risk

Engineering Contradiction:
Improveease of assemblyVSAvoidconnector breakage and contamination risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The connector design incorporates preliminary protective measures against harmful effects. The barb element is positioned to engage with the mating connector's threaded portion during assembly, creating friction-based locking that prevents accidental disconnection before contamination can occur. The stop element is pre-positioned to engage with the mating connector's threaded portion, preventing over-tightening that could cause breakage. These preliminary anti-action mechanisms protect against harmful factors while maintaining ease of assembly through standard threading operations.

Inventive Principle:
Principle #9Preliminary anti-action

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 design ensures secure fluid transfer by increasing friction and providing tactile feedback, reducing the risk of accidental disconnection and breakage, while preventing over-tightening.

Implementation Method 1

The at least one protrusion is sized and positioned such that the increase in friction provided by contact with each successive portion of the protrusion is greater than the increase in friction provided by a previously contacted portion of the protrusion

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3498331B1Mechanical friction enhancement for threaded connection incorporating opposing barb
Publication Date: 2025.10.15 BECTON DICKINSON & CO LTD
  • EP3498331B1 patent drawingFigure 1
  • EP3498331B1 patent drawingFigure 2
  • EP3498331B1 patent drawingFigure 3

AI summary

A medical connector includes a body having a distal end, a proximal end, and a sidewall extending between the distal end and the proximal end. The medical connector further includes a helical thread extending radially outward from a surface of the sidewall and at least one protrusion extending radially outward from a surface of the sidewall. The at least one protrusion has a first side and a second side. A radial height of the at least one protrusion from the surface of the sidewall tapers circumferentially from the first side of the at least one protrusion to the second side of the at least one protrusion.