Multi-Line Knuckle Boom Crane for Deep Water Lifting
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Solution Overview
Problem
Current knuckle boom cranes face limitations in achieving high lifting capacities and accessing deep waters due to the constraints of cable diameter and weight, which restrict their ability to reach depths beyond 3500 meters with sufficient lifting capacity.
Innovation Solution
A multi-line material handling system with guide assemblies and a doubly articulable boom system that reduces the required line diameter, allowing for longer payout lengths and increased lifting capacity, enabling cranes to reach depths of 3500 meters with a capacity of up to 800 metric tons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cable diameter and length are increased to achieve higher lifting capacity and deeper water access, then lifting capacity and payout length are improved, but cable weight and spool size increase to unacceptable levels
Solution Approach 1:
The single cable system is segmented into multiple parallel cables (typically 6-12 cables). Each cable carries a fraction of the total load, allowing the use of thinner, lighter individual cables while achieving the required total lifting capacity. For example, a 800-ton crane uses multiple cables each with diameter significantly less than a single cable would need to be, reducing overall cable weight and spool size to manageable levels.
2Force
If cable diameter is increased to support higher lifting capacity, then lifting capacity is improved, but the cable becomes too heavy and bulky for practical spooling and handling
Solution Approach 1:
The load is distributed across multiple parallel cables, allowing each cable to have a smaller diameter suitable for standard spooling operations. This segmentation enables the use of conventional spool sizes and handling equipment while achieving high total lifting capacity through the combined strength of multiple cables.
3Device complexity
If single-line system is used to simplify the structure, then device complexity is reduced, but the line diameter and weight increase, limiting payout length and lifting capacity
Solution Approach 1:
The single-line system is replaced with a multi-line system where the load is distributed across multiple parallel lines. This segmentation allows each line to be thinner and lighter, enabling much greater payout lengths (exceeding 3500 meters for deep water applications) while maintaining structural manageability through the use of multiple smaller-diameter lines rather than one large-diameter line.
Data Source
AI summary
A crane including an inner boom, an outer boom, a plurality of guide assemblies arranged along the length of the inner and outer boom and adapted for guiding a plurality of lines, and a multi-line material handling system including a first line having an outgoing portion extending to a sheave block, and an incoming portion returning from the sheave block to a supported anchor device, and a second line having an outgoing portion extending to the sheave block, and an incoming portion returning from the sheave block to the supported anchor device.