Arch-Back Dragline Bucket Arm Geometry to Reduce Digging Wear
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Solution Overview
Problem
Conventional dragline buckets experience notches and material wear in the arm due to direct hits during digging, leading to cracks in the weldment and parent material, especially in underwater operations.
Innovation Solution
The dragline bucket design features a fabricated bucket with a tilted arm in the form of an arch, angled between 17.5 to 22.5 degrees relative to the vertical plane, and a single-thickness sidewall construction, along with a balanced weight distribution and cutout portions to reduce weight and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional dragline bucket uses a vertical arm configuration, then the bucket can achieve direct digging capability, but the arm suffers from direct hits causing notches, material wear, and potential cracks
Solution Approach 1:
The arm is configured with an asymmetric tilt angle of 17.5 to 22.5 degrees relative to the vertical plane, deviating from the conventional vertical alignment. This asymmetric positioning allows the arm to clear material more effectively while avoiding direct impact hits, thereby maintaining productivity while improving structural reliability
Solution Approach 2:
The solution moves the arm configuration from a purely vertical one-dimensional alignment to a tilted configuration that introduces angular positioning in another dimension. This dimensional change enables the arm to clear material along a different trajectory, avoiding direct hits while maintaining digging effectiveness
2Reliability
If the dragline bucket uses a tilted arm configuration at 17.5 to 22.5 degrees, then material wear and arm damage are reduced, but the bucket design complexity increases
Solution Approach 1:
The invention specifies a precise parameter range for the arm tilt angle (17.5 to 22.5 degrees) to optimize performance. By defining this specific parameter range, the design achieves improved reliability through reduced arm damage while maintaining manageable complexity through standardized angular specifications
3Ease of manufacture
If the sidewalls use single uniform plate thickness construction, then manufacturing is simplified and weight is reduced, but structural strength may be compromised
Solution Approach 1:
The sidewalls incorporate window portions with varying local characteristics - specifically, these window portions have different structural properties compared to the main sidewall plates. This local quality variation allows the single uniform plate thickness construction to maintain overall simplicity in manufacturing while providing enhanced strength where needed through the strategically designed window portions
Data Source
AI summary
A dragline bucket can comprise a bottom wall; a first sidewall defining a first upper edge; a second sidewall opposite the first sidewall defining a second upper edge; a first forward-facing projection on a first side of the dragline bucket; a second forward-facing projection on a second side of the dragline bucket opposite the first side; a lip assembly at a front of the bottom wall; and an arm extending from the first side to the second side of the dragline bucket, a distal end of the arm being at a height greater than a height of respective first and second upper edges of the first and second sidewalls. In a side elevational view of the dragline bucket, the arm is tilted away from the rear wall at an angle of from 17.5 to 22.5 degrees relative to a vertical plane extending through a forward-most edge of the arm.