Hydraulic Drive Device for Vertical Pivoting Load Carrying Platform
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Solution Overview
Problem
Conventional hydraulic drive systems for vertical pivoting load carrying platforms on dump trucks require complex directional control valves with four switch positions, leading to high manufacturing costs and complex switching control, especially due to the placement of the switch position for the platform free-fall permitting operation between the neutral and forced-lowering positions.
Innovation Solution
The system employs two directional control valves, each with three switch positions, including a neutral position, to simplify the switching control by assigning specific switch positions for platform raising, forced-lowering, and free-fall permitting operations, using on-off valves to control the pilot pressure and prevent complex analog and digital signal control requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single directional control valve with four switch positions is used, then all platform operations can be controlled, but the valve structure becomes complex and manufacturing cost increases
Solution Approach 1:
The patent divides the single complex four-position directional control valve into two simpler three-position directional control valves. The first valve controls the raise and forced-lower operations, while the second valve controls the free-fall and stay holding operations. This segmentation reduces the complexity of each individual valve while maintaining all required platform operation capabilities.
2Adaptability or versatility
If a four-position directional control valve is used, then all operations can be performed, but switching control becomes difficult and complex
Solution Approach 1:
The control functionality is segmented across two three-position valves instead of one four-position valve. Each valve has a neutral position and two active positions, making the switching logic simpler and more intuitive. The first valve handles raise/forced-lower transitions while the second valve handles free-fall/stay holding transitions, reducing overall control complexity.
3Adaptability or versatility
If a four-position directional control valve is used, then complete platform control is achieved, but manufacturing cost increases
Solution Approach 1:
The patent segments the control function into two standard three-position directional control valves rather than one custom four-position valve. Three-position valves are commercially standard components with established manufacturing processes, making them more cost-effective and easier to manufacture than custom four-position valves, while still providing complete platform operation control when used in combination.
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 configuration simplifies the switching control and reduces manufacturing costs by using valves with fewer and simpler structures, allowing for efficient performance of platform raising, forced-lowering, free-fall permitting, and stay holding operations while preventing pull-outs and excessive load depression.
Implementation Method 1
a hydraulic pump for delivering pressure oil to operate said hoist cylinder
Implementation Method 2
a directional control valve arranged between the hydraulic pump and the hoist cylinder to control operations of the hoist cylinder
Data Source
AI summary
In a hydraulic drive device for vertical pivoting movement of a load carrying platform, a first directional control valve has only three switchover positions, including a neutral position relating to operation of stopping and holding a load carrying platform, a switching position relating to operation of lifting the load carrying platform, and a switch over position relating to operation of forced lowering of the load carrying platform. A second directional control valve has only three switchover positions, including a neutral position, a switching position, and a switchover position relating to operation of allowing the load carrying platform to fall by its own weight. The device includes a first on-off valve, a second on-off valve, and a third on-off valve that are proportional control solenoid valves for switching an appropriate one of the first and second directional control valves.