Demountable Pin and Collet Assembly for Longwall Shearer Ranging Arm

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Solution Overview

Problem

Existing longwall shearer systems face issues with the secure fastening of ranging arms to lifting brackets, leading to vibration, damage, and downtime due to loose pins and deformation of cylindrical holes in bushing designs, which are not easily removable or adaptable for changing mining directions.

Innovation Solution

A demountable pin-and-collet assembly with two pins inside a collet, sandwiched between end caps, where a bolt loads the pins and fasteners secure the assembly to prevent loosening, allowing for secure and adaptable fastening of ranging arms to lifting brackets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single straight pin is used in a cylindrical bushing to fasten the ranging arm, then the assembly is simple and easy to install, but the pin comes loose during operation causing vibration, damage, and downtime

Engineering Contradiction:

Improvefastening assembly complexityVSAvoidpin retention reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The single pin is segmented into two separate pins that are positioned at different locations within the collet. This segmentation prevents the pins from loosening simultaneously and reduces vibration, while maintaining the simplicity of the overall assembly structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A collet is introduced as an intermediary component that holds and secures the pins in place. The collet acts as a mediator between the pins and the surrounding structure, preventing the pins from coming loose while allowing for easy installation and removal of the entire assembly.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If a cylindrical bushing with a straight pin is used for fastening, then installation is easy, but the cylindrical hole deforms into an ovoid shape causing the bushing to no longer fasten securely

Engineering Contradiction:

Improveinstallation easeVSAvoidcylindrical hole dimensional stability

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The single fastening point is segmented into two separate pins positioned at different locations. This distribution of fastening points prevents localized deformation of the cylindrical hole and maintains dimensional stability while preserving ease of installation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The collet serves as a protective element that prevents deformation of the cylindrical hole before it can occur during operation. By securing the pins in place beforehand, the collet prevents the hole from deforming into an ovoid shape.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If ranging arms are welded solid to lifting brackets, then the connection is strong and permanent, but the arms cannot be removed or repositioned for changing mining directions

Engineering Contradiction:

Improveconnection strengthVSAvoidarm repositionability

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The fastening system transitions from a static welded connection to a dynamic demountable connection. The ranging arm can be securely fastened during operation and easily removed or repositioned when needed, providing both strength and adaptability through the controllable nature of the demountable fastening system.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The demountable fastening system allows for the temporary 'discarding' of the ranging arm from the lifting bracket when repositioning is needed, and subsequent 'recovering' or reattachment. This enables changing mining directions while maintaining secure connection during operation.

Inventive Principle:

Principle #34Discarding and recovering

4Adaptability or versatility

If a demountable fastening system is used to allow easy removal and repositioning, then adaptability improves, but the connection may become less secure and allow vibration and loosening

Engineering Contradiction:

Improvefastening system adaptabilityVSAvoidconnection security

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The single fastening element is segmented into two pins within the collet, providing multiple points of contact and distribution of forces. This segmentation maintains connection security while preserving the demountable nature of the system for adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The collet acts as an intermediary component that enhances the security of the demountable connection. It secures the pins in place and distributes loads effectively, maintaining reliable connection while allowing for easy removal and repositioning when needed.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8979211B2Demountable pin and collet assembly and method to securely fasten a ranging arm to a longwall shearer using such assembly

Publication Date: 2015.03.17 SOLVAY CHEM INC

AI summary

A pin-and-collet assembly, a longwall shearer comprising a ranging arm attached to a lifting bracket with such assembly, a method for the secure fastening of one piece to another, such as securely fastening the ranging arm to the lifting bracket of a longwall shearer using such assembly as a bushing, and a method for longwall mining of ore, such as trona, using such longwall shearer. This assembly is easy to install, does not have to be tightened during longwall operation of an ore panel, and is also demountable when it is time to stop the longwall mining operation and time to remove/replace the ranging arm for maintenance and/or when the end of the ore panel is reached.