Angled Bicycle Rim Spoke Bed for Lower Nipple Stress
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Solution Overview
Problem
Conventional bicycle rim designs lead to uneven stress distribution and fatigue in spokes and rims due to torsion on the nipples, particularly in composite materials, resulting in potential spoke failure and rim cracking.
Innovation Solution
A bicycle rim with a spoke bed featuring a pattern of spoke attachment segments angled at complex angles, each segment having a central axis that combines camber and crossing angles, with surfaces adjacent to the spoke opening extending perpendicular to the central axis, allowing for even pressure distribution and reducing the need for additional alignment structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional radial spoke openings are used, then the rim structure is simple, but stress concentrates on the nipple causing spoke fatigue and rim cracking
Solution Approach 1:
The patent applies local quality by creating spoke attachment segments with specific geometric features (angled surfaces, varying thicknesses) at localized positions around the rim. Each segment is tailored to distribute stress evenly across its specific location, with the inner and outer surfaces angled to match the spoke angle requirements. This localized geometric customization allows the rim to handle complex spoke angles without requiring the entire rim structure to be redesigned, thus improving strength while controlling complexity.
Solution Approach 2:
The patent transitions from conventional radial spoke openings to three-dimensional angled spoke attachment segments. The segments feature inner and outer surfaces that are angled relative to the rim's radial plane, creating a multi-dimensional geometry that accommodates complex spoke angles (combining camber and crossing angles). This dimensional change allows spokes to be attached at optimal angles for stress distribution without requiring additional alignment components, resolving the contradiction between strength and structural complexity.
2Shape
If spokes are bent and tensioned to achieve complex spoke angles, then the desired spoke angle is achieved, but torsion on the nipple causes uneven contact and stress concentration
Solution Approach 1:
The patent applies preliminary action by pre-forming the spoke attachment segments with the correct angular geometry during rim manufacturing. The inner and outer surfaces of each segment are angled to match the desired spoke angle before spoke installation. This preliminary geometric preparation ensures that when spokes are installed and tensioned, they contact the nipple evenly across the entire head surface, eliminating the need to bend spokes or apply torsion to achieve proper alignment, thus preventing stress concentration.
3Manufacturing precision
If additional alignment structures or bushes are used to accommodate complex spoke angles, then spoke angle accuracy improves, but device complexity and weight increase
Solution Approach 1:
The patent merges the functions of alignment structures, angle adjustment mechanisms, and spoke attachment features into a single integrated spoke attachment segment. The segment combines the rim's structural function with the alignment function by incorporating angled inner and outer surfaces that directly guide spoke insertion at the correct angle. This consolidation eliminates the need for separate alignment bushes or adjustment components, achieving precise spoke angle control while reducing overall device complexity and weight.
Data Source
AI summary
A bicycle rim comprising a circumferential outer portion adapted to receive a tire and a spoke bed. The spoke bed may comprise a pattern of spoke attachment segments at varying tilt angles and spaced by intermediate segments. Each spoke attachment segment may comprise an inner surface, an outer surface and a spoke opening extending from the inner surface to the outer surface. The spoke opening may be sized to accommodate a spoke nipple. The spoke opening may have a central axis angled at a complex angle that is a combination of a respective camber angle and a respective crossing angle. The complex angle may be selected to achieve a respective spoke angle. The outer surface of the spoke attachment segment adjacent to the spoke opening may extend perpendicular to the central axis of the spoke opening.