Retractable Thruster Assembly Locking Mechanism

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Solution Overview

Problem

Existing retractable thruster assemblies for vessels face challenges in securely locking the thruster assembly to the thruster well, particularly in the extended position, which can lead to misalignment and damage during operation and retraction.

Innovation Solution

A locking device with mobile locking pins and a positioning device are used to accurately align and lock the thruster assembly in both horizontal and vertical planes, allowing for secure engagement and efficient transfer of reaction forces, while a thruster hoisting device enables the assembly to be lowered fully out of the well for maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking device with mobile locking pins is used to secure the thruster assembly in the extended position, then the reliability of locking is improved, but the device complexity increases

Engineering Contradiction:
Improvelocking reliabilityVSAvoidlocking device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking device is segmented into multiple mobile locking pins distributed around the periphery of the thruster assembly. Each pin operates independently to engage with corresponding recesses in the hull, distributing the locking function across multiple discrete elements rather than a single complex mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mobile locking pins are pre-positioned and spring-loaded to automatically engage with the locking recesses when the thruster assembly reaches the extended position. This preliminary positioning ensures that locking occurs automatically at the correct moment without requiring additional control mechanisms.

Inventive Principle:
Principle #10Preliminary action

2Ease of repair

If the thruster assembly is made fully retractable for maintenance access, then the ease of repair is improved, but the reliability of secure locking may worsen

Engineering Contradiction:
Improvemaintenance accessibilityVSAvoidlocking security
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The thruster assembly is designed with dynamic retractability, allowing it to move between extended operational position and fully retracted maintenance position. The mobile locking pins dynamically adjust their engagement state based on the assembly's position, providing secure locking when extended and disengagement when retracted for maintenance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mobile locking pins serve as intermediaries between the thruster assembly and the hull structure. They provide the necessary mechanical connection for secure locking during operation while allowing complete disengagement when the assembly is retracted for maintenance, mediating between the conflicting requirements of security and accessibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If multiple mobile locking pins are used to prevent misalignment and damage, then the strength of connection is improved, but the device complexity increases

Engineering Contradiction:
Improveconnection strengthVSAvoidlocking mechanism complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The connection strength is achieved through segmentation into multiple locking pins distributed around the periphery. Each pin provides a discrete locking point, and the collective effect of multiple pins distributes the mechanical loads, preventing misalignment and damage without requiring a single overly complex locking mechanism.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2977312B1A vessel with a retractable thruster assembly
Publication Date: 2019.12.11 ITREC BV
  • EP2977312B1 patent drawingFigure 1~2
  • EP2977312B1 patent drawingFigure 3~4
  • EP2977312B1 patent drawingFigure 5~6

AI summary

A vessel with a retractable thruster assembly (1), the vessel comprising a hull, a vertical thruster well (20) within the hull, said thruster well having a bottom opening in a bottom plane of the hull. The vessel further comprises a retractable thruster assembly (1). This thruster assembly comprises: - a thruster head (2) with a propeller (3), - a casing structure (10) vertically guided in the thruster well (20), the casing structure (10) having a lower end portion to which the thruster head (2) is mounted so as to extend below the casing structure (10), the casing structure including a watertight compartment (11), a drive motor (12) being housed in said compartment.