Bicycle Rim Alternating Projections for Tire Clinching
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Solution Overview
Problem
Conventional clincher bicycle rims have low tire clinching force, especially at low air pressure or under lateral force, but increasing the size of projecting edges for better clinching power complicates tire installation and removal.
Innovation Solution
A bicycle rim design featuring an annular bridge with alternating first and second projections of different sizes along the tire support surface, maintaining ease of assembly while enhancing tire clinching power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the projecting edges are made bigger (wider width and/or higher height), then the tire clinching (holding) power (force) is improved, but the difficulty to attach and/or detach the tire from the wheel rim increases
Solution Approach 1:
The projecting edge is segmented into multiple portions (first portion, second portion, third portion) with different heights along the circumference. This segmentation allows different sections to serve different functions: taller portions provide enhanced clinching force while shorter portions facilitate easier tire installation and removal, thereby resolving the contradiction between holding power and ease of operation.
Solution Approach 2:
Different portions of the projecting edge are given different local qualities (heights) to optimize specific functions at different locations. The first portion has a greater height for strong tire retention, while the second and third portions have reduced heights to ease installation and removal. This local differentiation resolves the contradiction by providing both strong holding force and ease of operation at appropriate locations.
2Force
If the projecting edges are made bigger (wider width and/or higher height), then the tire clinching (holding) power (force) is improved, but the device complexity increases
Solution Approach 1:
The projecting edge is divided into multiple segments with different heights rather than creating a completely new complex structure. This segmentation approach increases clinching force through strategic height variations while maintaining relative structural simplicity by using a modular, repetitive pattern around the rim circumference.
Solution Approach 2:
The projecting edge employs asymmetric height variations (first portion taller than second and third portions) to optimize clinching force distribution. This asymmetric design provides enhanced holding power where needed while avoiding unnecessary symmetry that would increase complexity, thereby resolving the contradiction between force and device complexity.
Data Source
AI summary
A bicycle rim includes a first annular side wall, a second annular side wall and an annular bridge extending between the first and second annular side walls. The annular bridge has an annular tire support surface extending between the first and second annular sidewalls. The annular tire support surface has a first projection. The first projection has at least one first portion and at least one second portion. The second portion has a different size from the first portion.