Excavation Bucket Joint Strength via Variable Thickness Design
Solution Overview
Problem
Excavation buckets, particularly larger ones, face weakness and failure due to fatigue stress at weld joins between assembled pieces, which are prone to cracking, especially in the ground engaging lip.
Innovation Solution
The design incorporates members with thicker portions forward of thinner ones, featuring recesses and weakened regions that deform under load to relieve stress, and wear members with wrapping portions and legs that fit into recesses to protect edges and reduce wear, enhancing joint strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If excavation buckets are constructed from separately formed pieces welded together, then ease of manufacture is improved, but strength and reliability deteriorate due to weld joins being prone to cracking and fatigue failure
Solution Approach 1:
The bucket is divided into separately formed pieces (sides, bottom, lip) that are assembled together, allowing easier manufacturing of each component while maintaining overall structural integrity through careful design of joint regions with varying thickness
Solution Approach 2:
The bucket members feature varying thickness throughout their structure, with thicker sections at critical stress areas (such as near weld joins and the lip) and thinner sections where less strength is required, optimizing both strength and weight
2Ease of manufacture
If excavation buckets are constructed from separately formed pieces welded together, then ease of manufacture is improved, but reliability deteriorates due to fatigue stress causing weld join failure
Solution Approach 1:
The bucket is divided into separately formed pieces that are assembled together, allowing easier manufacturing of each component while maintaining overall structural integrity through careful design of joint regions
Solution Approach 2:
The design incorporates thicker sections at critical stress areas before fatigue damage can occur, providing a margin of safety and allowing for fatigue crack initiation without immediate failure, thereby improving reliability
3Strength
If thicker portions are added to members to increase joint strength, then strength is improved, but weight increases excessively
Solution Approach 1:
The bucket members feature varying thickness throughout their structure, with thicker sections at critical stress areas and thinner sections where less strength is required, optimizing both strength and weight
Solution Approach 2:
Instead of uniformly increasing thickness throughout the members, the design varies thickness in specific locations and dimensions, adding material only where structurally necessary to improve joint strength without excessive weight gain
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
This design increases the strength of joints without excessive weight, reduces the likelihood of cracking, and protects edges from wear, thereby enhancing the durability and performance of excavation buckets.
Implementation Method 1
a weakened region that is arranged to preferentially deform under load so as to relieve loading in the excavator bucket joint
Implementation Method 2
wear members with wrapping portions and legs that fit into recesses to protect edges and reduce wear
Data Source
AI summary
A member for assembly with other members in an assembled condition to form an excavation bucket, the member forming at least part of one of the walls of the bucket when in its assembled condition, the member comprising a body having a forward edge; a rearward edge; opposite inner and outer surfaces that extend between the edges; a first portion of the member being thicker between its inner and outer surfaces than a second portion of the member, the first portion being disposed forward of the second portion.