Handlebar Brake Lever Geometry for Finger-Matched Piston Actuation
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Solution Overview
Problem
Existing human-powered vehicle operating devices do not effectively utilize the finger movement of users, leading to suboptimal operability and efficiency in actuating the vehicle's components, such as brakes.
Innovation Solution
The operating device features a base with a piston and an intermediate member, where the first pivot axis is closer to the mounting axis than the second pivot axis, allowing for a movement of the operating member suitable for finger movement, and includes a cam surface to adjust the piston's stroke to pivot angle ratio, enhancing operability and reducing friction during actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the first pivot axis is positioned closer to the mounting axis than the second pivot axis, then the operability is improved by matching finger movement, but the device structure becomes more complex
Solution Approach 1:
The intermediate member acts as a mediator between the operating member and the piston, enabling the complex pivot axis arrangement to achieve finger-friendly motion transformation while maintaining a relatively simple overall structure. The intermediate member with its cam surface and follower mechanism translates the pivotal motion into suitable linear motion for the piston.
2Volume of moving object
If the operating device is made smaller by adjusting pivot axis positions, then the compactness is improved, but the finger movement suitability may be compromised
Solution Approach 1:
The invention optimizes the geometric parameters of the pivot axes positions and the cam surface profile to achieve a compact device size while maintaining suitable finger movement characteristics. By carefully selecting the distances and angles of the pivot axes relative to each other, the device achieves small dimensions without sacrificing operability.
3Productivity
If the piston stroke to pivot angle ratio is adjusted via cam surface, then the actuation efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The cam surface is designed to provide the necessary motion transformation only over the required operating range, rather than over the entire possible range of motion. This allows for adequate actuation efficiency while reducing the overall precision requirements, as the cam surface needs to be precise only within the functional operating envelope.
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
This configuration improves the operability of the device by aligning the operating member's movement with finger motion, enhancing the efficiency of actuating components like brakes and allowing for a more suitable movement of the piston, thereby improving the overall user experience and device performance.
Implementation Method 1
The base and the piston define a hydraulic chamber in the hole
Data Source
AI summary
An operating device for a human-powered vehicle comprises a base, a piston, an operating member, an intermediate member, and a mounting structure. The base includes a hole. The piston is movably provided in the hole. The operating member is pivotally coupled to the base about a first pivot axis. The intermediate member is pivotally coupled to the base about a second pivot axis to transmit a pivotal movement of the operating member to the piston. The mounting structure is configured to couple the base and a handlebar of the human-powered vehicle. The mounting structure defines a mounting axis extending along the handlebar in a mounting state where the mounting structure couples the base and the handlebar. The first pivot axis is closer to the mounting axis than the second pivot axis in a perpendicular direction perpendicular to the mounting axis as viewed along the first pivot axis.