Retractable Mooring Connector with Segmented Lever Arm

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Solution Overview

Problem

Existing mooring chain connector assemblies require significant space and are challenging to handle, especially in confined areas and during sailing, due to their design, which includes a long lever arm that hangs below the chain table, and they are prone to corrosion and complex sea fastening processes.

Innovation Solution

A mooring leg connector with a retractable elongate tubular member and a ratchet mechanism, featuring a double articulation assembly with perpendicular pivot axes, a housing, and cathodic protection, allowing the connector to be easily retracted and preventing chain hanging, while a counterweight maintains the ratchet open when disconnected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a long lever arm is used in the chain connector assembly, then the connector can follow the mooring line movements, but it requires a lot of space and is difficult to handle in confined areas

Engineering Contradiction:
Improveability to follow mooring line movementsVSAvoidspace required
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The chain connector assembly is divided into multiple segments including the chain table, lever arm, and chain stopper assembly that can move independently. This segmentation allows the lever arm to follow mooring line movements while reducing the overall space footprint of the stationary components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lever arm is designed as a dynamic component that can pivot and adjust its position to follow the movements of the mooring lines, rather than being a fixed static structure. This dynamic capability allows the connector to adapt to chain movements without requiring excessive space.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a long lever arm hangs below the chain table, then the connector can accommodate mooring line movements, but it creates sea fastening concerns due to high current and inertia loads

Engineering Contradiction:
Improveability to accommodate mooring line movementsVSAvoidcurrent and inertia loads
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The chain stopper assembly acts as a counterweight mechanism that balances the lever arm, reducing the net loads from currents and inertia. The counterweight system offsets the harmful forces acting on the lever arm during vessel movements and sea conditions.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The chain stopper is extracted as a separate movable component from the main lever arm structure. This allows the chain stopper to be positioned optimally to minimize exposure to current and inertia loads while still enabling the lever arm to follow mooring line movements.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If the chain connector is designed with articulations and a long lever arm, then it can follow mooring line movements, but the installation and relocation operations become time-consuming

Engineering Contradiction:
Improveability to follow mooring line movementsVSAvoidinstallation and relocation time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The connector assembly is segmented into modular components (chain table, lever arm, chain stopper) that can be independently installed and relocated. This modularity significantly reduces installation and relocation time compared to moving the entire assembly as one unit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dynamic pivot connections between components allow for quick adjustment and installation without requiring complex alignment procedures. The lever arm and chain stopper can be rapidly positioned and secured, reducing overall installation time.

Inventive Principle:
Principle #15Dynamics

4Ease of operation

If the elongate tubular member is retractable, then the connector can be easily retracted and handled in confined spaces, but the mechanism becomes more complex

Engineering Contradiction:
Improveease of retraction and handlingVSAvoidmechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The housing is nested within the elongate tubular member, allowing the housing to be retracted inside the tubular member. This nesting arrangement enables easy retraction and compact storage while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The elongate tubular member is designed as a dynamic retractable component that can extend and retract along its axis. This dynamic capability provides ease of operation for retraction and handling in confined spaces while using a straightforward mechanical guidance system.

Inventive Principle:
Principle #15Dynamics

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 simplifies the installation and relocation of floating units, reduces corrosion risk, and simplifies the sling arrangement, ensuring efficient operation without the need for extensive space or complex repositioning, thereby enhancing handling and reducing corrosion-related issues.

Implementation Method 1

the movable part is provided with cathodic protections against the corrosion

Methodology Applied
Scientific EffectCathodic protection:

Implementation Method 2

the ratchet is provided with a counterweight to maintain the ratchet open when the connector is not connected to a mooring leg

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3181440B1Retractable chain connector
Publication Date: 2020.04.29 SINGLE BUOY MOORINGS INC
  • EP3181440B1 patent drawingFigure 1
  • EP3181440B1 patent drawingFigure 2
  • EP3181440B1 patent drawingFigure 3a~3b

AI summary

A mooring leg connector for use with a mooring leg (3) that has an upper portion with an axis, where the mooring leg (3) extends up from the sea floor, to connect a floating body (1) to the seabed The mooring leg connector includes one part (20) fixed with regard to the floating body (1) and another part (30) which is movable with regard to the fixed part (20) from a first position to a second position. The invention further relates to an offshore construction including such a mooring leg connector and a method to retract such a mooring leg connector when disconnected.