Motion Control Linkage for Power Mower Speed Adjustment
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Solution Overview
Problem
Conventional power mowers face issues with maintaining optimal belt angle and vehicle speed control, leading to belt wear and reduced cutting efficiency, as the fixed stop configuration for drive control levers limits speed adjustment without affecting throttle settings.
Innovation Solution
A motion control linkage system with a platform displacement mechanism and adjustable stop bars allows incremental control of drive unit input members and control levers, maintaining consistent input to the drive system regardless of platform position, enabling precise speed adjustment without altering the throttle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control lever is positioned at the full forward position against the fixed stop bar, then the lever stability and operator comfort are improved, but the vehicle speed becomes excessive for some mowing tasks
Solution Approach 1:
The stop bar is made movable rather than fixed, allowing it to be repositioned along the control lever's arc of motion. This dynamic adjustment enables the operator to set the stop bar at different positions to achieve desired speed reductions while still allowing the lever to rest against the stop for comfort during normal operation.
Solution Approach 2:
The position of the stop bar along the lever's arc is changed to adjust the maximum speed. By moving the stop bar to different locations, the operator can modify the lever's range of motion and corresponding vehicle speed without changing other system parameters.
2Speed
If the engine throttle is reduced to decrease vehicle speed, then the vehicle speed is reduced to appropriate levels, but the rotational speed of the cutting deck blades is also reduced, decreasing cutting efficiency
Solution Approach 1:
The control system is segmented into independent functions: the control lever and stop bar control vehicle speed by adjusting drive unit input, while the throttle independently controls engine RPM and blade speed. This segmentation allows speed control without affecting cutting efficiency.
Solution Approach 2:
The drive unit acts as an intermediary between the engine and the drive wheels. By adjusting the drive unit input through control lever positioning rather than throttle adjustment, the system can control vehicle speed while maintaining engine RPM and blade speed.
3Adaptability or versatility
If the cutting deck is moved relative to the engine to adjust cutting height, then the cutting height is varied, but the belt angle changes causing belt separation and wear
Solution Approach 1:
The platform is made movable relative to the chassis to adjust cutting height, and the linkage system dynamically adjusts to maintain proper belt alignment. The system adapts its configuration to preserve the belt angle despite platform position changes.
Solution Approach 2:
The system changes geometric parameters of the linkage system as the platform moves to compensate for position changes and maintain the belt angle within acceptable ranges, preventing belt separation and wear.
Data Source
AI summary
A vehicle including a linkage-based motion control system for varying a parameter (e.g., velocity) of the vehicle as a geometric relationship between a vehicle input (e.g., velocity control lever) and a vehicle output (e.g., drive train) is modified. In one embodiment, the control system provides a linkage that allows a fixed level of input applied to the control lever to produce a repeatable output to a variable drive unit even as the drive unit is moved relative to the control lever. In another embodiment, an adjustable stop for use with setting a terminal position of a control lever (e.g., a velocity control lever) is provided. Accordingly, the maximum potential speed of the vehicle may be adjusted (e.g., reduced) without altering the speed of the vehicle engine.