Bicycle Shifting Mechanism with Independent Release and Pull Ratchets
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Solution Overview
Problem
Existing bicycle operating devices lack efficiency in performing quick and precise releasing and pulling operations, particularly in adjusting bicycle components like gear shifting devices, due to complex mechanisms and potential interference during operations.
Innovation Solution
A bicycle operating device comprising a base member, positioning ratchet, positioning member, pulling member, pulling pawl, first release member, and second release member, which allows for bi-directional pivoting and independent operation of the positioning ratchet, enabling efficient releasing and pulling operations by preventing interference and facilitating smooth transitions between gear positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional bicycle operating device uses a single integrated mechanism for releasing and pulling operations, then the structure is simpler, but the operation speed and precision are reduced due to mechanical interference
Solution Approach 1:
The operating device is divided into separate releasing and pulling mechanisms. The releasing mechanism includes a release lever, release cable, and ratchet mechanism, while the pulling mechanism includes a pull lever, pull cable, and drum mechanism. This segmentation allows independent operation of each function, eliminating mechanical interference and improving operation speed and precision.
2Measurement precision
If the positioning ratchet is constrained to prevent interference during releasing operation, then the releasing precision improves, but the pulling operation becomes slower due to additional constraints
Solution Approach 1:
The positioning ratchet is designed with dynamic positioning members that can pivot between engaged and disengaged states. During releasing operation, the positioning member engages with the ratchet teeth to prevent backward movement, ensuring precise positioning. During pulling operation, the positioning member can disengage to allow free rotation of the drum, eliminating time loss. This dynamic adaptability resolves the contradiction between positioning precision and operation speed.
3Stability of the object's composition
If the pulling pawl is held in engagement with the pulling member during releasing operation, then the pulling position is maintained, but the releasing operation is hindered due to mechanical conflict
Solution Approach 1:
The device uses separate pawls for releasing and pulling functions. The release pawl engages with the ratchet wheel to maintain position during releasing operation, while the pull pawl engages with the drum to maintain position during pulling operation. This segmentation of locking functions eliminates mechanical conflict between pawls, ensuring both position stability and operation smoothness.
4Productivity
If the first release member and second release member operate independently, then the releasing and pulling operations can be performed quickly without interference, but the device structure becomes more complex
Solution Approach 1:
The operating device uses a common base structure, pivot axis, and housing for both releasing and pulling mechanisms. The first release member and second release member share the same ratchet wheel and positioning member system. This multi-functionality design allows independent operation of releasing and pulling functions while minimizing overall device complexity through shared components.
Data Source
AI summary
A bicycle operating device includes a base member, a positioning ratchet, a positioning member, a pulling member, a pulling pawl and first and second release members. The positioning ratchet pivots in first and second directions. The positioning member moves between a holding position that prevents pivoting of the positioning ratchet in the first direction, and a releasing position that releases the positioning ratchet in the first direction. The pulling member pivots the positioning ratchet in the second direction as the pulling member is moved by the pulling pawl. The first release member moves the positioning member from the holding position to the releasing position. The second release member moves the pulling pawl away from the pulling member. The second release member extends between opposite axial sides of the positioning ratchet. The first release member and the pulling member are positioned on opposite axial sides of the positioning ratchet.