Intermodal Container Coupling Means for Ship Transport

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Solution Overview

Problem

The existing twistlock system for intermodal containers on ships is limited by its maximum permitted tension force of 250 kN, restricting the size and weight of container stacks, which hinders the increase in transportation capacity and efficient use of ship space.

Innovation Solution

The system employs additional coupling means installed in the gripping holes of the corner castings, alongside conventional twistlocks, to distribute the lifting force and enhance the locking strength between containers, allowing for increased container stacks by bearing tensile stress together with the twistlocks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If only conventional twistlocks are used for locking containers, then the locking mechanism is simple, but the maximum permitted tension force is limited to 250 kN, restricting container stack size and weight

Engineering Contradiction:
Improvelocking strengthVSAvoidlocking system complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent combines multiple coupling means (first coupling means in front gripping holes, second coupling means in rear gripping holes) with conventional twistlocks to create a composite locking system. This merging allows the system to bear tensile stress collectively, increasing the maximum permitted tension force beyond the 250 kN limit of single twistlocks while distributing the load across multiple components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking system is segmented into multiple independent coupling means positioned at different locations (front and rear gripping holes of corner castings). Each coupling means can independently bear portion of the tensile stress, and the segmented structure allows for modular installation and maintenance while collectively achieving the required locking strength.

Inventive Principle:
Principle #1Segmentation

2Strength

If additional coupling means are installed alongside twistlocks, then the locking strength increases, but the device complexity increases

Engineering Contradiction:
Improvelocking strengthVSAvoidnumber of coupling components
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The coupling means are designed to be universal components that can be installed in standardized gripping holes of ISO corner castings. These multi-functional components serve both as structural connectors and as load-bearing elements, replacing the need for multiple different types of locking devices while achieving enhanced locking strength through their universal applicability and integrated design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If higher and heavier container stacks are transported, then the transportation capacity increases, but the existing twistlock system cannot withstand the increased tension forces

Engineering Contradiction:
Improvetransportation capacityVSAvoidtension force on locking system
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The patent merges multiple coupling means with conventional twistlocks to create a composite locking system capable of withstanding increased tension forces. This combined system distributes the tensile stress from higher and heavier container stacks across multiple components, enabling the transportation of larger container loads that would exceed the 250 kN capacity of single twistlocks.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking system is segmented into multiple coupling means positioned at front and rear gripping holes, allowing the tension force from heavier container stacks to be distributed across multiple segments. Each segment bears a portion of the total load, enabling the system to handle increased transportation capacity without any single component being overloaded.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3700834B1System comprising coupling means for locking together intermodal containers being transported on a ship
Publication Date: 2023.07.19 MACGREGOR FINLAND
  • EP3700834B1 patent drawingFigure 1~2
  • EP3700834B1 patent drawingFigure 3~4
  • EP3700834B1 patent drawingFigure 5~6

AI summary

Method for locking together intermodal containers being transported on a ship, by means of the corner castings (1, 2) on the containers, whereby intermodal containers that are one above another are locked to each other by means of twistlocks (3) to be fastened into the corner castings. The method according to the invention is implemented in such a way that the corner castings (1, 2) of intermodal containers that are one above another and/or one beside another are coupled to each other also with one or more separate coupling means (7). The object of the invention is also a coupling means (7).