Wedge-Grip Pipe Coupling for Variable Diameter Restraint

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Solution Overview

Problem

Existing restraint couplings struggle to provide a safe and reliable connection for pipes with varying outside diameters, particularly across different materials like steel, ductile iron, cast iron, PVC, and PE, due to inconsistencies in diameter sizes resulting from material and fabrication processes.

Innovation Solution

A universal restraint coupling design featuring a main body with a through hole, end rings, and independent wedge-shaped gripping elements with toothed and slanted surfaces, allowing for self-adjustment and secure gripping of pipes, along with a gasket system for leak-tight sealing, accommodating a wide range of diameters and materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a restraint coupling is designed to accommodate pipes with varying outside diameters across different materials, then the adaptability and versatility of the coupling is improved, but the manufacturing precision and consistency of the connection are worsened due to diameter variations

Engineering Contradiction:
Improveadaptability to different pipe diametersVSAvoidconnection precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The restraint coupling is divided into multiple independent wedge-shaped gripping elements that can individually adjust to the pipe's outside diameter. Each gripping element acts as an independent segment that responds to the specific diameter of the pipe it contacts, allowing the coupling to adapt to various pipe sizes while maintaining precise gripping force through the mechanical action of each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The gripping elements are designed to be movable rather than fixed, allowing them to dynamically adjust their position and gripping force based on the pipe's outside diameter. The wedging action creates a dynamic system where the gripping elements self-adjust to the specific dimensions of the pipe being connected, ensuring reliable connection despite diameter variations across different pipe materials and fabrication processes.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If independent wedge-shaped gripping elements are used to enable self-adjustment to different pipe diameters, then the ease of operation and installation is improved, but the device complexity increases due to multiple independent components

Engineering Contradiction:
Improveease of installationVSAvoidcomplexity of coupling structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The gripping elements are designed to self-adjust and self-grip through the wedging action without requiring external adjustment mechanisms or complex control systems. When the coupling is installed, the gripping elements automatically respond to the pipe's outside diameter and adjust their gripping force accordingly, making the installation process simple and intuitive while reducing the need for operator intervention or complex adjustment procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Multiple independent gripping elements are combined within a single coupling body, allowing them to work together as an integrated system. The coupling body serves as a common structure that houses and coordinates the actions of multiple gripping elements, reducing the overall complexity compared to using separate couplings for each pipe. The gripping elements collectively provide the gripping function while sharing the structural support of the coupling body.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If the gripping elements are arranged in a non-linked fashion to allow independent movement, then the adaptability to different pipe diameters is improved, but the reliability of the connection is worsened due to potential uneven distribution of gripping forces

Engineering Contradiction:
Improveadaptability to pipe diameter variationsVSAvoidreliability of pipe connection
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

Each gripping element is designed with specific local characteristics, including toothed surfaces for gripping and slanted surfaces for the wedging action. The toothed surfaces are specifically configured to engage with the pipe's outside surface, providing reliable mechanical interlocking. The slanted surfaces are angled to convert the axial clamping force into radial gripping force, ensuring that each element independently provides reliable gripping action adapted to the local conditions of the pipe surface it contacts.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The gripping elements are pre-configured with the appropriate geometry and surface characteristics to automatically engage and grip the pipe upon installation. The toothed surfaces are designed to immediately bite into the pipe's outside surface when the wedging action occurs, providing preliminary gripping action that secures the connection before any operational loads are applied. This preliminary engagement ensures reliable connection from the moment of installation.

Inventive Principle:
Principle #10Preliminary 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

Enables safe, reliable, and leak-tight connections across various pipe materials and diameters, ensuring secure gripping and fluid-tight sealing without requiring precise diameter matching, while maintaining equal spread of gripping elements to prevent stress concentrations.

Implementation Method 1

The slanted surface (8) is slanted with respect to the toothed surface (7) and is in contact with an inside surface (5) of the end ring (4). The end ring (4) can be clamped to the main body (3) via mounting elements (9). Due to the end ring (4) being clamped to the main body (3), the inside surface (5) of the end ring (4) presses on the slanted surface (8) of each gripping element (6). The resulting wedge effect causes a shift of each gripping element (6) towards the middle axis (100)

Methodology Applied
Scientific EffectWedge effect: Wedge

Implementation Method 2

the toothed surface (7) of each of the gripping elements (6) is pressed against said pipe such that the pipe is firmly held by the restraint coupling (1)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3567292B1Restraint coupling
Publication Date: 2022.04.20 BELGICAST INT S L U
  • EP3567292B1 patent drawingFigure 1
  • EP3567292B1 patent drawingFigure 2~3
  • EP3567292B1 patent drawingFigure 4

AI summary

The invention regards a restraint coupling (1) for coupling at least one pipe (2a, 2b) comprising a main body (3) including a through hole (24) with a middle axis (100), at least one end ring (4) extending around the middle axis (100), and a plurality of wedge-shaped gripping elements (6), provided around the middle axis in an annular arrangement, wherein each gripping element (6) has a toothed surface (7) adapted to contact the pipe (2a, 2b) and a slanted surface (8) slanted with respect to the toothed surface (7), the slanted surface (8) being in contact with an inside surface (5) of the end ring (4), wherein the gripping elements (6) are arranged in a non-linked fashion with each gripping element (6) being provided independent from each other gripping element (6) between the main body (3) and the end ring (4), and wherein the end ring (4) can be clamped to the main body (3) via mounting elements (9) thereby pressing the inside surface (5) of the end ring (4) against the slanted surface (8) of each gripping element (6) to shift each gripping element (6) towards the middle axis (100).