Segmented Hoisting Rope Reduces Winch Volume
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hoisting systems for vertically-suspended objects become bulky and costly due to the requirement for long, thick hoisting ropes designed for minimum breakable load, especially in offshore applications where rope lengths can reach several kilometers.
Innovation Solution
A hoisting system with a winch rope comprising two parts of different diameters, where the inner part (thinner) is wound last and the outer part (thicker) is connected to the object, with a diameter ratio ensuring the minimum breakable load of both parts differs by less than a factor of four, allowing for reduced rope diameter and length optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hoisting rope is designed for the full minimum breakable load required by the application, then the strength and safety are ensured, but the winch becomes very bulky and costly
Solution Approach 1:
The hoisting rope is divided into two distinct parts: a first part with a smaller diameter and a second part with a larger diameter. The first part (inner part on winch drum) has reduced strength requirements, while the second part (outer part connected to object) provides the full minimum breakable load capacity. This segmentation allows the winch to be sized for the smaller first part, reducing winch volume while maintaining overall system strength through the second part.
Solution Approach 2:
Different sections of the hoisting rope are assigned different diameters and strength characteristics based on their specific functional requirements. The first part has a smaller diameter optimized for storage on the winch drum, while the second part has a larger diameter optimized for bearing the full load during hoisting operations. This local differentiation of properties resolves the contradiction between winch size and required strength.
2Volume of moving object
If the hoisting rope diameter is reduced to decrease material cost and winch size, then the system becomes more compact and economical, but the minimum breakable load capacity is compromised
Solution Approach 1:
The hoisting rope is segmented into a first part with smaller diameter for winch storage and a second part with larger diameter for load-bearing operations. This segmentation ensures that the full minimum breakable load capacity is maintained in the second part while the first part can be optimized for compact storage, resolving the contradiction between size reduction and strength maintenance.
Solution Approach 2:
The hoisting rope exhibits local quality variation with different diameters in different sections. The first part has reduced diameter optimized for winch drum storage, while the second part has increased diameter optimized for full load capacity. This local differentiation allows the system to achieve compact size where needed while maintaining full strength where required.
3Strength
If a uniform thick hoisting rope is used throughout its length, then the minimum breakable load capacity is ensured, but the material cost and system weight increase significantly
Solution Approach 1:
The hoisting rope is segmented into a first part with smaller diameter and a second part with larger diameter. The first part requires less material while the second part provides the necessary strength. This segmentation reduces the total quantity of high-strength material needed compared to a uniformly thick rope, resolving the contradiction between strength and material quantity.
Solution Approach 2:
The hoisting rope is designed with local quality variation where the first part has smaller diameter and the second part has larger diameter. This allows material to be concentrated where it is most needed (in the second part for load-bearing) while reducing material usage in the first part, thereby resolving the contradiction between maintaining minimum breakable load and reducing material quantity.
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
This design reduces the effective load on the hoisting rope by up to 50% when submerged, enabling a smaller, less costly winch and rope system while maintaining safety and strength, particularly effective in offshore operations.
Implementation Method 1
When a heavy and bulky load is hoisted offshore, either lifted from the seabed or placed onto the seabed the buoyancy forces acting by the water on the object cause the load on the hoisting rope to be significantly smaller.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Disclosed is a hoisting system (10) for hoisting a vertically-suspended object (50), the hoisting system (10) having a winch (20) having a winch drum (21) with a hoisting rope (25), wherein a first part (25-1) of the hoisting rope (25) has a first diameter (d1) and a second part (25-2) has a second diameter (d2) being larger than the first diameter (d1), the first part (25-1) being connected with a first end (25fe) of the second part (25-2), wherein the first part (25-1) is an inner part (20i) on the winch drum (21) when the winch drum (21) is completely wound, wherein the second part (25-2) has a further end (25se) that is connectable to the object (50) for hoisting the object (50), wherein a ratio between the first diameter (d1) and the second diameter (d2) is chosen such that the minimum breakable load of the first part (25-1) differs less than a factor of four from the minimum breakable load of the second part (25-2), and preferably less than a factor of three. Further disclosed is a method for hoisting a vertically-suspended object (50) with such hoisting system (10) and a winch (20) for such hoisting system (10). A much more compact and less-costly hoisting system is thereby obtained.