Derricking Cylinder Control Valve for Balance Valve Failure Protection
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Solution Overview
Problem
Conventional derricking cylinders in aerial work platforms are prone to failure of the balance valve connected to the rodless cavity, leading to uncontrolled downward movement and potential accidents due to tilting or tipping of the work bucket and platform.
Innovation Solution
A control valve with pilot-type overflow function portions and a switch valve that seals the rodless cavity when the balance valve fails, integrated with a hydraulic sensor to detect pressure deviations and trigger an alarm for maintenance, ensuring double insurance on the oil circuit and preventing uncontrolled movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional balance valve is used to control the rodless cavity of the hydraulic cylinder, then the derricking cylinder can control the lifting arm's upward and downward movement, but the balance valve is prone to failure leading to uncontrolled downward movement and potential accidents
Solution Approach 1:
The patent introduces a switch valve that can be closed before potential failure occurs to seal the rodless cavity. This preliminary action prevents oil leakage and uncontrolled movement if the balance valve fails, addressing the reliability issue while maintaining operational control through the redundant sealing mechanism
Solution Approach 2:
The patent implements a backup sealing approach by closing the switch valve to isolate the rodless cavity from the oil supply system. This beforehand cushioning creates a safety barrier that prevents catastrophic failure and uncontrolled movement, ensuring the lifting arm remains stable even if the balance valve malfunctions
2Reliability
If the balance valve fails, then uncontrolled downward movement occurs causing tilting or tipping of the work bucket and platform, but adding a switch valve and monitoring system increases device complexity
Solution Approach 1:
The patent introduces a switch valve as an intermediary component between the oil supply system and the rodless cavity. This mediator can be closed to seal the cavity and prevent uncontrolled movement, adding a layer of safety without requiring complete redesign of the balance valve itself
Solution Approach 2:
The patent implements a monitoring system with a hydraulic sensor that detects pressure changes in the rodless cavity and provides feedback to the control system. When abnormal pressure indicating balance valve failure is detected, the system can trigger an alarm or automatically close the switch valve, adding safety through intelligent monitoring rather than purely mechanical redundancy
3Reliability
If the rodless cavity is sealed when the balance valve fails, then the lifting arm remains stable preventing accidents, but the oil pressure in the rodless cavity increases
Solution Approach 1:
The patent extracts the sealing function from the balance valve by introducing a separate switch valve that can be closed to isolate the rodless cavity. This separation allows the balance valve to continue its pressure control function while the switch valve provides fail-safe sealing, preventing uncontrolled movement without requiring excessive pressure buildup
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
Enhances the operational reliability and safety of the aerial work platform by preventing uncontrolled movements and ensuring the lifting arm remains stable, even when the balance valve fails, thereby reducing the risk of accidents.
Implementation Method 1
a hydraulic sensor to detect pressure deviations
Implementation Method 2
a switch valve that seals the rodless cavity when the balance valve fails
Implementation Method 3
A control valve with pilot-type overflow function portions
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Provided are a control valve, a derricking cylinder and a working method thereof, and an aerial work platform, relating to the field of aerial work. The control valve of the derricking cylinder includes a first balance valve provided on the oil circuit between the first port G and the second port F, and a second balance valve provided on the oil circuit between the third port H and the fourth port E; and a switch valve in series with the first balance valve is further provided on the oil circuit between the first port G and the second port F.