Bicycle Chain Guide with Movable Cage for Front Sprocket
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Solution Overview
Problem
Fixed chain devices for bicycles are less effective in maintaining the chain on the front sprocket due to the changing chain path caused by the rear derailleur's movement, requiring enlarged chain passages which compromises efficiency.
Innovation Solution
A bicycle chain device with a movable cage and actuator system that aligns with the front sprocket's rotational center axis, coupled to the rear derailleur's mechanical operation cable, allowing the cage to adjust its position in response to shifting operations, ensuring continuous chain alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed chain devices are used, then the structure is simple and easy to manufacture, but the chain passage must be enlarged to accommodate rear derailleur movement, making them less effective in maintaining the chain on the front sprocket
Solution Approach 1:
The cage is made movable relative to the mounting bracket through an actuator mechanism. The actuator responds to cable tension changes from rear derailleur shifting operations and moves the cage along the rotational center axis of the front sprocket, allowing the chain device to dynamically adapt to changing chain positions while maintaining compact dimensions
Solution Approach 2:
The actuator is operatively coupled to the mechanical operation cable that controls the rear derailleur. As the cable tension changes during shifting operations, the actuator detects this change and automatically adjusts the cage position accordingly, creating a feedback loop that maintains optimal chain alignment without requiring manual intervention
2Adaptability or versatility
If the chain passage is enlarged to accommodate rear derailleur movement, then the device can work with shifting operations, but the chain alignment effectiveness is reduced
Solution Approach 1:
Rather than creating a statically large passage to accommodate all possible chain positions, the invention uses a movable cage that dynamically adjusts its position. This allows the chain passage to remain compact in any given moment while adapting to different chain positions through actuator-driven movement, maintaining both versatility and alignment effectiveness
Solution Approach 2:
The system changes the positional parameter of the cage in response to cable tension variations. As the rear derailleur shifts and cable tension changes, the actuator translates this into precise cage position adjustments, allowing the chain device to adapt to different operating conditions while maintaining optimal chain alignment throughout the shifting range
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device effectively maintains chain alignment with the front sprocket across various gear shifts, preventing chain fall-off and enhancing the chain's path efficiency by dynamically adjusting to the rear derailleur's movements.
Implementation Method 1
an actuator, which is configured to move the cage in accordance with a shifting operation of a bicycle rear derailleur
Implementation Method 2
the first actuating member includes one of a rack and pinion and the second actuating member includes the other of the rack and pinion
Data Source
AI summary
A bicycle chain device that includes a mounting bracket configured to be affixed to a bicycle. The bicycle has a solitary bicycle front sprocket. A cage is movably mounted to the mounting bracket so that the cage is positioned adjacent to the front sprocket. The cage has a chain-receiving slot, through which a bicycle chain passes. The cage is configured to move in accordance with a shifting operation of a bicycle rear derailleur to maintain alignment with a chain to prevent the chain from falling off the sprocket.