Bicycle Drive Assembly Axle Release Mechanism
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Solution Overview
Problem
Conventional bicycle drive assemblies are time-consuming and messy to maintain due to the need to release and reattach the chain when removing or replacing the wheel, and they can be unsafe as the axle can drop out if not properly secured, with limited cassette length restricting sprocket count.
Innovation Solution
A bicycle drive assembly with a freewheel mechanism and an axially movable axle that allows for quick release and reattachment of the wheel without disengaging the chain, featuring resilient catch fingers for secure attachment and a cassette assembly that can be easily modified with a greater number of sprockets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the wheel is removed using conventional dead axle construction, then the wheel can be removed from the frame, but the chain must be released and reattached which is time-consuming and messy
Solution Approach 1:
The invention separates the wheel assembly from the chain drive system by using a live axle that rotates with the wheel, allowing the wheel to be removed independently without disturbing the chain-cassette connection. The chain remains engaged with the cassette while the wheel detaches from the axle.
Solution Approach 2:
The live axle acts as an intermediary between the wheel and the frame, providing a rotating connection point that allows wheel removal without chain disengagement. The axle serves as the mediator that couples wheel rotation to frame movement while enabling independent wheel detachment.
2Speed
If quick-release cam-levers are used to loosen fasteners for speed, then removal speed increases, but the axle can drop out and the rider will crash
Solution Approach 1:
The invention transitions from static dead axle construction to dynamic live axle construction, where the axle rotates with the wheel and maintains continuous engagement through rotational motion. This dynamic connection provides inherent security against dropout while enabling quick release when needed.
Solution Approach 2:
The live axle construction preliminarily establishes a secure rotating connection between wheel and frame before wheel removal is needed. The axial engagement and rotational coupling are pre-configured to prevent dropout during normal operation, allowing safe quick-release when required.
3Adaptability or versatility
If the cassette length is limited by chainstay spacing, then the bicycle structure remains compact, but the number of sprockets is restricted
Solution Approach 1:
The invention addresses the spatial constraint by changing the dimensional relationship between cassette and chainstays. The live axle construction allows the cassette to extend beyond the traditional chainstay spacing limitation, effectively adding dimensional flexibility to accommodate more sprockets.
Data Source
AI summary
The invention is a bicycle drive assembly and it generally includes a drive chain, a drive wheel including a hub, a frame including left and right chainstays, each having a raced bearing, a cassette assembly, and an axle assembly. The cassette assembly includes a body having an inner end rotatably mounted on the right chainstay bearing, an outer free end, and a cassette including a plurality of sprockets. Cooperative torque-transferring components transfer torque between cassette and body, body and axle, and axle and hub. A freewheel mechanism, as one of the cooperative torque-transferring components, allows the bicycle to coast. A drive axle is selectably movable axially between a riding position, wherein it is rotatably mounted on the chainstay bearings and supports and drives the wheel, and a release position wherein the wheel is removable.