Split Collet Connector With Opposite-Handed Threads

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Solution Overview

Problem

Existing connector devices fail to provide a satisfactory locking mechanism, especially in high-pressure offshore environments subjected to torsional and lateral forces, due to inadequate sealing and locking capabilities.

Innovation Solution

The connector device employs interengaging screwthreads of opposite handedness between the collar and the male part, along with a split collet and chamfered surfaces, to ensure a strong connection and seal, while a nut facilitates torque application and splaying of the collet for enhanced locking. The collet is splayed as the nut is tightened, engaging the wedge part to secure the male and female parts against forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional gland nut with wedge part is used to lock the male part, then the device can be assembled, but it fails to provide satisfactory locking under high pressure and torsional forces

Engineering Contradiction:
Improvelocking capabilityVSAvoidresistance to torsional and lateral forces
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The locking mechanism is divided into two independent but complementary functions: the collet provides radial clamping force through splaying, while the collar with opposite-handed screwthreads provides axial locking. This segmentation allows each component to specialize in one aspect of force resistance, with the collet handling radial forces and the collar handling axial forces, together providing comprehensive locking capability under high pressure and torsional loads.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The collar employs screwthreads of opposite handedness relative to the collet's external screwthread and the female part's internal screwthread. This asymmetric threading configuration creates a mechanical interlock where friction between the collet and collar cannot undo the collar during tightening, providing inherent resistance to unscrewing under torsional forces and enhancing the overall reliability of the locking mechanism.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If the collet is made as a single solid piece, then it provides continuous structure, but it cannot be splayed effectively to engage the female part

Engineering Contradiction:
Improvesealing engagementVSAvoidsplit collet structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The collet is divided into multiple segments by longitudinal slots, transforming it from a solid cylindrical structure into a splittable component. This segmentation enables the collet to splay outward when the nut is tightened, allowing the segmented surfaces to engage with corresponding surfaces in the female part to create an effective seal, while the slots provide the necessary flexibility for this transformation.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the collar screwthreads have the same handedness as the collet external screwthread, then assembly is simpler, but friction during tightening can undo the collar

Engineering Contradiction:
Improvetightening processVSAvoidcollar retention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The collar employs screwthreads of opposite handedness relative to the collet's external screwthread and the female part's internal screwthread. This asymmetric threading configuration creates a mechanical interlock where friction between the collet and collar cannot undo the collar during tightening, providing inherent resistance to unscrewing under torsional forces and enhancing the overall reliability of the locking mechanism.

Inventive Principle:
Principle #4Asymmetry

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

This configuration provides a robust and reliable seal and locking mechanism capable of withstanding high torsional and lateral forces, ensuring effective transmission of axial forces and maintaining a secure connection under challenging offshore conditions.

Implementation Method 1

A wedge part has a forward portion which extends within the said sleeve portion and a rearward portion which abuts a portion of the gland screw, a forward portion of the wedge part and the said sleeve portion having mutually engaging wedge surfaces.

Methodology Applied
Scientific EffectWedge: Wedge

Implementation Method 2

The fact that the interengaging screwthreads on the collar and on the male part are of opposite handedness to the said external screwthread of the collet and the internal screwthread of such a female part ensures that any friction between the collet and the collar does not undo the collar whilst the collet is screwed into such a female part.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3175162B1A connector device
Publication Date: 2020.02.12 KUTTING UK
  • EP3175162B1 patent drawingFigure 1~2
  • EP3175162B1 patent drawingFigure 3~4
  • EP3175162B1 patent drawingFigure 5

AI summary

A connector device (10) comprising a male part (12) and a female part (50) which engages the male part (12) when those two parts (12 and 50) are connected together, those two parts (12 and 50) having respective passageways which are coaxial when those two parts (12 and 50) are connected together. A collet (24) surrounds the male part (12) and is coupled thereto, which collet (12) has an external screwthread which engages an internal screwthread on the female part (50), so that relative rotation between those screwthreads in a given sense causes the female part (50) to sealingly engage the male part (12). The collet (24) has at least one slot (40) in it extending longitudinally with respect to the axis of the screwthreads to enable it to be splayed. A wedge part (34) is located between the male part (12) and the collet (24) and is displaceable longitudinally with respect to the axis of the screwthreads to splay the collet (24) thereby to lock the male and female parts (12 and 50) in such a sealing engagement with one another.