Press Coupling Sleeve Openings for Cross-Brand PEX Tubing Fit

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Solution Overview

Problem

Existing coupling devices for plastic tubing in tap water systems are often manufacturer-specific, leading to compatibility issues during post-installation work, as the outer and inner diameters vary slightly between manufacturers, necessitating the need to bring multiple devices to ensure proper fitting.

Innovation Solution

A coupling device comprising a core member with a metal sleeve featuring circumferential ridges and elongate openings, allowing for radial compression by a press tool to securely engage tubing of varying dimensions, ensuring compatibility across different manufacturers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a coupling device is designed to fit tubing from a specific manufacturer, then the connection reliability for that manufacturer's tubing is improved, but the adaptability to tubing from other manufacturers deteriorates

Engineering Contradiction:
Improveconnection reliabilityVSAvoidcompatibility with tubing from various manufacturers
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The coupling device is designed with a universal interface that can accommodate tubing from different manufacturers. The core member features a conical seating surface and circumferential ridges that can adapt to slight variations in tubing outer diameters, allowing a single coupling device design to work with multiple tubing specifications without sacrificing connection reliability

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

Solution Approach 2:

The metal sleeve incorporates localized deformation zones with circumferential ridges that can adapt to different tubing dimensions. The ridges are positioned to create localized sealing and gripping points that adjust to the specific tubing being connected, while the overall coupling device structure remains standardized

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If multiple coupling devices are brought to ensure compatibility with different tubing manufacturers, then the adaptability is improved, but the device complexity and inventory requirements worsen

Engineering Contradiction:
Improvecompatibility coverageVSAvoidnumber of coupling device variants
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The coupling device incorporates a universal design with adjustable features that allow a single device type to serve multiple tubing specifications. The core member's conical geometry and the metal sleeve's deformation capabilities enable one coupling device design to replace what would traditionally require multiple specialized devices

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

3Strength

If the metal sleeve is compressed radially to engage the tubing, then the connection strength is improved, but the risk of losing the sleeve during handling worsens

Engineering Contradiction:
Improveconnection strengthVSAvoidrisk of sleeve loss
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The metal sleeve is pre-attached to the core member at a predetermined position before the compression operation. This preliminary attachment ensures the sleeve remains in place during handling and installation, eliminating the risk of loss while still allowing radial compression to engage the tubing through the elongate openings

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If elongate openings are provided in the metal sleeve, then the evenness of radial press force application is improved, but the structural strength of the sleeve deteriorates

Engineering Contradiction:
Improveevenness of radial press forceVSAvoidsleeve structural strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The metal sleeve is designed as a thin-walled structure with elongate openings that allow flexible radial compression. The openings enable the sleeve to deform uniformly under press tool application, distributing the radial force evenly across the tubing surface while the attached state to the core member maintains overall structural integrity

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution provides a robust and reliable connection by maintaining the metal sleeve's position during installation, reducing the risk of loss and ensuring a proper seal without requiring excessive material deformation, thus facilitating easy and secure attachment of tubing to the coupling device.

Implementation Method 1

Upon compression, the metal sleeve is plastically deformed and thus remains compressed after removal of the press tool

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

the circumferential ridges are forced radially into the material of the tubing and thereby mechanically engages the tubing

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP4653742A1A press coupling for PEX-tubing
Publication Date: 2025.11.26 GUSTAVSBERG
  • EP4653742A1 patent drawingFigure 1~3
  • EP4653742A1 patent drawingFigure 4~7
  • EP4653742A1 patent drawingFigure 8~9

AI summary

The coupling device (1) for tubing, typically for plastic tubing such as PEX-tubing or ALU PEX-tubing, comprises a core member (2) and a metal sleeve (3). The core member (2) includes a substantially cylindrical first end portion (4) designed for insertion into a piece of tubing (T). This first end portion (4) extends along a longitudinal axis (L) from a base portion (4a) to a free end portion (4b) and is equipped with multiple circumferential ridges (5) on its radial outside. The metal sleeve (3), which is also substantially cylindrical, is positioned radially outside the first end portion (4), creating a space (S) between them to accommodate the tubing (T). The metal sleeve (3) is securely attached to the core member (2) at a specific position and extends axially along the longitudinal axis (L) between an inner end portion (3a) and an outer end portion (3b). Additionally, the metal sleeve (3) features one or more elongate openings (6), each extending along the longitudinal axis (L) and forming a confined through opening that spans from the inner end portion (3a) to the outer end portion (3b).