Crusher Roll-off Bushing Collet Mechanism for Wear Insert Replacement

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing methods for replacing worn-out wear inserts in crusher axles are cumbersome and risky, requiring heating or destruction due to thermal conductivity issues, leading to high maintenance costs and downtime.

Innovation Solution

Designing the rolling bush as a collet that frictionally clamps the wear insert using a conically tapering inner cone and a traction mechanism, allowing for easy installation and removal without heating or destruction, facilitated by a screw connection and slots for radial tensioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wear insert is shrunk into the rolling bush during assembly, then the wear insert is firmly connected and secure hold, but it becomes difficult to remove at the end of service life

Engineering Contradiction:
Improvesecure hold of wear insertVSAvoidremoval of wear insert
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The rolling bush is designed with a dynamic expansion/contraction mechanism through radial slots that allow the bush to change its internal diameter. During assembly, the bush is in a contracted state to firmly hold the wear insert. During disassembly, the bush expands to release the wear insert, enabling easy removal without destruction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The rolling bush's internal diameter parameter is changed dynamically through the radial slots. When the bush is contracted, the internal diameter is small for secure holding. When expanded via the disassembly mechanism, the internal diameter increases to release the wear insert, allowing parameter change to control the holding state.

Inventive Principle:
Principle #35Parameter changes

2Ease of repair

If the rolling bush is heated to expand it for removal, then the wear insert can be removed, but it requires great time and risks damage to the rolling bush

Engineering Contradiction:
Improveremoval of wear insertVSAvoiddowntime of crusher
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The thermal expansion method is replaced with a mechanical expansion system. Instead of heating the rolling bush to expand it, a disassembly mechanism with lever and wedge elements provides mechanical force to expand the bush radially through the slots, releasing the wear insert quickly without thermal processing time.

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

Solution Approach 2:

The disassembly mechanism acts as an intermediary between the operator and the rolling bush. The lever and wedge elements translate applied force into radial expansion of the bush, mediating the removal process and eliminating the need for direct thermal treatment of the bush.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the wear insert is firmly shrunk into the rolling bush, then secure connection is achieved, but cutting or burning is required which risks damage to the rolling bush

Engineering Contradiction:
Improvefirm connectionVSAvoidrisk of damage to rolling bush
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The connection between wear insert and rolling bush is made dynamic rather than permanent. The radial slots enable the bush to expand and contract, allowing the connection to be firm during operation but releasable during maintenance, eliminating the need for destructive cutting or burning methods.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The rolling bush is segmented by the radial slots that divide the bush wall into sections. This segmentation allows independent radial movement of the bush sections, enabling expansion and contraction while maintaining structural integrity, thus avoiding damage from forced removal methods.

Inventive Principle:
Principle #1Segmentation

4Reliability

If conventional shrink-fit method is used, then wear insert is securely held, but on-site removal facilities are not available

Engineering Contradiction:
Improvesecure hold of wear insertVSAvoidon-site replacement capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The rolling bush incorporates a self-contained disassembly mechanism with lever and wedge elements that can be operated on-site without external heating facilities. The mechanism uses the bush's own structural features (radial slots) to enable expansion and release, making the system self-sufficient for maintenance operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The rolling bush serves multiple functions: it provides secure holding of the wear insert during operation through contraction, and enables easy removal during maintenance through expansion. The integrated disassembly mechanism makes the bush a multi-functional component that handles both installation and removal operations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables simple and precise installation and replacement of wear inserts on-site, reducing maintenance time and risk of damage, and eliminating the need for costly and hazardous removal methods.

Implementation Method 1

the rolling bush as a kind of collet, which is pulled into the inner cone of the receptacle with the traction means and deformed in such a way that it frictionally clamps the wear insert

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

design the rolling bush as a kind of collet, which is pulled into the inner cone of the receptacle with the traction means

Methodology Applied
Scientific EffectMechanical advantage through conical geometry: Wedge

Data Source

PatentEP3131677B1Roll-off bushing in a crusher
Publication Date: 2019.11.06 THYSSENKRUPP IND SOLUTIONS AG
  • EP3131677B1 patent drawingFigure 1
  • EP3131677B1 patent drawingFigure 2

AI summary

Cone or gyratory crusher with a crusher axle, the head of which is mounted in an upper axle bearing held by a crossbeam, wherein the upper axle bearing has a roll-off bushing accommodated in a central socket, wherein an annular abrasion insert is held in the roll-off bushing, and the head of the crusher axle rolls off against said abrasion insert, wherein the socket forms a conically tapering inner cone, and a pulling means is provided for drawing the roll-off bushing into the socket, and wherein the roll-off bushing becomes narrower when drawn in and thus frictionally clamps the abrasion insert in the roll-off bushing.