Bicycle Gear Shift Lever with Intermediary Spring Mechanism
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Solution Overview
Problem
Current bicycle gear shifting apparatuses require simultaneous replacement of both the derailleur and gear shift operating apparatus, leading to heavy operation due to spring force, potential chain derailment, and difficulty in fixing the shift cable at the gear shift position.
Innovation Solution
A bicycle gear shift operating apparatus coupled to a transmission via a shift cable, featuring a gear shift operating lever unit, a replaceable gear shift position notification unit, a pressure unit to cancel reverse input, and a reverse input shutoff unit, allowing easy stoppage and notification of gear shift positions without replacing all constituent parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gear shift operating lever is operated against the spring force of the tension spring, then the gear shift position can be changed, but the operation becomes heavy
Solution Approach 1:
A spring mechanism is introduced as an intermediary between the gear shift operating lever and the derailleur. This spring absorbs the spring force from the tension spring, allowing the operating lever to move smoothly without directly opposing the tension spring's force. The spring mechanism transmits the operating force to the derailleur while canceling out the harmful spring force, thus resolving the contradiction between reliable gear shift control and ease of operation.
2Reliability
If the spring force of the tension spring is added to the gear shift operating lever, then the derailleur can maintain chain tension, but the gear shift operating lever tends to be displaced and the shift cable cannot be fixed at the gear shift position
Solution Approach 1:
The spring mechanism serves as a mediator that decouples the tension spring's force from the gear shift operating lever. It allows the tension spring to maintain chain tension on the derailleur side while preventing this force from being transmitted to the operating lever, thereby eliminating lever displacement and ensuring stable gear shift position fixation.
Solution Approach 2:
The harmful spring force is extracted from the gear shift operating lever system and isolated to only act on the derailleur through the spring mechanism. This separation allows the tension spring to fulfill its chain tensioning function while its destabilizing effect on the operating lever position is removed.
3Reliability
If all constituent parts of a component are replaced to ensure compatibility, then the gear shifting apparatus functions properly, but the number of parts to be replaced increases
Solution Approach 1:
The gear shifting system is segmented into independent replaceable modules: the derailleur, the operating lever, and the spring mechanism. This segmentation allows each component to be replaced independently based on its own wear or compatibility requirements, rather than requiring replacement of the entire component set. The standardized interface between these modules ensures compatibility while minimizing the number of parts that need replacement.
4Device complexity
If the gear shift operating lever is operated without a mechanism to determine gear shift position, then the structure is simplified, but the gear shift position cannot be easily stopped at the desired position
Solution Approach 1:
The spring mechanism provides self-service by automatically determining and indicating the gear shift position through its own mechanical state. As the operating lever moves the derailleur through different gear positions, the spring mechanism's configuration naturally corresponds to these positions, providing tactile feedback and visual indication without requiring additional complex position-determining mechanisms.
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
Enables easy stopping of the gear shift operating lever at the desired position, reduces the number of parts replaced, provides light operation, and maintains the transmission at a predetermined position, eliminating the need for complete component replacement.
Implementation Method 1
a derailleur is provided with a tension spring for applying predetermined tension to a chain
Implementation Method 2
A friction type is known which, when the control force is released from the gear shift operating lever, uses a frictional force to stop the gear shift operating lever at the position
Data Source
AI summary
A bicycle gear shift operating apparatus is provided which can easily stop a gear shift operating lever at a gear shift position without replacing all constituent parts of a component. A gear shift operating apparatus 100 is an apparatus that is coupled to a rear derailleur 70 of a bicycle via a shift cable 60. The gear shift operating apparatus 100 includes a gear shift operating lever unit 40, an operating shaft 1 that rotates by operation of the gear shift operating lever unit 40 and pulls and releases the shift cable 60, and a replaceable gear shift position notification unit 10. Rotation stop positions corresponding respectively to gear shift positions of the rear derailleur 70 that are switched in accordance with the rotation of the operating shaft 1 are set in the gear shift position notification unit 10.