Forklift Lifting Device Automatic Load Deposition Control
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Solution Overview
Problem
Industrial truck lifting devices face issues with abrupt lowering movements during load deposition, leading to potential damage and wear, especially when the traction mechanism becomes loose, and existing load protection functions are limited to heavy attachments, requiring complex operator sequences and potential grinding on the setting surface.
Innovation Solution
An electronic control device with an automatic deposit mechanism and pressure sensor system that detects pressure changes in the pressure medium line, actuating the control valve to stop the lowering process before the load touches the setting surface, ensuring the load is deposited at a controlled speed and preventing traction mechanism overload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the load handling device is lowered using a lifting cylinder device with a flexible traction mechanism, then the load can be deposited on a setting surface, but the traction mechanism becomes loose causing abrupt lowering movements and potential damage
Solution Approach 1:
A pressure sensor device continuously monitors the pressure in the pressure medium line and provides feedback to the electronic control device. When the pressure drops below a predetermined threshold (indicating the load has touched down), the control device automatically actuates the control valve to stop the lowering process, preventing the traction mechanism from becoming loose and eliminating abrupt movements.
Solution Approach 2:
The patent replaces the purely mechanical load protection function (pressure cut-off valve) with an electronic control system that uses electronic sensors and control valves. This substitution allows for more precise and reliable control of the lowering process, preventing traction mechanism loosening while enabling operation with lighter attachments.
2Reliability
If a pressure cut-off valve is used to prevent the traction mechanism from becoming loose, then the load protection function is achieved, but it requires a sufficiently heavy attachment (greater than 500 kg) to generate adequate pressure
Solution Approach 1:
The patent changes the critical parameter from attachment weight to pressure threshold detection. By using an electronic pressure sensor with a programmable threshold, the system can detect load touchdown conditions regardless of attachment weight. This allows the load protection function to work with lighter attachments (less than 500 kg) while maintaining reliable traction mechanism protection.
3Productivity
If the load handling device is lowered to deposit a load, then the load can be placed on the setting surface, but the operator must perform additional readjustment operations to prevent grinding on the surface
Solution Approach 1:
The system performs the readjustment operation automatically without operator intervention. After the load is deposited and the pressure sensor detects touchdown, the electronic control device automatically actuates the control valve to lift the load handling device slightly, preventing it from grinding on the setting surface. This self-service function eliminates the need for additional manual readjustment operations.
4Reliability
If the lowering process is stopped abruptly to prevent traction mechanism overload, then the mechanism is protected, but the load deposition process becomes less smooth and more jerky
Solution Approach 1:
The system takes preliminary action by continuously monitoring pressure during the lowering process and detecting the touchdown condition before the load handling device can cause abrupt movements. The electronic control device actuates the control valve in advance to gently stop the lowering process, preventing both traction mechanism overload and abrupt jerky movements.
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
Simplifies the operating sequence for the operator, reduces wear on the load handling device, and prevents damage by automatically stopping the lowering movement before contact, allowing for safe and efficient load placement without readjustment, regardless of load type or attachment weight.
Implementation Method 1
a pressure sensor device (30) is provided, which detects the pressure in a pressure medium line (18) routed from the control valve device (12) to the lifting cylinder device (11)
Data Source
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AI summary
The invention relates to a lifting device (1) of a forklift truck with a load handling device (3) arranged on a lifting frame (2) that can be raised and lowered, wherein a hydraulic lifting cylinder device (11) is provided for raising and lowering the load handling device (3), which can be actuated by means of an electrically actuated control valve device (12), wherein an electronic control device (25) is provided for controlling the control valve device (12).The electronic control unit (25) has an automatic lowering mechanism in which, during a lowering process of the load-handling device (3) to lower a load located on the load-handling device (3) onto a lowering surface, the control valve device (12) is actuated to a lowering position (13c) depending on the deflection of an operating element (25) into a lowering position (S), the load is lowered onto the lowering surface at the lowering speed specified by the deflection of the operating element (28), and with the operating element (28) still deflected into the lowering position (S), the electronic control unit (25) terminates the lowering process of the load-handling device (3) by actuating the control valve device (12) into a locking position (13a) in such a way that the load-handling device (3) is prevented from touching the lowering surface.