Lifting Device Hoist Control for Uniform Cable Tension
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lifting devices with four pairs of V-shaped hoisting cables are time-consuming to adjust, requiring precise cable length matching for uniform tension, which affects the lifetime and maintenance of the cables due to positional and material tolerances, leading to high maintenance costs and short cable life.
Innovation Solution
The implementation of two mechanically separate hoists, each driven by its own motor, controlled by a common device to achieve uniform cable tensions without exact cable length adjustments, eliminating the need for deflection pulleys and reducing wear on cables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If precise cable length adjustments are made to achieve uniform cable tensions, then cable loading uniformity is improved, but adjustment time and maintenance complexity increase
Solution Approach 1:
The patent replaces manual mechanical cable length adjustment with an automated control system that uses sensors to detect cable tensions and a control unit to coordinate cable drum rotations, automatically adjusting cable lengths to achieve uniform tension without time-consuming manual intervention
Solution Approach 2:
The patent implements a feedback mechanism where sensors continuously monitor cable tensions and provide data to the control unit, which then adjusts the cable drum rotations to maintain uniform cable loading, enabling real-time optimization without repeated manual adjustments
2Reliability
If manual cable length adjustments are performed to compensate for tolerances, then cable tension uniformity is improved, but maintenance frequency increases
Solution Approach 1:
The patent replaces manual adjustment operations with an automated control system that continuously monitors and adjusts cable tensions through coordinated cable drum rotation, eliminating the need for frequent manual maintenance interventions
Solution Approach 2:
The patent maintains continuous cable tension optimization through the automated control system that operates throughout the lifting device's service life, preventing tension deviations before they require maintenance rather than correcting them periodically
3Shape
If deflection pulleys are used to form V-shaped cable arrangements, then cable geometry is improved, but cable wear increases
Solution Approach 1:
The patent extracts and eliminates the deflection pulleys from the system by using directly opposing cable drum arrangements that form the V-shaped cable configurations without requiring intermediate pulleys, thereby removing the source of cable wear while maintaining the necessary geometry
Solution Approach 2:
The patent divides the cable support function between two independently controllable cable drum units, allowing each unit to be optimized for its specific cable pair without the need for shared deflection pulleys, reducing overall cable wear in the system
Data Source
AI summary
A lifting device comprises four pairs of hoisting cables arranged in a V-shape relative to one another for lifting and lowering a load suspension apparatus at which they engage and which are taken off from drivable cable drums. The free lengths of the hoisting cables of two longitudinal pairs of cables lie in longitudinal planes which are located at a distance from one another, and the free lengths of the hoisting cables of two transverse pairs of cables lie in transverse planes which are located at a distance from one another and which extend at right angles to the longitudinal planes. Two mechanically separate hoists are provided for the hoisting cables of the two longitudinal cable pairs and for the hoisting cables of the two transverse cable pairs, each of the hoists is drivable by its own driving motor, and the driving motors are controlled by a common control device.