Strutted Master Link Reduces Fastener Stress in Track Chains

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Solution Overview

Problem

Existing master links in track chains experience mechanical failure due to undesired stresses on fasteners, which are caused by the direct transfer of transverse stresses from pins to fasteners, leading to axial tension and potential failure.

Innovation Solution

A master link design with a strutted body member that includes first and second apertures, third and fourth apertures separated by a strut member, and gaps that reduce in width when fastened, minimizing stress on fasteners by converting axial tension into contact friction, thereby reducing shear stresses and enhancing stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If gaps extend from apertures to a third aperture in the master link body, then the fasteners can decrease aperture diameters to secure pins, but transverse stresses are directly transferred to fasteners causing axial tension and mechanical failure

Engineering Contradiction:
Improveclamping force on pinsVSAvoidfastener durability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The master link body is segmented into multiple sections with three gaps (first gap from first aperture to third aperture, second gap from second aperture to third aperture, and third gap from third aperture to fourth aperture) instead of a single continuous gap structure. This segmentation distributes the stress paths and prevents direct transfer of transverse stresses to fasteners, while still enabling the fasteners to apply clamping force to secure pins through the aperture diameter reduction mechanism

Inventive Principle:
Principle #1Segmentation

2Strength

If fasteners are tightened to overcome natural rigidity of the master link body, then the gaps close to provide clamping force, but axial tension on fasteners increases leading to potential failure

Engineering Contradiction:
Improveclamping forceVSAvoidaxial tension on fasteners
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The third aperture and third gap act as an intermediary stress distribution zone between the first and second apertures. When fasteners are tightened, the stress is distributed through the third gap and third aperture region, converting direct axial tension into a more distributed stress pattern that includes contact friction effects, thereby reducing the peak axial tension on fasteners while maintaining effective clamping force on pins

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design increases the durability of track chains by reducing the likelihood of fastener failure and maintaining stability through reduced lateral movement, thereby lowering maintenance costs and enhancing the overall performance of tracked machines.

Implementation Method 1

Decreasing the first and second gaps reduces the respective diameters of the first and second apertures and may provide a clamping force on the pins to secure the master link to the adjacent links of the track chain

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2356015B1Master link for a track chain
Publication Date: 2015.01.14 CATERPILLAR INC
  • EP2356015B1 patent drawingFigure 1
  • EP2356015B1 patent drawingFigure 2~3
  • EP2356015B1 patent drawingFigure 4~5

AI summary

A master link (62, 64) for a chain assembly (22) is provided. The master link includes a body member (66) with a first side (68), a second side (70) positioned opposite the first side, a shoe surface (76) configured to receive a track shoe (24), and a rail surface (78) positioned opposite the shoe surface. The master link also includes first and second apertures (72, 74) extending through the body member from the first side to the second side and third and fourth apertures (80, 82) extending through the body member from the first side to the second side and located between the first and second apertures. The master link also includes a strut member (84) dividing the third and fourth apertures. The master link also includes a first gap (90) located in the body member and extending from the first aperture to the third aperture and a second gap (92) located in the body member and extending from the fourth aperture to the second aperture. The master link further includes a third gap (94) located in the strut member and extending from the third aperture to the fourth aperture.