Bicycle Chain Ring Ramps for Stable Up-Shifting Under Load

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Solution Overview

Problem

Conventional bicycle chain rings face challenges in achieving quick and efficient shifting, especially under extreme loading conditions, as they often increase stress on the chain, leading to wear and reduced longevity, and fail to effectively address up-shifting performance.

Innovation Solution

The design incorporates ramps with lifting surfaces and wear pins on the inner surface of the chain ring, allowing for stable lift and engagement of multiple chain links during up-shifts without assistance from teeth or shift pins, distributing load points more evenly and reducing slippage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional chain rings are used for shifting, then the structure is simple, but shifting performance is poor under extreme loading conditions

Engineering Contradiction:

Improveshifting performanceVSAvoidchain ring structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The chain ring is segmented into multiple functional zones: ramps with lifting surfaces for chain engagement, wear pins positioned at specific locations, and toothed portions. This segmentation allows each element to perform a specific function in the shifting process, improving reliability without creating a monolithic complex structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Ramps with lifting surfaces act as intermediaries between the chain and the chain ring teeth. These ramps provide a gradual transition surface that guides the chain during shifting, reducing impact forces and improving shifting performance under load while maintaining structural simplicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If conventional shifting methods are used, then the chain ring structure is simple, but stress on the chain increases leading to wear

Engineering Contradiction:

Improvechain durabilityVSAvoidchain stress

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

Ramps with lifting surfaces provide beforehand cushioning by creating a gradual transition zone before the chain engages with the teeth. This cushioning effect reduces impact stress on the chain during shifting, preventing wear and extending chain durability while maintaining a simple chain ring structure.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The ramps serve as intermediary elements that mediate the interaction between the chain and teeth, distributing forces more evenly and reducing peak stress concentrations that would otherwise damage the chain.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Speed

If ramps with lifting surfaces are added to the chain ring, then up-shifting performance improves, but the device complexity increases

Engineering Contradiction:

Improveshifting speedVSAvoidchain ring features

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into unified structures: ramps combine lifting surfaces with wear pin integration, and toothed portions are incorporated into the same continuous structure. This merging reduces the number of separate components, improving shifting speed while controlling overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The ramps serve multiple functions simultaneously: they provide lifting surfaces for chain engagement, accommodate wear pins for force distribution, and transition to toothed portions for power transmission. This multi-functionality improves shifting performance without requiring separate dedicated components for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Stress or pressure

If wear pins are positioned at specific locations on ramps, then load distribution improves, but manufacturing complexity increases

Engineering Contradiction:

Improveload distributionVSAvoidchain ring manufacturing

Core Design Contradiction:

Stress or pressureVSEase of manufacture

Solution Approach 1:

Wear pins are positioned at specific local locations on the ramps where force concentration occurs during shifting. This local quality approach addresses stress distribution only where needed, improving load distribution without requiring complex modifications to the entire chain ring structure, thus maintaining ease of manufacture.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12123486B2Chain ring

Publication Date: 2024.10.22 RAMPWERKS LLC

AI summary

A chain ring for engaging a chain link of a chain, the 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 includes a lifting surface for initiating lift of a chain without assistance from the plurality of chain ring teeth. The lifting surface extends radially along the inner surface toward the outer edge, and the at least one ramp has a first end proximate the inner edge and a second end proximate the outer edge. The second end of the at least one lifting surface terminates before reaching the bottom of a trough positioned between two or more of the plurality of chain ring teeth.