Closed-System Transfer Device With Two-Position Luer Coupling

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Solution Overview

Problem

Current CSTD systems require users to choose between the safety of free rotation and the flexibility of disconnection, lacking a design that allows easy connection and disconnection while maintaining safety.

Innovation Solution

A CSTD system with a Luer connector that has two axial positions: one allowing free rotation and one preventing rotation, achieved through a form fit engagement between the Luer connector and housing, enabling secure attachment and disconnection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the Luer connector is designed to allow free rotation for safety, then safety is improved, but the ability to securely attach and prevent accidental disconnection deteriorates

Engineering Contradiction:
ImprovesafetyVSAvoidsecure attachment
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The Luer connector is designed with dynamic characteristics, allowing free rotation during connection to accommodate misalignment and ensure safe coupling. The system transitions from a static fixed-position design to a dynamic one where rotation is permitted during the connection process, improving safety while maintaining connection capability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connection process is segmented into distinct phases: a first axial position allowing free rotation for safe connection, and a second axial position with form fit engagement for secure attachment. This segmentation allows each phase to optimize for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the Luer connector is designed to prevent rotation for secure attachment, then secure attachment is improved, but the safety feature of free rotation deteriorates

Engineering Contradiction:
Improvesecure attachmentVSAvoidsafety
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The system uses dynamic characteristics to allow free rotation during the connection phase for safety, then transitions to a static form fit engagement state for secure attachment. This dynamic approach resolves the contradiction by applying different rotational constraints at different stages of the connection process.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The design incorporates preliminary action by allowing free rotation during the connection phase to ensure safe coupling before establishing the final secure attachment. The rotation freedom is provided in advance during the connection process, and then the form fit engagement is established to prevent subsequent accidental disconnection.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If a single axial position is used for the Luer connector, then device complexity is reduced, but the functionality of allowing both free rotation and secure attachment deteriorates

Engineering Contradiction:
ImprovestructureVSAvoidfunctionality
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The Luer connector is segmented into two distinct axial positions: a first position allowing free rotation for safe connection and a second position with form fit engagement for secure attachment. This segmentation enables the single connector to perform multiple functions that would otherwise require separate components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The single Luer connector is designed to be multi-functional, serving both as a safe connection interface (first axial position with free rotation) and a secure attachment interface (second axial position with form fit engagement). This universality eliminates the need for separate connectors while maintaining both safety and security functions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4620508A1Closed system transfer device and adapted luer connector
Publication Date: 2025.09.24 B BRAUN MELSUNGEN AG
  • EP4620508A1 patent drawingFigure 1A~1B
  • EP4620508A1 patent drawingFigure 1C
  • EP4620508A1 patent drawingFigure 2

AI summary

A closed system transfer device (CSTD) is described with a housing (15) and a detachable Luer connector (20) received in an axial recess (60) of the housing. The Luer connector (20) is attached to the housing (15) via at least one snap hook (68) inside the housing (15) that engages a snap ledge (70) on a central axial pin (40) of the Luer connector (20) to thereby defining a first axial coupling position (CP1) of the Luer connector (20). In this first axial coupling position (CP1) the Luer connector is allowed to freely rotate in both (CW and CCW) directions within the housing (15). The Luer connector (20) is further configured to be axially shiftable further into a second axial coupling position (CP2) in which rotation of the Luer connector (20) is prevented by form fit engagement between Luer connector (20) and housing (15).