Switchable Valve Unit for Windrower Boom Arm Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rakes face difficulties in reliably transferring boom arms from the transport position to the working position due to insufficient hydraulic oil flow against relief pressure, especially with single-acting hydraulic cylinders.
Innovation Solution
Incorporation of a switchable valve unit connected in parallel to the pressure relief valve, which assumes different switching positions based on the boom arm's pivoting range to either function as a check valve or bypass, ensuring reliable movement between positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure relief valve is used in the hydraulic system to limit maximum pressure, then the hydraulic system is protected from overpressure, but the boom arm cannot be reliably moved from the transport position to the working position because hydraulic oil cannot flow against the relief pressure
Solution Approach 1:
The system dynamically switches between two valve configurations based on the boom arm's position. A first valve unit provides a bypass function when the boom arm is in the transport position, allowing free flow. When the boom arm reaches the headland position, a second valve unit activates to provide a check valve function, preventing backflow. This dynamic switching resolves the contradiction by adapting the hydraulic circuit's flow characteristics to the current operational phase.
Solution Approach 2:
The patent introduces intermediate valve units (first and second valve units) as mediators between the hydraulic pump and the boom arm actuator. These valve units control the direction and restriction of hydraulic oil flow, enabling the system to overcome the relief pressure barrier during position transitions while maintaining normal pressure relief functionality during operation.
2Length of moving object
If the boom arm lever arm is short when near the transport position, then the structural design is compact, but the weight of the boom arm and windrower is insufficient to move the boom arm against the relief pressure
Solution Approach 1:
The patent uses hydraulic pressure control to compensate for the insufficient mechanical leverage. By providing a bypass function through the first valve unit, hydraulic oil can flow freely to the actuator, generating sufficient force to move the boom arm even when the lever arm is short and the mechanical advantage is low. This hydraulic assistance resolves the contradiction between compact structure and reliable movement.
3Device complexity
If a single-acting hydraulic cylinder is used to actuate the boom arm, then the hydraulic system is simpler, but the boom arm cannot be reliably moved from transport to working position because the hydraulic oil must flow against relief pressure
Solution Approach 1:
The hydraulic control system is segmented into multiple functional valve units: a pressure relief valve for normal operation, a first valve unit for bypass functionality during transport, and a second valve unit for check valve functionality during work. This segmentation allows each component to perform its specific function optimally while maintaining overall system simplicity and reliability.
Solution Approach 2:
The system transitions from a static pressure relief valve configuration to a dynamic multi-valve configuration that adapts to different operational phases. The valve units switch between bypass and check valve functions based on the boom arm's position, enabling reliable movement while maintaining system simplicity through coordinated valve operation.
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
Ensures safe and reliable movement of boom arms from the transport to the working position by adjusting the hydraulic system's operation based on the boom arm's position, utilizing the weight of the arm and swath rotor to overcome hydraulic pressure challenges.
Implementation Method 1
a hydraulic system (17) of the swather (10) comprises a pressure relief valve (19) and at least one switchable valve unit (20) connected in parallel to the pressure relief valve (19)
Implementation Method 2
the available leverage of the boom arm (14) is sufficient to reliably move it into the working position solely due to the weight of the boom arm (14) and the windrower (16)
Implementation Method 3
the weight of the boom arm (14) and the windrower (16) ensures that the boom arm (14) is reliably moved towards the headland position and ultimately towards the working position
Data Source
Figure 1~2
Figure 3
AI summary
A rake with a base frame that can be supported on wheels on the ground to be worked and by means of which the rake can be coupled to a towing vehicle, with at least two boom arms pivotally mounted on the base frame, each boom arm carrying a rake rotor, and each boom arm being assigned a single-acting hydraulic actuating cylinder (18) by means of which the respective boom arm can be moved. The rake has a hydraulic system (17) which includes a pressure relief valve (19) and at least one parallel-connected, switchable valve unit (20). Depending on its switching position, the at least one switchable valve unit provides the function of a check valve (21) or a bypass valve (22).The at least one switchable valve unit is operatively connected to a respective boom arm in such a way that when the respective boom arm assumes a first position, the respective switchable valve unit (20) assumes a first switching position in which the function of the check valve (21) is active and the function of the bypass (22) is inactive, and that when the respective boom arm assumes a second position, the respective switchable valve unit (20) assumes a second switching position in which the function of the check valve (21) is inactive and the function of the bypass (22) is active.