Roller Rim and Tread Design for Pull-Out Guide Load Distribution

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Solution Overview

Problem

Conventional rollers for pull-out guides face challenges in balancing load capacity, smooth running, rolling friction, and durability, particularly under high loads, due to material compromises and inadequate bonding between the tread and rim, leading to stress peaks and material degradation.

Innovation Solution

A roller design featuring a rim with a high modulus of elasticity and a tread with a convex curvature, where the tread extends beyond the rim's axial extent, providing a strong bond and distributing loads effectively, with the rim's neck section offering additional flexibility to absorb misalignment stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If a rubber-like material is used for the running surface to improve smooth running, then the rolling noise decreases, but the load-bearing capacity decreases

Engineering Contradiction:
Improverolling noiseVSAvoidload-bearing capacity
Core Design Contradiction:
Object-generated harmful factorsVSStrength

Solution Approach 1:

The roller is divided into two distinct parts: a rigid rim structure and a separate rubber-like running surface (tread) that is applied to the rim. This segmentation allows each part to fulfill its specific function - the rim provides structural strength while the tread provides smooth running characteristics

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The roller combines two different materials with complementary properties: a rigid material (metal or hard plastic) for the rim to ensure load-bearing capacity, and a rubber-like material for the running surface to reduce rolling noise and improve smooth running. This composite structure resolves the contradiction by allowing both materials to coexist and perform their respective functions

Inventive Principle:
Principle #40Composite materials

2Strength

If the tread extends beyond the rim's axial extent to improve bonding, then the bond strength increases, but stress peaks occur at the interface under misalignment

Engineering Contradiction:
Improvebond strengthVSAvoidstress peaks
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

The rim's lateral surface features convex curvature in edge sections rather than being purely cylindrical. This curvature creates a gradual transition zone that distributes stresses more evenly when the roller experiences misalignment, preventing concentrated stress peaks at the interface between the tread and rim

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The axial extent of the neck section is specifically controlled to be at most 70% of the head section's axial extent, creating an optimized geometric parameter that balances bond strength with stress distribution. The convex curvature radius and extent are also carefully parameterized to achieve the desired stress distribution

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If a cylindrical interface between rim and tread is used to simplify manufacturing, then the manufacturing process is easier, but the bond strength and durability decrease under load

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddurability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Instead of a purely cylindrical interface, the rim features convex curvature in the edge sections of the lateral surface. This curved geometry improves the bonding area and stress distribution, enhancing durability while remaining manufacturable through standard forming processes

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The lateral surface of the rim has different geometric characteristics in different regions: convex curvature in edge sections for improved bonding and stress distribution, and potentially cylindrical or grooved sections in the middle area for manufacturing ease and tread retention. This local variation optimizes both manufacturing and performance

Inventive Principle:
Principle #3Local quality

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 design enhances load-bearing capacity, reduces stress peaks, and improves durability, allowing the roller to handle high loads and misalignments without material degradation, while maintaining low rolling friction.

Implementation Method 1

the lateral surface has a convex curvature at least in first and second edge sections of the axial extent of the head section, which then extend to the respective end of the axial extent of the head section over at least a third of the axial extent of the head section

Methodology Applied
Scientific EffectPressure distribution through convex curvature:

Implementation Method 2

a rim to which the tread is applied and which consists of a material, whose modulus of elasticity is greater than the modulus of elasticity of the material of the tread

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

the tread protrudes by at least 5%, preferably at least 10%, of the axial extent of the head section of the rim beyond the respective end of the axial extent of the head section

Methodology Applied
Scientific EffectGeometric constraint:

Data Source

PatentEP3041385B1Roller
Publication Date: 2019.06.05 FULTERER AG & CO KG
  • EP3041385B1 patent drawingFigure 1~4
  • EP3041385B1 patent drawingFigure 5~6
  • EP3041385B1 patent drawingFigure 7~8

AI summary

The invention relates to a roller, in particular for pull-out guides for furniture parts (36) that can be pulled out, which roller can be rotated about an axis (13). The roller comprises a running covering (15), which forms a running surface (21) of the roller, and a rim (14), to which the running covering (15) is applied and which is made of a material having a modulus of elasticity that is greater than the modulus of elasticity of the material of the running covering (15). The rim has a head segment (19) and a neck segment (20) lying radially inside of the head segment (19). The head segment (19) has a lateral surface (22) directed away from the axis (13) of the roller, which lateral surface forms an interface with the running covering (15) and extends to ends (23, 24) of the axial extent of the head segment (19). As viewed in a cross-section through the roller, the lateral surface (22) has a convex curvature at least in first and second edge segments (29, 30) of the axial extent of the head segment (19). The running covering (15) protrudes beyond the head segment (19) in the axial direction of the roller at each end (23, 24) of the axial extent of the head segment (19) by at least 5% of the axial extent of the head segment (19) of the rim (14).