Excavator Blade Float Valve Control for Safe Jacking and Leveling
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Solution Overview
Problem
Construction machines, such as hydraulic excavators, face issues where the blade is inadvertently put into a float state during jacking operations, leading to machine body lowering, and struggle with effective leveling on rugged terrain due to improper operation of the blade control valve and selector valve configurations.
Innovation Solution
A construction machine equipped with a float valve, pressure sensor, and controller that determines the machine's jacking state and controls the float valve to prevent blade floatation during jacking and enable it during leveling operations, ensuring the blade is not put into a float state when the machine body is raised and allowing proper leveling when it is not.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the blade control valve is configured with a float position to enable leveling work on rugged terrain, then the blade can follow the ground contour effectively, but the machine body may be inadvertently lowered during jacking operations due to misoperation
Solution Approach 1:
The patent applies dynamics by making the control valve's functionality changeable based on operational state. The control valve can dynamically switch between two modes: (1) float position capability for leveling work when the blade is on the ground, and (2) restricted mode during jacking operations where the float position is ineffective. This dynamic adaptation resolves the contradiction by allowing the system to be versatile when needed but safe when jacking.
Solution Approach 2:
The patent implements feedback through detection means that monitor whether the blade is in contact with the ground. This feedback information is used by the control means to determine the appropriate operational mode. When the detection means indicates the blade is grounded, the control valve enables float position for leveling. When jacking is detected (blade not on ground), the control means restricts the float position effect, preventing inadvertent lowering.
2Reliability
If a selector valve is added to control the float state independently of the blade control valve, then misoperation during jacking can be prevented, but the device complexity increases
Solution Approach 1:
The patent merges the functions of the blade control valve and the float state control into a single integrated control valve. This unified valve has multiple positions (raising, lowering, neutral, and float) that can be selectively activated. By combining these functions, the patent achieves the safety benefits of independent float control without adding a separate selector valve, thus reducing device complexity while maintaining reliability.
Solution Approach 2:
The control valve is designed as a multi-functional device that can perform multiple operations: raising the blade, lowering the blade, maintaining neutral position, and enabling float state. This universal valve replaces what would traditionally require separate valves, simplifying the overall system while providing the same safety and functional benefits.
3Reliability
If the blade is kept in a fixed state during jacking operations, then machine body stability is improved, but the ability to perform leveling work is reduced
Solution Approach 1:
The system dynamically adjusts the blade's state based on operational context. During jacking operations, the control means restricts the float position effectiveness, keeping the blade in a fixed state to maintain machine body stability. When leveling work is required and the blade is on the ground, the control valve enables the float position, allowing the blade to follow ground contours. This dynamic state adjustment resolves the contradiction between stability and adaptability.
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
Prevents machine body lowering during jacking operations due to misoperation and ensures effective leveling by maintaining the blade in a float state only when necessary, enhancing operational safety and efficiency.
Implementation Method 1
a pressure sensor that detects a pressure in at least one of the bottom-side hydraulic chamber and the rod-side hydraulic chamber of the blade cylinder
Implementation Method 2
a blade cylinder that is operated by a hydraulic fluid delivered from a hydraulic pump and that drives the blade in the vertical direction
Implementation Method 3
a float valve that is provided in hydraulic lines communicating respectively with a bottom-side hydraulic chamber and a rod-side hydraulic chamber of the blade cylinder, and that has a reference position where driving of the blade cylinder is possible and a float position where the bottom-side hydraulic chamber and the rod-side hydraulic chamber of the blade cylinder communicate with a tank
Data Source
AI summary
Provided is a construction machine that can prevent a machine body from being lowered since a blade is not put into a float state even where a misoperation is made by an operator when the machine body is in a jacked-up state, and that can perform a favorable leveling operation by putting the blade into the float state in accordance with an operator's operation when the machine body is not in the jacked-up state. A hydraulic excavator includes a controller 42 that determines whether or not the machine body is in a jacked-up state and controls a float valve 41. In the case where it is determined that the machine body is not in the jacked-up state, the controller 42 changes over the float valve 41 to a float position V and invalidates an operation of a blade control valve 22, in accordance with a float instruction. In the case where it is determined that the machine body is in the jacked-up state, the controller 42 holds the float valve 41 in a reference position IV and validates the operation of the blade control valve 22, irrespectively of the presence or absence of the float instruction.