Bicycle Sprocket Support Structure to Prevent Chain Drop Jamming
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Solution Overview
Problem
The 'chain drop' phenomenon, where the transmission chain disengages from the sprocket assembly, especially from the largest diameter sprocket, can cause the rear wheel to lock, posing a safety risk and complicating chain repositioning, as the chain jams between the sprocket and spokes.
Innovation Solution
A supporting assembly that projects axially beyond the inner surface of the largest toothed wheel to support the chain at a predetermined radial distance from the hub, preventing chain jamming and locking of the rear wheel by intercepting the chain in case of a drop, without restricting the number of toothed wheels and allowing smooth chain engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the chain supporting structure projects axially beyond the axially inner surface of the first toothed wheel, then the chain is supported at a predetermined radial distance from the hub preventing jamming between spokes and toothed wheel, but the structure complexity increases due to additional supporting assembly
Solution Approach 1:
The supporting assembly is segmented into multiple axial protuberances that are circumferentially spaced around the first toothed wheel. Each protuberance independently supports the chain at different angular positions, distributing the support function across multiple discrete elements rather than requiring a continuous complex structure.
Solution Approach 2:
The axial protuberances serve multiple functions: they support the chain when engaged with the first toothed wheel, prevent chain drop to the spoke area, and maintain proper chain tension. This multi-functionality reduces the need for separate dedicated components for each function.
2Reliability
If the distance between the free end of the supporting assembly and the spokes is less than the chain thickness, then the chain is prevented from passing over the supporting assembly and jamming, but the ease of operation decreases as chain repositioning becomes more difficult
Solution Approach 1:
The supporting assembly provides localized support only at critical areas where chain drop to the spoke region is most likely to occur. The axial protuberances are positioned to create just enough interference to prevent jamming while maintaining sufficient clearance elsewhere for chain manipulation and repositioning.
3Reliability
If a ring is inserted in the space between the smallest toothed wheel and the bicycle frame, then the chain is prevented from dropping off the smallest sprocket, but the adaptability decreases as the solution is specific to the smallest toothed wheel only
Solution Approach 1:
The supporting assembly with axial protuberances is designed to work with the first toothed wheel (largest diameter sprocket) and can be applied to any toothed wheel in the sprocket assembly. This universal design provides chain support functionality across all sprockets, not just the smallest one, enhancing adaptability.
Data Source
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AI summary
The invention relates to a sprocket assembly component (10) comprising at least one first toothed wheel (11) configured to be the toothed wheel having the most teeth (14) of the sprocket assembly, the first toothed wheel (11) comprising an axially inner surface (19); a supporting assembly (21) that extends in the axial direction up to a free end (22) arranged axially more internally with respect to the axially inner surface (19) of the first toothed wheel (11)