Eccentric Crank Mechanism for Exercise Bike Vibration Generation
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Solution Overview
Problem
Conventional exercise bikes lack an effective mechanism to generate and transmit vibrations to the pedals, requiring additional dampening to reduce vibration transmission to the frame, which increases mass and volume.
Innovation Solution
The introduction of a second set of eccentrically mounted crank arms, coupled to a sleeve shaft, generates vibrations that are superposed on the revolutions of the pedals, reducing the need for dampening by distributing the mass and volume of vibrating components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional exercise bikes are designed without eccentric crank arms, then the structure is simpler, but vibrations cannot be generated and transmitted to the pedals
Solution Approach 1:
The patent applies asymmetry by mounting the second set of crank arms eccentrically with respect to the rotational axis of the shaft. This asymmetric positioning creates an offset between the crank arm rotation center and the pedal axis, generating vibrations when the cranks rotate. The eccentric mounting allows the mechanism to produce the desired vibratory motion without requiring complex additional components.
2Object-affected harmful factors
If additional dampening components are added to reduce vibration transmission to the frame, then vibration control is improved, but mass and volume increase
Solution Approach 1:
The patent converts the potentially harmful vibrations into a beneficial feature by using them for therapeutic purposes. The vibrations generated by the eccentric crank arms are directed to the pedals and transmitted to the user's feet and legs, providing massaging and therapeutic effects. This approach transforms what could be considered a harmful vibration into a useful therapeutic function, eliminating the need for dampening components.
3Volume of moving object
If a compact vibration generation mechanism is implemented, then mass and volume of vibrating components are reduced, but the mechanism complexity increases
Solution Approach 1:
The patent merges two crank arm sets into a single integrated mechanism. The first set of crank arms is mounted concentrically on the shaft, while the second set is mounted eccentrically on the same shaft. Both sets rotate together as a unified mechanism, eliminating the need for separate vibration generation components and reducing overall complexity despite the sophisticated motion generation capability.
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
This design allows for a compact mechanism to generate and transmit vibrations to the pedals, reducing the overall mass and volume of vibrating components and minimizing the need for vibration dampening during use.
Implementation Method 1
at least a second set of crank arms mounted eccentrically with respect to the rotational axis of the shaft
Implementation Method 2
generating vibrations and transmitting such vibrations to e.g. pedals mounted on the ends of the cranks
Data Source
AI summary
An exercise device, such as a bicycle or spinning bike, includes a frame, a first set of crank arms connected to a rotary shaft supported by the frame and having an imaginary rotational axis stationary with respect to the frame. A second set of crank arms is mounted eccentrically with respect to the rotational axis of the rotary shaft. A second shaft is coupled to the second set of crank arms such that rotation of the second shaft generates vibrations of the crank arms in the second set of crank arms.