Segmented Bushing Exchange in Mooring Winch Drums
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Solution Overview
Problem
The existing methods for exchanging bushings or bearings in winch drums are complex and often require complete disassembly, making it impractical and costly to perform repairs at sea due to the heavy weight of the winch drum, which can lead to damage during exchange operations.
Innovation Solution
A drum assembly design that allows for the easy removal and replacement of bushings by dividing them into arcuated parts and using spacers to facilitate sliding and access, minimizing the need for disassembly and using threaded fixations to secure the bushings, enabling the exchange without destructive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the winch drum is removed from its main shaft to exchange bushings, then the bushings can be accessed and replaced, but the heavy weight of the drum (2-5 tons) makes the operation impossible at open sea without damaging the drum and/or shaft
Solution Approach 1:
The bushing is divided into two arcuate parts that can be separated from each other. This segmentation allows the bushing to be removed from the drum shaft without requiring complete disassembly of the drum, enabling bushing exchange at open sea while avoiding the need to handle the entire heavy drum assembly
Solution Approach 2:
The bushing is extracted from the drum shaft as a separate component that can be removed independently. By designing the bushing to be removable without removing the drum from the shaft, the harmful factor of drum weight is eliminated while maintaining the ability to exchange bushings
2Strength
If the bushing is designed as a single piece, then it provides structural integrity, but it requires complete disassembly of the drum and complex operations to exchange
Solution Approach 1:
The bushing is segmented into two arcuate parts that can be separated. This allows the bushing to be exchanged by removing only the bushing parts themselves, not the entire drum assembly, thereby reducing disassembly complexity while maintaining sufficient structural integrity during operation
Solution Approach 2:
The bushing design transitions from a static single-piece structure to a dynamic segmented structure that can be assembled and disassembled. The arcuate parts can be separated for maintenance and reassembled to restore structural integrity, adapting the bushing from a permanent to a maintainable component
3Stability of the object's composition
If the drum is kept fixed on the shaft, then structural stability is maintained, but bushing exchange becomes impossible without complex disassembly operations
Solution Approach 1:
The bushing is extracted as a separate removable component from the drum-shaft assembly. This allows the drum to remain fixed on the shaft while the bushing can be independently removed and replaced, maintaining structural stability while enabling easy repair operations at open sea
Data Source
Figure 1A~1B
Figure 1C
Figure 2A
AI summary
The invention concerns a drum (3) assembly for a mooring winch and a method of exchanging a bushing (6) within the drum (3) assembly. The drum (3) assembly comprises a rotatable drum shaft (1) having a rotational axis along the drum shaft (1), a drum support (2) comprising a first pedestal (2B) supporting a first axial end (3A) of the drum shaft (1) and a second pedestal (2B) supporting a second axial end (3B) of the drum shaft (1) and an axially slidable drum (3) arranged between the first and second pedestals (2A, 2B). Both a first axial end (3A) of the drum (3) and a second axial end (3B) of the drum (3) is supported on a bushing (6) axially surrounding the drum shaft (1). A drum (3) length difference (L, L') corresponding to the minimum distance between the two pedestals (2A, 2B) minus the axial length of the drum (3) is equal or longer that the axial length of each bushing.