Cam-Locked Crank Preload Collar for Tool-Free Axial Adjustment
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Solution Overview
Problem
Current crank preload systems for pedal-driven vehicles often require a secondary fastener that is small and tool-dependent, making adjustments cumbersome, and lack adequate positional fixing, leading to potential misalignment and ease of displacement.
Innovation Solution
A crank preload collar assembly utilizing a split thread with a 'quick release' cam lever to apply a circumferential load, allowing for tool-free adjustment and robust positional fixing, and optionally incorporating a multi-pivot link system or integral fastener for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a threaded interface with spring or elastomeric is used to apply axial load, then precise adjustment of axial load is achieved, but the secondary fastener is small and requires a tool to adjust, making it cumbersome for the user
Solution Approach 1:
The patent replaces the traditional threaded fastener system with a cam-based locking mechanism. The cam lever provides mechanical advantage to lock the preload collar in position without requiring a secondary threaded fastener, enabling tool-free adjustment while maintaining precise axial load control through the threaded interface.
Solution Approach 2:
The cam lever system allows the preload collar to be adjusted and locked by the user directly without requiring additional tools. The cam mechanism provides self-locking capability that secures the adjustment in position, making the system self-sufficient for user operation.
2Reliability
If a threaded fastener is used to fix the preloader position, then adequate fixing is provided, but the secondary fastener is often small and requires a tool to adjust, which can be a hassle for the user
Solution Approach 1:
The patent substitutes the secondary threaded fastener with a cam lever mechanism that provides equivalent or superior locking reliability. The cam lever engages with the preload collar to prevent rotation and maintain position, offering reliable fixing without the need for small threaded fasteners that require tools.
Solution Approach 2:
The patent extracts and eliminates the secondary threaded fastener from the system, replacing it with an integrated cam lever mechanism that performs the same locking function. This removal of the problematic secondary fastener simplifies the user interface while maintaining reliability.
3Ease of operation
If no fastener is used to fix the preloader, then tool-free adjustment is achieved, but the solutions do not provide adequate positional fixing and can be knocked out of place easily
Solution Approach 1:
The patent replaces the inadequate non-fastener solutions with a cam lever mechanism that provides positive mechanical locking. The cam lever engages with the preload collar to create a secure connection that prevents accidental displacement while still allowing intentional tool-free adjustment by the user.
Solution Approach 2:
The cam lever mechanism provides dynamic locking that adapts to operational forces. The cam profile is designed to maintain engagement under load while allowing controlled release when the user applies force to the lever, achieving both reliability and ease of operation.
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
Enables easy and secure adjustment of the preload without tools, providing robust positional fixing and maintaining the alignment of components, thus improving user convenience and system reliability.
Implementation Method 1
a cam lever to apply a circumferential load across the split and circumferentially load the thread to fix the preloader in place
Implementation Method 2
Many of the current embodiments of crank preloaders utilize a threaded interface along the same axis of the crank spindle
Data Source
AI summary
A crank preload collar assembly is disclosed. The crank preload collar assembly includes a preload collar body having an axial opening therein to fit around a spindle of a crank assembly. The crank preload collar assembly also includes a clampable opening formed in a portion of the preload collar body. A cam lever is coupled with both sides of the clampable opening, wherein the cam lever provides a clamping force to the preload collar body with respect to the spindle.