Hydraulic Crane Load Registration via Cylinder Force Rate
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Solution Overview
Problem
Current methods for calculating the fatigue stressing of hydraulic cranes, such as registering operating time, are inadequate as they do not accurately reflect the varying intensity of different working operations, leading to potential crane breakdowns and safety issues.
Innovation Solution
Registering lifting up and putting down of loads based on the rate of changes in the cylinder force of the hydraulic cylinder, rather than hydraulic pressure, to accurately count lifting cycles and assess fatigue stressing without erroneous registrations during lowering movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If operating time is registered by means of a time counter, then the registration method is simple, but the accuracy of fatigue stressing measurement deteriorates
Solution Approach 1:
The patent replaces the mechanical time counter system with a hydraulic pressure-based detection system. Instead of measuring time directly, the system uses pressure sensors to detect pressure changes in the hydraulic cylinder, which correspond to lifting cycles. This substitution allows accurate fatigue measurement through pressure signal analysis rather than time tracking.
Solution Approach 2:
The patent changes the measurement parameter from time to hydraulic pressure. By monitoring pressure changes in the hydraulic cylinder during lifting operations, the system can identify lifting cycles based on pressure thresholds and patterns. This parameter change enables accurate fatigue assessment that reflects actual operational intensity rather than just elapsed time.
2Device complexity
If hydraulic pressure on piston side is used for registration, then the measurement is simple, but erroneous registrations occur during lowering movements
Solution Approach 1:
The patent introduces an intermediary evaluation process that analyzes multiple pressure parameters (piston side pressure and piston stem side pressure) together with their rates of change. This intermediary analysis layer filters out erroneous signals by checking whether pressure changes meet specific criteria for valid lifting cycles, preventing false registrations during lowering movements or other non-lifting operations.
Solution Approach 2:
The system uses feedback from pressure sensors to continuously monitor hydraulic conditions and adjust registration decisions. By evaluating the rate of pressure change and comparing it against predetermined thresholds, the system provides feedback that confirms or rejects potential lifting cycle detections, ensuring accurate registration only when actual lifting occurs.
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
This method provides a more reliable and cost-effective means to determine the number of lifting cycles, effectively measuring the accumulated fatigue stressing of the crane, reducing the risk of breakdowns and enabling safer operations.
Implementation Method 1
a first pressure sensor (34a) for measuring a hydraulic pressure (p1) on a piston side of the hydraulic cylinder (8) and a second pressure sensor (34b) for measuring a hydraulic pressure (p2) on a piston stem side of the hydraulic cylinder (8)
Data Source
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AI summary
A hydraulic crane (1) comprising a liftable and lowerable crane boom (5), a hydraulic cylinder (8) for lifting and lowering the crane boom (5) and registration means (35) adapted to register lifting up or putting down of a load in dependence on the rate of the changes in the cylinder force (Fc) of the hydraulic cylinder (8). The registration means (35) is adapted to register that the crane executes a lifting up or putting down of a load when the rate of a detected change in the cylinder force (Fc) exceeds a predetermined value. The invention also relates to the method for registration of lifting up or putting down of a load by a hydraulic crane, and a method for calculating the fatigue stressing of a hydraulic crane based on the registered number of liftings up and/or puttings down of load.