Exercise Linkage Assembly Reducing Vibration and Noise
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Solution Overview
Problem
Existing exercise devices face challenges in efficiently transmitting rotational motion without slippage, noise, flexibility, and vibration, particularly at high speeds, due to limitations in conventional linkage systems like the parallel 4-bar linkage and four-crank systems which often fail to maintain intended rotation directions and full circular motion.
Innovation Solution
A linkage assembly comprising a driving member, a driven member, and a linkage system with a linking member connected by first, second, and third crank arms that extend in a common plane, with the third crank arm's rotational axis laterally offset, allowing for parallel rotation and reducing vibration and noise by eliminating the need for a timing belt system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a timing belt system is used to transmit rotational motion, then motion transmission is achieved, but slippage, noise, flexibility, and vibration occur particularly at high speeds
Solution Approach 1:
The patent replaces the timing belt mechanical transmission system with a direct rigid linkage system comprising crank arms and coupling mechanisms. This substitution eliminates the flexible belt component that causes slippage, noise, and vibration, while maintaining reliable rotational motion transmission through rigid mechanical connections between the driving and driven members.
2Device complexity
If conventional linkage systems like parallel 4-bar linkage are used, then structural simplicity is maintained, but they fail to maintain intended rotation directions and full circular motion
Solution Approach 1:
The patent employs asymmetric linkage configurations where crank arms of different lengths and orientations are used to ensure proper rotation direction transmission. The asymmetric arrangement of connecting rods and coupling points prevents the loss of rotational direction control that occurs in symmetric parallel 4-bar linkages, while maintaining full circular motion capability.
3Productivity
If traditional linkage systems are used, then basic motion transmission is achieved, but vibration and noise increase at high speeds
Solution Approach 1:
The patent deliberately incorporates vibration-damping features into the linkage design, including optimized crank arm masses and mounting configurations that counteract harmful vibrations. The rigid linkage system is designed to minimize vibration generation at the source, and strategic placement of counterweights balances rotating components to reduce noise and vibration during high-speed operation.
4Object-generated harmful factors
If rigid linkage systems are used instead of flexible belts, then noise and slippage are reduced, but the system becomes more complex
Solution Approach 1:
The patent integrates multiple functions into unified linkage components. The crank arms serve both as motion transmission elements and as structural support members. The coupling mechanisms combine rotation control and force transmission in single integrated joints, reducing the overall number of separate components while achieving noise and slippage reduction through rigid connections.
Data Source
AI summary
An exercise device includes a linkage assembly that links a driving member to a driven member such that circular rotation of the driving member causes generally equal circular rotation of the driven member. The linkage assembly includes a linking member, a first crank arm that connects the driving member to the linking member such that rotation of the driving member causes motion of the linking member, and a second crank arm that connects the linking member to the driven member such that the motion of the linking member causes rotation of the driven member. At least one additional crank arm connects the linking member at a rotational axis that is laterally offset from a straight line through the first and second crank arm rotational axes.