Tower Crane Stepped Taper Profile Buckling Resistance
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Solution Overview
Problem
Tower cranes with thin solid wall profiles face challenges in achieving sufficient buckling resistance while maintaining low weight, especially under varying directional loads such as wind and dynamic influences, which can lead to multi-directional buckling and instability.
Innovation Solution
The tower crane's profile cross-section is contoured with a stepped taper on the side flanks and asymmetrical front and rear sides, featuring channel-like indentations or bulges, which increases buckling resistance without compromising functionality or internal space for components like cable pulleys and energy supply lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If thin solid wall profiles are used for tower parts, then weight is reduced, but buckling resistance deteriorates under varying directional loads
Solution Approach 1:
The tower profile is designed with non-uniform wall thickness distribution, featuring local thickening at critical positions (front and rear sides) while maintaining thin walls elsewhere. This allows the structure to provide enhanced buckling resistance at load-critical locations without increasing overall tower weight, directly resolving the contradiction between weight reduction and buckling resistance.
Solution Approach 2:
The patent employs an asymmetric profile design where the front and rear sides of the tower have different geometric characteristics compared to the side flanks. This asymmetric configuration optimizes the structural response to directional loads (wind, boom movements) while maintaining lightweight construction, addressing the buckling resistance issue without compromising weight efficiency.
2Strength
If wall thickness is increased to improve buckling resistance, then strength is improved, but weight increases
Solution Approach 1:
Instead of uniformly increasing wall thickness throughout the tower, the invention applies local thickening only at critical positions (front and rear sides) where buckling resistance is most needed. This selective approach provides the necessary strength improvement while minimizing the associated weight increase, as thin walls are maintained in less critical areas.
3Strength
If cross-sectional changes are made to increase buckling stiffness, then buckling resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The invention implements cross-sectional changes through localized features (different wall thicknesses at front/rear vs. side flanks) rather than complex overall shape modifications. This approach provides the necessary buckling stiffness while keeping the manufacturing process relatively simple, as the basic profile geometry remains straightforward with only specific local variations.
Data Source
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Figure 3(a)~3(c)
AI summary
The present invention relates to a tower crane with a tower to which a jib is attached, wherein the tower comprises at least one tower section whose cross-sectional profile has tower front and rear faces through which a crane plane passes, containing the longitudinal axis of the jib and the longitudinal axis of the tower. According to the invention, the tower cross-sectional profile has a stepped cross-sectional taper in the region of the side flanks between the tower front and rear faces, which tapers the profile width transversely to the aforementioned crane plane of the cross-sectional profile from a wider central side flank section to a narrower side flank end section adjacent to the transition to the tower rear or the tower front.