Bicycle Cassette Segmented Sprocket Bayonet Locking

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Solution Overview

Problem

Conventional bicycle cassettes face limitations in accommodating smaller sprockets, as they cannot overhang the hub driver body, restricting flexibility and requiring complex fixing structures, which can compromise bearing strength and assembly efficiency.

Innovation Solution

A bicycle cassette design featuring two segments with a locking, bayonet-style attachment allows a small sprocket assembly to overhang the hub driver body, using a combination of materials like aluminum and steel/titanium for the large and small sprocket assemblies, respectively, and a single locking ring for attachment, simplifying assembly and enhancing durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a smaller sprocket is used, then the cassette allows for more compact design and overhanging capability, but the sprocket cannot be properly supported by the hub driver body

Engineering Contradiction:

Improvesprocket sizeVSAvoidsprocket support stability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The cassette is divided into two separate segments: a large sprocket assembly that provides structural support and a small sprocket assembly that enables compact design. The small sprocket assembly is attached to the large sprocket assembly rather than directly to the hub driver body, allowing the small sprocket to overhang while maintaining stability through the two-segment configuration.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If a locking ring is used to secure the cassette, then the assembly is simplified, but the fixing structure becomes complex and bearing strength is compromised

Engineering Contradiction:

Improveassembly structureVSAvoidbearing strength

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

By segmenting the cassette into two assemblies connected by a locking bayonet attachment, the design achieves structural integrity without requiring a complex single-piece locking ring. The segmentation allows each assembly to be optimized independently while maintaining overall strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using a traditional locking ring that secures all sprockets together as a single unit, the invention inverts the approach by using a locking mechanism that attaches the small sprocket assembly to the large sprocket assembly. This allows the large sprocket assembly to provide the primary structural support and bearing strength.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If multiple fixing structures are used to accommodate small sprockets, then the sprocket can be secured, but the assembly process becomes more complex and time-consuming

Engineering Contradiction:

Improvesprocket fixationVSAvoidassembly time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The locking bayonet attachment merges the fixation function into a single integrated mechanism that secures the small sprocket assembly to the large sprocket assembly. This eliminates the need for multiple separate fixing structures and reduces assembly steps while maintaining reliable fixation.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11485449B2Bicycle cassette with locking connection

Publication Date: 2022.11.01 THE HIVE GLOBAL

AI summary

A bicycle cassette comprises two segments that are attached together thereby forming a composite cassette that can be attached to a rear bicycle hub driver body. The bicycle cassette allows for the use of a smaller sprocket on one segment of the cassette because the smaller sprockets can overhang the hub driver body. Specifically, the cassette allows a small 9 or 10 tooth sprocket to overhang the cassette driver body on the bicycle hub by attaching a small sprocket assembly to a larger sprocket assembly using a locking, bayonet style attachment.