Plastic Pipe Connection Device with Elastic Spring Ring

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Solution Overview

Problem

Existing connecting devices for plastic pipes face issues with securely holding the pipe between the expanding ring and sleeve due to increased sliding resistance and risk of the expansion ring not being pushed onto the outer cone, leading to incomplete clamping and complex assembly.

Innovation Solution

A rubber-elastic spring ring is arranged between the expansion ring and the support ring in a shear-resistant manner, with the expansion ring, support ring, and spring ring forming a composite body that ensures the expansion ring lies within the circumference of the nipple during assembly and is securely carried along during disassembly, maintaining defined contact pressure and preventing radial deflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an expanding ring with retaining claws is used to hold the plastic pipe, then the pipe can be secured between the expansion ring and sleeve, but the sliding resistance increases and the expansion ring may not be pushed onto the outer cone during assembly

Engineering Contradiction:
Improvesecure clamping of plastic pipeVSAvoidassembly difficulty
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The support ring is designed to be elastically deformable, allowing it to dynamically adapt its state: compressed during assembly to reduce resistance, and expanded during disassembly to increase clamping force. This dynamic behavior resolves the contradiction between secure clamping and ease of assembly.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The support ring's radial dimension changes under axial load: it compresses radially when axially compressed during assembly, reducing the friction coefficient and allowing smooth passage of the plastic pipe. During disassembly, the axial force causes radial expansion, increasing the clamping force on the expansion ring.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the expansion ring is supported by a rubber-elastic support ring on the axial stop, then assembly is simplified, but the support ring may be forced out of its receiving groove and pushed along the connection nipple, impairing the spring function

Engineering Contradiction:
Improveassembly simplicityVSAvoidsupport ring functionality
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The support ring is segmented with radial slots that allow controlled deformation. This segmentation enables the ring to compress radially during assembly while remaining confined to its receiving groove, preventing it from being pushed along the connection nipple while maintaining its spring function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support ring is designed as a flexible elastic component that can deform radially under axial compression. This flexibility allows it to accommodate the expansion ring during assembly while maintaining its position in the receiving groove, preventing displacement along the connection nipple.

Inventive Principle:
Principle #30Flexible shells and thin films

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 configuration simplifies assembly, ensures secure clamping forces between the expansion ring and sleeve, and prevents incorrect assembly, while maintaining effective contact pressure and reducing the risk of the spring ring jamming between the nipple and pipe.

Implementation Method 1

a rubber-elastic spring ring (8) is arranged between the expansion ring (5) and the support ring (9)... the expansion ring (5), support ring (9) and spring ring (8) form a shear-resistant composite body

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the corresponding protruding retaining claws (7) force the expansion ring (5) to be carried along safely with the plastic pipe (1), with the result that the on the plastic pipe effective clamping forces between the expansion ring (5) and the sleeve (4) increase with increasing deduction

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2534401B1Connection device for a plastic pipe
Publication Date: 2014.01.01 KE KELIT KUNSTSTOFFWERK GMBH
  • EP2534401B1 patent drawingFigure 1
  • EP2534401B1 patent drawingFigure 2~4
  • EP2534401B1 patent drawingFigure 5

AI summary

The invention relates to a connection device for a plastic tube (1), comprising a connection nipple (2) that receives the plastic tube (1) and forms an outer cone (6) widening towards the free nipple end. An expansion ring (5) that can be slid over the outer cone (6) and comprises outwardly protruding retaining claws (7) is provided between the outer cone and an axial abutment (11), said expansion ring being supported on the axial abutment (11) of the connection nipple (2) by means of a supporting ring (9). Said device also comprises a sleeve (4) surrounding the plastic tube (1) that has been pushed onto the connection nipple (3) and gripping in a traction-resistant manner onto an abutment flange (3) of the connection nipple. In order to create advantageous assembly conditions, a rubber-elastic spring ring (8) is arranged between the expansion ring (5) and the supporting ring (9). The expansion ring (5), the supporting ring (10) and the spring ring (8) are interconnected in a shear-resistant manner.