Tube Connector Locking Ring With Visual Locked-State Indication

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Solution Overview

Problem

Existing connectors with snap fit mechanisms for outer diameter applications lack a reliable visual indication of the locked position, and previous solutions are limited to inner diameter connectors, making it difficult to distinguish between locked and unlocked states, especially when the connector and tube are similar in color.

Innovation Solution

A connector design that uses a cap with a different color or material for visual contrast, combined with a locking ring that provides a tactile click and visual indication through strategically positioned windows, allowing the user to determine the locked state without requiring a direct line of sight to the tube, and is applicable to both inner and outer diameter connectors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a snap fit engagement is used to replace ultrasonic welding, then the manufacturing complexity and material compatibility requirements are reduced, but the cap is subjected to radial expansion strains and bending stresses that can cause cracking or dislodgement

Engineering Contradiction:
Improvemanufacturing complexityVSAvoidcap strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The cap is divided into multiple flexible fingers instead of a single rigid annular structure. Each finger can independently deflect and absorb stress, preventing the cap from cracking or dislodging under bending loads while maintaining the snap fit engagement advantage.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If an annular shoulder snap fit is used, then ultrasonic welding equipment is eliminated, but the cap must expand radially during assembly creating strain on the cap

Engineering Contradiction:
Improvewelding equipment requirementVSAvoidradial expansion strain
Core Design Contradiction:
Ease of manufactureVSStress or pressure

Solution Approach 1:

The cap is segmented into multiple fingers that can deflect independently during assembly. This eliminates the need for radial expansion of a rigid annular structure, reducing assembly strain while maintaining the simple snap fit engagement without ultrasonic welding equipment.

Inventive Principle:
Principle #1Segmentation

3Reliability

If a locking ring is added to provide locked/unlocked positions, then the connector can prevent accidental release, but the structure becomes more complex and manufacturing costs increase

Engineering Contradiction:
Improveprevention of accidental releaseVSAvoidconnector structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking ring is integrated with the existing cap structure, combining the locking function with the grip ring assembly. This provides reliable prevention of accidental release while minimizing additional structural complexity and manufacturing cost by reusing existing components and assembly processes.

Inventive Principle:
Principle #5Merging (Combining)

4Loss of information

If a visual indication system is added to show locked state, then user confidence and safety are improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvevisual indication of locked stateVSAvoidvisual indication system complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

Different colored sections are incorporated into the cap and locking ring structures. When the locking ring rotates to the locked position, the colored sections align to provide a clear visual indication of the locked state. This simple color-coding system provides reliable visual feedback without adding complex mechanical or electronic indication systems.

Inventive Principle:
Principle #32Color changes

5Ease of operation

If the locking ring is made accessible from the outer end of the connector, then ease of operation is improved, but the structural integrity and sealing may be compromised

Engineering Contradiction:
Improveaccessibility of locking mechanismVSAvoidsealing integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking ring is nested within the cap structure at the outer end, allowing user access while being protected by the cap's outer wall. The cap acts as a protective enclosure that maintains sealing integrity while providing access to the locking ring through designated openings or by temporarily displacing the cap, thus balancing ease of operation with sealing reliability.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3784945B1connector
Publication Date: 2022.06.08 JOHN GUEST INT LTD
  • EP3784945B1 patent drawingFigure 1A~1C
  • EP3784945B1 patent drawingFigure 2~3
  • EP3784945B1 patent drawingFigure 4~5

AI summary

A connector comprising a body (1) having a through-way (5) which is open at one end. A shoulder (7) in the through-way faces the open end and supports an O-ring (9). A cap (2) is fitted to an open end of the body and extends from the open end towards the opposite end. The cap is a different colour to the body. A gripping ring (3) in the cap has a plurality of inwardly facing teeth (32) to grip, in use, a tube in the through-way to prevent it from being pulled out of the open end of the connector. A locking ring (4) is fitted over the open end of the body and cap, the locking ring being rotatable between a locked position in which the teeth of the gripping ring can engage the tube and an unlocked position in which the teeth of the gripping ring are prevented from engaging the tube. The locking ring has a window (44) which lines up with the body in one of the locked and unlocked positions and the cap in the other of the locked and unlocked positions.