Adhesive-Bonded Working Arm Structure for Weld Stress and Fatigue

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Solution Overview

Problem

Welded plate construction of working arms in machines leads to stress and fatigue issues due to welding, limiting material choices and increasing mass and corrosion risks.

Innovation Solution

The use of structural adhesives to bond structural panels, eliminating the need for welding and allowing for different material strengths to be used based on load requirements, reducing stress, mass, and corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If welded plate construction is used to manufacture working arms, then manufacturing simplicity and cost-effectiveness are improved, but stress and fatigue issues worsen due to welding-induced stress

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidstress and fatigue resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the welding process (mechanical joining method) with adhesive bonding (chemical joining method). Instead of using welds to join structural panels, the invention applies adhesive bonds between panels, eliminating the harmful thermal stress and fatigue issues associated with welding while maintaining structural integrity and manufacturing simplicity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If welding is used to join structural panels, then structural integrity is improved, but mass increases due to additional reinforcement requirements

Engineering Contradiction:
Improvestructural integrityVSAvoidworking arm mass
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent substitutes adhesive bonding for welding, allowing for more efficient stress distribution across the joint area. Adhesive bonds create a continuous load path across the entire panel interface, whereas welds concentrate stress at specific points requiring additional reinforcement plates and material, thereby reducing the overall mass of the working arm while maintaining structural integrity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If welded plate construction is used, then manufacturing process is simplified, but corrosion resistance worsens due to weld-related corrosion issues

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidcorrosion resistance
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces welding with adhesive bonding, eliminating the creation of weld beads and heat-affected zones that are susceptible to corrosion. Adhesive bonds create a seamless joint without the metallurgical changes and potential corrosion pathways introduced by welding, thereby improving corrosion resistance while keeping the manufacturing process simple.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Ease of manufacture

If uniform thickness steel panels are used in welded construction, then manufacturing is simplified, but material efficiency worsens due to inability to optimize for load distribution

Engineering Contradiction:
Improvepanel manufacturing simplicityVSAvoidmaterial efficiency
Core Design Contradiction:
Ease of manufactureVSWeight of moving object

Solution Approach 1:

The patent enables the use of adhesive bonding to join panels of varying thicknesses and material properties without the constraints of welding. This allows optimization of panel thickness and material selection based on local load requirements - thicker or stronger materials where loads are highest, and thinner or lighter materials where loads are lower - thereby improving material efficiency and reducing overall weight while maintaining manufacturing simplicity.

Inventive Principle:
Principle #3Local quality

5Strength

If welding is used to join panels, then structural strength is improved, but aesthetics worsen due to visible weld beads

Engineering Contradiction:
Improvepanel joint strengthVSAvoidsurface aesthetics
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The patent replaces welding with adhesive bonding, which creates a flush, seamless joint between panels without the protruding weld beads characteristic of welded construction. The adhesive bond maintains structural strength while providing a smooth, aesthetically pleasing surface that requires no post-weld cleaning or cosmetic repair.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach reduces stress and fatigue, enables lighter and more cost-effective construction, and improves aesthetics by avoiding weld beads, while allowing for the use of stronger materials where needed.

Implementation Method 1

a first structural panel and a second structural panel which oppose one another, a third structural panel and a fourth structural panel, wherein the third panel extends between a first edge of the first and second panels and the fourth panel extends between a second edge of the first and second panels, wherein the panels are bonded together using a structural adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4431665A1A method of manufacturing a working arm for a working machine
Publication Date: 2024.09.18 J C BAMFORD EXCAVATORS LTD
  • EP4431665A1 patent drawingFigure 1~2
  • EP4431665A1 patent drawingFigure 3~4
  • EP4431665A1 patent drawingFigure 5~6

AI summary

Disclosed is a structural member of a working arm of a working machine, comprising: a first end and a second end having an elongate body extending therebetween, the body comprising: first and second opposing panels; third and fourth opposing panels, the third panel extending between a first edge of the first and second panels and the fourth panel extending between a second edge of the first and second panels to provide a box section; the third and fourth panels comprising: at least one pivot mount for connecting the working arm member to a further working arm member or the working machine; and, at least one actuator mount for connecting a working actuator, the working actuator being operable to move the working arm member, wherein the first, second, third and fourth panels are structurally bonded together by an adhesive.