Crank-Integrated Front Shifting for Frame-Flex Misalignment
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Solution Overview
Problem
Traditional front derailleurs on bicycles cause design constraints, misalignment issues, and poor shifting performance due to frame flexing, making installation and setup difficult and time-consuming.
Innovation Solution
A front shifting system integrated into the crank assembly, featuring a shift mechanism with electronic control and gearmotor units, allowing smooth and consistent shifting without frame attachment, eliminating design constraints and improving shifting quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a front derailleur is mounted to the bicycle frame, then the chain can be shifted between chain rings, but the frame design is constrained and misalignment occurs due to frame flexing
Solution Approach 1:
The patent combines the front derailleur mounting function directly into the crank arm structure. The derailleur is mounted to the crank arm rather than the frame, integrating two previously separate components (derailleur mounting system and crank assembly) into a unified structure that eliminates frame design constraints and flexing issues.
2Ease of operation
If a front derailleur is mounted to the bicycle frame, then gear shifting is enabled, but installation and setup become difficult and time-consuming
Solution Approach 1:
The patent integrates the derailleur mounting function into the crank arm, creating a pre-assembled unit that requires no separate frame mounting operations. This reduces installation complexity and setup time while maintaining reliable shifting operation.
3Ease of manufacture
If the frame is made accessible for derailleur mounting, then the derailleur can be attached, but the frame must be left open and positioned close to chain rings
Solution Approach 1:
The patent merges the derailleur mounting location with the crank arm structure, eliminating the need for open frame sections or close positioning requirements. The integrated design allows the derailleur to be mounted on the crank arm without compromising frame structural integrity or requiring frame modifications.
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
The integrated front shifting system provides enhanced design freedom, improved shifting performance under heavy loads, and easier installation, eliminating frame-related misalignment issues.
Implementation Method 1
a gearmotor unit, the gearmotor unit including a housing, a stator, a rotor, and a shaft
Data Source
AI summary
A bicycle front shifting system includes operable to transmit a wireless signal, a crank assembly with two crank arms and a pedal on each of the two crank arms. The crank assembly is rotatable about a rotation axis. A front shift unit is coupled to the crank assembly and is rotatable about the rotation axis. The front shift unit includes a chain ring component with a big chain ring and a small chain ring. The small chain ring has a small diameter and the big chain ring has a big diameter that is larger than the small diameter. A shift mechanism is coupled to and rotatable with the chain ring component about the rotation axis. The shift mechanism is configured to receive the wireless signal from the shifter and to shift a chain between the big chain ring and the small chain ring according to the wireless signal.