ZTR Mower Park Brake Linkage Using Outward Steering Lever Motion
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Solution Overview
Problem
Existing zero turning radius (ZTR) mowers lack a cost-effective park brake system that can be easily engaged and disengaged using the steering levers without complex mechanisms.
Innovation Solution
A zero turning radius mower park brake system that utilizes a steering arm bracket connected by a wire cable to a park brake actuator, which is actuated only when the steering arm is pivoted outward, avoiding actuation in forward or reverse positions, and incorporates an over center spring to maintain brake engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex mechanisms (hydraulic actuators, solenoids, electric motors) are used for park brake engagement, then reliability of brake engagement is improved, but device complexity and cost increase
Solution Approach 1:
The park brake system utilizes the operator's existing steering lever movements to automatically engage and disengage the brake through cable actuation. The system serves itself by converting normal steering operations into brake control actions, eliminating the need for separate actuators, solenoids, or electric motors while maintaining reliable engagement through the mechanical cable linkage
2Adaptability or versatility
If separate pump systems are used for each drive wheel, then adaptability of steering control is improved, but device complexity increases
Solution Approach 1:
The steering levers perform dual functions: they control the drive wheels through hydraulic pumps during operation and simultaneously actuate the park brake through cable linkage when positioned in the park brake range. This multi-functionality eliminates the need for separate brake control mechanisms while preserving independent wheel control capability
Solution Approach 2:
The patent combines the steering control function and park brake actuation function into a single integrated system. The steering levers and their associated mechanisms serve both purposes, merging what could be separate systems into one unified control arrangement that reduces overall complexity
3Reliability
If park brake is engaged during forward or reverse operation, then brake reliability is improved, but ease of operation deteriorates
Solution Approach 1:
The park brake engagement capability is localized to a specific position range of the steering levers. The brake is only actuated when the levers are positioned within the defined park brake range, while remaining disengaged during forward and reverse operational positions. This spatial differentiation ensures reliable braking when needed without interfering with normal operation
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
Provides a simple and effective park brake system that engages and disengages with the steering levers, ensuring reliable brake operation without additional mechanical complexity or cost.
Implementation Method 1
incorporates an over center spring to maintain brake engagement
Implementation Method 2
A zero turning radius mower park brake system includes a steering arm bracket connected by a wire cable to a park brake actuator
Data Source
AI summary
A zero turning radius mower park brake system includes a pair of steering levers attached to steering arm brackets that are pivotable forward and reverse on a first axis for rotating a pair of traction drive wheels in forward or reverse, and pivotable outwardly on a second axis while in a neutral position. A wire cable connects each steering arm bracket to a park brake. The wire cable retracts sufficiently to actuate the park brake when the steering arm bracket is pivoted outwardly on the second axis, but does not actuate the park brake when the steering arm bracket it pivoted forward or reverse. At least one spring provides a force urging the park brake into engagement when the steering arm pawls to park brake engaged position.