Crane Hoist Rope Drum Helical Winding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing crane hoist systems face challenges in minimizing wear on cable strands due to the need for multiple deflection pulleys, which increases with lifting height, limiting the simplification of load-calmed crane hoisting mechanisms.
Innovation Solution
The implementation of a crane hoist design where at least one rope strand is wound helically onto the rope drum at a skew angle, keeping the pitch angle constant over the lifting height, allowing the strand to run directly to the load handling device without additional deflection pulleys, and utilizing a third strand in the middle plane for stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cable strands are routed directly from the cable drum to the load handling device without deflection pulleys, then the number of bending cycles is reduced and wear is minimized, but the slip angle increases with lifting height causing improper functioning
Solution Approach 1:
The cable drum is designed with a conical surface where the winding radius varies with height. As the load is lifted and the drum rotates, the winding point naturally migrates toward the periphery, dynamically adjusting the cable angle to maintain a constant slip angle throughout the lifting range, eliminating the need for deflection pulleys
Solution Approach 2:
The drum surface geometry is changed from cylindrical to conical, altering the winding parameters (radius and angle) as a function of height. This parameter change ensures that the slip angle remains constant despite variations in lifting height, allowing direct routing without additional pulleys
2Duration of action of stationary object
If the number of deflection pulleys is minimized to reduce wear, then cable strand wear is reduced, but the slip angle increases with lifting height
Solution Approach 1:
The conical drum surface enables dynamic adjustment of the winding geometry. As the drum rotates during lifting, the effective winding radius increases, which dynamically compensates for the increasing height and maintains a constant slip angle, extending cable life without compromising angle control
Solution Approach 2:
The drum surface is effectively segmented into different radial zones (inner near the axis, outer near the periphery) that are utilized at different heights. This segmentation allows the system to transition from inner to outer zones as lifting progresses, maintaining optimal slip angle throughout the range
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The crane hoisting gear (10) has cable drive (12) having ropes which are hung from rope drum (18) to lifting attachment and are displaced against each other along the drum axles portions of common rope drum or rope drums which are drive-connected by common drum axle. The ropes are bent around a drift angle opposite the vertical center plane between drum portions. The pitch angles of windings (24) correspond to drift angles.