Plug-In Pipe Connection With Internal Spring Locking

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Solution Overview

Problem

Existing pipe connectors with external securing clips pose risks of injury from sharp edges, snagging, and potential damage to sealing elements during handling and assembly.

Innovation Solution

A plug connection design featuring a spring element on the inner tube with an outer tube expansion that engages with an engagement structure, providing a hidden safety function that is visually and tactilely controllable, and includes a fastening structure for the spring element, such as a retaining bead, to secure the connection without protruding outward and ensuring the sealing element is protected during assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an external locking clamp is used to secure the pipe connection, then the connection reliability is improved, but the risk of injury from sharp edges and snagging increases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidinjury risk and snagging
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The harmful external locking clamp is extracted and replaced by an internal spring element that is integrated into the inner tube structure. The spring element protrudes inward into the inner tube's lumen rather than extending outward, eliminating sharp external edges and protrusions that cause injury and snagging while maintaining the locking function through engagement with the outer tube's expansion.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The spring element is nested within the inner tube structure, with its fastening structure integrated into the inner tube wall. The spring element's locking engagement is nested within the outer tube's first expansion, creating a concealed locking mechanism that is not externally visible and eliminates external sharp edges.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If an external locking clamp is used to secure the pipe connection, then the connection reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveconnection reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring element and its fastening structure are merged into a single integrated component that is directly formed on the inner tube. The fastening structure is combined with the inner tube wall, eliminating the need for separate external clamps or additional fastening parts, thereby reducing device complexity while maintaining reliable locking.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring element serves multiple functions: it provides the locking force through its elastic deformation, engages with the outer tube's expansion to secure the connection, and its fastening structure integrates with the inner tube to prevent detachment. This multi-functional design eliminates the need for separate locking mechanisms.

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

3Reliability

If a spring element with external fastening structure is used, then the locking function is improved, but the sealing element may be damaged during assembly

Engineering Contradiction:
Improvelocking functionVSAvoidsealing element damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Instead of having the fastening structure protrude outward from the inner tube, it is inverted to protrude inward into the inner tube's lumen. This inversion repositions the spring element and its fastening structure away from the sealing element location, eliminating the risk of damage during assembly while maintaining the locking function through engagement with the outer tube's internal expansion.

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

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 design eliminates the risk of injury and snagging, ensures the sealing element is not damaged during assembly, and allows for easy assembly and disassembly of the pipe connection, maintaining the security function while being cost-effective and visually inspectable.

Implementation Method 1

a spring element (4), which is arranged on the outside of the inner tube (2) in the region of its end

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4293267A1Plug-in pipe connection
Publication Date: 2023.12.20 WITZENMANN GMBH
  • EP4293267A1 patent drawingFigure 1~2
  • EP4293267A1 patent drawingFigure 3~4
  • EP4293267A1 patent drawingFigure 5

AI summary

A plug connection (1) is proposed, comprising an inner tube (2) and an outer tube (3), the outer tube (3) being fitted with one end onto an end of the inner tube (2), the plug connection (1) being characterized by the fact that a spring element (4) is arranged on the outside of the inner tube (2) in the region of its said end; the outer tube (3) having a first expansion (3a) at its said end, in the region of which first expansion (3a) the outer tube (3) is spaced (A) from the inner tube (2) and the spring element (4) overlaps; and the outer tube (3) having an engagement structure (3b) in the region of the first expansion (3a), with which engagement structure (3b) the spring element (4) engages.