Electrically Locking Caster Assembly for Zero-Turn Hill Stability
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Solution Overview
Problem
Zero-turn mowers face stability issues when navigating hills due to the lack of traction in front caster wheels, which can freely pivot and align with the path of least resistance, leading to reduced stability when tilted side-to-side on slopes.
Innovation Solution
A system that facilitates the manual or automatic locking of zero-turn caster wheels using a solenoid and locking pin mechanism, where the solenoid reversibly moves a plunger at a non-zero angle to engage a locking void on a pivoting support, allowing for transitions between unlocking and locking states in response to a caster locking signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the caster wheels are allowed to freely pivot, then the vehicle can navigate turns easily, but the stability on hills deteriorates due to the wheels aligning with the path of least resistance
Solution Approach 1:
The caster assembly incorporates a solenoid-actuated locking mechanism that dynamically transitions between locked and unlocked states. When unlocked, the caster pivots freely for easy turning; when locked, it maintains a fixed orientation for stability on hills. This dynamic switching resolves the contradiction by allowing the system to adapt its degree of freedom based on operational requirements.
Solution Approach 2:
The system changes the rotational parameter of the caster assembly by using a solenoid to move a plunger that engages with a locking void on the pivoting support. This mechanical parameter change (from free rotation to fixed position) allows the caster to switch between providing ease of operation and ensuring stability on slopes.
2Stability of the object's composition
If a locking mechanism is added to prevent caster rotation on hills, then stability improves, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical locking systems with a solenoid-actuated plunger mechanism. The solenoid electrically actuates the plunger to engage or disengage from the locking void, simplifying the control system while providing reliable locking. This substitution reduces mechanical complexity compared to traditional mechanical latch systems.
Solution Approach 2:
The plunger acts as an intermediary element between the solenoid and the locking void. It translates the solenoid's linear motion into the engagement or disengagement of the locking mechanism, providing a simple and effective means of control that minimizes overall system complexity.
3Reliability
If the solenoid plunger moves at a non-zero angle to the engagement surface, then the locking engagement is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The locking mechanism deliberately employs asymmetric geometry where the plunger moves at a non-zero angle relative to the engagement surface. This asymmetric design allows the plunger to cam into the locking void, ensuring positive engagement and reliable locking. The asymmetric geometry is precisely manufactured to ensure proper engagement while maintaining manufacturability.
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
Improves stability on hills by preventing the caster wheels from freely rotating away from the desired steering angle, enhancing the vehicle's stability during operation on uneven terrain.
Implementation Method 1
a solenoid fixably mounted to the frame of the work vehicle and electrically operable to reversibly move a plunger in an axial direction
Data Source
AI summary
A work vehicle has at least one caster wheel on an end of the work vehicle. In response to a caster locking signal sent via an electrical controller, a solenoid is electrically activated to reversibly move a locking pin in an axial direction, causing transitions between unlocking and locking states. In the unlocking state, the locking pin is pulled away from the engagement surface. In the locking state, the locking pin is pushed towards the pivoting support to engage the locking void when the pivoting support is oriented in a predetermined rotation angle.