Intelligent Motor Brake for Crane Length Sensor
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Solution Overview
Problem
Existing crane length sensors rely on purely mechanical spring systems for generating restoring forces, which are inefficient and prone to wear, and lack the flexibility to adapt to changing operational conditions, posing safety and maintenance challenges.
Innovation Solution
A length sensor system utilizing a controllable electric motor to generate a constant restoring force, integrated with a force sensor for real-time force measurement and control, ensuring precise length determination and reducing wear by maintaining consistent mechanical tension, and providing an intelligent engine brake that reacts to operational states and potential cable issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a purely mechanical spring system is used to generate restoring force, then the structure is simple, but the wear is high and precision is poor
Solution Approach 1:
The patent replaces the purely mechanical spring system with an intelligent motor system that uses electrical control to generate restoring force. The motor-controlled drum winds and unwinds the cable with precisely controlled force, eliminating the wear and precision limitations of mechanical springs while maintaining structural feasibility through the integration of motor, drum, and cable assembly.
Solution Approach 2:
The intelligent motor system automatically adjusts the restoring force based on real-time feedback from force sensors and position sensors. The control unit continuously monitors cable tension and drum position, automatically regulating motor output to maintain optimal force levels without manual intervention, thereby reducing wear and improving measurement precision.
2Device complexity
If a purely mechanical spring system is used, then the device is simple, but the adaptability to changing operational conditions is poor
Solution Approach 1:
The patent transforms the static mechanical spring system into a dynamic, adaptive system. The intelligent motor can continuously adjust its output force based on real-time operational conditions, cable position, and load requirements. The control unit processes sensor data and dynamically regulates motor parameters, enabling the system to adapt to varying crane operations, cable lengths, and environmental conditions.
Solution Approach 2:
The system changes key operating parameters dynamically - specifically, the restoring force applied by the motor is continuously adjusted based on cable position, tension measurements, and operational state. The control unit modifies motor current, speed, and torque parameters in real-time to optimize performance for different operational conditions, something impossible with fixed mechanical springs.
3Ease of manufacture
If a mechanical spring system is used, then the cost is low, but the precision in length determination is poor
Solution Approach 1:
The patent implements a closed-loop feedback system where force sensors measure cable tension and position sensors monitor drum rotation and cable length. This feedback is processed by the control unit, which continuously adjusts motor output to maintain precise cable tension and accurate length measurement. The feedback mechanism compensates for variations in cable elasticity, drum friction, and external forces, achieving high measurement precision that mechanical springs cannot provide.
Solution Approach 2:
The patent replaces the imprecise mechanical spring measurement system with an electronically controlled motor system coupled with electronic sensors and digital control. The motor's precise control over cable winding, combined with electronic force and position sensing, provides superior length measurement accuracy while remaining cost-effective through reduced maintenance and longer service life compared to wear-prone mechanical springs.
4Ease of operation
If the cable is wound onto or unwound from the drum with varying force, then the system is simple to operate, but the wear increases significantly
Solution Approach 1:
The control unit dynamically adjusts the motor's output force parameters during cable winding and unwinding operations. By monitoring cable position, tension, and drum rotation speed, the system optimizes motor torque and speed in real-time to maintain constant, optimal cable tension. This prevents excessive force that would increase wear while ensuring sufficient force for reliable cable handling throughout the entire operational range.
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 system significantly reduces wear and enhances precision in length measurement, ensures consistent mechanical tension, and provides a flexible, cost-effective solution that adapts to changing operational requirements, improving safety and reducing maintenance needs.
Implementation Method 1
a controllable electric motor (16) is provided which replaces a previously known mechanical restoring system based on spring force
Implementation Method 2
a force sensor (13) assigned to the cable (12), with which the force acting on the cable (12) in its axial alignment is detected
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a length sensor, in particular a length/angle sensor (10) of a crane (1), said length sensor comprising a restoring system, which restoring system has a drum and a cable, which cable is wound on said drum and can be unwound from said drum in order to detect a length, characterised in that the restoring system has a controllable electric motor.