Bicycle Crank Assembly With Rotating Arm for Higher Torque Stability
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Solution Overview
Problem
Existing bicycle cranks lack extendable moment arms to enhance torque, have poor ergonomics, complex structures causing user fatigue, and suffer from structural weaknesses and assembly alignment issues.
Innovation Solution
A crank apparatus with a labor-saving mechanism featuring a crank mechanism, transmission mechanism, supporting modules, and rotating arm module, incorporating gears and rollers to facilitate smooth circular motion and enhance structural strength and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the crank is made extendable to increase moment arm length, then torque is enhanced, but ergonomics deteriorates and structure becomes complicated causing user fatigue
Solution Approach 1:
The crank is divided into a fixed base portion and a movable extension portion that can independently rotate. This segmentation allows the extension portion to provide torque multiplication while maintaining proper pedal positioning through independent rotation, resolving the conflict between torque enhancement and ergonomic operation.
Solution Approach 2:
The crank extension portion is designed to be dynamically adjustable, allowing it to rotate independently from the base crank. This dynamic capability enables the system to maintain optimal ergonomics while providing variable torque multiplication as needed, rather than being fixed in a compromised position.
2Force
If the crank structure is made complex to allow extension, then torque can be increased, but reliability decreases due to insufficient structural strength
Solution Approach 1:
The crank employs composite construction with strategically placed reinforcing ribs and integrated support structures. The base crank and extension portion are designed as interconnected components with optimized material distribution, providing high structural strength and reliability while maintaining the complexity needed for torque multiplication.
3Force
If the crank structure is made complex to allow extension, then torque can be increased, but manufacturing precision becomes difficult due to alignment issues
Solution Approach 1:
The mounting structure integrates the base crank, extension portion, and support elements into a unified assembly with built-in alignment features. By merging these components with integrated positioning ribs and standardized connection interfaces, the design simplifies the alignment process during manufacturing while maintaining the complex functionality needed for torque enhancement.
4Duration of action of stationary object
If larger rollers are used in supporting modules, then useful lifetime is extended, but device complexity increases
Solution Approach 1:
The supporting modules are designed as multi-functional units that combine larger diameter rollers with integrated bearing structures and positioning features. These universal modules serve multiple purposes: supporting the crank, enabling rotation, providing alignment, and extending service life through the larger roller diameter, thereby reducing overall device complexity despite the increased roller size.
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 design allows for increased torque without user fatigue, improved transmission stability, and extended useful lifetime by accommodating larger rollers and torsional deformation, reducing noise and improving precision.
Implementation Method 1
each one of the rollers is received inside each one of the circular grooves and clamped between the rotating axle and each one of the outer rings
Implementation Method 2
the first gear is connected to the first end and engaged with the axle-end gear for transmission, the second gear is connected to the second end and engaged with the pedal-end gear for transmission
Data Source
AI summary
A crank apparatus equipped with a labor-saving mechanism and a bicycle crank assembly are disclosed. The crank apparatus includes a crank mechanism, a transmission mechanism, a supporting module and a rotating arm module. The crank mechanism includes a crank, an axle-end gear and a pedal-end gear. The transmission mechanism includes a rotating axle having a circular groove. The supporting module is adapted to sheathe the rotating axle and includes an outer ring and rollers received inside the circular grooves and clamped between the rotating axle and the outer ring. The rotating arm module includes a first rotating arm and a second rotating arm. One end of the second rotating arm is connected to the first rotating arm, and another end of the second rotating arm is connected to the pedal-end gear. Accordingly, the transmission stability and useful lifetime of the crank apparatus and bicycle crank assembly are increased.