Retainer System Cover Reduces Friction in Earth-Working Tools

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Solution Overview

Problem

Existing retainer systems for ground engaging tools on earth-working machines face issues with secure attachment and detachment, as well as increased friction due to work material accumulation, which affects the longevity and efficiency of the tools.

Innovation Solution

A retainer system comprising a lock with a head and skirt portion, and a retainer bushing with a C-shaped skirt, featuring detent projections and recesses for secure rotation, and a cover piece to prevent work material entry, reducing friction and facilitating easy tool exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a retainer system uses a lock with detent projections and recesses for secure attachment, then the reliability of tool attachment is improved, but the friction increases due to work material accumulation in the detent mechanism

Engineering Contradiction:
Improveattachment securityVSAvoidfriction from work material
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the harmful work material from the detent mechanism area by providing a cover that seals the space around the lock and retainer bushing. This prevents work material from entering and accumulating in the detent projections and recesses, thereby maintaining low friction while preserving the secure attachment function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cover is installed beforehand to prevent work material from entering the detent mechanism. This preliminary protective action stops the accumulation of work material before it can cause increased friction, ensuring the detent mechanism operates smoothly throughout the tool's service life.

Inventive Principle:
Principle #9Preliminary anti-action

2Reliability

If the detent recess has a length greater than required to receive the detent projection, then the reliability of engagement is improved, but the device complexity increases

Engineering Contradiction:
Improvedetent engagementVSAvoidretainer system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The extended detent recess length provides a preliminary engagement zone that guides the detent projection into proper alignment before final engagement. This preliminary action ensures reliable engagement while maintaining a relatively simple structure by utilizing the existing recess geometry rather than adding separate alignment features.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the outer surface of the lock and inner surface of the retainer bushing are aligned parallel to the rotation axis, then the ease of operation is improved, but the friction from work material increases

Engineering Contradiction:
Improvelock rotationVSAvoidfriction from work material
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The cover removes work material from the interface area between the lock's outer surface and the retainer bushing's inner surface. This extraction of harmful material maintains the beneficial parallel alignment for easy rotation while eliminating the friction problem that would otherwise result from work material accumulation.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of repair

If ground engaging tools are removably attached using customized retainer systems, then the ease of repair is improved, but the loss of time for tool replacement increases

Engineering Contradiction:
Improvetool replaceabilityVSAvoidtool exchange time
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The lock is designed to rotate dynamically between locked and unlocked positions, enabling quick tool replacement. The cover protects this dynamic mechanism from work material contamination, ensuring that the rotational movement remains smooth and rapid throughout the tool's service life, thus minimizing tool exchange time while maintaining ease of repair.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3004472B1Retainer systems for ground engaging tools
Publication Date: 2019.05.22 CATERPILLAR INC
  • EP3004472B1 patent drawingFigure 1
  • EP3004472B1 patent drawingFigure 2
  • EP3004472B1 patent drawingFigure 3

AI summary

Disclosed are various exemplary embodiments of a retainer system for a ground engaging tool. In one exemplary embodiment, the retainer system may include a lock having a lock rotation axis and including an outer surface extending about the lock rotation axis. The retainer system may also include a retainer bushing including an inner surface extending about the lock rotation axis, where the inner surface is configured to rotatably receive the outer surface of the lock. The outer surface of the lock and the inner surface of the retainer bushing may be aligned substantially parallel to the lock rotation axis.