Retaining Pin Assembly for Excavator Tooth Wear Resistance
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Solution Overview
Problem
Existing excavator tooth assemblies face issues with inadequate resistance to rotational moment forces, premature wear, and complex retention systems, leading to increased downtime and fabrication costs due to the loosening of locking pins under vertical and twisting loads.
Innovation Solution
A retaining pin assembly with non-circular cross-sectional shapes and tapered wedge portions is used, where locating members are inserted into a mounting aperture on the excavator nose, and a tensionable screw-threaded fastener is applied to secure the wear member, providing wedging engagement and resistance to rotational forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional locking pin system is used to secure the wear member, then the wear member can be retained on the excavator nose, but the locking pins loosen under vertical and twisting loads causing premature failure and increased downtime
Solution Approach 1:
The retaining pin assembly incorporates a split pin design that can dynamically adjust and expand within the mounting aperture. The split pin is divided into segments that can spread apart to engage with the aperture walls, creating a self-adjusting retention mechanism that maintains secure engagement under varying loads including vertical and twisting forces.
Solution Approach 2:
The retaining pin assembly uses a non-circular cross-sectional shape for the pin and corresponding mounting aperture. This asymmetric geometry prevents rotational movement and ensures proper orientation of the wear member on the excavator nose, eliminating the loosening issue associated with circular pin designs.
2Strength
If a complex retention system with multiple components is used, then resistance to rotational moment forces is improved, but the system becomes more complex requiring specialized tools for installation and removal
Solution Approach 1:
The retaining pin assembly combines multiple functions into a single integrated component. The split pin simultaneously provides rotational resistance through its non-circular cross-section, retention through expansion within the aperture, and structural support for vertical loads. This merging eliminates the need for multiple separate components and specialized installation tools.
Solution Approach 2:
The pin is segmented into multiple sections that can independently engage with the mounting aperture walls. This segmentation allows each section to provide resistance to rotational moment forces while maintaining overall structural integrity, achieving high strength without requiring a complex multi-component system.
3Strength
If a non-circular cross-sectional retaining pin is used, then resistance to rotational moment forces is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The design transitions from a circular cross-section to a non-circular cross-section with specific geometric parameters. The pin features flat surfaces and rounded corners with defined dimensions that match corresponding features in the mounting aperture. This parameter change provides inherent rotational resistance while maintaining manufacturability through standard machining processes.
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
The solution enhances the resistance to rotational moment forces, reduces premature wear, and simplifies the retention system, allowing for quick and easy installation and removal of wear members without the need for complex tools, thereby reducing downtime and fabrication costs.
Implementation Method 1
a tensionable screw-threaded fastener is applied to secure the wear member, providing wedging engagement and resistance to rotational forces
Data Source
AI summary
A retaining pin assembly for an excavator tooth assembly. The retaining pin assembly has opposable locating members each having a shank portion able to be slidably insertable via a respective retaining pin aperture on opposite sides of a wear member into a transversely extending mounting aperture of a mounting nose of an excavator. Each locating member also has an enlarged inwardly convergent tapered wedge portion adjacent a normally outer end. The retaining pin assembly also has a tensionable retaining member extending between the locating members from one side of the retaining pin assembly. When tension is applied to the retaining member relative contraction of the locating members occurs to urge the wear member into engagement with the mounting nose by wedging engagement between each of the wedge portions and a rear wall of respective retaining pin apertures.