Tube Fitting Snap Coupling Tool-Less Assembly

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Solution Overview

Problem

Existing tubing connections face issues with improper torque application, ergonomic challenges, and difficulty in installation in hard-to-reach spaces, leading to prolonged assembly times and lack of indication for proper connection.

Innovation Solution

A tube fitting system featuring a first coupling member with a snap coupling and a second coupling member with both quick-connect and threaded engagement sides, utilizing elastomeric seals and angled surfaces for secure engagement and easy assembly, which provides tactile, aural, and visual indications of a proper seal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If threaded connection with high torque is used to ensure secure connection, then connection strength is improved, but ergonomic difficulty and risk of over-tightening increase

Engineering Contradiction:
Improveconnection strengthVSAvoidergonomic difficulty
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent replaces the traditional threaded mechanical connection system with a snap-fit coupling system that uses elastic deformation and geometric interlocking instead of high torque threading. The snap coupling engages through elastic deflection of the coupling members, eliminating the need for high torque application and associated ergonomic difficulties.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the connection mechanism from high-torque threaded engagement to low-force snap-fit engagement. The coupling members are designed with elastic properties that allow them to deflect and snap into place with minimal force, fundamentally changing the force parameter from high torque to low insertion force.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If threaded connection with tools is used to achieve proper torque, then connection reliability is improved, but assembly time and complexity increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The snap coupling system is designed to self-align and self-lock through its geometric features. The coupling members automatically engage with each other when brought together, with the elastic deflection providing both the connection force and the locking mechanism, eliminating the need for external tools and complex assembly procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts the tool requirement from the assembly process entirely. By designing a tool-less snap-fit system, all tool-related steps (torque measurement, wrench application, etc.) are removed, reducing assembly time and procedural complexity while maintaining connection reliability through the snap engagement mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If traditional connection methods are used in limited space applications, then connection security is achieved, but ease of installation deteriorates due to hard-to-reach locations

Engineering Contradiction:
Improveconnection securityVSAvoidease of installation
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

Instead of requiring the installer to apply torque from an external direction (which is difficult in tight spaces), the snap coupling system inverts the connection approach by having the coupling members engage through simple insertion and elastic deflection. This reversal of the connection mechanism allows installation from any direction without requiring torque application tools or significant access space.

Inventive Principle:
Principle #13The other way round (Inversion)

4Reliability

If metal on metal seals are used to ensure connection integrity, then seal reliability is improved, but torque requirements and ergonomic difficulty increase

Engineering Contradiction:
Improveseal reliabilityVSAvoidtorque requirements
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent employs composite sealing by combining elastomeric material with the rigid coupling members. The elastomeric seal provides the sealing function through its compliant nature, while the rigid snap-fit structure provides the mechanical connection. This composite approach eliminates the need for high torque metal-on-metal sealing surfaces.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The sealing mechanism changes from high-contact-pressure metal-on-metal sealing to low-force elastomeric sealing. The elastomeric material deforms to create the seal under minimal compressive force, fundamentally changing the pressure parameter from high contact pressure to low compressive stress.

Inventive Principle:
Principle #35Parameter changes

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 tool-less installation with reduced assembly time, ensures positive low-force seals, and prevents over-tightening, allowing for quick and secure connection of tubing in various fluidic systems.

Implementation Method 1

at least one elastomeric seal disposed between the first coupling member and the second coupling member

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a first coupling member having at least a snap coupling, and a second coupling member having a first quick-connect side having a mating snap coupling

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2894382B1Tube fitting
Publication Date: 2019.02.20 THE BOEING CO
  • EP2894382B1 patent drawingFigure 1~2
  • EP2894382B1 patent drawingFigure 3~4
  • EP2894382B1 patent drawingFigure 5

AI summary

A tube fitting (105) including a first coupling member (100) having at least a snap coupling (115), and a second coupling member (101) having a first quick-connect side having a mating snap coupling (106) disposed at a first end of the second coupling member, and a second quick-connect side configured for threaded engagement disposed at a second end of the second coupling member, the second end being opposite the first end, wherein the mating snap coupling (106) is configured to engage the snap coupling (115) to effect coupling of the first (100) and second (101) coupling member.