Anti-rotation Strip for Pipe End Fitting Connection

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Solution Overview

Problem

Existing connecting devices for pipes with end fittings are complex, costly, and prone to malfunctions due to complex anti-rotation mechanisms that can trap pieces, leading to untimely unscrewing issues, especially under vibrations or jarring conditions.

Innovation Solution

A compact and cost-effective anti-rotation mechanism using metal strips with protrusions that elastically engage with concavities on the end fittings, preventing untimely unscrewing by locking only when a predetermined torque is exceeded, allowing easy assembly and smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex anti-rotation mechanisms with multiple elements are used, then untimely unscrewing is prevented, but device complexity increases and assembly becomes lengthy and difficult

Engineering Contradiction:

Improveprevention of untimely unscrewingVSAvoidnumber of elements in anti-rotation mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The anti-rotation mechanism is segmented into simple, discrete components: protrusions on the nut and corresponding concavities on the end fitting. These segmented features distribute the anti-rotation function across multiple simple contact points rather than requiring a complex integrated mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention extracts the essential anti-rotation function from complex mechanical mechanisms and implements it through simple geometric features (protrusions and concavities). This extraction eliminates unnecessary intermediate elements while preserving the core functional effect of preventing rotational movement.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If complex anti-rotation mechanisms are used, then untimely unscrewing is prevented, but manufacturing cost increases

Engineering Contradiction:

Improveprevention of untimely unscrewingVSAvoidmanufacturing cost of anti-rotation mechanism

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The anti-rotation mechanism uses simple, inexpensive geometric features (protrusions and concavities) that can be manufactured as integral parts of the nut and end fitting. These features require minimal additional material and processing, making them cost-effective compared to complex mechanical anti-rotation devices.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The anti-rotation features are merged with the primary structural components (nut and end fitting) rather than being separate assemblies. The protrusions and concavities are formed as integral features during the manufacturing of the main parts, eliminating the need for separate anti-rotation components and reducing overall manufacturing cost.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If deep grooves are used to accommodate spring anti-rotation mechanisms, then untimely unscrewing is prevented, but the nut is weakened

Engineering Contradiction:

Improveprevention of untimely unscrewingVSAvoidstructural strength of the nut

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

Instead of using deep grooves that would significantly weaken the nut, the invention uses shallow protrusions and concavities that provide sufficient anti-rotation capability with minimal material removal. This partial action approach achieves the required functional effect while preserving the structural integrity of the nut.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The invention extracts the anti-rotation function from the nut's structural material by adding minimal geometric features (protrusions) rather than removing significant material to create deep grooves. This extraction approach maintains the nut's strength while providing the necessary anti-rotation capability.

Inventive Principle:

Principle #2Taking out (Extraction)

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 secure, self-locking connection that prevents untimely unscrewing while allowing intentional disassembly, reducing the risk of malfunctions and assembly complexity, and maintaining structural integrity under stress conditions.

Implementation Method 1

said strip comprising at least one protrusion cut out of its thickness, which is capable of entering radially and elastically into at least one concavity, during the relative rotation between the nut and the locking end fitting

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

emerging therefrom when a torque exceeding a predetermined threshold is applied between the nut and the locking end fitting

Methodology Applied

Scientific EffectTorque: Torque

Data Source

PatentUS9163758B2Device for the secured connection of two end fittings, particularly of a pipe

Publication Date: 2015.10.20 JPB SYST

AI summary

The device connects a first end fitting to a second end fitting, particularly of a pipe. A nut is provided with a threaded bore into which the first end fitting is screwed along a longitudinal axis. In the tightened position, the first end fitting is axially stressed relative to the second end fitting housed in the nut. Rotation-proofing structure is provided between the nut and at least one of the first and second end fittings hereafter referred to as the locking end fitting. The rotation-proofing structure includes at least one strip arranged around the locking end fitting. The strip comprises at least one protrusion radially penetrating into at least one concavity.