Asymmetric Container Lock Geometry for Reducing Vertical Slack

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Solution Overview

Problem

Existing container locks have significant clearance between contact surfaces and container corners, leading to increased dynamic tension forces and vertical gaps when ships heel at sea, limiting cargo capacity and stability.

Innovation Solution

A container lock with optimized geometry, featuring a stopper and chamfered surfaces to minimize clearance and prevent horizontal movement, reducing vertical slack and dynamic tension forces by maintaining a back wall clearance greater than front wall clearance under tension loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional container locks with large clearance are used, then manufacturing is simpler and costs are lower, but vertical gap and dynamic tension forces increase when ship heels

Engineering Contradiction:
Improvecontainer locking securityVSAvoidcontainer lock geometry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The container lock employs asymmetric geometry where the back wall clearance is designed to be greater than the front wall clearance. This asymmetric configuration allows the lock to maintain optimal contact with container corners under tension loads while the stopper prevents excessive horizontal movement, resolving the contradiction between simplicity and security by using geometric asymmetry rather than complex mechanisms

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention changes the geometric parameters of the container lock, specifically optimizing the relationship between back wall clearance and front wall clearance. By adjusting these dimensional parameters and introducing a stopper element, the lock achieves reduced vertical gap and minimized dynamic tension forces without requiring fundamentally complex manufacturing processes

Inventive Principle:
Principle #35Parameter changes

2Reliability

If container lock clearance is reduced to improve security, then vertical slack decreases and cargo capacity increases, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecontainer-to-container locking securityVSAvoidcontact surface clearance tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The stopper element is pre-positioned in the container lock geometry to automatically limit horizontal direction movement and maintain optimal back wall clearance. This preliminary geometric constraint ensures that under tension loads, the lock maintains reduced vertical gap without requiring high-precision manufacturing tolerances, as the stopper pre-establishes the correct clearance relationship

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention applies different clearance characteristics to different parts of the container lock: the back wall clearance is optimized to be greater than the front wall clearance. This local differentiation of clearance quality allows the lock to function effectively with reduced overall clearance, improving security without uniformly increasing manufacturing precision requirements across all surfaces

Inventive Principle:
Principle #3Local quality

3Productivity

If heavier containers are loaded to increase cargo capacity, then ship productivity improves, but dynamic tension forces on container locks increase

Engineering Contradiction:
Improvecargo carrying capacityVSAvoiddynamic tension force on container lock
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The container lock design incorporates dynamic characteristics through its asymmetric clearance geometry and stopper mechanism. The greater back wall clearance allows the lock to accommodate dynamic movements and tension forces generated by heavier cargo loads, while the stopper prevents excessive horizontal displacement. This dynamic geometric configuration enables the lock to handle increased forces from heavier containers without failure

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4458729A1Locking arrangement for joining containers together and method for joining together an upper container and a lower container
Publication Date: 2024.11.06 MACGREGOR FINLAND
  • EP4458729A1 patent drawingFigure 1~2b
  • EP4458729A1 patent drawingFigure 3~4
  • EP4458729A1 patent drawing

AI summary

A locking arrangement for joining together an upper container (5) and a lower container (6). The locking arrangement comprises a lower corner piece (7) of the upper container (5) comprising a bottom flange (9) and an upper opening (8) comprising a left upper opening wall (15a) and a right upper opening wall (15b); an upper corner piece (10) of the lower container (6) comprising a top flange (12) and a lower opening (11) comprising a lower opening wall (24); and a container lock (1) for locking to each other the lower corner piece (7) and the upper corner piece (10). The container lock (1) comprises a front wall (25), a back wall (26), a central flange (3), and a stopper (27), wherein the stopper (27) is configured to limit horizontal direction movement, wherein a horizontal direction (X) is from the front wall (25) to the back wall (26); prevent the back wall (26) to contact with the left upper opening wall (15a) ; and form a back wall clearance (X1) between the back wall (26) and the left upper opening wall (15a). Also a method is disclosed.