Adhesive Hose-to-Fitting Connection Without Crimping Stress

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Solution Overview

Problem

Existing methods for connecting tubular elements, such as hoses, to hydraulic or pneumatic systems using crimping face challenges like inconsistent deformation, potential fractures, and the need for specialized equipment, which can lead to reduced flow characteristics and mechanical stress due to the use of metal fittings and crimping machines.

Innovation Solution

A method that uses a recess with an outer surface for introducing a bonding compound to create a sealed connection between a tubular element and a fitting without crimping, allowing forces to be transferred through both adhesive strength and the shape-defined connection, enabling a stronger and more reliable assembly with reduced mechanical stress and equipment requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If crimping is used to attach the fitting to the hose, then a strong mechanical connection is achieved, but the hose may suffer from bending, cracking or fracture due to high mechanical force

Engineering Contradiction:
Improveconnection strengthVSAvoidhose integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces the mechanical crimping system with a chemical bonding system using adhesive. The adhesive is introduced into the fitting and bonds the hose to the fitting through chemical adhesion rather than mechanical deformation, eliminating the high forces that cause hose damage while maintaining connection strength

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

Solution Approach 2:

The adhesive acts as an intermediary substance between the hose and the fitting. Instead of direct mechanical contact and deformation, the adhesive mediates the connection by bonding to both surfaces, distributing forces evenly and preventing the concentrated stress that leads to cracking and fracture

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If crimping machines with specialized dies are used to ensure consistent deformation, then manufacturing precision is improved, but device complexity and the need for multiple tool variants increase

Engineering Contradiction:
Improvedeformation consistencyVSAvoidtool variants
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent eliminates the need for specialized crimping machines and dies by replacing the mechanical deformation process with adhesive bonding. This single bonding method can accommodate different hose and fitting combinations without requiring multiple specialized tools, significantly reducing device complexity while maintaining connection quality

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

Solution Approach 2:

The adhesive bonding system provides universal applicability across different hose and fitting types. Instead of requiring specific crimping dies for each combination, the same adhesive bonding process can be used universally, making the system adaptable to various materials and dimensions without increasing tool complexity

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

3Ease of manufacture

If metal fittings are used to provide deformation properties for crimping, then ease of manufacture is improved, but flow characteristics are degraded due to reduced internal diameter

Engineering Contradiction:
Improvedeformation capabilityVSAvoidflow characteristics
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent replaces metal fittings designed for mechanical deformation with a bonding system that does not require material deformation properties. This allows the use of fittings with optimized flow characteristics and larger internal diameters, as the connection strength comes from adhesive bonding rather than mechanical crimping

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

Solution Approach 2:

The patent enables the use of alternative materials such as composites or polymers for fittings instead of traditional metal. These materials can be engineered to provide optimal flow characteristics while the adhesive bonding system provides the necessary connection strength, eliminating the need to sacrifice internal diameter for deformation capability

Inventive Principle:
Principle #40Composite materials

4Strength

If crimping action is applied to create a sealed connection, then connection strength is improved, but sealing consistency becomes difficult to achieve

Engineering Contradiction:
Improveclamping forceVSAvoidsealing consistency
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical crimping action that creates sealing through surface deformation with a chemical bonding process. The adhesive forms a seal through molecular adhesion to the hose and fitting surfaces, providing consistent sealing that is not dependent on achieving uniform mechanical deformation across the circumference

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

Solution Approach 2:

The adhesive serves as an intermediary that creates the seal between the hose and fitting. Instead of relying on the precise mechanical deformation of the hose surface to create a seal, the adhesive bonds to both surfaces and forms a consistent chemical seal, eliminating the variability associated with mechanical crimping precision

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method provides a robust, equipment-independent connection that maintains the inner diameter of the tubular element, reduces mechanical stress, and enhances flow characteristics by eliminating the need for high mechanical force and specialized tools, while allowing for easy assembly and improved sealing without the limitations of metal fittings.

Implementation Method 1

The bonding compound then retains the tubular element and in the same time provides the seal between the tubular element and the device. Forces subjected to the hose are transferred via the bonding compound onto the sleeve both by adhesive strength as well as the shape defined connection of bounding compound and sleeve due to the cavity.

Methodology Applied
Scientific EffectAdhesive: Adhesive

Data Source

PatentEP3686469B1A method for connecting a device with a tubular element
Publication Date: 2021.12.22 DANFOSS POWER SOLUTIONS II TECH AS
  • EP3686469B1 patent drawingFigure 1
  • EP3686469B1 patent drawingFigure 2A
  • EP3686469B1 patent drawingFigure 2B

AI summary

Device for connecting a tubular element, such as a hose or pipe, to another part of a hydraulic or pneumatic system, which device comprises a body having a connection end and a tubular element insertion end, having a cylindrical channel extending from the connection end to the tubular element insertion end, where the connection end serves the purpose of connecting to another part of the hydraulic or pneumatic system, and wherein the cylindrical channel comprises a first part and a second part, wherein the first part is arranged in the tubular element insertion end and wherein the second part is arranged in the connection end, wherein the tubular element insertion end comprises at a middle section a recess extending radially from the first part of the cylindrical channel, along the entire circumference and which recess borders the second part of the cylindrical channel; and wherein the tubular element insertion end comprises at least one bore connecting said recess with the outer surface of the body.