Thick-Walled Tube Fitting With Flared Bite-Seal Connection

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Solution Overview

Problem

Existing tube fitting technologies face challenges in achieving reliable sealing and resistance to vibration, especially when used with varying tube wall thicknesses and materials, and often require multiple assembly steps or complex tolerancing.

Innovation Solution

A process for making a tube fitting that involves placing a thick-walled tube into a frusto-conical die, sliding a sleeve over the tube with a sharp annular biting portion, securing it, and using a hydraulic cylinder to flare the tube end while deforming the sleeve, creating a mechanical bite and flared connection in a single operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional tube fitting methods are used, then assembly may be simpler, but sealing reliability and vibration resistance deteriorate

Engineering Contradiction:
Improvesealing reliabilityVSAvoidfitting structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fitting is divided into distinct functional segments: a crimping section with internal ridges for mechanical gripping, a sealing section with O-ring grooves for fluid sealing, and a flared section for structural support. This segmentation allows each portion to optimize its specific function, improving overall reliability without excessive complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tube end is pre-flared before the fitting is installed, creating a prepared receiving structure. The fitting itself is pre-formed with integrated sealing and crimping features. This preliminary preparation ensures that when assembled, the sealing surfaces and mechanical engagement points are already in the correct configuration, improving sealing reliability

Inventive Principle:
Principle #10Preliminary action

2Reliability

If traditional tube fitting methods are used, then manufacturing may be simpler, but resistance to vibration deteriorates

Engineering Contradiction:
Improvevibration resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple functions are merged into a single fitting component: the crimping action, sealing mechanism, and structural reinforcement are all integrated into one piece. The internal ridges provide mechanical interlocking, O-ring grooves provide sealing, and the flared geometry provides structural support—all in one manufactured part, improving vibration resistance

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fitting system combines different materials with complementary properties: the fitting body (typically stainless steel or nickel alloy) provides structural strength and vibration resistance, while elastomeric O-rings provide sealing. This composite approach allows each material to optimize its specific function, improving overall reliability under vibration

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If fittings are designed for specific tube thicknesses, then manufacturing precision may be easier, but adaptability to varying tube thicknesses deteriorates

Engineering Contradiction:
Improveaccommodation of varying tube thicknessesVSAvoidfitting tolerance requirements
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The fitting incorporates dynamic adjustment capabilities through its crimping section. The internal ridges are designed to deform and conform to the specific tube geometry during installation, allowing the fitting to adapt to varying tube wall thicknesses. This dynamic conformance enables versatility without requiring extremely tight manufacturing tolerances

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The fitting geometry includes variable parameters such as the angle and depth of the flare reception, the spacing and profile of internal crimping ridges, and the compression force applied during installation. By optimizing these parameters, the fitting can accommodate a range of tube thicknesses while maintaining adequate sealing and mechanical engagement

Inventive Principle:
Principle #35Parameter changes

4Reliability

If multiple assembly steps are used, then connection security may be improved, but assembly time increases

Engineering Contradiction:
Improveconnection securityVSAvoidassembly speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

Multiple functions that traditionally required separate assembly steps are merged into a single integrated fitting component. The crimping features, sealing elements, and structural support are all built into one piece that can be installed in a single operation, improving assembly speed while maintaining connection security

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fitting is pre-assembled with all sealing elements and structural features in place before installation. The tube is pre-flared to the correct geometry. This preliminary preparation allows the final assembly step to simply involve inserting and crimping, achieving both security and speed

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

This process ensures a secure, vibration-resistant connection with simultaneous sealing at multiple points, accommodating varying tube thicknesses and materials, and provides a visual indication of correct assembly, reducing the risk of improper fitting and potential failures.

Implementation Method 1

driving the die into the thick-walled tube and the sleeve with the driving piston; flaring the end portion of the thick-walled tube

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

deforming the sleeve into engagement with the thick-walled tube

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2626150B1Process for making a tube fitting in combination with a thick walled tube and tube fitting in combination with a thick walled tube made by such a process
Publication Date: 2021.02.24 SNAP TITE TECH
  • EP2626150B1 patent drawingFigure 1~5
  • EP2626150B1 patent drawingFigure 6~6B
  • EP2626150B1 patent drawingFigure 7

AI summary

The invention refers to a tube fitting for use in combination with a thick walled tube, a process for making a tube fitting and a die (705). The tube fitting for use in combination with a thick-walled tube (701), comprising: a sleeve (704) in engagement with said thick-walled tube (71); said sleeve being generally cylindrically shaped; said sleeve includes an interior and an exterior; said exterior of said sleeve having a coating (791) thereover; said sleeve includes a sharp annular biting portion (749A) engaging said thick walled tube; said sleeve includes an interior concavity (741); said concavity of said sleeve interengaging said thick-walled tube after deformation thereof; said thick-walled tube includes an end portion (701C); and, said end portion of said thick walled tube being flared.