Dynamic Chain Casing With Tensioner for Quiet Bicycle Drivetrains
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Solution Overview
Problem
Existing chain casings for bicycles cause wear and noise due to their tight design, which is exacerbated by the need for frequent adjustments as the chain length varies, and are not compatible with chain tensioners used in wheel hub transmissions.
Innovation Solution
A chain casing system that includes a main chain sprocket cover, pulling chain part cover, returning chain part cover, and chain tensioner cover, integrated with a chain tensioner assembly featuring guide sprockets and a tensioning arm, allowing for adjustable tensioning without contact and compatibility with wheel hub transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a tight chain casing is used to protect the chain, then protection and sleek design are improved, but wear and noise increase due to contact between the chain and casing
Solution Approach 1:
The patent applies the dynamics principle by making the chain casing movable rather than fixed. The casing is supported by a support element at the crank axle, allowing it to move dynamically with chain length variations. This dynamic positioning ensures the casing remains tight and protective while avoiding contact with the chain, thereby eliminating wear and noise issues.
2Volume of moving object
If a tight chain casing is used to reduce space, then compactness is improved, but frequent adjustment is required as chain length varies
Solution Approach 1:
The support element dynamically adjusts the position of the chain casing according to chain length variations. This dynamic adaptation allows the casing to remain tight and compact throughout the entire range of chain wear and extension, eliminating the need for frequent manual adjustments.
Solution Approach 2:
The chain casing system performs self-adjustment through the support element that automatically positions the casing according to chain length. This self-service mechanism eliminates the need for user intervention and frequent adjustments, saving time and maintenance effort.
3Adaptability or versatility
If a chain tensioner is added to accommodate wheel hub transmission, then compatibility and tension control are improved, but device complexity increases
Solution Approach 1:
The patent merges the chain tensioner function with the existing chain casing structure. The tensioner is integrated into the casing assembly, allowing the system to accommodate wheel hub transmissions and control chain tension without requiring separate, complex components. This merging approach maintains simplicity while achieving the desired functionality.
Data Source
AI summary
The present invention relates to a chain casing for encasing of a chain spanning a main chain sprocket and a driven chain sprocket, such as having two free chain parts, a pulling chain part and a returning chain part, of preferably a vehicle, such as a bicycle having a frame, the chain casing having: —a main chain sprocket cover element for covering of the chain at the main chain sprocket, such as a pedal spindle chain sprocket; —a pulling chain part cover element for covering of at least a part of a pulling chain part between a main chain sprocket and the driven chain sprocket; —a returning chain part cover element for covering of at least a returning chain part between the main chain sprocket and the driven chain sprocket; —a chain tensioner cover element for covering of a chain tensioner assembly with the chain arranged therethrough. Furthermore, the present invention relates to a chain tensioner assembly, preferably fitting in the chain casing.