Zero-Turn Pivot Bar Control With Return-to-Neutral Damping
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Solution Overview
Problem
Existing control systems for vehicles with zero turn drive systems and hybrid or electric vehicles with electric actuators do not effectively utilize a return to neutral assembly, limiting performance and operator control.
Innovation Solution
A speed control assembly that includes a return to neutral assembly engaged to each pivot bar of a vehicle, providing a direct return to neutral force to improve performance and operator control, and optionally incorporates a damper to dampen this return bias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a return to neutral assembly is used on hydrostatic transmission control arms, then the transmission returns to neutral position when operator releases controls, but this setup is not feasible or less desirable in hybrid or electric vehicles with electric actuators
Solution Approach 1:
The patent replaces the traditional mechanical return-to-neutral assembly (springs and linkages on hydrostatic transmission control arms) with an electronic control system that uses electric actuators to return control elements to their neutral positions. This substitution enables the same functional outcome across different vehicle types (hydrostatic, hybrid, and electric) without requiring mechanically feasible configurations for each.
2Ease of operation
If a damper is incorporated in the speed control assembly to damp return to neutral bias, then sudden deceleration is prevented and vehicle maneuver feel is improved, but device complexity increases
Solution Approach 1:
The patent merges the damper function with the existing electric actuator and control assembly by incorporating damping capability into the same structural elements that provide return-to-neutral bias. Rather than adding a completely separate damping mechanism, the system integrates multiple functions (return bias and damping) into unified components, thereby improving maneuver feel while minimizing the increase in overall device complexity.
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
The solution enhances vehicle performance and operator control by ensuring a reliable return to neutral position, even in vehicles where traditional return to neutral assemblies are not feasible, and the damper improves the feel of vehicle maneuvers by preventing sudden deceleration.
Implementation Method 1
a return to neutral assembly engaged to each pivot bar (or pivot arm) of a vehicle to provide a return to neutral force (or return force) directly thereto
Implementation Method 2
In certain embodiments, a damper may be incorporated in the speed control assembly to damp this return to neutral bias
Data Source
AI summary
A control assembly for a lawn mower includes a shaft configured to rotate about a first axis and a pivot bar coupled to and configured to rotate with and pivot relative to the shaft. The pivot bar is configured to rotate with the shaft between a forward position, a neutral position, and a rear position about the first axis and pivot relative to the shaft between an operative position and a stopped position about a second axis. The control assembly includes a magnet coupled to an end of the shaft, a position sensor positioned to interact with a magnetic field of the magnet to detect rotation of the pivot bar about the first axis, and a return-to-neutral assembly configured to bias the pivot bar toward the neutral position about the first axis.