Crane Girder Planar Struts Buckling Resistance
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Solution Overview
Problem
Conventional crane girders face challenges in optimizing buckling resistance, reducing production costs, and minimizing dead weight while maintaining load-bearing capacity, particularly due to limitations in strut design and material usage.
Innovation Solution
The use of planar struts with elongated shapes and folded secondary surfaces, which extend transversely to the longitudinal direction of the crane girder, enhances buckling resistance and allows for reduced material usage by eliminating non-structurally required sheet metal areas, enabling flexible dimension selection and simplified manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional rod-shaped struts are used in crane girders, then manufacturing is simpler and standards are easier to meet, but buckling resistance and load-bearing capacity are insufficient
Solution Approach 1:
The patent transitions from rod-shaped struts (one-dimensional) to planar struts with folded surfaces (two-dimensional). The struts include a main surface and at least one folded secondary surface that extends in a direction transverse to the longitudinal axis, adding dimensional complexity to enhance buckling resistance without significantly increasing manufacturing complexity
Solution Approach 2:
The struts are formed from sheet metal through laser cutting and folding, creating a composite structure that combines the main surface with folded secondary surfaces. This composite construction provides enhanced structural properties, particularly in buckling resistance, while using the same base material (sheet metal) to maintain manufacturing simplicity
2Strength
If sheet metal areas are added to enhance structural strength, then load-bearing capacity improves, but production costs and dead weight increase
Solution Approach 1:
The folded secondary surfaces are positioned specifically at the ends of the struts where buckling resistance is most critical. The main surface extends over at least half the width of the crane girder, providing localized reinforcement exactly where needed to prevent buckling, rather than uniformly strengthening the entire strut
Solution Approach 2:
By folding the sheet metal to create secondary surfaces that extend transversely to the longitudinal direction, the patent adds structural strength in a space-efficient manner. The folded surfaces create rigid triangular or rectangular panels that resist buckling without requiring substantial material addition, thus minimizing weight increase
3Adaptability or versatility
If conventional strut designs are used, then manufacturing processes are simpler, but flexibility in dimension selection is limited
Solution Approach 1:
The patent enables flexible dimension selection by allowing the main surface and folded secondary surfaces to be configured with various dimensions and geometries through laser cutting. The folded surfaces can be positioned at different locations and folded at different angles, providing adaptability in designing struts for different crane girder configurations while using the same basic manufacturing process
4Reliability
If planar struts with folded surfaces are implemented, then buckling resistance is optimized, but manufacturing complexity increases
Solution Approach 1:
The strut is segmented into distinct functional surfaces: a main surface extending transversely to the longitudinal direction and at least one folded secondary surface. This segmentation allows each surface to be optimized for its specific function (main surface for overall structure, folded surfaces for buckling resistance) while being manufactured as a single integrated piece through laser cutting and folding
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
The invention relates to a crane (1a, 1b), particularly a bridge crane or gantry crane, comprising at least one crane girder (2) extending horizontally and designed as a truss with a plurality of braces (5), on which girder a crane trolley (9) with a lifting gear is movable, at least some of the braces (5) having a flat shape. In order to provide a crane (1a, 1b), particularly a bridge crane or gantry crane, with an improved crane girder (2), the invention proposes that the flat-shaped braces (5) each have a flat main surface (5a) which extends in each case transversely to a longitudinal direction (LR) of the crane girder (2).