Plug-in Pipe Coupling with Deformable Retaining Ring

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing plug-in connections for pipelines lack reliability in ensuring proper locking, leading to potential disconnection under pressure, and are difficult to produce and maintain high holding forces, with existing solutions either requiring complex tools for disassembly or limited peripheral engagement.

Innovation Solution

The plug-in connection features a plug-in pin with inclined surfaces and a radially deformable retaining ring that engages in multiple positions, allowing for easy recognition of incomplete insertions and secure locking, along with a simple unlocking mechanism using a movable sleeve that can be easily mounted and secured without high precision requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single locking position is used, then the structure is simple, but it is difficult to determine whether the plug-in pin is properly locked and may come loose under pressure

Engineering Contradiction:
Improvelocking reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism is divided into two distinct positions: a pre-locking position with the first retaining ring and a fully locked position with the second retaining ring. This segmentation allows the system to provide intermediate feedback (pre-locking) before achieving full locking, enabling verification of proper insertion while maintaining structural simplicity through the use of standard ring components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first retaining ring provides a preliminary locking action at the pre-locking position before the plug-in pin reaches the final locked position. This preliminary action serves as an intermediate checkpoint that indicates proper insertion has occurred, allowing operators to verify locking status without requiring complex sensing systems.

Inventive Principle:
Principle #10Preliminary action

2Force

If the retaining ring engages in a limited peripheral area, then the structure is simple, but high holding forces cannot be absorbed

Engineering Contradiction:
Improveholding forceVSAvoidengagement structure complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The solution transitions from single-point or limited peripheral engagement to distributed engagement along the entire circumference of the plug-in pin. The retaining rings engage with the grooves around the full perimeter, distributing the holding force across multiple contact points in the circumferential dimension, thereby achieving high holding forces without requiring complex localized engagement structures.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The retaining rings provide uniform engagement around the entire circumference of the plug-in pin through the grooves. This homogeneous distribution of engagement points ensures that holding forces are evenly distributed, maximizing the overall holding capacity while maintaining structural simplicity through the use of standard circular ring components.

Inventive Principle:
Principle #33Homogeneity

3Reliability

If specialized tools are required to remove the retaining ring, then the locking is secure, but the unplugging process becomes complex and requires additional tools

Engineering Contradiction:
Improvelocking securityVSAvoidunplugging ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The unlocking mechanism is designed to be self-service, allowing the operator to release the retaining ring directly through the groove structure without requiring specialized tools. The groove geometry enables the retaining ring to be manipulated and released using simple manual actions, making the unplugging process as easy as the locking process while maintaining secure locking during operation.

Inventive Principle:
Principle #25Self-service

4Reliability

If the plug-in pin must be pushed very deep to achieve locking, then secure locking is achieved, but incomplete insertion cannot be detected and may cause leakage

Engineering Contradiction:
Improvelocking securityVSAvoidinsertion depth detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The system provides tactile and positional feedback through the two-stage locking mechanism. When the plug-in pin reaches the pre-locking position, the first retaining ring engages and provides a noticeable stop or resistance change, giving the operator immediate feedback that proper insertion has occurred. This feedback mechanism eliminates the need for precise depth measurement while ensuring reliable locking.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs visual indicators (such as colored rings or markings on the retaining rings or pin) that change position or become visible when the plug-in pin reaches the correct locking position. This visual feedback allows operators to immediately verify proper insertion without requiring measurement tools, while the two-stage design ensures that incomplete insertion is physically prevented from achieving full locking.

Inventive Principle:
Principle #32Color 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

This design ensures reliable locking and easy disassembly, prevents incomplete insertions from coming loose, and allows for high holding forces while being cost-effective and easy to produce, with visual pressure leaks indicating incomplete connections.

Implementation Method 1

the retaining ring being radially elastically deformable through the second shoulder during the plugging and unplugging process

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP1770320B1Releasable plug-in coupling for pipes
Publication Date: 2008.04.30 JOHANNES SCHAFER VORMALS STETTINER SCHRAUBENWERKE GMBH & CO KG
  • EP1770320B1 patent drawingFigure 1
  • EP1770320B1 patent drawingFigure 2
  • EP1770320B1 patent drawingFigure 3

AI summary

Detachable plug-in connection has a spigot (5) and second annulus recess (11) in plug-in direction in front of first shoulder (8). A second annulus shoulder (7) in front of a second annulus has inclined surfaces on both sides whereby retainer ring (3) is radially elastically deformed during plugging and releasing process by second shoulder and is displaced into internal recess (24) of external part (2). The retainer ring intervenes in pre-locking position in second annulus recess of the spigot and retains the spigot in the external part. A joint ring (29) is arranged in such a manner at external part or internal part (1) that it acquire in pre-locking position in a sealing contact with internal part or external part.