Bicycle Rear Derailleur Lateral Chain Guide Adjustment
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Solution Overview
Problem
Bicycle rear derailleurs face challenges in fitting a wide range of sprocket assemblies and protruding less from the frame to avoid collisions, while maintaining stability, especially with conventional direct and non-direct mount designs.
Innovation Solution
A bicycle rear derailleur design featuring a base member, chain guide, movable member, and link members that allow lateral movement of the chain guide between two positions, with a single mounting axis and a resistance mechanism, ensuring the derailleur fits various sprocket sizes and reduces protrusion by adjusting its posture and using a pulley plane that intersects the link member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a direct mount design with a single mounting axis is used, then the device complexity is reduced, but the adaptability to different sprocket assemblies is limited
Solution Approach 1:
The patent implements a movable member that can pivot about a pivot axis, allowing the chain guide to dynamically adjust its position laterally between a first lateral position and a second lateral position. This dynamic adjustment mechanism enables the derailleur to adapt to different sprocket configurations while maintaining a simple single-axis mounting structure, resolving the contradiction between device complexity and adaptability.
2Adaptability or versatility
If the derailleur protrudes more from the frame to accommodate larger sprockets, then the adaptability to sprocket sizes is improved, but the harmful factors such as collision risk with obstacles increase
Solution Approach 1:
The patent utilizes lateral movement of the chain guide in the horizontal dimension to accommodate different sprocket sizes, rather than increasing protrusion in the forward dimension. By moving the chain guide laterally between two positions, the system adapts to various sprocket configurations while maintaining a compact profile that reduces collision risk with obstacles.
3Adaptability or versatility
If the chain guide is made movable to adjust position, then the adaptability to different sprocket assemblies is improved, but the stability of the derailleur decreases
Solution Approach 1:
The patent incorporates a resistance applying mechanism that applies resistance to the rotational movement of the chain guide. This resistance mechanism controls the movement parameters, allowing the chain guide to adjust to different sprocket configurations while maintaining stability during operation. The resistance prevents excessive or uncontrolled movement, thereby preserving derailleur stability.
4Adaptability or versatility
If a larger derailleur linear distance is used to fit larger sprockets, then the adaptability to sprocket sizes is improved, but the length of the derailleur increases causing more protrusion
Solution Approach 1:
The patent employs a movable chain guide that can pivot laterally to adjust its position relative to the base member. This dynamic adjustment allows the system to accommodate different sprocket sizes and configurations without requiring a fixed increase in derailleur length. The chain guide moves laterally between two positions, enabling adaptability while maintaining a compact overall length and minimizing protrusion from the frame.
Data Source
AI summary
A bicycle rear derailleur includes a base member, a chain guide, a movable member and a first link member. The base member is configured to be mounted to a bicycle frame at a frame mounting axis. The chain guide includes a first pulley rotatably arranged around a first pulley axis in a first pulley plane. The movable member pivotally supports the chain guide about a pivot axis. The first link member moves the chain guide between first and second lateral positions. The first lateral position is closer to a bicycle center plane. The first pulley plane intersects the first link member in a state where the chain guide is located at the second lateral position. The frame mounting axis is spaced from the pivot axis by a distance equal to or larger than eighty-nine millimeters when the chain guide is at the first lateral position.