Bicycle Derailleur Alignment Indicators for Noise Reduction
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Solution Overview
Problem
Derailleur-type bicycles experience rasping noise due to chain contact with the side plates of the front derailleur when engaged with outermost or innermost rear cogs, necessitating a solution to prevent unwanted contact and noise reduction.
Innovation Solution
A front derailleur design featuring a moveable chain guide with discrete alignment indicators to ensure proper alignment with the chainring plane, utilizing a linkage system and optional third alignment indicator for vertical positioning, allowing arcuate or rotational movement to achieve optimal alignment and reduce chain contact with the derailleur cage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the chain is engaged with an outermost or an innermost rear cog, then the chain contacts the side plates of the cage of the front derailleur causing a rasping noise, but if the alignment is adjusted to prevent contact, then the gear shifting may be affected
Solution Approach 1:
The patent applies preliminary action by providing discrete alignment indicators on the moveable chain guide that indicate when the chain guide is properly aligned with the chainring plane. This allows the installer to pre-align the chain guide before final assembly, ensuring that the chain will not contact the side plates during operation. The alignment indicators enable the chain guide to be positioned in advance at the correct angle and position relative to the chainrings, preventing the rasping noise issue from occurring in the first place.
Solution Approach 2:
The patent applies parameter changes by making the chain guide moveable and adjustable rather than fixed. The moveable chain guide can be positioned at different angles and distances relative to the chainrings, allowing optimization of the chain path to prevent contact with the side plates. By changing the positional parameters of the chain guide through the linkage mechanism, the system achieves both noise reduction and reliable gear shifting.
2Measurement precision
If the chain guide is made moveable to achieve proper alignment, then the alignment precision is improved, but the device complexity increases due to the linkage system
Solution Approach 1:
The patent applies self-service by designing the moveable chain guide with discrete alignment indicators that automatically indicate when proper alignment is achieved. The alignment indicators serve themselves by providing visual or physical cues (such as marks, ridges, grooves, pointers, colored zones, dots, openings, tolerance zones, and lines) that show when the chain guide is correctly positioned relative to the chainring plane. This self-indicating system eliminates the need for complex external alignment tools or procedures, achieving high alignment precision without proportionally increasing device complexity.
3Manufacturing precision
If discrete alignment indicators are added to the moveable chain guide, then the alignment accuracy is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by placing discrete alignment indicators at specific locations on the moveable chain guide rather than requiring precision throughout the entire component. The indicators (such as marks, ridges, grooves, pointers, colored zones, dots, openings, tolerance zones, and lines) are localized features that provide alignment information only where needed. This allows the majority of the chain guide to be manufactured using standard processes, while only small specific areas require additional precision or special features, thereby improving alignment accuracy without significantly increasing overall manufacturing complexity.
Data Source
AI summary
A front derailleur for use on devices such as bicycles includes a moveable chain guide for engaging a chain and able to cause the chain to be moved between two or more chainrings. The guide includes a first discrete alignment indicator and a second discrete alignment indicator for aligning the derailleur.