Low Profile Rear Derailleur with Diagonal Chain Guide
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Solution Overview
Problem
Existing bicycle rear derailleurs have a high profile due to their design, which limits their ability to closely follow the contour of the sprockets and requires excessive lateral spacing, leading to a bulky structure.
Innovation Solution
A low profile rear derailleur design featuring a continuous, one-piece bicycle frame end with a derailleur-attachment structure that allows the chain guide to move laterally and be positioned closer to the sprockets, utilizing a two-piece chain guide and a linking mechanism that adjusts to fit within a narrower lateral space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional rear derailleur design is used, then the derailleur can engage the chain with sprockets, but the lateral profile is high and excessive lateral spacing is required
Solution Approach 1:
The patent repositions the derailleur attachment point angularly (180°-240° in Cartesian coordinate system) and redesigns the linking mechanism to follow the diagonal contour of sprockets, transitioning from a conventional lateral movement pattern to a diagonal movement pattern. This dimensional change in the movement trajectory reduces the lateral profile height from conventional high profiles to under 1 inch while maintaining chain engagement functionality.
2Length of moving object
If the chain guide is positioned closer to the sprockets, then the lateral spacing is reduced, but the derailleur must follow a more complex diagonal contour
Solution Approach 1:
The patent employs a dynamic linking mechanism with movable members that can adapt their position and orientation to follow the diagonal contour of the sprockets. The chain guide moves laterally and diagonally through a coordinated mechanism involving movable members connected to the base member, allowing the system to dynamically trace the optimal path that minimizes lateral distance while maintaining proper chain engagement geometry.
Data Source
AI summary
A continuous, one-piece bicycle frame end includes a forward portion and a rearward portion, wherein the forward portion extends from a chain stay and a seat stay, and wherein the rearward portion extends rearward from the forward portion. The frame end defines an axle receiving opening dimensioned to receive a bicycle wheel axle therein to rotate around a rotational axis. The axle receiving opening is intersected by a horizontal axis of a Cartesian coordinate system, wherein the axle receiving opening forms the origin of the Cartesian coordinate system, and the zero axis of the Cartesian coordinate system is the portion of the horizontal axis forward of the origin. A derailleur-attachment structure is located from approximately 180° to approximately 240° in the Cartesian coordinate system.