Composite Bicycle Crank Integral Spindle Attachment
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Solution Overview
Problem
The manufacturing of bicycle cranks and crank arms requires different materials and processes for left and right sides, leading to increased time and cost, and necessitates distinct attachment methods, which complicates the creation of a lightweight and strong crank set.
Innovation Solution
A composite bicycle crank with an integral spindle attachment structure allows for the separate manufacturing of lightweight crank arms and spindles/inserts from different materials, using interfaces such as circular, square, or splined connections, and a method involving cleaning, applying adhesive, sliding, and torquing to securely attach them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If left side crank arm and right side crank arm are shaped differently and manufactured in separate processes, then the crank arms can be optimized for their specific functions, but the manufacturing time and cost increase
Solution Approach 1:
The patent applies universality by designing a single mold that can produce both left and right crank arms through different positioning. The mold includes a first positioning structure for the left crank arm and a second positioning structure for the right crank arm, allowing both sides to be manufactured in the same process while maintaining their specific functional requirements through geometric variations.
2Strength
If left side crank arm and right side crank arm are manufactured separately, then each can be optimized independently, but different attachment methods are required which complicates the assembly process
Solution Approach 1:
The patent implements universality in the attachment mechanism by providing a unified attachment structure that works for both left and right crank arms. The attachment structure includes a spindle with a unified interface design that accommodates both sides, eliminating the need for different attachment methods while maintaining optimized performance for each side through the mold positioning.
3Weight of moving object
If crank arms are manufactured from lightweight materials, then the overall weight of the crank set decreases, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies segmentation by separating the crank arm manufacturing from the spindle attachment in the design process, while integrating them in the molding process. The mold allows for separate positioning of crank arm and spindle components, enabling the use of lightweight materials for crank arms while maintaining simple manufacturing through a single integrated molding operation that assembles the components during fabrication.
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 approach enables the creation of a lighter and stronger crank assembly by allowing different materials and designs for each component, reducing manufacturing complexity and costs while maintaining structural integrity.
Implementation Method 1
applying an adhesive to the one or more bonding surfaces of the insert and the crank arm
Data Source
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AI summary
A composite bicycle crank with an integral spindle attachment structure provides a unique method for attaching a bicycle crank arm to a bicycle crank spindle, and also for attaching a bicycle crank arm to a crank arm insert. A light-weight crank arm is able to be manufactured separately from the crank spindle or insert, and then securely attached after both pieces have been made. This allows for the pieces of the crank assembly to be manufactured from one or more different materials, and securely connected after manufacturing, to create a lower weight assembly than would be possible otherwise.