Oven Pull-Out Guide With PTFE-Free Raceways for Clean Rolling

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Solution Overview

Problem

Existing pull-out guides for ovens face issues with running quality and contamination due to PTFE coatings on raceways, leading to jamming and abrasion, which compromise cleaning and longevity.

Innovation Solution

A pull-out guide design where only the exterior rails are coated with PTFE, while the raceways remain uncoated, ensuring easy cleaning and preventing contamination, with a hollow profile rail providing additional protection and adjustable rail configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the rails are coated with PTFE-containing coating on the raceways, then the running properties are improved and noise is dampened, but the rolling elements remove the coating from the raceways causing abrasion and contamination

Engineering Contradiction:
Improverunning propertiesVSAvoidabrasion and contamination
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The harmful PTFE coating is extracted and removed from the raceways where it causes abrasion and contamination, while retaining the beneficial coating on the exterior surfaces for easy cleaning. This selective removal resolves the contradiction by eliminating the source of harm while preserving the useful function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The PTFE-containing coating is applied selectively to different regions of the rails with different properties: the exterior surfaces receive the coating for easy cleaning, while the raceways are kept coating-free to prevent abrasion. This local differentiation of coating application resolves the contradiction by providing different surface qualities in different locations.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If the rails are coated with PTFE-containing coating, then cleaning is made easier, but the coating wears out over time increasing play and reducing running accuracy

Engineering Contradiction:
Improveease of cleaningVSAvoidrunning accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The PTFE coating is extracted from the raceways where it would wear out and reduce running accuracy, while maintaining the coating on exterior surfaces for easy cleaning. This resolves the contradiction by separating the cleaning function from the precision function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The coating is applied with local quality differentiation: exterior surfaces have the PTFE coating for easy cleaning, while raceways remain coating-free to maintain precise running accuracy throughout the service life. This local differentiation resolves the contradiction between ease of cleaning and long-term reliability.

Inventive Principle:
Principle #3Local quality

3Temperature

If sliding guides are made from heat-resistant sliding material, then they can be used in ovens, but they have poorer running properties and can easily jam if dirty

Engineering Contradiction:
Improveheat resistanceVSAvoidrunning properties
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The sliding mechanical system is replaced with a rolling system using roller bodies on raceways, providing superior running properties compared to traditional sliding guides. This substitution resolves the contradiction by replacing the inadequate sliding mechanism with a more efficient rolling mechanism suitable for oven environments.

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

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 solution maintains high running quality and longevity by preventing wear-induced contamination and facilitating easy cleaning, suitable for extreme conditions like ovens, with the PTFE coating on exterior rails enhancing durability and ease of maintenance.

Implementation Method 1

the PTFE-containing coating on the outside has an impregnating effect

Methodology Applied
Scientific EffectPTFE coating impregnating effect: Polytetrafluoroethylene (PTFE)

Implementation Method 2

roller bodies, the roller bodies being guided along raceways on the rails

Methodology Applied
Scientific EffectRolling: Roller

Data Source

PatentEP2342503B1Pull-out guide and baking oven
Publication Date: 2016.09.21 PAUL HETTICH GMBH & CO KG
  • EP2342503B1 patent drawingFigure 1~3
  • EP2342503B1 patent drawingFigure 4~6

AI summary

Pull-out guide (1, 1') in particular for baking ovens with a guide rail (2, 2') to which at least one additional rail (3, 4, 4') is displaceably mounted via roller elements (6), wherein the roller elements (6) are guided along running tracks (8, 9) on the rails (2, 3, 4; 2' 4'), wherein the rails (2, 3, 4; 2' 4') on the outside of the pull-out guide (1, 1') have at least in part a PTFE-containing coating and the running tracks (8, 9) are designed as coating-free.