Hoisting Crane Annular Bearing Radial Force Management
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Solution Overview
Problem
Hoisting cranes require a robust and heavy construction to compensate for radially outward directed forces, which increases weight and complexity, especially when handling heavier loads.
Innovation Solution
The introduction of a third column bearing surface oriented vertically and radially outward, along with pre-stressing or spline connections in the jib bearing parts, absorbs these forces, allowing for a lighter and less robust crane construction by preventing radial displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a more robust bearing structure is used to compensate for radially outward directed forces, then the strength and stability are improved, but the weight increases
Solution Approach 1:
The patent applies different bearing surface configurations at different radial positions. The third column bearing surface is positioned radially outward from the third jib bearing surface, creating a local structural arrangement that specifically addresses radially outward forces without requiring uniform reinforcement throughout the entire structure. This localized quality improvement allows weight reduction in non-critical areas while maintaining strength where needed.
Solution Approach 2:
The invention introduces a vertical dimension to the bearing surface arrangement by positioning the third column bearing surface vertically and radially outward from the third jib bearing surface. This three-dimensional configuration creates a more efficient force distribution system that handles radially outward forces through spatial arrangement rather than through increased material quantity, thereby reducing overall structure weight.
2Force
If pre-stressing is applied to the bearing surfaces, then the resistance against radially outward forces is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent utilizes thermal parameter changes to achieve pre-stressing. By heating the bearing surfaces during assembly and then allowing them to cool, the material undergoes thermal contraction that creates compressive pre-stresses in the bearing structure. This parameter-based approach (temperature change) provides a relatively simple manufacturing method compared to mechanical pre-stressing techniques, as it leverages natural thermal expansion and contraction properties of materials.
3Strength
If splines are provided to connect jib bearing parts with the jib connection member, then the resistance against tangentially directed forces is improved, but the device complexity increases
Solution Approach 1:
The patent employs splines as a composite structural element that combines multiple functions within a single component. The splines integrate the functions of mechanical connection, force transmission, and structural reinforcement against tangential forces. By combining these functions into a unified spline element rather than using separate components for each function, the overall device complexity is minimized while maintaining high strength characteristics.
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 enables a lighter crane construction while maintaining stability and resistance against radially outward forces, reducing the overall weight and complexity of the crane.
Implementation Method 1
radially outward directed forces are absorbed/ compensated by pre-stressing of the jib bearing surfaces associated with the jib
Implementation Method 2
heating the bearing surface provided on a bearing part associated with the jib connection member to cause expansion of the bearing part associated with the jib
Implementation Method 3
cooling down. Cooling down causes shrinkage of the bearing part, causing circumferentially uniform stresses in a radially inward direction
Data Source
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AI summary
This invention relates to a hoisting crane (20) comprising a column (21), a jib (24) and a jib connection member (28) which is disposed on the column and to which the jib is connected pivotably. The crane further comprises an annular bearing structure (25) extending around the column guiding and carrying the jib connection member rotatably about the column. The annular bearing structure comprises one or more column bearing parts (10, 11) connected to the column, comprising column bearing surfaces (10a, 10b, 10c, 10d) associated with the vertical column and one or more jib bearing parts (13) connected to the jib connection member, comprising jib bearing surfaces (13a, 13b, 13c, 13d) associated with the jib connection member. A first vertical column bearing surface (10a) is arranged in a radial direction more inwards than a first jib bearing surface (13a) A second horizontal column bearing surface (10b) is arranged below a second jib bearing surface (13b) and a third column bearing surface (10c) is oriented substantially vertically and is arranged in a radial direction more outwards than a third jib bearing surface (13c) arranged opposite the third column bearing surface.