Push-fit Connector with Disposable Cap for Fluid Tightness

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Solution Overview

Problem

Existing fluid-carrying line systems, particularly for water or aqueous solutions, face challenges in achieving long-term tightness and mechanical stability in plug-in connections, which are inferior to screw and press connections in terms of security and durability, and often rely on elastic O-rings that lose elasticity over time, compromising sealing effectiveness.

Innovation Solution

A connection piece featuring a cap part that encloses a second tubular part with a clamping/claw ring, which is displaced by a spring element and accommodates a ring seal, ensuring reliable axial securing and sealing through a combination of radial pressing and positive locking, with the ring seal being displaced to achieve permanent compression, preventing fluid leakage and maintaining tightness over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If elastic O-rings are used for sealing in plug-in connections, then the connection is simple to install, but the seal loses elasticity over time and reliability deteriorates

Engineering Contradiction:
Improveinstallation simplicityVSAvoidsealing effectiveness over time
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent employs a disposable cap that is destroyed during the connection process. This cap contains the sealing mechanism and is consumed to create the permanent compression seal, eliminating the need for reusable elastic seals that degrade over time. The cap's destruction is intentional and necessary to achieve the sealing function.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The sealing action is performed preliminarily during the connection process itself. The cap's destruction during insertion creates immediate permanent compression of the seal against the tube, establishing the seal before the connection is complete. This preliminary sealing action eliminates the need for ongoing elastic pressure maintenance.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If a claw ring is used to secure the tube, then mechanical connection is simplified, but a ring-shaped weakening point is created that may break under high loads

Engineering Contradiction:
Improveconnection structure simplicityVSAvoidtube mechanical strength
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The patent extracts the tube-clamping function from the cap itself and transfers it to a separate disposable cap component. The cap contains the clamping mechanism that secures the tube without creating weakening points in the tube wall, as the clamping force is applied externally by the cap rather than through penetration or internal reinforcement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The disposable cap provides beforehand cushioning by distributing the mechanical loads and stresses away from the tube. The cap absorbs and disperses forces that would otherwise concentrate at weak points in the tube, protecting the tube's structural integrity during and after connection.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the ring seal is radially compressed during insertion, then sealing is achieved, but the compression is limited to avoid damage and insertion difficulty

Engineering Contradiction:
Improvesealing securityVSAvoidinsertion ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The seal compression is performed preliminarily during the insertion process itself. As the tube is inserted, the cap is destroyed and the seal is immediately compressed against the tube, creating the seal during the insertion action rather than requiring separate compression steps or excessive pre-compression.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The insertion process rushes through the sealing phase by destroying the cap and compressing the seal in a single continuous motion. The seal is compressed just enough during insertion to create an effective seal, without applying excessive force that would damage the seal or make insertion difficult. The process skips unnecessary intermediate steps.

Inventive Principle:
Principle #21Skipping (Rushing through)

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 solution provides a stable mechanical connection and reliable sealing, ensuring the connection remains tight over a long period, even under varying conditions and tolerances, while preventing damage to the seal and maintaining fluid integrity.

Implementation Method 1

a spring element arranged on the front side, by which the clamping/claw ring can be displaced in the receiving groove and is pressed against the insertion/push-on direction

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the ring seal being displaced to achieve permanent compression, preventing fluid leakage and maintaining tightness over time

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

ensuring reliable axial securing and sealing through a combination of radial pressing and positive locking

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2192338B8Connecting piece
Publication Date: 2015.10.07 R NUSSBAUM & CO

AI summary

A connector (211.1, 211.2) comprises a first tubular part (221.1, 221.2) which can be fluid-tightly connected to a second tubular part (250) of a fluid-carrying piping system. The connector (211.1, 211.2) is designed such that one of the tubular parts (221.1, 221.2) is partially enclosed by the other tubular part (250) when connected. In the first tubular part (221.1, 221.2), an annular groove (216.1a, 216.1b, 216.2a, 216.2b) is recessed on a surface that contacts the second tubular part (250) when connected. A ring seal (217.1a, 217.1b, 217.2a, 217.2b) is inserted into this groove. The connecting piece (211.1, 211.2) is designed such that the second tubular part (250) can be connected to the first tubular part (221.1, 221.2) by sliding it onto the first part (221.1, 221.2) or by inserting it into the first part in a push-fit direction.The connecting piece comprises a cap section (222.1, 222.2) which partially encloses the second tubular section (250) when connected. The connecting piece (211.1, 211.2) further comprises a clamping/claw ring (224.1, 224.2) for axially securing the inserted second tubular section (250). The clamping/claw ring (224.1, 224.2) is received in a receiving groove (222.1b, 222.2b) in the cap section (222.1, 222.2) that widens in the insertion/adjustment direction, is displaceable in the receiving groove, and is pressed against the insertion/adjustment direction by a spring element arranged at its end face.