Container Lashing Bars With Position-Specific Strength Classes
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Solution Overview
Problem
Current lashing systems for cargo ships use uniformly strong lashing bars and turnbuckles across all positions, leading to oversized and heavier components, which are uneconomical and inefficient, especially since upper lashing bars often bear significantly higher tension loads than lower ones, resulting in 50-70% of elements being over-sized and increasing material usage and greenhouse gas emissions.
Innovation Solution
Designing lashing systems with upper and lower lashing elements of varying strengths, where the upper lashing bar has a greater cross-sectional area and diameter than the lower one, and using distinct connecting pieces to ensure compatibility only between components of the same strength category, allowing for lighter and more efficient material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniformly strong lashing bars and turnbuckles are used across all positions, then structural integrity and safety are maintained, but weight and material usage increase significantly
Solution Approach 1:
The patent applies different strength classes to lashing bars and turnbuckles based on their installation position. Upper lashing elements use higher strength class (e.g., 10.9) while lower lashing elements use lower strength class (e.g., 8.8), matching the actual load distribution where upper elements bear significantly higher tension forces during ship heeling.
Solution Approach 2:
The patent changes the physical parameters of lashing elements by varying the cross-sectional area and material strength based on position. Upper lashing bars have larger cross-sectional area and higher strength material to handle greater tension, while lower lashing bars have reduced parameters matching their lower load requirements.
2Reliability
If uniformly strong lashing bars and turnbuckles are used across all positions, then safety during heavy loads is ensured, but manufacturing costs and material usage increase
Solution Approach 1:
The patent implements position-specific strength classification where upper lashing elements (subject to 80-100% higher tension forces) are manufactured with higher material strength and larger cross-section, while lower lashing elements use reduced material properties matching their actual load requirements.
Solution Approach 2:
The patent varies material parameters including strength class (10.9 vs 8.8), cross-sectional area, and diameter based on installation position, reducing material consumption in lower positions where tension forces are significantly lower while maintaining adequate safety margins.
3Strength
If heavier lashing bars are used, then strength and load capacity are increased, but ease of operation and handling difficulty increase
Solution Approach 1:
The patent reduces the weight of lower lashing bars by using lower strength class material and smaller cross-sectional area, making them easier for stevedores to handle during loading operations while maintaining adequate strength for the lower tension loads they experience.
4Ease of manufacture
If all lashing elements are designed to the same strength, then consistency and ease of manufacture are maintained, but 50-70% of elements are over-sized
Solution Approach 1:
The patent divides lashing elements into different strength categories based on installation position, with upper elements requiring higher strength and lower elements accepting reduced strength, eliminating the 50-70% over-sizing problem while maintaining manufacturing feasibility through standardized production processes for each category.
Data Source
Figure 1~2
Figure 3~5b
Figure 6a~7b
AI summary
A lashing system (1) for supporting containers (8,9) located on top of each other, wherein the lashing system (1) comprises at least one upper lashing element (2) comprising an upper lashing bar (4) and an upper turnbuckle (5), wherein the upper lashing bar (4) is configured to be connected to an upper container (8) . At least one lower lashing element (3) comprises a lower lashing bar (6) and a lower turnbuckle (7), wherein the lower lashing bar (6) is configured to be connected to the lower container (9). The upper lashing bar (4) has a higher strength against the tension than the lower lashing bar (6). Also a lashing arrangement and a method is disclosed.