Bicycle Chain Ring Ramps for Fast Up-Shifting Under Load

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Solution Overview

Problem

Conventional bicycle chain rings struggle with quick shifting, especially during extreme loading conditions like sprinting or out-of-saddle climbing, as existing solutions either increase stress on the chain or do not effectively address up-shifting performance.

Innovation Solution

The design incorporates a bicycle chain ring with strategically placed ramps and features such as inside tapers, beveled teeth, and partially cutoff teeth to facilitate efficient up-shifting by engaging multiple chain links and reducing stress on the chain, including ramps with lifting surfaces to assist in chain transfer between rings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional lateral pushing method is used by front derailleur, then shifting function is adequate for most purposes, but shifting speed is insufficient during extreme loading conditions

Engineering Contradiction:

Improveshifting speedVSAvoidshifting reliability under extreme load

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

Instead of pushing the chain laterally from the side (conventional method), the invention inverts the approach by using ramps on the chain ring teeth that guide and lift the chain upward onto the larger ring. This inverted mechanism enables faster and more reliable up-shifting even under extreme loading conditions.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The chain ring teeth are segmented into different functional zones: climbing teeth with standard profiles for normal operation, and sprint teeth with ramp structures for rapid up-shifting. This segmentation allows the chain ring to provide different shifting characteristics for different riding conditions.

Inventive Principle:

Principle #1Segmentation

2Speed

If chain links are shaped to grab teeth quicker, then up-shifting speed improves, but stress on chain increases

Engineering Contradiction:

Improveup-shifting speedVSAvoidchain stress

Core Design Contradiction:

SpeedVSStress or pressure

Solution Approach 1:

The chain ring teeth have different local qualities: climbing teeth with standard profiles for normal operation, and sprint teeth with ramp structures that provide a lifting surface. This local quality differentiation allows rapid up-shifting on sprint teeth without requiring chain modification that would increase stress.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The ramp structure on the sprint teeth acts as an intermediary that facilitates chain transfer by providing a lifting surface. This intermediary mechanism enables quick up-shifting without requiring the chain links themselves to be modified, thereby avoiding increased chain stress.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Speed

If pins are added to chain ring to facilitate up-shifting, then shifting performance improves, but chain wear increases

Engineering Contradiction:

Improveup-shifting speedVSAvoidchain wear

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The chain ring has different local qualities for different functions: climbing teeth with standard profiles and sprint teeth with ramp structures. This eliminates the need for pins while providing rapid up-shifting capability, thereby avoiding the chain wear that pins would cause.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of using pins that cause wear and require maintenance, the invention uses a ramp structure on the chain ring teeth that provides the same function without the harmful side effects. The ramp is an integral part of the chain ring that does not wear down the chain.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Ease of manufacture

If uniform tooth height is used on chain ring, then manufacturing is simple, but up-shifting performance is insufficient under high load

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidup-shifting speed under load

Core Design Contradiction:

Ease of manufactureVSSpeed

Solution Approach 1:

The chain ring teeth have different local qualities: climbing teeth with standard profiles for normal operation and sprint teeth with ramp structures for rapid up-shifting. This local differentiation improves up-shifting performance under high load while maintaining relatively simple manufacturing processes.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12129918B2Bicycle chain rings

Publication Date: 2024.10.29 RAMPWERKS LLC

AI summary

A bicycle chain ring, including an inner edge fully circumscribing both an opening and an axis of rotation; an inner surface extending between the inner edge and an outer edge where a plurality of chain ring teeth emanate; and a plurality of ramps disposed about the inner surface, wherein at least one of the plurality of ramps has a lifting surface configured to concurrently engage at least one link of a bicycle chain at two or more distinct pivot points along the length of the chain link to initiate stable lift of the bicycle chain without assistance from any of the plurality of chain ring teeth; wherein the lifting surface has a first end proximate the inner edge and a second end proximate the outer edge.