Asymmetrical Bicycle Chain Links for Narrow Multi-Sprocket Drivetrains
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Solution Overview
Problem
The increasing number of sprockets in bicycle derailleur systems leads to obstructive chain pins, increased loads on chain parts, and challenges in correct chain mounting due to geometric differences between inner and outer link plates, which can result in incorrect mounting and malfunctions during gearshifts.
Innovation Solution
The design of asymmetrical roller-type chains with distinct inner and outer link plates, featuring different outer contours and bevels, ensures clear differentiation between the inner and outer sides of the chain loop, preventing incorrect mounting and enhancing load distribution by maintaining cross-sectional areas subjected to load, thus improving chain guidance and reducing loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of sprockets is increased, then the gear range is improved, but the chain pins become obstructive and interfere with adjacent sprockets
Solution Approach 1:
The patent extracts the protruding portions of the chain pins that cause obstruction against adjacent sprockets. By removing these harmful protrusions, the chain design eliminates the interference problem while maintaining the increased sprocket count for expanded gear range.
Solution Approach 2:
The patent applies different geometric characteristics to different parts of the chain link plates. The inner link plates have specific outer contour shapes and bevel configurations that differ from outer link plates, creating local geometric optimizations that prevent chain pin obstruction while maintaining proper chain function across multiple sprockets.
2Adaptability or versatility
If the dimensions of chain parts are reduced, then the chain adapts to closely spaced sprockets, but the loads on chain parts increase
Solution Approach 1:
The patent modifies geometric parameters of the link plates, specifically the spacings between inner link plates in the direction perpendicular to their inner surfaces. By optimizing these spacings and incorporating specific bevel angles, the chain achieves better adaptation to closely spaced sprockets while distributing loads more effectively across the chain structure.
3Ease of manufacture
If symmetrical chain link plates are used, then manufacturing is simplified, but incorrect mounting cannot be prevented
Solution Approach 1:
The patent introduces asymmetry into the chain link plate design by giving inner link plates specific outer contour shapes and bevel configurations that are different from outer link plates. This asymmetric design creates geometric features that only fit correctly in their intended positions, preventing incorrect mounting while maintaining manufacturing feasibility through standardized asymmetric components.
4Ease of operation
If the spacings between link plates are increased, then chain guidance is improved, but the cross-sectional area subjected to load is reduced
Solution Approach 1:
The patent optimizes the spacing parameters between link plates by incorporating specific bevel angles and outer contour configurations. These parameter changes improve chain guidance and engagement with sprockets while the overall link plate dimensions and material distribution are maintained to preserve sufficient load-bearing cross-sectional areas.
Data Source
AI summary
A roller-type chain for a bicycle is configured with asymmetrical chain link plates, the chain link plates applicable for use with a chain with reduced chain width as in use on chain drives with a high number of gear ratios. The chain link plates are configured at the inner side of the chain loop for engagement on the teeth of the rear sprocket and of the front chain wheel. The chain link plates are further configured at the outer side of the chain loop for interaction with the chain-guiding roller on the rear gearshift mechanism.