Bridge Crane Single Girder Rope Drum Reeving System
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Solution Overview
Problem
Existing bridge cranes are costly and structurally wide due to two main girders, and they suffer from sagging hoisting ropes, which cause safety issues and precision problems during lifting operations.
Innovation Solution
A bridge crane design with a single main girder and a rope drum mounted on bearings, where the hoisting ropes are guided through a reeving system with diverting pulleys to compensate rope forces, eliminating sagging and allowing for a narrower, more space-efficient structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If two main girders are used in the bridge crane structure, then the structural strength and stability are improved, but the width and weight of the crane increase, leading to higher material costs and reduced space efficiency
Solution Approach 1:
The bridge crane structure is segmented into a single main girder with end carriages at each end, eliminating the need for two full girders. The end carriages provide the necessary structural support and stability while reducing the overall width and material requirements of the crane system.
Solution Approach 2:
The end carriages combine multiple functions: they serve as structural supports, housing for rope drums, and mounting points for diverting pulleys. This merging of functions into compact end units reduces the overall crane width while maintaining structural integrity and operational capability.
2Device complexity
If the rope drum is fixed rigidly on the end carriage, then the structural simplicity is improved, but the rope sagging increases due to insufficient tensioning
Solution Approach 1:
The rope drum is mounted on bearings that allow it to rotate freely and adjust its position dynamically. This dynamic mounting enables the rope drum to self-align and maintain proper rope tension throughout the lifting operation, preventing sagging while keeping the overall structure simple.
Solution Approach 2:
Diverting pulleys are introduced as intermediary elements between the rope drum and the load. These pulleys guide the hoisting ropes and help maintain proper rope alignment and tension, eliminating sagging issues while adding minimal complexity to the system.
3Manufacturing precision
If diverting pulleys are added to compensate rope forces, then the rope sagging is reduced and lifting precision is improved, but the device complexity increases
Solution Approach 1:
The end carriages are designed as multi-functional units that house rope drums, mounting brackets for diverting pulleys, and structural support elements. This universal design approach consolidates multiple components into integrated units, reducing overall system complexity while maintaining the necessary rope force compensation functionality.
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 reduces sagging, enhances lifting precision, and allows for the use of smaller, lighter machinery, enabling the crane to handle large loads and operate in close proximity to other cranes, thus improving safety and operational efficiency.
Implementation Method 1
a rope drum (4) mounted in its position on bearings (not shown) near the first end of the main girder (1) and on the second side, i.e. on the opposite side to the hoisting trolley (3), of the main girder (1)
Implementation Method 2
the rope forces acting in the hoisting rope (4a) are compensated both in the hoisting trolley (3) and in the guide trolley (12)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The object of the invention is a bridge crane, which comprises a main girder (1), which is fitted to travel supported by end carriages (2) essentially at both ends and which bridge crane further comprises a hoisting trolley (3) traveling supported by the main girder (1) and a rope drum (4) mounted on bearings to rotate in an essentially stationary position, from which rope drum the hoisting rope (4a) is guided to a hook (7) traveling along with the hoisting trolley (3). The hoisting rope (4a) is supported from below for at least a part of its essentially. horizontal section.