Boom Lift Hydraulics With Slave Cylinder Load Sharing
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Solution Overview
Problem
Existing power machines, such as telehandlers, face challenges in increasing lift capacity without incurring high costs by enlarging lift cylinder dimensions or increasing hydraulic system pressure, as both methods are costly and not always preferred.
Innovation Solution
The implementation of a control system that includes a lift cylinder, a tilt cylinder, and a slave cylinder mechanically connected to assist the lift cylinder, where pressure from a hydraulic source is provided to the slave cylinder to aid in raising the boom, and load holding valves are opened to communicate hydraulic pressure from the tilt cylinder to the slave cylinder, enhancing the lift capacity without increasing system pressure or cylinder size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If lift capacity is increased by enlarging lift cylinder dimensions or increasing system pressure, then lifting capacity is improved, but cost increases
Solution Approach 1:
A slave cylinder is introduced as an intermediary component that receives hydraulic fluid from the tilt cylinder during boom lowering operations. This slave cylinder provides additional lifting force to assist the main lift cylinder, effectively increasing lifting capacity without requiring enlargement of the main cylinder or increase in system pressure. The slave cylinder acts as a mediator that utilizes otherwise wasted hydraulic energy to provide supplemental lifting force.
Solution Approach 2:
The system uses the hydraulic energy generated during boom lowering (when the tilt cylinder extends under load) to power the slave cylinder and assist the lift cylinder during boom raising operations. The hydraulic system essentially serves itself by recycling energy from the lowering operation to assist the lifting operation, reducing the need for larger components or higher system pressure.
2Force
If lift capacity is increased by enlarging lift cylinder dimensions, then lifting capacity is improved, but device complexity and cost increase
Solution Approach 1:
The lifting function is segmented between two separate cylinders: the main lift cylinder and the slave cylinder. Instead of using one large-lift-capacity cylinder, the system divides the lifting task between a standard-sized lift cylinder and a smaller slave cylinder that provides supplemental force. This segmentation allows the use of smaller, simpler components while achieving the same overall lifting capacity.
Solution Approach 2:
The slave cylinder serves multiple functions: it assists the lift cylinder during boom raising, utilizes hydraulic energy from tilt cylinder operations, and can be integrated into the existing hydraulic system without requiring a separate power source. This multi-functionality reduces overall system complexity despite adding a component.
3Force
If system pressure is increased to improve lift capacity, then lifting capacity is improved, but safety risks and cost increase
Solution Approach 1:
The slave cylinder acts as an intermediary that provides additional lifting force through a separate hydraulic circuit connected to the tilt cylinder. This approach avoids the need to increase system pressure in the main lift circuit, thereby maintaining safety margins while achieving increased lifting capacity. The supplemental force from the slave cylinder is added to the existing safe operating pressure of the lift system.
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 effectively increases the lifting capacity of the boom by utilizing the pressure from the tilt cylinder due to a heavy load, aiding the lift cylinder in raising the boom, thus enhancing operational efficiency without the need for costly upgrades.
Implementation Method 1
pressure from a hydraulic source is provided to the base side of a slave cylinder to aid in raising the boom. Resulting increased pressure on the rod side of the slave cylinder opens load holding valves to provide a hydraulic fluid path between the base side of the tilt cylinder and the base side of the slave cylinder, allowing hydraulic pressure from the base side of the tilt cylinder to be communicated to the base side of the slave cylinder
Data Source
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AI summary
Power machines (300) and control systems (360, 400) used thereon include a lift cylinder (333), a tilt cylinder (335), and a slave cylinder (337) mechanically connected to assist the lift cylinder with raising a boom (330). With a lift control valve (405) controlled to cause extension of the lift cylinder to raise the boom, pressure from a hydraulic source (362) is provided to the slave cylinder to aid in raising the boom. Resulting increased pressure on a side of the slave cylinder opens load holding valves (370, 460), allowing hydraulic pressure from the tilt cylinder to be communicated to the slave cylinder such that tilt cylinder pressure due to a heavy load on an implement aids in raising the boom.