Mower Brake Lock Assembly with Cam Actuation
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Solution Overview
Problem
Conventional brake assemblies for vehicles, such as mowing machines, require gear reduction and high actuation forces to engage and disengage, especially when parked on an incline, and often need external load-holding mechanisms, making them cumbersome and difficult to operate.
Innovation Solution
A brake apparatus with a brake gear and a lock assembly that includes rollers or jaw members meshing with the brake gear, guided by a rail assembly, allowing for low-force actuation through an actuator plate and cam follower mechanism, reducing friction and eliminating the need for gear reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional brake assemblies use gear reduction to amplify brake torque, then brake torque is improved, but device complexity and actuation force requirements increase
Solution Approach 1:
The patent removes the gear reduction mechanism from the brake assembly, extracting only the essential locking function. The brake gear directly engages with the output shaft without intermediate gear stages, eliminating unnecessary complexity while maintaining effective braking through direct mechanical interference.
Solution Approach 2:
Instead of using gear reduction to amplify torque from a small actuator, the invention inverts the approach by using the high torque already present at the output shaft and directly engaging it with the brake gear. The actuation force is applied directly to move the locking member into engagement with the brake gear teeth, reversing the conventional wisdom that smaller actuators need gear multiplication.
2Reliability
If conventional brake assemblies require larger actuation forces to engage the hub, then brake holding capability is improved, but ease of operation deteriorates
Solution Approach 1:
The patent introduces a cam mechanism as an intermediary between the actuator and the locking member. The cam converts small actuation forces into large locking forces through its geometric shape, providing mechanical advantage without requiring complex gear reduction. The cam follower rides on the cam surface, translating rotational or linear actuator motion into the radial movement needed to engage the locking member with the brake gear.
Solution Approach 2:
The brake assembly uses dynamic engagement where the locking member moves radially inward to engage the brake gear teeth only when needed. During normal operation, the locking member remains disengaged, allowing free rotation. The system transitions dynamically between locked and unlocked states through the cam mechanism, providing ease of operation while maintaining reliability when engaged.
3Force
If conventional brake assemblies use friction-based braking, then brake torque is achieved, but frictional forces increase operational difficulty especially on inclines
Solution Approach 1:
The patent inverts the conventional friction-based braking approach by using positive mechanical interference instead. The locking member directly engages with the brake gear teeth through meshing, creating a mechanical lock rather than relying on friction. This eliminates the need to overcome high frictional forces during disengagement, especially important when parked on inclines where friction brakes would require significant force to release.
Solution Approach 2:
The invention replaces the friction-based mechanical braking system with a positive locking mechanism using gear tooth engagement. Instead of using friction between brake pads and a drum or disc, the system uses the interlocking geometry of gear teeth and the locking member, substituting a mechanical interference system for a friction-based system, thereby reducing disengagement forces.
4Reliability
If conventional brake assemblies require external load-holding mechanisms, then brake reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the braking function and the load-holding function into a single integrated mechanism. The same locking member that engages the brake gear teeth to provide braking also serves as the load-holding mechanism when parked. By combining these functions, the invention eliminates the need for separate external load-holding mechanisms like parking brakes or holding springs, reducing device complexity while maintaining reliability.
Solution Approach 2:
The locking member is designed with multi-functionality, serving both as the brake engagement mechanism and the load-holding device. When engaged with the brake gear teeth, it provides braking torque; when maintained in engagement, it holds the vehicle on inclines. This universal component performs multiple functions that would traditionally require separate mechanisms, simplifying the overall system.
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 brake apparatus provides low-force engagement and disengagement, enabling electric actuation and improved operation on inclines, with reduced frictional forces and no requirement for external load-holding mechanisms, enhancing user experience and operational efficiency.
Implementation Method 1
a cam follower is movable by the actuator plate to effect movement of the engagement member. Rotation of the actuator plate moves the cam follower in a first direction relative to the axis of rotation to effect engagement of the engagement member with the brake gear
Implementation Method 2
the lock assembly includes rollers for meshing with the brake gear, and which provide for reduced surface contact and consequently reduced frictional forces during brake actuation
Data Source
AI summary
A brake apparatus for a mowing machine that includes a brake gear operatively rotatable with a rotatable member and a lock assembly for meshing with the brake gear to restrict rotation of the brake gear. A guide rail assembly is fixable relative to a support for supporting the rotatable member for rotation. The guide rail assembly guides a lock assembly movable between an unlocked arrangement and a locked arrangement. An actuator plate and the guide rail assembly jointly engage the lock assembly to effect meshing and unmeshing of at least one engagement member of the lock assembly, such as a roller or a jaw member, with the brake gear. The actuator plate is selectively rotatable about an axis of rotation of the brake gear relative to the guide rail assembly, where rotation of the actuator plate effects movement of the lock assembly between the unlocked and locked arrangements.