Hydraulic Arrangement for Lifting Unit with Mode Switching
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Solution Overview
Problem
Agricultural machines face challenges with hydraulic lifting and lowering arrangements due to mechanical and hydraulic friction, which hinder efficient operation of implements of varying weights, and require manual effort to switch between single and double acting modes, posing safety risks during maintenance.
Innovation Solution
A hydraulic arrangement using a 4/3 directional valve and a blocking valve, connected to dual acting cylinders, allows easy switching between single and double acting modes, and includes a control system with a pressure transducer and ECU for automatic weight distribution and safety locking, facilitating the lifting and lowering of both light and heavy implements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single acting hydraulic cylinder is used to lower the carrying arm under implement weight, then the cylinder can retract automatically, but the arrangement cannot be used when the implement is detached for maintenance
Solution Approach 1:
The hydraulic system dynamically switches between single-acting and double-acting modes based on operational requirements. The control valve enables the system to adapt its configuration: when an implement is attached, the system operates in single-acting mode for automatic retraction; when the implement is detached for maintenance, the system switches to double-acting mode allowing manual control of the carrying arm position.
2Adaptability or versatility
If a double acting hydraulic cylinder is used to enable both lifting and lowering, then the carrying arm can be positioned flexibly, but manual pushing is required to retract the cylinder when detached
Solution Approach 1:
The patent replaces the purely mechanical manual pushing operation with a hydraulic assistance system. When the implement is detached and the carrying arm needs to be lowered, the operator activates the control valve to switch to double-acting mode, allowing hydraulic pressure to assist in retracting the cylinder, thereby reducing the manual force required from the operator.
3Stability of the object's composition
If hydraulic friction is present in the lifting arrangement, then the system provides mechanical stability, but the friction prevents efficient operation with implements of varying weights
Solution Approach 1:
The control system dynamically adjusts hydraulic pressure parameters based on the detected implement weight. The pressure transducer measures the actual weight, and the ECU modifies the hydraulic pressure accordingly, optimizing the balance between overcoming friction for stability and minimizing excessive pressure for efficiency across different implement weights.
4Ease of operation
If manual pushing is required to lower the carrying arm during maintenance, then the system provides precise control, but the high frictional force cannot be overcome by human force alone
Solution Approach 1:
The control valve acts as an intermediary between the operator and the hydraulic cylinder. Instead of directly pushing against the high-friction cylinder, the operator manipulates the valve to control hydraulic fluid flow, which then applies the necessary force to move the carrying arm. This intermediary mechanism amplifies the operator's input force to overcome the high frictional forces.
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 solution reduces frictional forces, enabling easier operation of implements of different weights and ensuring safety during maintenance by automatically adjusting pressure and locking the hydraulic cylinders, thus enhancing operational efficiency and safety.
Implementation Method 1
pressurisation of the cylinder extends the piston rod which raises a carrying arm and implement
Implementation Method 2
Owing to mechanical and hydraulic friction in a hydraulic arrangement, the weight of the attached implement may not be sufficient to contract the cylinder to lower the carrying arm
Data Source
AI summary
A hydraulic arrangement for lifting and/or lowering at least one implement carrying arm on an agricultural machine. The arrangement comprises an inlet hydraulic line and an outlet hydraulic line connecting a fluid pump and a fluid reservoir respectively to a first valve means, said arrangement comprising at least one dual acting hydraulic cylinder for lifting/and or lowering the implement carrying arm. The at least one cylinder is connected to the first valve means allowing the cylinder to be switched between a single acting mode wherein the arm can be lifted and a double acting mode wherein the arm can be lifted and lowered.