Working Machine Linkage Mechanism for Breakout Force Control
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Solution Overview
Problem
Existing loader linkage mechanisms, such as z-bar and parallel linkages, face challenges in maintaining breakout force and control while lifting the shovel, with z-bar linkages requiring hydraulic cylinder operation to keep the shovel level and parallel linkages providing weak breakout force.
Innovation Solution
A pivoting mechanism is introduced, comprising a Z bar link, a chassis link, and a first actuator, positioned between the opposing lateral ends of the working arm, which allows for improved breakout forces and dumping angles without significantly increasing the load on the support, and enables increased crowding angles without actuator operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a z-bar linkage mechanism is used, then breakout force is improved, but the hydraulic cylinder must be operated to keep the shovel level increasing control difficulty
Solution Approach 1:
The linkage mechanism is segmented into multiple independent components: a first linkage member connecting the shovel to the working arm, a second linkage member connecting the working arm to the support, and a hydraulic cylinder connecting the working arm to the support. This segmentation allows each component to perform its specific function independently, enabling the hydraulic cylinder to control working arm elevation while the linkage members handle shovel positioning, thus reducing control difficulty while maintaining breakout force.
2Force
If a z-bar linkage mechanism is used, then breakout force is improved, but breakout forces decrease dramatically when the shovel is lifted to a raised position
Solution Approach 1:
The linkage mechanism employs dynamic geometric relationships where the first and second linkage members are configured with specific pivot points and connection geometries that maintain favorable force transmission angles throughout the working range. As the shovel is lifted, the linkage members automatically adjust their orientations to preserve mechanical advantage, ensuring breakout force remains stable across different elevation positions rather than decreasing dramatically.
3Ease of operation
If a parallel linkage mechanism is used, then the shovel is automatically kept level as the working arm is raised, but breakout force is relatively weak
Solution Approach 1:
The mechanism applies different functional qualities to different components: the first linkage member (shovel link) is designed with specific pivot geometry to maintain shovel level automatically, while the second linkage member (bell crank) and hydraulic cylinder are configured to optimize breakout force generation. This local differentiation of functional qualities allows automatic level maintenance in one area while preserving strong breakout force in another, overcoming the weakness of uniform parallel linkage designs.
Data Source
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AI summary
A working machine comprising a support, and a material handling assembly movable relative thereto, the material handling assembly comprising: a working arm pivotally mounted to the support at a first pivot, and configured to be pivotally mounted to a material handling implement at a second pivot; and a pivoting mechanism configured to be pivotally mounted to the implement at a third pivot, and comprising: a Z bar link; a chassis link; and a first actuator operable to extend and retract. The Z bar link is pivotally mounted to the working arm at a fourth pivot. The chassis link is pivotally mounted to the Z bar link at a fifth pivot. The chassis link is pivotally mounted to the support at a sixth pivot. The first actuator is pivotally mounted to the Z bar link at a seventh pivot. The fourth pivot is interposed between the fifth and seventh pivots. The pivoting mechanism is configured to pivot the implement relative to the working arm about the second pivot via pivoting of the working arm relative to the support about the first pivot, and via operation of the first actuator. The pivoting mechanism is interposed between opposing lateral ends of the working arm.