Offset Bicycle Chain Links for Smoother Coaxial Chainwheel Shifting

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Solution Overview

Problem

Conventional bicycle chains lack the shifting capability and functional scope of traditional chains, as they are primarily composed of identical chain links that do not facilitate the alternating tooth engagement and axial approaching necessary for efficient shifting between coaxial chain wheels.

Innovation Solution

The bicycle chain features a design where chain links are pivotable relative to each other about parallel virtual pivot axes, with each chain link having offset chain plates that create a trapezoidal tooth engagement space, allowing for axial leeway and improved shifting readiness between coaxial chain wheels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional bicycle chains with identical chain links are used, then the chain structure is simple and manufacturing is easy, but the shifting capability between coaxial chain wheels is insufficient

Engineering Contradiction:

Improveshifting capabilityVSAvoidchain link structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The chain link is segmented into distinct functional regions: a wider longitudinal end region and a narrower longitudinal end region. This segmentation allows different parts of the same chain link to serve different purposes during shifting operations, enabling both simple manufacturing and improved shifting capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the chain link are given different local qualities: the wider longitudinal end region provides a larger clear inner chain link width for easy tooth engagement, while the narrower longitudinal end region provides a smaller clear inner chain link width for axial approaching. This local differentiation resolves the contradiction between simple structure and shifting capability.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If chain links have uniform width, then manufacturing is simple, but axial approaching of the sprocket during shifting is limited

Engineering Contradiction:

Improveaxial approaching capabilityVSAvoidchain plate fabrication

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The chain link is designed with asymmetric width along its longitudinal axis, featuring a wider longitudinal end region and a narrower longitudinal end region. This asymmetric design enables axial approaching of the sprocket during shifting while maintaining relatively simple manufacturing processes for the chain plates.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS20250172193A1Shifting bicycle chain having uniform offset chain links, and chain wheel assembly cooperating therewith

Publication Date: 2025.05.29 SRAM

AI summary

A bicycle chain having a plurality of chain links, the chain plates of which are formed and arranged in an offset manner along a longitudinal chain path such that each chain link has a wider longitudinal end, along the transverse chain axis, with a larger link width and a narrower longitudinal end, opposite the wider longitudinal end along the longitudinal chain path, with a smaller link width, is designed for shifting between two coaxial chain wheels that are adjacent along the transverse chain axis.