Offshore Crane Bearing Layout for Heavy Loads in a Compact Pedestal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Heavy lift cranes face challenges in offshore applications due to high loads and structural limitations, such as high mast heights that prevent passage through narrow sea lanes, and existing solutions like slewing rolling bearings are expensive and require precise machining.
Innovation Solution
A crane structure with a boom and support structure featuring distributed bearing means, including upper radial contact rolling bearings and lower radial and thrust bearings, allowing for rotational motion while resisting loads and maintaining compactness, with the ability to deform under load while maintaining optimal guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single large slewing rolling bearing is used to support the crane, then the crane can handle heavy loads, but the diameter becomes very large and the cost increases significantly
Solution Approach 1:
The patent divides the single large bearing into multiple smaller bearings distributed around the pedestal circumference. Specifically, it uses several radial rolling bearings arranged in a circle, each handling a portion of the total load. This segmentation allows the crane to support heavy loads while keeping the pedestal diameter compact, as each individual bearing is smaller than a single equivalent bearing would be.
Solution Approach 2:
The patent combines multiple bearings working together to achieve the load capacity of a single large bearing. The radial rolling bearings are positioned at different angular locations around the pedestal, and their combined support capability enables them to collectively bear the same or greater load than a single large bearing, while occupying less overall space.
2Strength
If mast cranes with two bearings are used to reduce load, then the load is distributed and cost is reduced, but the mast height becomes very high for long boom cranes
Solution Approach 1:
The patent transitions from a vertical stacking arrangement (mast cranes with bearings positioned high up the mast) to a horizontal distribution arrangement (multiple bearings positioned around the circumference of a compact pedestal). This dimensional change allows the crane to achieve load distribution benefits without increasing the vertical height, enabling passage through narrow sea lanes while maintaining long boom capability.
3Strength
If slewing rolling bearings with large surfaces are used, then heavy loads can be supported, but extreme machining accuracy is required and cost increases
Solution Approach 1:
The patent segments the large bearing surface into multiple smaller bearing surfaces distributed around the pedestal. Each individual bearing requires less machining accuracy than a single large bearing would require, while the collective assembly maintains the necessary precision for heavy load support. This segmentation reduces the complexity and cost of manufacturing each individual component.
4Adaptability or versatility
If bogies on four corners are used to transfer load, then the crane can rotate and cover large deck area, but the structure becomes cumbersome and platform space is reduced
Solution Approach 1:
The patent merges the rotation function into a single integrated pedestal structure with distributed bearings, eliminating the need for separate bogie assemblies at four corners. The multiple radial rolling bearings are directly mounted on the pedestal, providing both support and rotation capability in one unified structure, thereby reducing overall structural complexity and freeing up platform space.
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
The solution provides efficient guidance and resistance to loads, reduces the crane's diameter, and allows for lower pedestal heights, enabling passage through narrow sea lanes while being more cost-effective and producible than traditional solutions.
Implementation Method 1
The upper bearing means comprise a radial contact rolling bearing, comprising: rolling elements, and a smooth cylindrical raceway, coaxial to the axis of rotation, said radial contact rolling bearing allowing a longitudinal translational degree of freedom of said rolling elements along the height of said cylindrical raceway
Data Source
AI summary
Disclosed is a crane, in particular for offshore application. The crane includes a bearing the assembly between a pedestal and a carrier frame. The bearings are distributed over the height of the support structure and include upper bearing, which include a radial contact rolling bearing including rolling elements and a smooth cylindrical raceway, coaxial to the axis of rotation. The radial contact rolling bearing allows a longitudinal translational degree of freedom of the rolling elements over the height of the cylindrical raceway.