Threaded Fluid Coupling with Visual Assembly Indication

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Solution Overview

Problem

Existing threaded coupling assemblies for fluid-carrying conduits lack effective means to ensure complete assembly and are prone to cross-threading and misalignment, leading to potential leaks and inefficiencies.

Innovation Solution

A threaded coupling assembly featuring tapered threads, self-alignment mechanisms, and a visual indicator system with contrasting visual characteristics to clearly indicate complete assembly, minimizing the risk of cross-threading and misalignment, and ensuring a secure, leak-free connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If straight threads are used for coupling assemblies, then ease of manufacture is improved, but the assembly is prone to cross-threading and requires a large assembly angle

Engineering Contradiction:
Improveease of manufactureVSAvoidcross-threading resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the thread geometry from straight to tapered threads. The tapered thread profile (with a typical included angle of 60 degrees) provides self-aligning characteristics that eliminate cross-threading issues while reducing the assembly angle required, thus improving reliability without significantly complicating manufacturing

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The tapered thread creates an asymmetric geometry where the thread angle varies along the length of the thread. This asymmetry provides a mechanical self-correcting feature that guides the mating threads into proper alignment during assembly, preventing cross-threading while requiring minimal assembly angle

Inventive Principle:
Principle #4Asymmetry

2Device complexity

If no integral means to verify proper assembly is provided, then device complexity is reduced, but measurement precision of assembly completion is insufficient

Engineering Contradiction:
Improvedevice complexityVSAvoidassembly completion verification
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent employs a visual indicator system using color-coded markings (such as green for complete assembly, red for incomplete) on the coupling components. This allows installers to quickly and accurately verify proper assembly completion without adding complex mechanical verification mechanisms, thus maintaining low device complexity while achieving high measurement precision

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent replaces complex mechanical verification systems (such as torque sensors, position sensors, or interlocking mechanisms) with a simple visual indication system. This substitution achieves accurate assembly verification through optical means rather than mechanical measurement, keeping the device simple while providing precise feedback on assembly completion

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If two-color visual indication system is used, then ease of operation is improved, but erroneous interpretation may occur due to poor lighting, limited viewing angle, or installer visual impairment

Engineering Contradiction:
Improveease of operationVSAvoidindication accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent enhances the visual indicator system by adding multiple visual characteristics (different colors, patterns, or textures) at different locations on the coupling components. For example, the complete assembly state may be indicated by a specific color combination, a particular pattern alignment, or a visible gap closure, providing redundant visual cues that can be detected from various angles and lighting conditions, thus maintaining ease of operation while improving indication accuracy and reducing erroneous interpretation

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3953629B1Threaded coupling assemblies for interconnecting fluid-carrying conduits
Publication Date: 2023.12.06 PARKER HANNIFIN CORP
  • EP3953629B1 patent drawingFigure 1~2
  • EP3953629B1 patent drawingFigure 3~4
  • EP3953629B1 patent drawingFigure 5A~6B

AI summary

A threaded coupling assembly include a union (12), a tube end (14), and a coupling nut (16). A pair of telescoping indicator rings (30, 32), a radially outer ring and a radially inner ring, are respectively connected to the union and the nut. The inner ring has a first visual characteristic contrasting with a second visual characteristic of the inner ring. The outer ring has a third visual characteristic contrasting with the second visual characteristic of the inner ring. The first visual characteristic is aligned with and viewable through the window (60) of the outer ring when the threaded coupling assembly is in the fully assembled state, and the first visual characteristic is out of alignment with the window when the threaded coupling assembly is not in the fully assembled state. The assembly may utilize tapered threads and have one or more features for self-alignment and/or sealability.