Alternating-Crank Indoor Cycling Trainer with Dynamic Resistance
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Solution Overview
Problem
Existing indoor cycling devices, such as exercise bikes, are inefficient for developing specific muscle groups due to the top dead center issue, limiting the ability to apply maximum force and requiring complete pedal strokes, and lack the flexibility to vary resistance torque based on crank angle.
Innovation Solution
A gymnastic apparatus with alternating cranks and adjustable resistance, using hydraulic or electronic actuators to manage torque and resistance dynamically, allowing continuous variation and eccentric work, with real-time control and feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If complete pedal strokes are required in traditional exercise bikes, then continuous rotation is achieved, but the ability to apply maximum force from standstill is lost due to top dead center limitations
Solution Approach 1:
The pedal stroke is segmented into a fraction of the full circular arc, allowing athletes to push only through the most effective angular range where maximum force can be applied, avoiding the top dead center positions where force application is mechanically disadvantaged
Solution Approach 2:
The apparatus dynamically adjusts the resistance torque based on the instantaneous angular position of the crank, enabling maximum force application at each moment during the fractional arc movement, rather than requiring completion of the entire circular stroke
2Adaptability or versatility
If fixed resistance torque is used throughout the pedal stroke, then simple mechanical structure is maintained, but the ability to develop specific muscle groups efficiently is reduced
Solution Approach 1:
The resistance torque is made dynamic by continuously varying it according to the crank's angular position, allowing the apparatus to adapt to different training objectives and muscle groups by adjusting the resistance curve profile
Solution Approach 2:
The apparatus changes the resistance parameter as a function of angular position, enabling different resistance curves to be applied for different training purposes, thus increasing adaptability without requiring completely different mechanical structures
3Strength
If continuous rotation is enforced, then aerobic training capability is maintained, but strength development through alternating motion is limited
Solution Approach 1:
The pedal motion transitions from continuous rotation to periodic alternating motion, where the crank moves back and forth through a fractional arc, allowing for rest periods and high-intensity strength intervals that are more effective for muscle development
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
Enables athletes to apply maximum force from a standstill, effectively develop targeted muscle groups, and perform varied workouts with adjustable resistance, ensuring fluid movement and efficient muscle training.
Implementation Method 1
a first hydraulic actuator (53) whose second end (532) is rotationally connected to the first crank (51), and a second hydraulic actuator (54) whose first end (541) is rotationally connected to the second crank (52) and whose second end (542) is rotationally connected to the base (1)
Implementation Method 2
a spring element (402) connected to the rotating element (401) and to the housing (403) of the contrast unit
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A gymnastic apparatus for indoor cycling training that includes two cranks with alternating movement, each of which is contrasted by a device capable of varying the resistance of the crank in real time depending on the position and load.