Backhoe Arm Stroke Control for Bucket Reach Near the Dozer Blade
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Solution Overview
Problem
Existing working machines, such as backhoes, are limited in their ability to bring the distal end of the bucket sufficiently close to the blade of a dozer due to stroke length restrictions, preventing optimal operation.
Innovation Solution
Incorporating an arm crowd restricting unit and a crowd restriction releasing unit to control the stroke of the arm cylinder, allowing the bucket to be positioned closer to the blade by releasing restrictions when necessary, and using controllers to manage the boom and arm movements to prevent interference with the boom cylinder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the arm cylinder stroke is restricted to prevent the bucket from contacting the boom cylinder, then the reliability of the system is improved, but the working range is reduced and the bucket cannot be positioned sufficiently close to the blade
Solution Approach 1:
The patent applies dynamics by making the arm cylinder stroke limit adjustable rather than fixed. The control unit dynamically changes the stroke limit based on boom position: when the boom is in positions where contact risk exists, the stroke is restricted; when the boom is in safe positions, the restriction is released, allowing full stroke. This resolves the contradiction by making the system adaptive to different operational conditions.
2Productivity
If the arm cylinder stroke is extended to allow the bucket to reach closer to the blade, then the productivity is improved, but the risk of contact with the boom cylinder increases
Solution Approach 1:
The patent changes the parameter of arm cylinder stroke length dynamically based on boom position. When the boom is positioned where it would interfere with the bucket's path, the stroke parameter is reduced. When the boom is in non-interfering positions, the stroke parameter is increased to allow the bucket to reach the blade. This parameter adaptation enables both high productivity and reliability.
3Device complexity
If a fixed stroke limit is imposed on the arm cylinder, then the device complexity is reduced, but the ease of operation is worsened due to inability to optimize positioning
Solution Approach 1:
The system applies self-service by automatically adjusting the arm cylinder stroke limit based on boom position detection. The control unit monitors the boom position and autonomously determines the appropriate stroke restriction without requiring manual intervention from the operator. This maintains device simplicity while enabling optimized positioning through automatic adaptation.
Data Source
AI summary
A working machine includes a machine body, a dozer, a boom, an arm, a working tool, a boom cylinder, and an arm cylinder. The working machine also includes an arm crowd restricting unit and a crowd restriction releasing unit. The arm crowd restricting unit imposes a restriction on a stroke of the arm cylinder in an arm crowd direction so that a swing track of a distal end portion of the working tool is spaced from the boom cylinder. The crowd restriction releasing unit releases the restriction on the stroke of the arm cylinder to enable the arm to swing to an end of a swing range in the arm crowd direction when the boom is at a swing position at which the working tool in an operating position close to a working-tool dump position is disposed in a vicinity of a blade.