Cartridge Bushing with Internal Seals for Mining Shovel Pivot Pins

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Solution Overview

Problem

Conventional mining machines face challenges in maintaining effective and durable bushing assemblies at pivot pin locations, leading to issues with debris entry and frequent replacement of components during digging operations.

Innovation Solution

A cartridge assembly with a spherical bushing, internal seals, and an end cap is designed to support pivot pins, providing a sealed and self-lubricating mechanism that prevents axial movement and debris entry, allowing for retrofitting without reworking existing machinery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional bushing assemblies are used at pivot pin locations, then the structure is simple and easy to manufacture, but debris enters the bushing, causing frequent replacement and reduced durability

Engineering Contradiction:

Improvebushing assembly durabilityVSAvoidbushing assembly structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The bushing assembly is segmented into multiple functional components: a cartridge body, spherical bushing, internal seals, and end cap. This segmentation allows each component to perform its specific function while collectively preventing debris entry and improving durability without excessive complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bushing is nested within the cartridge body, with the end cap nested within the aperture of the cartridge. The internal seals are disposed axially on either side of the bushing within the cartridge. This nested arrangement creates a compact, sealed structure that prevents debris entry while maintaining ease of installation.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If bushing assemblies are designed without effective sealing, then the structure is simpler and easier to manufacture, but debris enters and causes frequent replacement

Engineering Contradiction:

Improvecomponent lifespanVSAvoidassembly manufacturing

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The internal seals are integrated into the cartridge assembly, creating a self-contained sealed structure. The cartridge assembly serves itself by incorporating the sealing function within its own structure, eliminating the need for separate sealing components or complex assembly procedures while preventing debris entry and extending component lifespan.

Inventive Principle:

Principle #25Self-service

3Reliability

If pivot pins are supported without axial movement prevention, then the structure is simpler, but the bushing moves axially leading to premature failure

Engineering Contradiction:

Improvepivot pin support stabilityVSAvoidsupport structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The end cap acts as an intermediary component between the pivot pin and the cartridge body. It prevents axial movement of the bushing by abutting against it, while the guide components serve as intermediaries to control rotational movement. This intermediary approach provides stable support without requiring complex constraints.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The spherical bushing allows for self-aligning and self-centering functionality, where the curvature of the sphere enables the pin to rotate smoothly while the end cap prevents axial movement. This spheroidality provides stable pivot support through geometric constraints rather than complex mechanical structures.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Adaptability or versatility

If bushing assemblies require reworking of existing machinery for installation, then the integration is more precise, but the retrofitting process becomes more complex and time-consuming

Engineering Contradiction:

Improveretrofitting capabilityVSAvoidretrofitting time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The cartridge assembly is designed as a pre-fabricated, self-contained unit with all components (bushing, seals, end cap) assembled before installation. This preliminary assembly allows the unit to be installed as a single module into existing machinery without requiring reworking or complex assembly procedures, enabling quick retrofits while maintaining precise integration.

Inventive Principle:

Principle #10Preliminary action

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 cartridge assembly enhances durability and reduces maintenance by acting as a labyrinth seal, extending the lifespan of bushing components and preventing debris entry, thus improving operational efficiency and reducing replacement frequency.

Implementation Method 1

providing a sealed and self-lubricating mechanism

Methodology Applied

Scientific EffectSelf-lubrication: Lubrication

Implementation Method 2

acting as a labyrinth seal, extending the lifespan of bushing components and preventing debris entry

Methodology Applied

Scientific EffectLabyrinth seal: Physical Containment

Data Source

PatentUS9784103B2Mining shovel with bushings at pin locations

Publication Date: 2017.10.10 JOY GLOBAL SURFACE MINING INC

AI summary

A cartridge includes a body, an aperture extending through the body sized to receive a pivot pin, and a spherical bushing disposed within the body. The cartridge also includes a first internal seal disposed axially on one side of the bushing and a second internal seal disposed axially on an opposite side of the bushing. The cartridge also includes an end cap disposed at least partially within the aperture that abuts the bushing and prevents the bushing from moving axially in a first direction within the aperture.