Hydraulic Actuator Descent Control via Load-Induced Pressure
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Solution Overview
Problem
Existing hydraulic systems for controlling load movement are inefficient in terms of energy consumption and lack a reliable mechanism for emergency load descent, especially in systems without external power sources, limiting their application and safety.
Innovation Solution
A hydraulic actuator control system featuring a directional valve with a flow-controlled descent control valve driven by a pressure control valve, which opens hydraulically during load descent, reducing energy consumption and ensuring safe operation even in power outages by utilizing the load's weight-induced pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure from the first working duct is used to actuate the over-center valve, then the valve can be driven to open for discharge, but energy consumption increases even for spontaneous load lowering maneuvers
Solution Approach 1:
The system uses the load's own weight to generate the pressure needed for valve actuation. The hydrostatic pressure from the load acting on the piston area of the over-center valve provides the driving force for descent, eliminating the need for external pressurization during lowering maneuvers.
Solution Approach 2:
The gravitational force that causes the load to descend is converted into a beneficial pressure source. The weight of the load creates hydrostatic pressure that automatically actuates the descent control valve when needed, turning the potential harmful uncontrolled descent into a controlled, energy-free lowering mechanism.
2Reliability
If external pressure sources or electro-hydraulic drives are used to actuate the descent control valve, then reliable descent control is achieved, but system complexity and cost increase
Solution Approach 1:
The first working duct, originally designed for supplying pressure during lifting operations, is made multi-functional by also serving as the pressure source for descent control valve actuation. This eliminates the need for separate external pressure sources or independent driving lines.
Solution Approach 2:
The invention merges the lifting and lowering control functions into a single integrated hydraulic circuit. The descent control valve is actuated using the same hydraulic fluid and pressure source that serves the lifting operation, combining multiple functions into one system.
3Ease of operation
If electro-hydraulic drives are used for descent control, then precise control is achieved, but the system becomes unsafe during electrical outages
Solution Approach 1:
The invention replaces electro-hydraulic actuation with a purely mechanical/hydraulic solution. The over-center valve is actuated by hydrostatic pressure from the load itself rather than by electrical signals, eliminating dependence on electrical systems while maintaining reliable control.
Solution Approach 2:
The system is designed to automatically function during emergency conditions without requiring external power. The hydrostatic pressure build-up from the load weight automatically triggers valve opening when needed, providing inherent safety coverage for outage scenarios.
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 system minimizes energy consumption for load descent maneuvers and ensures safe automatic operation during emergencies without requiring significant changes to existing hydraulic circuit architectures.
Implementation Method 1
a hydraulic actuator (2) for the rise and descent of a load (L), comprising a directional valve (6) for distributing a pressurized working fluid, from which the following branch out: a first working duct (7) connected to a first chamber (4) of said actuator adapted to actuate the descent of the load (L) if supplied and a second working duct (8) connected to a second chamber (5) of said actuator which is adapted to actuate the rise of the load (L) if supplied
Implementation Method 2
it comprises a line (10) for driving said descent control valve which is in fluid connection with said second chamber and is flow controlled by a downstream pressure control valve (11), which is normally closed hermetically and is switched to open by actuation means (12) operable by an operator to obtain a preset pressure reduction
Implementation Method 3
driven hydraulically to open in the direction for discharge of said second chamber during descent of the load
Data Source
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AI summary
The present invention relates to system (1) for controlling a hydraulic actuator (2) for the rise and descent of a load, comprising a directional valve (6) for distributing a pressurized working fluid, from which the following branch out: a first working duct (7) associated with a first chamber (4) of the actuator (2) adapted to actuate the descent of the load if supplied and a second working duct (8) associated with a second chamber (5) of the actuator which is adapted to actuate the rise of the load if supplied, and a descent control valve (9) for controlling the descent of the load which is arranged along the second working duct (8), is normally closed in the discharge direction and can be opened in the direction for supplying the second chamber (5) and is driven hydraulically to open in the direction for discharge of the second chamber during descent of the load. The control system comprises a line (10) for driving the descent control valve (9) which is in fluid connection with the second chamber (5) and is flow controlled by a downstream pressure control valve (11), which is normally closed hermetically and is switched to open by actuation means (12), operable by an operator to obtain a preset pressure reduction, and has at least one inlet (13) associated with the second chamber (5) and at least one outlet (14) associated with the descent control valve (9) to drive opening of the valve (9).