Alternating Chain Ring Teeth for Secure Bicycle Chain Engagement

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Solution Overview

Problem

Conventional bicycle drive chains with uniform teeth suffer from chain disengagement, increased weight, and debris entrapment due to larger teeth sizes, which can lead to damage or injury, and hinder proper meshing with the chain.

Innovation Solution

A chain ring design featuring alternating teeth subsets with distinct shapes and sizes, where one subset has a rectangular top surface and the other a hat-shaped top surface, providing tapered sides to apply lateral forces and ensure proper engagement with drive chain links while minimizing weight and debris entrapment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If teeth of larger size are used to improve engagement with the chain, then chain disengagement risk is reduced, but the weight of the chain ring increases

Engineering Contradiction:

Improvechain engagement reliabilityVSAvoidchain ring weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies local quality by creating two distinct subsets of teeth with different geometries: a first subset with a first geometry optimized for engaging inner links, and a second subset with a second geometry optimized for engaging outer links. This allows each tooth to be precisely tailored to its specific engagement requirement, achieving reliable chain engagement without uniformly increasing the size and weight of all teeth.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the teeth into two alternating subsets around the circumference of the chain ring. The first subset of teeth has a first geometry while the second subset has a second geometry, creating an alternating pattern that corresponds to the alternating inner and outer links of the chain. This segmentation allows optimized engagement for each link type without requiring all teeth to be large.

Inventive Principle:

Principle #1Segmentation

2Reliability

If teeth of larger size are used to improve engagement with the chain, then chain disengagement risk is reduced, but the risk of tooth catching on chain portions increases

Engineering Contradiction:

Improvechain engagement reliabilityVSAvoidtooth catching risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Reliability

If teeth of larger size are used to improve engagement with the chain, then chain disengagement risk is reduced, but the likelihood of debris becoming entangled increases

Engineering Contradiction:

Improvechain engagement reliabilityVSAvoiddebris entrapment

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

4Ease of manufacture

If uniform teeth design is used, then manufacturing simplicity is maintained, but proper engagement with alternating chain links is hindered

Engineering Contradiction:

Improvetooth manufacturing simplicityVSAvoidchain meshing quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP3283792B1Chain ring with teeth oppositely laterally engaging a drive chain

Publication Date: 2024.12.25 EKO SPORT INC

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AI summary

A drive system for a vehicle includes a chain ring and a drive chain. The chain ring has a plurality of teeth serially arranged and joined to one another. A first subset of teeth has a first outer face that applies a lateral pressure to a link of a drive chain in a first direction. A second subset of teeth has a second outer face that applies a lateral pressure to another link of a drive chain in a second direction. The teeth all have substantially the same width. The top surfaces of the teeth are offset from the centerline of the drive chain. The centerlines of the top surfaces of the teeth are arranged asymmetrically on one side of the centerline of the drive chain.