Electric Parking Brake System for Zero-Turn Mowers
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Solution Overview
Problem
Current parking brake systems for vehicles, particularly zero-turn radius mowing vehicles, require substantial operator effort to engage and often lack automatic or semi-automatic control, posing a safety risk as they may roll when unattended.
Innovation Solution
A parking brake system comprising a first member mounted to a vehicle wheel assembly, a spindle shaft block, a backer plate, and an actuation lever that allows for automatic engagement when the vehicle is in a neutral state, reducing the need for manual activation and ensuring the vehicle remains stationary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual levers or foot pedals are used to operate the parking brake, then the operator can control the brake engagement, but substantial force is required from the operator
Solution Approach 1:
The patent replaces the traditional mechanical lever or foot pedal system with an electric motor-driven system. The motor (240) converts electrical energy to mechanical rotation, which is then transmitted through a reduction gear assembly (250) to amplify torque. This substitution eliminates the need for the operator to apply substantial manual force, as the motor automatically provides the necessary activation force through electrical power conversion.
Solution Approach 2:
The patent utilizes a cable-actuated mechanism (230, 232, 234) that functions similarly to pneumatic or hydraulic systems by transmitting force through a flexible medium. The cable assembly transmits the rotational force from the motor through the vehicle frame to the brake mechanism, allowing force transmission without direct mechanical connection and reducing the operator effort required at the control interface.
2Reliability
If automatic parking brake engagement is implemented, then safety is improved by preventing vehicle roll, but the system complexity increases
Solution Approach 1:
The patent integrates multiple functions into a single control system. The switch assembly (220) detects various operational states (vehicle movement, neutral position, operator presence) and automatically controls the motor to engage or disengage the brake. This multi-functional approach consolidates what would otherwise require separate sensors, control logic, and actuation mechanisms into one integrated unit, achieving automatic safety engagement while managing system complexity through functional integration.
Solution Approach 2:
The system is designed to automatically monitor vehicle conditions and self-regulate brake engagement without continuous operator intervention. The switch assembly detects when the vehicle is in neutral or when the operator leaves the seat, and the motor automatically applies the brake. This self-service capability improves safety by ensuring the brake is engaged under critical conditions while minimizing the need for complex manual control systems.
3Device complexity
If the parking brake requires manual engagement, then the system is simpler, but the vehicle may roll when unattended
Solution Approach 1:
The system performs preliminary action by automatically engaging the parking brake before the operator leaves the vehicle or when the vehicle is placed in neutral. The switch assembly continuously monitors vehicle state and proactively activates the motor to apply the brake, preventing the harmful condition of vehicle roll before it can occur. This preliminary protective action eliminates the need for the operator to manually remember to engage the brake.
Solution Approach 2:
The switch assembly (220) provides continuous feedback about vehicle operational state to the control system. It detects signals from the transmission (neutral position), vehicle movement (reverse or forward), and operator presence (seat occupancy), and uses this feedback to automatically control motor activation. This feedback mechanism ensures the brake is engaged only when appropriate conditions are met, preventing vehicle roll while avoiding unnecessary brake engagement during normal operation.
Data Source
AI summary
A parking brake system for a vehicle includes a first member adapted to be mounted to a wheel assembly of the vehicle, a spindle shaft block adapted to be mounted to a spindle shaft of the vehicle, a backer plate disposed about a portion of the spindle shaft block, a second member mounted to the backer plate for engagement and disengagement with the first member, and an actuation lever adapted to receive an input to move the first member and the second member into engagement to perform a parking brake function. The parking brake system disclosed requires very little or no force to engage and disengage. The parking brake system has an input for obtaining engage or disengage information from a vehicle operator or from a vehicle independent of the operator. The information will engage the parking brake of the vehicle in a low force and cost effective manner.