Treadle Scooter Drive Train With Equalized Chain Pull
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Solution Overview
Problem
Prior art treadle scooter drive trains using locking roller clutches experience issues with immediate actuation, noise during free-wheeling, wear, and uneven chain pull, requiring more force on one side and less on the other, leading to inefficient energy transmission and user discomfort.
Innovation Solution
The drive train incorporates an auxiliary pulley positioned to equalize the drive line pull on both sides of the rocker board, utilizing locking roller clutches with an auxiliary pulley that directs the drive line pull forward of the actuation pulley's axis and features radially extending flanges to prevent chain jumping and finger pinching, ensuring balanced force application and efficient energy transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If locking roller clutches are used in the drive train, then immediate actuation and reduced wear are achieved, but uneven chain pull occurs requiring more force on one side and less on the other
Solution Approach 1:
The patent introduces an auxiliary pulley that creates an asymmetric force distribution to counterbalance the inherent asymmetry in chain pull. The auxiliary pulley is positioned to apply a corrective force that equalizes the tension on both sides of the drive train, allowing the locking roller clutches to function effectively while eliminating the uneven force requirement.
2Reliability
If locking roller clutches are used in the drive train, then immediate actuation is achieved, but noise during free-wheeling occurs
Solution Approach 1:
The auxiliary pulley acts as an intermediary element that modifies the force transmission path. By introducing this intermediate component, the system achieves smoother operation during free-wheeling, reducing the noise generated by the locking roller clutches while maintaining their immediate actuation capability when driving.
3Ease of operation
If the actuation pulley is positioned to equalize drive line pull, then balanced force application is achieved, but device complexity increases
Solution Approach 1:
The auxiliary pulley serves multiple functions simultaneously: it equalizes the drive line pull on both sides of the rocker board, guides the chain properly, prevents chain jumping, and reduces noise during operation. By consolidating these multiple functions into a single component, the patent minimizes the increase in device complexity while achieving balanced force application.
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 configuration ensures balanced power application to the rear wheel, reduces chain jumping, and enhances energy transmission efficiency, providing a smoother and more balanced user experience by equalizing the force required on both sides of the rocker board, while minimizing wear and noise during free-wheeling.
Implementation Method 1
A tensioning pulley is attached by a tensioning spring to the frame proximate the first end of the frame
Implementation Method 2
A first locking roller clutch is operatively associated with a right side of the second wheel to rotate the second wheel in a drive direction when an actuation pulley operatively associated with the first locking roller clutch is rotated
Data Source
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AI summary
A drive train for a treadle scooter using a locking roller clutch (50) on each side of a drive wheel substantially equalizes drive line pull at actuation pulleys (48a, 52) operatively associated with the locking roller clutches as a user pivots a rocker board (38) having its ends attached to ends of the drive line (56).