Hydraulic Flow Meter for Industrial Truck Lifting Height
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Solution Overview
Problem
Existing methods for determining the lifting height of a load-carrying means on an industrial truck are prone to errors due to slippage, contamination, and complex assembly, and require additional markings or mechanisms that can obstruct the view and are costly.
Innovation Solution
A flow meter is installed in the hydraulic line between the pump and lifting cylinders, with an evaluation unit calculating the lifting height from the flow rate, and a reference point on the mast helps eliminate measurement errors, allowing for easy retrofitting and minimal mechanical parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a roller with an integrated measuring unit is used to determine lifting height, then the lifting height can be measured, but slippage occurs between the roller and the lifting mast causing measurement errors
Solution Approach 1:
The patent replaces the mechanical roller-based measurement system with a hydraulic flow metering system. Instead of using a roller that physically contacts and rotates on the lifting mast, the invention measures the volume of hydraulic fluid consumed by the lifting cylinder to calculate lifting height. This substitution eliminates slippage errors entirely, as fluid volume measurement in a closed hydraulic system is precise and不受 mechanical friction or wear affects.
2Measurement precision
If optical markings are attached to the mast for measurement, then lifting height can be determined, but contamination of the markings and measurement optics leads to measurement errors
Solution Approach 1:
The patent replaces the optical measurement system with a hydraulic flow measurement system. Instead of using optical markings on the mast that can be contaminated by dirt or grease, the invention uses a flow meter integrated into the hydraulic circuit. This internal measurement approach completely avoids external contamination issues, as the hydraulic fluid and meter are enclosed within the system.
3Measurement precision
If a toothed belt or cable is laid on the mast to drive a roller, then lifting height can be measured, but the assembly becomes expensive and requires multiple components
Solution Approach 1:
The patent merges the measurement function with the existing hydraulic lifting system. Instead of adding a separate mechanical transmission system (toothed belt, cable, and roller), the invention utilizes the hydraulic fluid already present in the lifting circuit as the measurement medium. The flow meter is integrated into the existing hydraulic line, combining the lifting function and measurement function into a single unified system, thereby reducing component count and complexity.
4Measurement precision
If a toothed belt or cable is used on the mast, then lifting height can be measured, but it makes it difficult to see through the mast
Solution Approach 1:
The patent extracts the measurement function from the external mast structure and relocates it to the internal hydraulic circuit. By removing the toothed belt or cable from the mast exterior and using the hydraulic fluid as the measurement medium instead, the mast remains visually transparent. The flow meter is installed in the hydraulic line away from the mast structure, preserving the clear view through the mast while maintaining measurement capability.
5Measurement precision
If hydraulic pump revolutions are counted to determine lifting height, then lifting height can be calculated, but the method does not account for efficiency losses in the lifting system
Solution Approach 1:
The patent replaces the pump-revolution-based calculation method with direct hydraulic flow measurement. Instead of counting pump revolutions and applying efficiency factors to calculate lifting height, the invention uses a flow meter to directly measure the volume of hydraulic fluid consumed by the lifting cylinder. This direct measurement approach eliminates the need for efficiency corrections, as it measures the actual fluid volume that directly correlates to cylinder piston displacement and thus lifting height, providing more reliable and accurate results.
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 solution provides accurate and reproducible lifting height measurements without additional markings, maintaining a clear view and avoiding errors from soiling or temperature changes, and accounts for free lift without extra measures.
Implementation Method 1
A flow meter is arranged in the line between a hydraulic pump and at least one lifting cylinder
Implementation Method 2
A flow meter is arranged in the line between a hydraulic pump and at least one lifting cylinder
Implementation Method 3
A flow meter is arranged in the line between a hydraulic pump and at least one lifting cylinder
Data Source
AI summary
The device includes a meter measuring the through flow volume and mounted in the line (14) between a hydraulic pump (16) and the free lift cylinder (10). An evaluator unit is connected to the meter and a calculates from the measuring signal of same the relevant lifting height. A detection device detects the end of the free lift movement and the start of the movement of the load lift cylinder and sends a signal to the evaluator unit for applying a modified factor to the calculation of the lift height. A reference point (22) on the lifting frame is detected by means of a switch, approach sensor or similar to produce a reference signal for the evaluator unit (18).