Shrouded Pipe Coupling for Visual Assembly Without Over-Tightening

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Solution Overview

Problem

Existing mechanical couplings for joining pipe elements face challenges in ensuring proper assembly, particularly when the pipe elements are out of round, out of specification, or require deformation, leading to potential over-tightening and high stresses in bolt and nut assemblies, exacerbated by the use of battery-powered impact wrenches lacking torque feedback.

Innovation Solution

The coupling design features shrouds and recesses on opposing faces of segment attachment members that provide visual alignment indicators, preventing over-tightening by blocking the line of sight to traditional gap indicators, and includes a hinge mechanism for partial contact assembly, ensuring proper engagement without excessive force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the installer continues to tighten the bolts to attempt to achieve planar face-to-face contact, then the visual indication of proper assembly is improved, but high stresses are created within the bolt and nut assemblies

Engineering Contradiction:
Improvevisual indication of assemblyVSAvoidstress in bolt and nut assemblies
Core Design Contradiction:
Measurement precisionVSStress or pressure

Solution Approach 1:

The patent introduces shrouds as intermediary elements that block the line of sight to the gap between bolting lugs. These shrouds act as a mediator between the installer and the traditional visual indicator, preventing the installer from seeing the gap and thus preventing over-tightening while still allowing proper assembly to occur

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the visual feedback mechanism by blocking the traditional gap indicator. Instead of providing continuous visual feedback that encourages tightening, the shrouds create a feedback system that signals proper assembly is achieved when the shrouds meet, preventing excessive tightening feedback

Inventive Principle:
Principle #23Feedback

2Productivity

If battery powered impact wrenches are used to tighten the nut and bolt assemblies, then the tightening speed is improved, but the ability to provide torque feedback to the installer is reduced

Engineering Contradiction:
Improvetightening speedVSAvoidtorque feedback
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The shrouds serve as an intermediary visual indicator system that replaces the traditional gap indicator. This new indicator system works independently of the torque feedback mechanism, providing visual confirmation of assembly progress without relying on the installer's ability to sense torque through the impact wrench

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical torque feedback mechanism (which relies on the installer sensing resistance) with a visual indicator system based on shroud alignment. This substitution allows the use of automated impact wrenches while maintaining assembly control through visual rather than tactile feedback

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

3Adaptability or versatility

If the coupling is assembled with pipe that is grooved incorrectly, out of round, or out of specification, then the coupling must accommodate these conditions, but the traditional visual gap indicator becomes unreliable

Engineering Contradiction:
Improveaccommodation of pipe conditionsVSAvoidreliability of visual gap indicator
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The shrouds introduce a new reference frame for visual indication that is independent of the pipe element conditions. By measuring gap closure between the bolting lugs rather than relying on the traditional indicator, the system adapts to various pipe conditions while maintaining reliable assembly indication

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of using the traditional gap indicator that becomes unreliable under certain conditions, the patent inverts the approach by using the shroud alignment as the primary indicator. This reversal creates a more reliable indication system that works consistently regardless of pipe element variations

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP4707654A1Shrouded coupling
Publication Date: 2026.03.11 VICTAULIC
  • EP4707654A1 patent drawingFigure 1
  • EP4707654A1 patent drawingFigure 2
  • EP4707654A1 patent drawingFigure 3

AI summary

Couplings for joining pipe elements have segments with attachment members with faces which contact one another when the segments are properly installed on the pipe elements. Each segment has one or more shrouds and recesses positioned along the faces. The shrouds on one segment are received within respective recesses on the other segment. The shrouds block the line of sight toward the central space which the segments surround and which receives the pipe elements. Index markings on the segments show visual inspection points to confirm proper engagement between the segments and the pipe elements.