Variable Stride Crank Mechanism for Low-Impact Exercise
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Solution Overview
Problem
Existing exercise devices, such as treadmills and elliptical machines, are often large, noisy, and do not provide a natural walking or running motion, lacking variability in stride length and increasing the risk of injury due to high impact forces.
Innovation Solution
A low-impact exercise machine with a frame that includes first and second crank systems allowing for synchronous rotation, enabling a more natural gait with variable stride length, and incorporating a control system with a drive shaft and braking mechanism to adjust resistance and simulate inclines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If treadmills are used to simulate walking, then indoor exercise is enabled, but the device becomes large, noisy and requires regular maintenance
Solution Approach 1:
The treadmill is divided into separable components: the deck assembly can be detached from the frame, allowing the belt to be removed and the deck stored vertically against a wall or in a compact space, significantly reducing the horizontal footprint when not in use
Solution Approach 2:
The deck is designed with a tilt mechanism that allows it to be adjusted to different angles, enabling the user to simulate walking on inclines without requiring a larger flat surface area, thus maintaining compact dimensions while providing varied exercise options
2Ease of operation
If treadmills are used to simulate walking, then indoor exercise is enabled, but noise and parts wear increase
Solution Approach 1:
The belt is completely removed from the system, eliminating the primary source of friction-generated noise and wear between the belt and deck. The user walks directly on the deck surface, which is designed with a non-slip texture to provide adequate traction without requiring a moving belt
Solution Approach 2:
The deck surface is designed to be replaceable and relatively inexpensive, allowing for easy replacement when wear occurs, rather than maintaining a complex belt-and-deck friction system that requires ongoing maintenance and generates noise
3Object-affected harmful factors
If elliptical machines are used for low-impact exercise, then impact stress is reduced, but the gait becomes unnatural and stride length is fixed
Solution Approach 1:
The crank assemblies are designed with adjustable arm lengths that can be modified to change the stride length and pedal path geometry, allowing users to vary their gait pattern while maintaining the low-impact benefits of the seated position, thus providing adaptability without increasing impact stress
Data Source
AI summary
An exercise machine with a more natural gait which, in some embodiments, further allows for a variable stride length while in use. In one configuration, each side of the exercise machine has a first crank assembly connected at an upper location on a pedal arm and a second crank connected at a middle location on the pedal arm, and a pedal is attached to a lower location of the pedal arm. The first crank assembly is connected to the pedal arm by a crank arm. The second crank assembly is connected to the pedal arm via a crank arm pivotally attached to a crank link. The path of each pedal is determined by the lengths of crank arms and crank links of the first and second crank assemblies rotating in synchronous motion.