Bimaterial Elevator Flight Assembly for Wheel Tractor Scraper

Solution Overview

Problem

Elevator flights in wheel tractor scrapers experience significant wear due to operating hours and the type of material being moved, leading to reduced efficiency and increased maintenance needs.

Innovation Solution

A bimaterial flight assembly is designed, featuring a support member made of a first material and an edge plate made of a harder, less flexible second material, specifically using hardened, heat-treated steel for the edge plate and rolled steel for the support member, to enhance wear resistance and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the flight is made of hard material to improve wear resistance, then wear resistance is improved, but toughness decreases and brittle failure tendency increases

Engineering Contradiction:

Improvewear resistanceVSAvoidbrittle failure tendency

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The flight is constructed with different materials for different parts: the edge plate (contact area) is made of hard material for wear resistance, while the support member (structural area) is made of tougher material for impact resistance and preventing brittle failure. This local differentiation of material properties resolves the contradiction between wear resistance and toughness.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The flight uses a composite structure combining two different materials: a hard edge plate material for wear resistance and a tougher support member material for structural integrity. This composite approach allows each part to have optimized material properties for its specific function, resolving the contradiction between hardness and toughness.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the flight is made of tough material to improve impact resistance, then impact resistance is improved, but wear resistance decreases

Engineering Contradiction:

Improveimpact resistanceVSAvoidwear resistance

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The flight is constructed with different materials for different parts: the edge plate (contact area) is made of hard material for wear resistance, while the support member (structural area) is made of tougher material for impact resistance. This local differentiation of material properties resolves the contradiction between wear resistance and toughness.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The flight uses a composite structure combining two different materials: a hard edge plate material for wear resistance and a tougher support member material for structural integrity. This composite approach allows each part to have optimized material properties for its specific function, resolving the contradiction between hardness and toughness.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If a single material is used for the entire flight, then manufacturing is simplified, but the flight cannot simultaneously optimize wear resistance and toughness

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidoverall durability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The flight is constructed with different materials for different parts: the edge plate (contact area) is made of hard material for wear resistance, while the support member (structural area) is made of tougher material for impact resistance. This local differentiation of material properties resolves the contradiction between wear resistance and toughness.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The flight uses a composite structure combining two different materials: a hard edge plate material for wear resistance and a tougher support member material for structural integrity. This composite approach allows each part to have optimized material properties for its specific function, resolving the contradiction between hardness and toughness.

Inventive Principle:

Principle #40Composite materials

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 bimaterial flight assembly provides improved wear resistance and toughness, reducing the tendency of the edge plate to brittle failure while maintaining impact resistance, thus extending the lifespan and reducing maintenance of elevator flights.

Implementation Method 1

the edge plate is made of a second material that is harder and less flexible than the first material

Methodology Applied

Scientific EffectHardness:

Implementation Method 2

specifically using hardened, heat-treated steel for the edge plate

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentUS8869972B2Bimaterial flight assembly for an elevator system for a wheel tractor scraper

Publication Date: 2014.10.28 CATERPILLAR INC

AI summary

An improved flight assembly for an elevator used with a wheel tractor scraper is provided. The flight assembly comprises a support member made of one type of material and an edge plate made of a second type of material that is harder and less flexible than the support member material. The edge plate is mounted to the support member and includes the cutting/digging edge of the flight assembly. In one embodiment the support member is made of a rolled steel material having a hardness of about 205 BHN and the edge plate is made of a hardened, heat treated steel material having a hardness of between about 360 BHN and about 440 BHN.