Bicycle Brake Lever Roller Coupling Profile
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Solution Overview
Problem
Bicycle brakes of types B and C face challenges in achieving optimal braking conditions, including quickness, graduality, and uniform wear of brake pads, as the levers do not rotate by equal angles, leading to uneven movement and stress distribution on the wheel rim.
Innovation Solution
A bicycle brake design with two levers pivoted around parallel rotation axes, featuring a roller for mutual coupling that rolls on a surface portion of the other lever, with a profile defined by a curve passing through points corresponding to equal angles of rotation, ensuring synchronous and uniform movement of the brake pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the levers are articulated around parallel rotation axes with a roller coupling mechanism, then the braking force distribution and lever rotation uniformity are improved, but the device complexity increases due to additional components
Solution Approach 1:
A roller element is introduced as an intermediary component between the two levers to transmit and synchronize their motion. The roller couples the levers mechanically, ensuring that when one lever rotates, the other follows in a synchronized manner, thereby achieving uniform braking force distribution across both brake pads.
Solution Approach 2:
The roller employs a curved, cylindrical surface that rolls along the lever arms. This curvature enables smooth transmission of rotational motion from one lever to the other, maintaining continuous contact and ensuring synchronized angular displacement of both levers during braking operation.
2Reliability
If the levers rotate by equal angles for optimal braking, then the brake pad wear uniformity improves, but the manufacturing precision requirements increase for the surface profile
Solution Approach 1:
The lever surface is pre-formed with a specific curved profile during manufacturing that corresponds to the rolling path of the roller. This preliminary shaping of the surface ensures that as the roller moves along the lever, it naturally guides the lever through equal angular rotations, achieving uniform brake pad wear without requiring active control during operation.
3Speed
If a roller is used for mutual coupling of the levers, then the braking quickness and graduality are enhanced, but the friction and rolling resistance increase
Solution Approach 1:
The roller is designed to make contact only at specific points or narrow regions on the lever surfaces, minimizing the contact area and thereby reducing frictional losses. By extracting the coupling function to a small, efficient rolling element rather than a large contact surface, the system achieves quick braking response with minimal energy dissipation through rolling resistance.
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 design enhances braking quickness and graduality, evenly distributes braking force, and ensures simultaneous wear of brake pads, reducing stress on the levers and promoting uniform rim heating.
Implementation Method 1
a roller for mutual coupling of the two levers, wherein the roller is pivoted to one of the two levers and is in rolling contact with a surface portion of the other lever
Data Source
AI summary
A bicycle brake including a first lever and a second lever is provided. A roller for mutual coupling of the first lever and second lever is pivoted to one of said first lever and second lever and is in rolling contact with a surface portion of the other between said first lever and second lever. The surface portion has a profile defined by a curve that passes by a predetermined number of points of the roller. Each of the points are defined as function of the position taken by the roller during a respective rotation of the roller about a first rotation axis (X1) of the first lever by a respective predetermined angle of rotation and about a second rotation axis (X2) of the second lever by a respective angle substantially equal to said respective predetermined angle of rotation.