Stacked Hoist Drum Frames for Compact Crane Rotating Beds
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Solution Overview
Problem
Mobile lift cranes with multiple hoist drums face challenges in compact design and transportation due to the length and weight of the rotating bed, which increases tail swing and manufacturing costs, and complicates access for service when hoist drums are mounted on the boom or mast.
Innovation Solution
A drum frame system allows multiple hoist drums to be stacked on the rotating bed without increasing its length, with frames connected by removable pins for easy assembly and disassembly, enabling the mounting of other major crane components indirectly through the drum frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple hoist drums are mounted on the rotating bed, then the crane can perform multiple functions, but the rotating bed becomes longer and heavier
Solution Approach 1:
The patent arranges multiple hoist drums in a stacked vertical configuration rather than spreading them horizontally across the rotating bed. This dimensional change from horizontal to vertical arrangement allows multiple drums to be mounted without increasing the rotating bed's length or weight, while still providing multiple crane functions.
2Length of stationary object
If hoist drums are mounted on the boom or mast, then the rotating bed length is reduced, but access for service becomes difficult
Solution Approach 1:
By mounting hoist drums vertically on the rotating bed rather than horizontally on the boom or mast, the patent reduces the rotating bed length while keeping drums accessible at ground level. This vertical stacking arrangement eliminates the need to reach high up the boom or mast for maintenance.
3Adaptability or versatility
If the rotating bed is made longer to accommodate multiple drums, then more functions are available, but tail swing increases
Solution Approach 1:
The patent uses vertical stacking of hoist drums on the rotating bed instead of horizontal arrangement. This dimensional change allows multiple crane functions to be achieved without increasing the rotating bed's length, thereby preventing increased tail swing during repositioning operations.
4Length of stationary object
If hoist drums are removed for transportation, then highway limits are met, but setup time increases
Solution Approach 1:
The patent designs the drum frame system with removable pins that allow individual drums or frame assemblies to be easily detached and transported separately. This segmentation enables compliance with highway transportation limits while minimizing setup time, as drums can be quickly reinstalled at the destination using the simple pin connection system.
5Length of stationary object
If a compact drum frame system is used, then the rotating bed can be shorter, but the complexity of connection increases
Solution Approach 1:
The patent employs a modular drum frame system with standardized removable pin connections. This segmentation into discrete, pre-fabricated modules with simple connection mechanisms allows for compact rotating bed design without significantly increasing complexity, as the modular approach simplifies both assembly and maintenance.
Data Source
AI summary
A mobile lift crane includes a carbody having movable ground engaging members; a rotating bed rotatably connected to the carbody; a boom pivotally mounted on the rotating bed; a first hoist drum mounted in a first frame connected to the rotating bed; a second hoist drum mounted in a second frame connected to the rotating bed. Connectors used to connect the load hoist drum frames to the rotating bed include engagement members and alignment surfaces such that as the two crane components are brought close to their operational position during an assembly operation, the engagement member and the alignment surface of the connectors come into contact with one another to guide the crane components into their operational orientation so that a main pin can be placed through the through-holes of the extensions of the connectors.