Kingpost Crane Load-Equalizing Bearing for Precise Slewing
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Solution Overview
Problem
Existing crane designs with rotating kingposts suffer from imprecise slewing operations due to high friction and non-uniform roller loading, leading to reduced bearing life, increased maintenance costs, and limited precision, while stationary kingpost cranes face challenges with large, complex bolted flanges and custom machining requirements.
Innovation Solution
A load-equalizing, radial upper bearing assembly with a shape-optimized rotating kingpost design that distributes loads evenly through a set of circumferentially arranged bearing rollers, minimizing friction and allowing for easy access and maintenance, using a linkage mechanism to ensure precise slewing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nonmetallic bearing surfaces are used to prevent wear on the kingpost perimeter, then wear resistance is improved, but sliding friction increases and slewing precision deteriorates
Solution Approach 1:
The patent replaces sliding friction-based nonmetallic bearing surfaces with a roller bearing system that uses rolling contact instead of sliding contact. This substitution maintains wear resistance while dramatically reducing friction and improving slewing precision through the roller mechanism.
Solution Approach 2:
The patent employs cylindrical rollers with curved surfaces that conform to the kingpost perimeter geometry. The curved roller surfaces enable smooth rolling contact that distributes loads evenly and maintains precise slewing motion while preventing wear on the kingpost surface.
2Measurement precision
If slew-ring bearing cranes are used to achieve precision slewing, then slewing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent divides the bearing system into discrete roller elements arranged around the kingpost perimeter, each roller being independently supported by bearing blocks. This segmentation allows for simpler manufacturing and assembly compared to monolithic slew-ring bearings, while maintaining precision through the distributed roller contact system.
Solution Approach 2:
The patent changes the fundamental parameter of the bearing system from a single large-scale slew-ring bearing to multiple smaller roller elements. This parameter change simplifies the overall device complexity and manufacturing requirements while achieving comparable or superior slewing precision through the distributed roller arrangement.
3Force
If large roller bearing races are used to support the bearing assembly, then load capacity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent segments the large bearing race into multiple smaller roller elements, each requiring less precision to manufacture. The collective arrangement of these segmented rollers provides the necessary load capacity while reducing the precision requirements for individual component manufacturing.
Solution Approach 2:
The patent applies different quality standards to different parts of the bearing system. The roller elements and their supporting bearing blocks require high precision locally, while the overall raceway structure can be manufactured with standard tolerances. This localized quality approach maintains load capacity while reducing overall manufacturing precision requirements.
4Device complexity
If nonuniform roller loading is accepted, then device complexity is reduced, but bearing life decreases
Solution Approach 1:
The patent employs a dynamic loading distribution system where the roller elements are arranged and supported to automatically equalize loads based on operational conditions. This dynamic adaptation ensures uniform load distribution across all rollers during operation, extending bearing life without requiring complex static pre-loading mechanisms.
Solution Approach 2:
The bearing system incorporates inherent feedback mechanisms through the roller arrangement and support structure that automatically adjust load distribution in response to operational variations. This feedback mechanism ensures uniform loading across all rollers, extending bearing life while maintaining relatively simple device complexity.
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 high precision slewing capability, reduces maintenance downtime, and optimizes space and weight efficiency, while enabling cost-effective and robust bearing arrangements with reduced friction and wear, facilitating easy inspection and replacement of components.
Implementation Method 1
A load-equalizing, radial upper bearing assembly with a shape-optimized rotating kingpost design that distributes loads evenly through a set of circumferentially arranged bearing rollers, minimizing friction and allowing for easy access and maintenance
Implementation Method 2
distributes loads evenly through a set of circumferentially arranged bearing rollers, minimizing friction and allowing for easy access and maintenance
Data Source
AI summary
A heavy-lift rotating kingpin slewing crane is disclosed having an upper bearing for a rotating kingpost crane which achieves equalized radial loading on all boom-side bearing rollers arranged in tandem on approximately a 120 degree arc segment of an upper radial bearing assembly when reacting the crane's operating load-moment couple-forces transferred from the rotating kingpost structure into the stationary kingpost housing at the upper bearing outer race surface. The bearing system comprises a concentrically nested set of load spreader bodies interconnected by pins and arranged to transfer the horizontal couple-forces from each side of the kingpost structure via a linkage to centrally located, largest spreader bodies which progressively reduce and transfer the load radially into smaller spreader bodies until an equal set of radial loads arrive on a set of bearing rollers.