Integrally Cast Hinge Assembly for Excavator Bucket
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Solution Overview
Problem
Excavator buckets face failures due to fatigue stress at welded joints, particularly in the hinge assembly, leading to reduced durability and increased maintenance costs and productivity losses.
Innovation Solution
An integrally cast hinge assembly is developed, manufactured through a casting process using suitable cast steel, which forms a strong, integral structure with features like mirror-image hinge plates and torque tube portions, reducing the need for welds and enhancing structural strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a bucket is made from welded-together pieces, then the manufacturing flexibility and ease of assembly are improved, but the reliability and strength are worsened due to fatigue stress at welded joints
Solution Approach 1:
The patent merges multiple separate components (bucket body, hinge assembly, torque tubes, side plates) into a single integrally cast structure. This eliminates welded joints between these components, removing the fatigue stress concentration points that would otherwise compromise reliability. The hinge assembly is formed as one continuous piece with the bucket, ensuring structural integrity while maintaining manufacturing feasibility through specialized casting processes.
2Ease of operation
If a bucket is made from welded-together pieces, then the ease of assembly and manufacturing flexibility are improved, but the durability is worsened due to cracks and failures at welded joints
Solution Approach 1:
The bucket components are merged into an integral casting, eliminating the need for field assembly of critical stress-bearing parts. The hinge assembly, torque tubes, and bucket body form a unified structure that cannot develop cracks at joint interfaces, significantly extending service life and durability under cyclic loading conditions.
3Strength
If an integrally cast hinge assembly is used, then the strength and durability are improved, but the device complexity and manufacturing complexity increase
Solution Approach 1:
While the hinge assembly itself is integral, the overall bucket system is segmented into modular components that can be cast separately and then assembled. The hinge assembly is one module, the bucket body is another, allowing the complex casting process to be broken into manageable segments that can be produced, inspected, and assembled systematically.
Solution Approach 2:
The patent employs specialized casting parameters and materials (such as high-strength steel alloys, controlled cooling rates, and precise temperature profiles) to enable the production of complex integral structures. By optimizing casting parameters, the manufacturing process can handle geometrically complex hinge assemblies while maintaining structural integrity and reducing defects.
Data Source
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AI summary
An integrally cast hinge assembly (240) for a bucket, including a first and second hinge plates (242,246), a first torque tube portion (234) extending from the first hinge plate, a secon (248) extending between the first hinge plate and the second hinge plate, and a support plate (222) extending along a bottom portion of the hinge assembly. The first torque portion is weldlessly connected to the first hinge plate, the second torque tube portion is weldlessly connected to the second hinge plate, the third torque tube portion is weldlessly connected to both the first hinge plate and the second hinge plate, and the support plate is weldlessly connected to the first hinge plate, the second hinge plate, the first torque tube portion, the second torque tube portion, and the third torque tube portion. A method of manufacturing a machine bucket (210), comprises the steps of welding a first side plate (218) to a first side edge of a wrapper (224); welding a second side plate (220) to a second side edge of a wrapper; providing a cast hinge assembly having a width formed as an integral, weldless structure; cutting cast hinge assembly such that the width of the cast hinge assembly fits between, and spans the distance between, the first side plate and the second side plate, and welding the cast hinge assembly to the first hinge plate and the second hinge plate.