Loading Crane Jib Hydraulic Circuit for Sequential Retraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulically actuable jibs for loading cranes face inefficiencies in sequential control and compact design, particularly in how retraction lines communicate with thrust cylinders, leading to suboptimal operation and structure.
Innovation Solution
A hydraulically actuable jib system with at least two jib extensions and thrust cylinders, featuring a retraction line that is independent of the inner thrust cylinder until the outer jib extension is fully retracted, allowing sequential control through a switching valve, and incorporating telescopic and sealed tubes for efficient oil flow and compact structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the retraction line is connected to both outer and inner thrust cylinders simultaneously, then the retraction operation is simplified, but the control precision and sequential operation capability deteriorate
Solution Approach 1:
The retraction line is segmented into two separate connection paths: one path connects to the outer thrust cylinder and another path connects to the inner thrust cylinder via a switching valve. This segmentation allows independent control of each cylinder's retraction sequence, resolving the contradiction between operational simplicity and control precision by dividing the hydraulic circuit into controlled segments.
Solution Approach 2:
A switching valve is introduced as an intermediary component between the retraction line and the inner thrust cylinder. This mediator enables selective connection and disconnection of hydraulic flow to different cylinders in a controlled sequence, achieving precise sequential retraction while maintaining system simplicity through a single retraction line source.
2Length of moving object
If the inner thrust cylinder is fully extended initially, then the jib reach is maximized, but the retraction control becomes complicated due to premature oil flow communication
Solution Approach 1:
The switching valve is pre-configured in a default closed position that prevents oil flow communication between the retraction line and the inner thrust cylinder before the outer cylinder completes retraction. This preliminary control action ensures that even when the inner cylinder is fully extended (maximizing reach), the retraction sequence can be controlled without premature oil flow interference.
Solution Approach 2:
The switching valve acts as a mediator that controls the timing of oil flow communication. It remains closed during the outer cylinder's retraction stroke, preventing premature communication with the inner cylinder, and only opens after the outer cylinder reaches its retraction position, thereby simplifying retraction control while maintaining maximum jib reach capability.
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
Enables sequential and efficient extension and retraction of thrust cylinders, maintaining a compact structure by ensuring oil flow control without premature communication, enhancing the reach and operational efficiency of the jib system.
Implementation Method 1
a hydraulic circuit for a working medium—in particular oil—with a retraction line for pressure-actuated retraction of the thrust cylinders
Implementation Method 2
the tube, when the piston is at least partially retracted, extending into the hollow piston rod in sealed relationship with the piston
Data Source
AI summary
A hydraulically actuatable jib for a loading crane includes at least two jib extensions, the first jib extension being designed as an outer jib extension and the second jib extension being designed as an inner jib extension. At least two feed cylinders extend and react the at least two jib extensions. A hydraulic circuit for a working fluid includes a retraction line for retracting the feed cylinders in a pressurized manner, and the retraction line opens into the feed cylinder of the outer jib extension. A tank is provided for releasing the working fluid, and a control valve can be switched into an open position when the outer jib extension reaches a defined retraction position, particularly when the outer jib extension is substantially fully retracted. The valve thereby supplies the feed cylinder of the inner jib extension with pressurized working fluid.