Alternating Tooth Chain Ring for Secure Chain Engagement

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Solution Overview

Problem

Conventional chain rings with uniformly sized teeth lead to gaps that can cause chain disengagement, increasing the risk of damage or injury, and may entangle debris, while attempting to address this with alternating teeth results in increased weight and potential for debris entrapment.

Innovation Solution

A chain ring design featuring teeth positioned at different lateral positions across its thickness, with some teeth configured to engage one side of a chain link laterally and others not, allowing the chain to flex and reducing debris entrapment, while maintaining a balanced weight distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If teeth are made larger to reduce gaps and improve chain engagement, then chain disengagement risk is reduced, but weight increases and debris entrapment risk increases

Engineering Contradiction:

Improvechain engagement securityVSAvoidchain ring weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies local quality by varying the lateral position of teeth across the chain ring thickness. Teeth are positioned at different lateral locations (first, second, and third positions) rather than uniformly, creating localized engagement points that match the alternating link widths. This resolves the contradiction by providing secure engagement without requiring uniformly large teeth throughout, thus avoiding excessive weight gain.

Inventive Principle:

Principle #3Local quality

2Reliability

If alternating teeth of larger size are used to match alternating link widths, then chain engagement is improved, but debris entrapment increases

Engineering Contradiction:

Improvechain engagement securityVSAvoiddebris entrapment

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the chain ring into multiple lateral positions for teeth (first, second, and third positions across the thickness). This segmentation allows different teeth to engage different link types (outer and inner links) independently, creating a more open engagement pattern that reduces continuous debris trapping zones while maintaining secure chain engagement.

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If uniform teeth are used, then manufacturing is simpler, but gaps between teeth and chain links increase causing disengagement

Engineering Contradiction:

Improvetooth uniformityVSAvoidchain engagement security

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces asymmetry by positioning teeth at different lateral locations across the chain ring thickness rather than uniformly. This asymmetric arrangement allows teeth to better match the alternating pattern of chain links (wider outer links and narrower inner links), improving engagement security while maintaining manufacturing feasibility through systematic positioning patterns.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS11713802B2Alternating tooth chain ring

Publication Date: 2023.08.01 EKO SPORT INC

AI summary

The present disclosure relates to a chain ring having teeth positioned in one of three lateral positions. At least one tooth may be placed in each lateral position. At least half the teeth may be positioned in a middle lateral position. The teeth in the first and third lateral positions may apply opposing lateral forces to a bicycle drive chain.