Hinged Fairlead Sectors for Ship Towing Cable Bend Radius Control

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Solution Overview

Problem

Existing towing devices for ships, particularly in underwater acoustics, face issues with cable mechanical stress due to bending beyond a minimum radius of curvature, leading to deterioration and damage, and require bulky actuators and articulated arms for maneuvering, which are inefficient and prone to cable stripping.

Innovation Solution

A towing device with a fairlead comprising multiple articulated sectors and limiting means to prevent cable curvature beyond a minimum radius, eliminating the need for an articulated arm by guiding the cable through grooves and controlling its direction with pivot joints, ensuring safe passage and storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed fairlead with trumpet shape is used to guide the cable, then the cable's effective bend radius is secured, but the device becomes bulky and requires additional components for maneuvering

Engineering Contradiction:
Improvecable bend radius protectionVSAvoidfairlead structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fairlead is divided into multiple articulated sectors that can move independently relative to each other. Each sector contains grooves that guide the cable, and the sectors are connected by articulations that allow them to pivot and adapt to changes in cable direction while maintaining the minimum bend radius constraint.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If an articulated arm is added to maneuver towed bodies, then the passage of towed bodies is facilitated, but the device becomes more complex and requires actuators

Engineering Contradiction:
Improvetowed body maneuveringVSAvoidactuator and articulated arm system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The fairlead's articulated sectors are designed to automatically adjust and pivot in response to the cable's movement and the towed body's position. The system uses the inherent forces from towing operations to drive the articulation movements, eliminating the need for external actuators and control systems.

Inventive Principle:
Principle #25Self-service

3Reliability

If the fairlead is designed with fixed structure to prevent cable direction changes, then cable damage is prevented, but the ability to adapt to vessel movements is reduced

Engineering Contradiction:
Improvecable mechanical stress preventionVSAvoidcable direction adaptation
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The fairlead employs articulated sectors that can pivot and rotate to dynamically adapt to changes in cable direction caused by vessel movements. The articulations allow the sectors to move relative to each other, enabling the fairlead to accommodate varying cable angles while maintaining the minimum bend radius through the groove geometry.

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 effectively prevents cable damage by maintaining a safe curvature radius and simplifies the towing process by eliminating the need for an articulated arm, enhancing operational efficiency and reducing mechanical stress on the cable.

Implementation Method 1

a first articulation with a degree of freedom in rotation around an axis, the articulation connecting the two sectors, the axis being substantially perpendicular to a direction in which the cable extends substantially in the fairlead at the articulation

Methodology Applied
Scientific EffectRotation:

Implementation Method 2

the fairlead comprises at least a first and a second sector, the sectors making it possible to guide the cable in a groove made in each of the sectors

Methodology Applied
Scientific EffectGeometric constraint: Geometry

Implementation Method 3

means for limiting the angular movement of the articulation, and in that the sectors and the limiting means are dimensioned so as to prevent the cable from exceeding a lower limit of the radius of curvature

Methodology Applied
Scientific EffectMechanical limitation: Mechanical Force

Data Source

PatentEP2776309B1Towing device with a hinged fairlead
Publication Date: 2016.01.13 THALES SA
  • EP2776309B1 patent drawingFigure 1
  • EP2776309B1 patent drawingFigure 2~4
  • EP2776309B1 patent drawingFigure 5

AI summary

The invention relates to a towing device intended to be fitted to the deck of a ship. The device comprises a winch, a cable (14) and a fairlead (20), the cable (14) passing through the fairlead (20) under the action of the winch. According to the invention, the fairlead (20) comprises at least first and second sectors (21, 22), the sectors allowing the cable (14) to be guided into a groove formed in each of the sectors (21, 22), a first hinge (27) with a degree of freedom in rotation about an axis (28), the hinge (27) linking the two sectors (21, 22), the axis (28) being substantially perpendicular to a direction according to which the cable (14) extends substantially in the fairlead (20) at the hinge (27), limiting means for limiting the angular displacement of the hinge (27). The sectors (21, 22) and the limiting means are dimensioned in such a way as to prevent the cable (14) from exceeding a lower limit of radius of curvature.