Two-Piece Bayonet Coupling Nut for Waterproof Tube Joints

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Solution Overview

Problem

Existing bayonet connections for tubular components in heating equipment are unsuitable for restrictive or poorly accessible areas due to the need for free rotation and are not easily demountable without specialized tools, and they do not utilize the superior sealing performance of C-seals.

Innovation Solution

A two-piece coupling nut with bayonet slots and pins, allowing rotation for connection and sealed with a C-seal, which can be tightened or loosened using a hexagonal wrench, and is designed for easy assembly and disassembly without specialized tools, using a C-seal for enhanced sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional bayonet connection is used requiring free rotation, then connection speed and ease of installation are improved, but applicability in restrictive or poorly accessible areas deteriorates

Engineering Contradiction:

Improveease of installationVSAvoidapplicability in restrictive areas

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

Instead of rotating the coupling nut around the tube axis as in conventional bayonet connections, the invention inverts the mechanism by having the bayonet pins on the second tube rotate relative to the coupling nut, enabling connection in restrictive areas where the coupling nut cannot be accessed for rotation

Inventive Principle:

Principle #13The other way round (Inversion)

2Strength

If threaded connection with union nut is used, then connection strength and sealing are improved, but ease of disassembly and replacement of damaged parts deteriorates

Engineering Contradiction:

Improveconnection strengthVSAvoidease of disassembly

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

The invention segments the connection system into modular components (first tube, coupling nut, second tube with bayonet mechanism) that can be independently replaced. The bayonet connection allows quick disassembly without specialized tools, enabling easy replacement of damaged parts while maintaining connection strength through proper locking mechanism design

Inventive Principle:

Principle #1Segmentation

3Reliability

If O-ring sealing is used in bayonet connection, then sealing performance is improved, but adaptability to high pressure and temperature conditions deteriorates

Engineering Contradiction:

Improvesealing performanceVSAvoidadaptability to heating equipment conditions

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention changes the sealing parameter from O-ring elastomeric sealing to C-seal rigid/semi-rigid sealing, which maintains reliable sealing performance under high pressure and temperature conditions typical of heating equipment, while preserving the bayonet connection's ease of installation and disassembly advantages

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3730827B1Waterproof demountable joint

Publication Date: 2021.12.22 VAILLANT GMBH(DE)

Figure 1
Figure 2a
Figure 2b

AI summary

Waterproof demountable joint including the first tubular component (1), second tubular component (15), two-piece coupling nut (5) and C-seal (14). The two-piece coupling nut (5) consists of two identical segments (5a, 5b).