Autonomous Mower Cutting Frame Height Adjustment With Guide Rods
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Solution Overview
Problem
Autonomous lawn mowers lack efficient mechanisms for adjusting the height of their cutting blades, which is necessary for varying lawn conditions and user preferences, and manual adjustments are often undesirable.
Innovation Solution
The implementation of a system with parallel guide rods, a rotatable drive screw, and biased bearings allows for automatic or manual adjustment of the cutting blade's height, enabling precise control through a controller or manual turn screw, and includes sensors for detecting the height-of-cut position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual adjustment mechanism is used, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent replaces manual mechanical adjustment with an automated motor-driven screw mechanism. The height adjustment motor rotates the drive screw, which moves the cutting frame vertically through threaded engagement, eliminating the need for manual operation while maintaining precise control.
Solution Approach 2:
The cutting height adjustment system operates autonomously through the motor-driven mechanism. The controller automatically controls the height adjustment motor to position the cutting frame at the desired height without requiring user intervention, making the system self-sufficient in its adjustment function.
2Extent of automation
If automated height adjustment is implemented, then extent of automation is improved, but device complexity increases
Solution Approach 1:
The patent substitutes manual mechanical adjustment with an automated motor-driven screw mechanism. The height adjustment motor rotates the drive screw, which moves the cutting frame vertically through threaded engagement, eliminating the need for manual operation while maintaining precise control.
Solution Approach 2:
The controller receives input about the desired cutting height and automatically controls the height adjustment motor to achieve the target position. This closed-loop control enables automated adjustment while managing system complexity through intelligent coordination of the motor and mechanical components.
3Manufacturing precision
If guide rods with biased bearings are used, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The guiding mechanism is segmented into multiple parallel guide rods, each supporting the cutting frame at different locations. This distribution of guidance functions across multiple independent elements improves overall positioning precision while managing the complexity of the guiding system through modular repetition.
Solution Approach 2:
Biased bearings are introduced as intermediary elements between the guide rods and the cutting frame. These bearings provide precise radial alignment and smooth movement along the guide rods, enhancing manufacturing precision while isolating the complexity of the guidance function from the main structural components.
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
This system allows for seamless and precise adjustment of the cutting blade height, ensuring effective cutting quality with minimal binding or chatter, and can be operated autonomously or manually, accommodating different lawn conditions and user preferences.
Implementation Method 1
a rotatable drive screw operatively connected to the chassis and defining a screw axis extending parallel to the first direction, the drive screw comprising a helical external thread; a driven member operatively connected to the frame and including a helical internal thread adapted to threadably receive the external thread of the drive screw
Implementation Method 2
a biasing member associated with the frame and adapted to bias a bearing associated with the frame directly against the first guide rod
Implementation Method 3
The biasing member may include a first spring
Data Source
AI summary
An autonomous vehicle (e.g., mower) includes two or more wheels supporting a chassis upon a ground surface. A cutting motor powers at least one cutting blade, and a cutting frame supports the cutting motor relative to the chassis. The cutting frame is movable, relative to the chassis, to allow adjustment of a height-of-cut of the cutting blade relative to the ground surface. First and second guide rods are operatively attached to the chassis and are received within corresponding first and second apertures of the cutting frame to guide movement of the cutting frame. Biased bearings associated with the cutting frame may bias associated bearing members against the guide rods.