Pipe Fitting Retainer Tabs for Assembly Orientation Verification

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Solution Overview

Problem

Existing mechanical fittings for joining plain end pipe elements face challenges in ensuring proper orientation of toothed retainers, which can lead to inadequate mechanical engagement and fluid tightness if incorrectly assembled, making it difficult to verify correct orientation before pressurization.

Innovation Solution

The design incorporates angularly oriented teeth and tabs within channels in the housing portions, with specific floor curvatures and apertures that allow for visual confirmation of proper retainer orientation and insertion, preventing improper assembly by resisting insertion if the retainer is misoriented.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If toothed retainers are used to provide mechanical restraint, then the pipe elements remain coupled under high pressure, but it becomes difficult to determine if the retainers are properly oriented before pressurization

Engineering Contradiction:
Improvemechanical engagementVSAvoidretainer orientation
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses visual indicators (such as colored markings or contrasting colors) on the retainer and housing to provide immediate visual feedback during assembly. When the retainer is properly oriented, the colors align or display a specific pattern, making it easy to detect correct orientation without pressurization.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent introduces an intermediary visual indication system that mediates between the retainer orientation and the assembler's knowledge. This intermediary (visual marker) translates the internal mechanical state into external observable information, solving the detection difficulty.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the retainer is improperly oriented, then insufficient mechanical engagement occurs, but the improper assembly cannot be detected until pressurization

Engineering Contradiction:
Improvejoint integrityVSAvoidassembly verification
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary verification through visual indicators that allow detection of retainer orientation before pressurization. This preliminary action prevents improper assembly from proceeding, saving time by avoiding rework after pressurization or system failure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The design incorporates features that prevent improper assembly from completing its harmful effect. The visual indicators serve as preliminary anti-action by alerting the assembler before the improper orientation can lead to joint failure under pressure.

Inventive Principle:
Principle #9Preliminary anti-action

3Strength

If angularly oriented teeth are used for self-actuating engagement, then mechanical restraint increases with applied force, but improper orientation cannot be detected during assembly

Engineering Contradiction:
Improvewithdrawal resistanceVSAvoidorientation correctness
Core Design Contradiction:
StrengthVSDifficulty of detecting and measuring

Solution Approach 1:

The patent employs asymmetric visual indicators on the retainer and housing that only align when the retainer is correctly oriented. This asymmetric design works in conjunction with the angular teeth, providing both the self-actuating mechanical engagement and the visual orientation detection capability.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3757437B1Fitting having tabbed retainer and observation apertures
Publication Date: 2023.09.06 VICTAULIC
  • EP3757437B1 patent drawingFigure 1
  • EP3757437B1 patent drawingFigure 2
  • EP3757437B1 patent drawingFigure 2A~4

AI summary

A pipe fitting (10) for plain end pipe is formed of housing portions (12, 14) defining receptacles(16, 18) for receiving pipe elements. The receptacles are coaxial with respective axes oriented angularly with respect to each other. Each receptacle has a channel (26, 28) that faces a respective axis with floors at different radii of curvature. Retainers (42) are received within the channels. The retainers have teeth and one or more offset tabs that cooperate with the channels to prevent improper assembly of the fitting. Ring seals are received within channels positioned adjacent to the receptacles. The ring seals cooperate with the retainers to hold the segments in spaced relation sufficient to insert pipe elements into the receptacles when the fitting is pre-assembled. Apertures (8) are provided in the receptacles to permit visual determination of the presence of the retainers post assembly.